How to Replace a Honda Accord I4 Head Gasket (1998-2002)
How I Knew My Head Gasket Had Failed
After I warmed up the engine, I found my Accord's exhaust pipe was billowing out white smoke, and the coolant was bubbling in the coolant reservoir tank. I added coolant to my radiator, and started the car with the radiator cap removed. Then coolant immediately shot out of the radiator filler neck—a clear indication of head gasket failure. Later I found a crack in the radiator. My cooling system had overheated to the point of head gasket failure.
Did this or something similar happen to you, as well? Read on to learn more.
The Honda F23 2.3L I4 Engine
The repair pictured below was done on a Honda F23 2.3L I4 engine—the engine also used in the '98-'99 Acura CL, '98 Odyssey, and '98-'99 Oasis.
Before You Decide to Replace the Head Gasket
Before you decide to replace the head gasket, consider the following:
- Replacing a head gasket is time-consuming. So after you remove the cylinder head, you should determine whether the engine block mating surface is warped by more than .002 of an inch. If it is, a new gasket installation may not fix the problem. Consider performing a complete engine swap or block replacement instead.
- The pistons must be checked for cracks. If there are cracks, consider an engine swap or block replacement.
- Once the cylinder head has been removed, have an automotive machine shop check it out for cracks, good valve seal, and warping of the mating surface and the block deck. Fortunately, the head I removed was only slightly warped. The machinist milled (shaved) the head by .001 to make the mating surface flat.
- If you decide to invest the time and effort involved in replacing the cylinder head, consider also replacing the water pump, thermostat, timing belt, intake and exhaust manifold gaskets, timing belt tensioner pulleys, valve cover gasket, spark plug seals, and accessory belts. Do it now and save the time and expense of having to do so in the future.
- Allocate around 16 hours of your time to complete the job, maybe even more. That includes time spent working on the car as well as time spent cleaning your parts, obtaining special tools and replacement parts, and dropping off and picking up the cylinder head from the machine shop. But keep in mind that doing it yourself instead of bringing the entire job to a repair shop may yield better quality results. Some repair shops will do anything to get the job finished as soon as possible.
- Have you ever replaced a timing belt and the water pump on an overhead-cam car? On these cars, a head gasket replacement effort is a timing belt job, except three or four times more difficult.
I will assume that you have a complete metric tool set with sockets that fit 1/4", 3/8" and 1/2" socket wrenches with extensions, box- and open-end wrenches, screwdrivers, and so forth. Whatever you don’t have you’ll have to buy at your local tool supplier or online.
Just to give you a major heads up, you will also need:
- a ½” 14 mm metric spline socket for the head bolts,
- (perhaps) a torque angle gauge,
- a 3/8" drive torque wrench
- an electric or air-powered impact driver
- 2 ½” breaker bars
- at least one hydraulic jack
- a good penetrating oil
- silicon spray for the rubber components
Parts to Buy
- New Torque-to-Yield (TTY) head bolts like this one
- Multi-layered steel (MLS) head gasket or a kit like this one
- Valve cover gasket
- Valve cover / spark plug seals
- Intake manifold gasket
- Exhaust manifold gasket
- Exhaust-manifold-to-exhaust-pipe gasket
- New hoses, based on condition
- Various other coolant-related gaskets, based on condition
- Silicone-based gasket sealant and maker
- Timing belt or a timing belt kit like this one
- Timing belt tensioner bearing
- Balance shaft belt
- Balance shaft tensioner bearing
I also highly recommend that you obtain a technical repair manual—from Haynes, Bentley or the manufacturer—to cross-reference with what I’ve done. When it came time to torque down the nuts and bolts for the cylinder head and the intake and exhaust manifolds, I referred back to the technical manual for torque specs, as well as the torque sequence.
The photos below are a combination of before and after dis-assembly and re-assembly steps. If I missed a photo during dis-assembly, I would use a photo during the assembly process to explain a dis-assembly step. It’s difficult at times to stop whatever you are doing to take a photo.
How to Replace a Honda Accord Head Gasket: Step by Step
Before You Start
Set aside an area in your garage to place removed parts in the order they were removed. This includes the nuts and bolts. Although this will add time to your work effort, the re-assembly of your parts will go much more quickly. Eliminate the guesswork of what nut or bolt goes with what part. Don’t mix them up in a coffee can!
