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How To Mechanically Check a Used Car Without Tools

Jerry Fisher writes about buying and selling cars. He has learned a lot about used vehicles and their owners.

how-to-mechanically-check-a-car-out-before-buying

You Are Thinking of Buying a Used Car ...

... so you need to go look at this used car, and go through this 20-point checklist to see if this machine really is what you need it to be.

The only tools you'll need to bring with you on your mechanical inspection are a torch, pen, and paper.

Phone the person advertising the car and make an appointment, but tell them two things.

1. "Please don't start the car before I arrive. I'd like to check it out when it's stone cold."

When a car is cold, many things are revealed that aren't apparent otherwise. When a car is cold, it is an ideal time to check the oil and see if a car has difficulty starting. When cars are warmed up, the oil level changes, engine rattles can disappear, transmissions seem to run fine, and so on.

2. "Please have all the service records available."

So as not to waste your time, when you make the appointment to view the car, ask them to please have all service records available. I've sometimes forgotten to ask this and been held up forever with 'I'm sure Bob put them in this drawer, but they're just not there." Service records are really important if you want a well-cared-for car.

The 20-Point Checklist for Checking Out a Used Car

  1. Engine oil
  2. Engine oil color
  3. Engine/Transmission leaks
  4. Coolant level
  5. Rubber cooling hoses
  6. Head gasket
  7. Power steering oil level
  8. Battery
  9. Timing belt/timing chain
  10. Hoses
  11. Automatic transmission
  12. Starting the car
  13. Suspension
  14. Steering
  15. Clutch
  16. Transmission synchromesh
  17. Brakes
  18. Handbrake
  19. Exhaust
  20. Rust

So, we'll check these off one by one. With your pen and paper, take a note and rate each item from one to ten—ten being the best.

Engine oil dipstick

Engine oil dipstick

1. Checking the Engine Oil Level

It’s always best to check this while the engine is cold. At that time, all the oil is sitting in the engine sump, where the rod with the indicator level is sitting. If the engine’s warm or hot, oil is transferred all around the engine, as it should be, so the indicator at that point is inaccurate.

All cars have an engine oil dipstick to tell you how much oil is in the engine. Older cars just have a rod with a bent loop, but newer cars have a stick, like in the photo above, with a plastic handle that may be yellow, red, or green. It will be prominent and stick slightly out of the side of the engine.

Have a small tissue or cloth ready and slowly pull the stick out. On the bottom six inches of the stick you’ll see the oil. Wipe that off with your tissue and you’ll see two marks on the stick: one for minimum oil level, and another, closer to the plastic handle, for the maximum oil level. Take a note and put the stick fully back into the hole again. Give it a twist to make sure it’s fully inserted. Then withdraw it again and see where the oil level is.

If it’s under minimum—under the lower mark—this should throw out a red flag. It likely means the car hasn’t been serviced regularly—but this needn’t be the end of the world.

If the car has a lot of mileage, say 120,000 miles or more, then it likely will burn through a bit of oil and needs more top-ups than a newer car would. If the car is cheap enough, the additional cost of tipping in a pint of oil every six to eight weeks may not seem like that much money.

Engine Oil Color

Engine Oil Color

2. Checking the Engine Oil Color

Next, take a look at the oil color on the stick. If it's blackish, then the oil hasn’t been changed for some time, or there are issues internally with the engine. If the oil is transparent, then that’s great. That’s how it should look. But if the oil is transparent and also at the minimum level, I’d be worried. To me, that suggests oil is getting burnt and blown out with the exhaust, or it’s leaking like anything out of the bottom or the side of the engine.

Engine oil leak

Engine oil leak

Read More from AxleAddict

In this photo the sump is the lower part of the engine, colored here in silver

In this photo the sump is the lower part of the engine, colored here in silver

3. Spotting Engine Oil Leaks

Reverse the car a few yards, turn it off, and have a look at the ground where the engine was above and see if there’s any oil lying there. If the car is cold, it's likely been sitting there for at least a few hours.