Also, consider taking "before" and "after" photos. A picture goes a long way when trying to figure out what goes where during the re-assembly process.
1. Set up the Job
Raise the driver’s side wheel and support the car with a jack stand. Disconnect the positive battery terminal, and drain the coolant at both the engine block and radiator. Dedicate an area where you can set down removed parts in the order in which you remove them.
2. Remove the Crankshaft Pulley Bolt
3. Prepare to Remove the Pulley Bolt
Insert the pulley holder tool to the crankshaft pulley and attach a long ½" drive breaker bar (like the one below) to the holder. Then, rotate the crankshaft pulley with another ½" socket wrench with an attached ½" extension and socket until the breaker bar is secured against the ground from moving. Since the crankshaft bolt may be torqued up to 180 lbs, use a jack stand to support the ½" drive extension for another breaker bar when applying force to remove the crankshaft bolt. I found my jack stand wasn't high enough, so I added a wooden block to gain the extra height.
4. Remove the Belts
Loosen the belt tension on both the power steering pump and alternator, then remove the belts.
On the power steering pump, there are two bolts—one on the top right and the other on the bottom left. After loosening them, push down on the pump to relieve the tension.
Loosen the top bolt that the alternator rotates on, followed by the nut on the bottom of the alternator bracket bolt. When loosened, rotate the adjustment bolt (which turns into the bracket bolt) counter-clockwise, and push down on the alternator to relieve the belt tension.
5. Remove the Side Engine Mount
Support the engine from canting with a hydraulic jack when the side engine mount is removed. To prevent damage to the oil pan, place a flat piece of wood between the oil pan and the hydraulic jack.
Remove the ground strap followed by the two nuts and one bolt. In addition, you need to loosen the nut that’s in the middle of the bracket, since there’s a small rotating metal bracket underneath that must be turned before pulling off the mount.
6. Remove the Spark Plug Wires, the Valve Cover Bolts, and the Valve Cover
7. Remove the Upper Timing Belt Cover
Now, there are only two bolts that need to be removed. Detach the alternator wires recessed within the cover, then pull up and out to remove the cover. Remove the oil dipstick as well.
8. Align and Remove the Crankshaft Pulley
Set the number-one cylinder to top dead center (TDC) and remove the crankshaft pulley.
You should rotate it counter-clockwise. If the spark plugs have been removed, you can grab the crank pulley with both hands and rotate it. Another method is to re-insert the crank pulley bolt back into the crankshaft and rotate it clockwise until you have alignment. Then, with a quick snap of the socket wrench, loosen the bolt back off. Align the rightmost notch on the pulley with the V-shaped alignment indicator on your timing belt cover. You can use a toothpick dipped into white paint to mark the notch on the pulley.
9. Remove the Lower Timing Belt Cover
Work around the perimeter of the lower cover, then remove each of the retaining bolts. In addition, detach the wire housing recessed into the right-hand groove of the belt cover.
10. Paint Alignment Marks on All Pulleys
Apply paint marks on your camshaft pulley, crankshaft, and balance shaft pulleys for re-assembly alignment. If the camshaft is off by one cog when you put things back together, that will completely screw up a timing belt replacement. The camshaft pulley sprocket will have a stamp indicating "up." Apply white paint dots to the other pulleys line them up with the engine block.
11. Remove the Timing Belt Tension Bearing Bolt, the Timing Belt, and the Balance Shaft Belt
After the pulley tensioner bolt has been removed, remove the spring from the timing belt tensioner bearing and balance shaft tensioner bracket/arm. I removed the side engine mount for easier viewing.
The timing belt tensioner bearing and the balance shaft tensioner bearing are connected together on one support shaft. The balance shaft tensioner bearing is covered by the tensioner bracket.
12. Remove the Power Steering Unit, Alternator, Alternator Bracket, and Power Steering Bracket
Next, remove the power steering unit, alternator, alternator bracket, and power steering bracket—in that order.
The power steering bracket cannot be removed unless the alternator bracket is removed first, since the bolt holding the lower part of the power-steering bracket is covered by the alternator bracket.
13. Remove the Exhaust Manifold
Now, you'll need to remove the exhaust manifold.
Disconnect the O2 sensor leading out of the manifold. Then, remove the three bolts securing the heat shield onto the manifold. Detach the manifold from the cylinder head and exhaust downpipe.