Obviously the preference is for no oil leaks at all. A few drops of oil on the ground are acceptable. But if I saw a pool of oil say 4 inches square, I’d walk away from the car. That’s quite a loss of oil and will only get worse. While driving it you could literally run out of oil, unless you’re regularly checking it, and the cost of that will be a blown engine.

If the accumulated oil is just a few drops, grab your torch and get under the engine to see how wet the bottom or sides of the engine are. A leak of just a few drops can just be a sump gasket leak, which is an easy and quite cheap repair, generally in the region of $120.00. But if the engine is wet with oil above the sump, then the oil is coming from somewhere else and the leak could be expensive to repair.

Auxiliary coolant tank

Auxiliary coolant tank

4. Checking the Coolant Level

The coolant tank should be obvious when you open the hood. It should be a large prominent clear plastic tank up on the right side up by the windscreen. The coolant fluid is generally green, but can also be a reddish color. There is usually an indentation on the plastic tank showing the minimum level.

An older car won't have a coolant tank but will have a fluid-filled radiator right in the front of the engine. This is a large tank that goes between the headlights and down deep—more than a couple of feet.

The car should be cold when you're first checking it out, but if the car has been warmed up and it does have a radiator, here's a safety warning: don't open the radiator cap until it's cooled right down. Many people have undone that radiator cap and got a face full of boiling water.

So, if the car does have a radiator and no coolant tank, and it's cold, unscrew the cap. Ideally, colored coolant should be visible. If there's none to be seen, be wary: either the owner has neglected to check this and let it run down, or the car has a leak somewhere in the cooling system.

how-to-mechanically-check-a-car-out-before-buying

5. Checking Rubber Cooling Hoses

Take your torch and have a look at the larger black rubber hoses around the engine. There aren't that many of them so it won't take long. Look more towards the end of them where the retaining clips are. This is where they can develop a split which will lead to pressure loss and therefore coolant loss. Even if a split isn't visible, you may still see a whitish mark caused by dried fluid, which tells you there is a leak in that hose.

Also, give the hoses a squeeze. They should be quite firm. If they're soft then they'll need replacing. This is only a minor expense, perhaps $30 a hose at most. You can usually do this yourself but it's best to look up on the internet how to do this. It's not tricky, but you have to get rid of all air bubbles in the system.

6. Checking the Head Gasket

The head gasket fits over the engine block and seals up with the cylinder head. If the engine becomes overheated, it's common that the cylinder head will slightly warp with the heat and then a pressure leak will develop in the gasket. This is caused a "blown head gasket" and causes coolant loss.

An owner who has had this problem will have seen his temperature gauge rise alarmingly as the car runs right out of coolant. This almost always happens in urban areas when traffic is crawling, because that's when a car doesn't get the natural cooling it get through the front grill when moving at speed.

The only way to repair this problem is to remove the cylinder head(s) and install a new gasket. On some cars this is a full day's work.

So an owner will may try to sell a car with a blown head gasket to someone else, simply by refilling the car with coolant, and knowing that during the test drive the problem won't appear until the coolant gets hot, and that's unlikely for the first 20 minutes after a cold start.

However, there is a simple test for a blown head gasket. Take the cap off the coolant tank and get someone to start the car. Watch the coolant very carefully. Get the person to rev the engine from 1000 rpm to say 3000-4000 rpm. If the head gasket is blown, the coolant will start to bubble when revved. Also look for white smoke coming out of the exhaust. This will happen under revving when the engine is warmed up.

If you've got a blown head gasket and you can't repair it yourself - I'd walk away, unless the car is being offered incredibly cheaply. Gasket repairs can be anywhere from $500 -$1500.

how-to-mechanically-check-a-car-out-before-buying
Power steering fluid

Power steering fluid

7. Checking the Power Steering Oil Level

Look for a small reservoir on the top and at the front of the engine with a strange round cap. This is the power steering reservoir. Undo the cap and you'll find underneath it a mini-dipstick. This shows the minimum and maximum oil levels. Wipe it with a cloth or paper towel and dip it in again to read the level. Take a look at your cloth and check the color next to the photo above to find out the age and quality of the fluid.

Car battery

Car battery

8. Checking the Car Battery

First, find the car battery: it may be on the left or right side of the engine, or in the trunk.

Modern car batteries have a much longer life than batteries from decades ago. These days they have to power quite a bit more stuff too, like computers, that wasn't around until the late 1980s.

The real test for a battery is starting the car, but you really want to hold that off until you've done your 20-point check. When you do, if the battery is in good condition, it will crank the car engine over quickly. If it's slow to start, then the battery is old and likely on its way out.

So right now, get your torch and take a good look at the battery. They generally have a birth date on them so you can see how old it is. But it also should look good. If it has any spillage by the terminals or down the sides, it likely has a crack in it and it's leaking fluid. Also look for bulges in the plastic casing. They shouldn't be there.

New batteries aren't the end of the world: $90-$200.

how-to-mechanically-check-a-car-out-before-buying

9. Checking the Timing Belt

The timing belt is critical. It's what drives the camshafts on the engine. It is a flexible rubber belt with teeth as in the above diagram. If it breaks, it can in an instant cause enormous and expensive damage.

Engines from most US and European manufacturers (BMW, Mercedes, etc.) use timing chains, not belts. Chains mostly last the lifetime of a vehicle; being chains, they are heavier than belts. Generally, the chain tensioner should be checked every 150,000 miles and that's that. If the tensioner needs tightening, you can usually hear a little knock in the front of the engine when it's idling indicating this. Tensioners are not expensive or difficult to tighten up.

But getting back to timing belts: most Japanese manufacturers use them. They're generally not visible, and unlike a chain, you won't detect any noise if there's an issue with them. If they're old they'll snap without warning.

It's recommended by manufacturers to have them replaced about every 60,000 miles, but most service garages will recommend every 50,000 miles to be safe. The cost is generally around $500.

You can check them with aid of a Phillips screwdriver and taking off the front plate, but I wouldn't bother. Normally service dealers will write somewhere on the engine in indelible ink at what mileage they've replaced the belt. If this note isn't there, then ask if it's in the service receipts of the car. Be very cautious about this one. If the car has done close to 50,000 miles without a belt change, then this is definitely a negotiating issue; if the car has done 65,000 miles or more, it's very definitely a negotiating issue, and if you do buy it, drive it carefully to the nearest garage for replacement.

If the owner says he's replaced it himself, then get him to take some plates off to prove it. Feel and look at the teeth on the underside of the belt for new depth. On an old belt, these will be well worn.

Coolant hose

Coolant hose

10. Checking the Coolant Hoses

Check the coolant hoses on the radiator and coolant tank for softness. For safety's sake, only do this when the car is cold. Squeeze the rubber and see if there are cracks along the way; if so, they may not be leaking yet, but it's a matter of time and they will need to be replaced. Take a look around the hose clips connecting the hoses to the radiator and coolant tank. There shouldn't be any seepage here—it will be a whitish color if it is leaking.

Hoses are not expensive, maybe $15-20, but if they fail in a traffic jam and you don't happen to notice your temperature gauge on red hot, you can destroy your engine.

Auto transmission selector

Auto transmission selector

11. Checking the Automatic Transmission

Okay, now it's time to turn the car on from cold.

Turn the car on and fire it up. Wait about 15 seconds for the engine to settle down. The engine should be smooth by this time. If it's a good engine, there will be no vibrations that you can notice or hear. If there's vibration, then the engine is running rough. Not a good sign, but possibly easy to fix too.

Now, if the car has an automatic transmission, here's an easy check for a common issue. Put your foot on the brake and keep it there hard, and meanwhile switch the gear shift selector into reverse. When you hit reverse, there shouldn't be any hesitation; you should immediately know you're in reverse. And the rear of the car should only rise a very small distance during the change. If it lurches up, you've got an issue with the transmission.

Once the transmission is warmed up, this lurching may go away, but you're still left with this issue, and to repair it will require an expert to pull it apart or replace the transmission. Either option is expensive.

However, if the car is going to be a cheap runaround and you don't really care about its resale, then this reverse issue won't get too much worse over time, and it won't usually show up when the car is warm. You'll find the forward gears are usually fine. If you can bring this issue to the sellers attention, you should be able to knock the price down a lot.

12. Starting the Car

Okay, now that the car's running you can check a few things under the hood while it's warming up.

First thing is to listen for a ticking noise that appears to come from inside the engine. If you hear a reasonably loud ticking noise inside the engine, almost like a loud clock—walk away. You've got piston damage internally and the engine can go at any time.

But, this shouldn't be confused with a ticking noise at the top of the engine. If the engine has done a fair mileage, then this ticking at the top is likely to be what's known as tappet noise and can be corrected quite easily by a good mechanic. He may not get rid of it completely, if the valves are worn, but he should be able to quieten it right down. However, you should ask some questions to the seller about this.

Here's a way to make certain it's the tappets: borrow, if you haven't got one yourself, a long screwdriver from the seller, and use it as a stethoscope by placing the sharp end on the top of the engine while the engine is idling (be careful of moving parts like the front fan and belts) and the other end on your ear. It should should carry the sound to your ear so you can locate the source.

Also check for noises from the moving belts. Make sure there's no squealing from them. Get inside the car and turn the steering from lock to lock, fast, while listening to sounds under the hood. If the belts and power steering are okay, there shouldn't be any added noise.

13. Checking the Suspension

Turn the car off again. The suspension is better tested while out on the road, but first take a long look at the car while standing back, from the front, back, and each side. The car should be even all around in height. If it's slightly dropped on one corner, then there will likely be a suspension issue on that corner. It may or may not be an expensive issue to fix. A drooping corner could also be an indicator of rust on that corner, which could be very dangerous to drive and very expensive to fix.

Next, go to each corner and push the car up and down as hard as you can. If it squeaks, it's old and tired and the suspension will need refreshing with new bushings, and possibly shock absorbers. Yep, can be expensive as any mechanic will tell you. For safety's sake, if you do one side, you've got to do the other side at the same time.

If you have got one corner raised higher than the other corners, as I said that's dangerous. When you take it for a test drive, for your own safety, don't push the car hard into corners or braking; you may end up upside down in a tree. Take it easy.

Your suspension problem might be something simple, though; if you love the car, just get it checked out properly to confirm.

how-to-mechanically-check-a-car-out-before-buying

14. Checking for Steering Problems

So now the car's warmed up and you're off for a test run. To do the first test for the steering, find a smooth longish road. The road should have no camber, and be even with no bumps. Get up to a cruising speed, say 50mph, and keep it steady there. Now take your hands just slightly off the steering wheel, maybe say an inch or two above it, so you can grab it quickly if you have to.

While the car is steering itself, ideally the car should keep going straight ahead. But when you let go the wheel does the car move off-center, say slightly to the left or to the right?

If it's moving to one side or the other it may be something easy to fix. Your tire shop is likely to have a wheel alignment machine that can replicate this problem. They'll put it up there and adjust it to run straight again.

But, the drift could be caused by the car having been in an accident that bent the chassis to one side. If you like the car, take it to the wheel alignment place and they'll be able to tell you pretty quickly if this has been the case. Depending on the severity of the accident they may or may not be able to fix it.

If not, a panel shop will likely have a chassis straightener that can do this, but at this stage you'll be spending dollars. If the car's cheap enough to warrant this, go for it, otherwise I'd walk away. You might be opening up a can of worms.

Another test while you're out there is to see if there's any vibration from the wheels or tires. You can do this from a standing start on a long straight road. Slowly—and I mean slowly—build up speed, all the way to 60 mph, or more if it's allowed. On the way, see if any vibration comes through the steering. It usually happens like this: you'll get to say 40 mph, and at a steady speed there you may get a constant vibration, but after you take it up to 50 or 60 mph, the vibration ceases. The problem is often a wheel that needs balancing (one for the tire shop and not expensive - $15-$20)

But vibration could also be caused by a faulty tire. If so, the vibration will likely be constant right through the speed range, not confined to a certain speed. If you do get vibration like this, I'd pull over and check all four tires for safety before continuing. Check to see if any of them has a bubble coming out the side; that means a soft spot that could blow out on you. If you see that, drive it slowly all the way back.

Of course, vibration could be caused by a tire that's a lot flatter than the others. You should be able to visibly see this. Go get them all pumped up at your nearest garage and continue. But if one is pretty flat, check it again before returning, in case you've got a puncture - which you likely have, even if it leaks only slowly.

One more cause of vibration, apart from a suspension problem it could be a warped or damaged brake disc. That could have been caused by the seller whacking it into a kerb at speed. A damaged brake disc could be expensive to repair as all sorts of things might need replacing along with the disc.

Clutch pedal

Clutch pedal

15. Checking the Clutch on a Manual Transmission

If the car has a manual transmission, here's how to use your test drive to test if the clutch is okay. Test your clutch when the car is cold and also at running temperature.

When you first start the car, deliberately push the clutch in slowly. Unless it's a performance car, the clutch should not seem heavy to push in. Listen carefully for any noises on the way. It should be free of any noise whatsoever.

When you slip the car into first gear, the clutch shouldn't "grab." Grabbing is when it suddenly catches and you have little control over its smoothness. You should be able to control the clutch and make a smooth takeoff.

Without wanting to sound discriminatory, older owners are generally the worst for clutch problems. They tend to just ride around town and keep their foot resting on the top of the clutch in case of emergency. That heats the clutch up, and that's when all those issues happen - noises and grabbing.

If the car has those issues, you're in for a new clutch. Bank on at least $500.

Gearshift on a manual transmission

Gearshift on a manual transmission

16. Checking the Synchromesh on a Manual Transmission

Make certain you also check the manual transmission synchromesh while the car is started when cold and also at running temperature.

Synchromesh wear causes a growling feel and sound when you change from gear to gear.

You're unlikely to feel it going up the gears, but if they're worn you will hear and feel it going down the gears. The transmission will be reluctant to select the gear you decide. Mostly this will be second gear, as it's the most used car in town on a car with manual transmission.

A performance car is very likely to have these problems as it's likely been driven hard. Italian cars are notorious for worn synchromesh, because they're so much fun to drive. Old people with manual transmission are also suspect as they tend to get a bit lazy and not use the clutch, or they may not have the for muscle for the clutch.

You should test when warm and use the gearbox as hard and fast as you can, changing up through the gears and down through the gears.

If you've got worn synchro's that means gearbox out and then generally a replacement gearbox put back in. Much cheaper than having the synchro's replaced. Bank on $1000 plus.

17. Checking the Brakes

So, you're on this long straight road still. You want to be doing about 30 mph as that's a relatively safe speed if anything strange happens. If you've got anyone else in the car with you, make sure they've got their seatbelt on, and warn them that you are about to test the brakes with a very sudden stop. Look behind you to make sure that no other car will be about to pile into your trunk on this test.

Count down for the sake of your passengers—5 4 3 2 1—and now sink your foot hard into the brake pedal. If the car lurches slightly off center—to the left or right—immediately take your foot off the pedal or you'll be in danger of losing control.

If you feel a vibration with your foot hard on the brake, that may be normal if the car has ABS, an anti-lock braking system (and even older cars are likely to have this). It's designed through the software on the car's computer to pull up straight if you hit the brakes hard, especially in wet conditions. ABS can keep you from getting into a violent skid.

If you stop evenly, with a squeal of tires, in a straight line then all sounds good. If the car goes off center, you've got one brake working well and another on the other side either worn or not catching at the same time. That's going to be a repair. If it's brake calipers: maybe $200. A new disc: about the same. Brake pads : $100-$120. Because the mechanic is bound to say, We have to do both sides to be sure even though one side seems okay," you can double these prices.

Handbrake

Handbrake

18. Checking the Handbrake

Firstly, the handbrake should be working when you pull it up a distance of say 4-6 inches. If it doesn't work until it reaches about 8 inches. It requires adjusting. That can only be done at the rear wheels. It's not expensive for a mechanic to do it; maybe half an hour labor only.

If the car has a manual gearbox, the handbrake is an important safeguard. On a step hill, you can use first gear like a brake when parking, but if your car got a tap from behind, it could jump out of gear, and if the handbrake is ineffective your car could be off on a trip of its own.

On a car with automatic transmission, the handbrake is not as important, as generally the car has 'park' in its selection range to act as a secure handbrake even when parking on a steep hill.

On your test drive if there are any hills at all in the vicinity you might like to park the car and test the handbrake out by leaving the car running and keep your foot on the foot brake, then pull the hand brake up, release your foot off the foot brake and see if the handbrake is working effectively without the car creeping forward.

Consider the color of the smoke coming out of the exhaust.

Consider the color of the smoke coming out of the exhaust.

19. Checking the Exhaust

Best do this test when you're ready to start the car from cold. Get someone else to start it for you, maybe the seller or a friend.

Before they turn it over, go to the rear of the car and fix your eyes on the exhaust. Get them to start it and give it some quiet revs on the accelerator—not hard revs at this stage. When an engine is cold you've got to let it warm up slowly. Revving hard straight away is never good for an engine.

What you're looking for is the color of the exhaust smoke (if any). If bluish color smoke comes out that means the engine is burning oil. Walk away at that point unless you want to go to the expense of reconditioning or replacing the engine. Be prepared to pay around $3000-$4000 if that's the case and you still want to buy it.

If quite a lot of grey smoke comes out, that is likely to mean the car has a blown head gasket (as discussed earlier up the top). This is serious too. The owner has run dry of coolant and could have warped the cylinder head. Bank on $2000-$3000 to fix if this damage has been done.

But if the car is fairly much free of colored smoke, that's a great sign.

Here's one more test tthat can't be done until the car is warmed up. When you're out test driving it, periodically look in the rear view mirror while revving it or accelerating. See if you see any smoke then. This could be still burnt oil coming through, or, it could be water trapped in the muffler. If the car has mostly had city miles, water can get trapped in the muffler, which when the car heats up turns to steam and exits. That's not a bad thing, but the end result, unless it's a stainless steel exhaust system, is that the water will eventually corrode through the muffler and that will require replacing: $200?

20. Looking for Rust

Checking for rust in cars is difficult. A lot of it depends on where the car is and its history. If it's been by the sea, well I'd get a specialist to put it up onto a hoist and thoroughly check underneath.

All these US states put salt on the road in winter:

Connecticut, Delaware, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Vermont, Virginia, West Virginia, Wisconsin.

If the car is located in any of these states, or has been, you've got to have it checked out underneath. Salt kills them. The car may look fine in the body, and you may not see any rust anywhere, but if it's attacked the suspension points or chassis in any way that's going to be dangerous.

A car from those states might be fine—some owners are fastidious, and will thoroughly clean their cars or not drive them in the winter. But just be wary.

Rust can also be caused by leakage from the battery. Batteries are usually hidden in one side or the other in the boot. Take a torch and check this out. Usually these days batteries don't leak like they used to, but you never know until you've checked.

Rust repairs are incredibly expensive. For example, insurance companies, if there is flood damage, will write a car off their books, even a brand new one. They don't even try to get a rust-damaged car cleaned up, as it may come back to bite them later.

how-to-mechanically-check-a-car-out-before-buying

How to Negotiate on the Car Now That You Have Done Your Mechanical Check

Okay, now you've done the 20-point mechanical check.

If nothing else, you have impressed the seller with your knowledge. If he had anything to hide, it may still be hidden, but if you've carefully checked, then that's doubtful.

Out of the 20 points you may have picked up a couple of things that aren't that serious. Whether you plan to drive the car anyway or get it fixed, you can use any faults to drive the price down. When talking about price, discuss what it would cost to fix those faults.

Buying a car with major faults is up to you. If it's a great classic car whose value will go up, you might consider buying it even if if the engine's about to fall apart. If you can knock $5000 off the price, it might be worth buying.

But if it's like a 5- or 10-year old Honda, be wary what you pay for a car with faults. All modern cars are on a price slide downwards. If you just want reliable transportation, don't buy a car like this with major issues. Unless the car is an absolute bargain to begin with and you can still knock a lot of money off it, walk until you find a better one.

Here's hoping this 20-point mechanical guide will be some help and save you money having to drag a mechanic along when you shop for a used car.

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