14. Remove the Distributor and All Other Connected Components
Remove the distributor, the air filter box to the throttle body tube, the upper radiator hose, the upper heater core to the cylinder head hose, the throttle cables, the throttle body, the intake manifold plenum, the fuel connector and various electrical fittings, and the vacuum hoses.
15. Remove the Fuel Injector Rail and Injectors
Next, remove the fuel injector rail and the injectors.
Two nuts secure the rail to the injectors. After removing these nuts, begin wiggling and pulling on the rail. Do not pull on the rail on an angle—try to pull straight out. Either the injector(s) will stay attached to the rail or stay recessed in the cylinder head. Don't lose the injector O-rings.
16. Remove the Cylinder Head With the Camshaft and Intake Manifold Attached
Remove the bottom mounting bolts secured to the intake manifold. One bolt is for the manifold support bracket, and the other two are for the switch brackets. I chose to remove the oil filter to get a better view of what I had to deal below the intake manifold.
Now, loosen and remove the cylinder head bolts and remove the cylinder head with the intake manifold attached. After the head is off the block, you can remove the camshaft pulley with an impact driver. In my case, it wasn’t on too tight and came off without a problem.
Loosen the head bolts in the sequence outlined in a repair manual. Do not loosen the bolts beyond ¼ turn during the initial release of tension on the bolt. You must use a 14mm spline socket.
I decided to remove the cylinder head with the intake manifold attached. First off, working under the car with limited lighting was a hassle. Also, the thought of getting below, then above, then below the car, and so forth during the intake nut tightening sequence seemed like a lot of hassle, especially when I could do it when the head was off the block.
So, using a step stool, I climbed into the engine compartment and positioned myself so I could get both leverage and control. There are no photos of this step here since I did this entire repair with no assistance.
Before attempting to remove the head, move the plastic wire protector for the fuel injectors out of the way. There are also various attachment points that need to be disconnected. Once this is done, you can move the wire protector out of the way so it won’t be an obstruction when removing the head with the attached manifold.
17. Send the Cylinder Head to an Auto Shop
I sent the cylinder head to an automotive machine shop for crack testing, valve condition testing, and testing for warpage. The valve cover, intake manifold, and plenum were also steam- and pressure-cleaned. Fortunately, the head was only slightly warped, which required only a .001 milling (shaving) to flatten the mating surface.
The cost of all this shop work came out to less than $100.
Photos of the Head After it Came From the Automotive Machine ShopClick thumbnail to view full-size
18. Prepare for Re-Assembly
The block deck surface must be true (completely flat) and free of any debris before mating the head with the block. Do not use any tool (like sandpaper) that could scratch the block deck. Although the roughness average (RA) is supposed to be around 30, which is almost a mirror finish, the automotive machinist told me that the current condition of the deck (it was from the factory) should be good enough. Just make sure that the surface is free of oil and debris. I used a combination of 0000 steel wool and ultrafine polishing compound to clean the block deck.
19. Attach the Intake Manifold to the Cylinder Head
Attach the intake manifold with the new gasket to the cylinder head. Then, torque each nut per the manufacturer’s specifications.
20. Install the Cylinder Head
Lubricate the TTY head bolt threads with 30-weight oil, including the head with the washer.
Remove any oil from both the cylinder head and the engine block deck with acetone or any other non-oil-containing oil solvent. Chase the bolt hole threads for any obstruction. Then, blow out any debris in the bolt holes with compressed air.
Now place the new head gasket on the block. The gasket I used was FelPro’s PermaSel MLS.
Ensure that the camshaft position is set to cylinder one top dead center. The groove in the camshaft for mounting the camshaft sprocket should be pointing up, and both the intake and exhaust rocker arms should be loose.
To ease alignment of the cylinder head TTY bolt holes with the gasket and engine block holes, place two oil-free bolts on the back left and right bolt hole-corners of the cylinder head. Angle the head on the block, aligning the two bolts that are protruding from the head with the holes in the engine block. After the head is mounted, jiggle and twist the TTY bolts to ensure that they cleared the head gasket. Do this for each of the ten bolt holes. (The bolt hole in the back center of the head uses the extra long bolt.)
After alignment, remove the old bolts and twist in the new bolts, hand-tightening each bolt with a 14-mm spline socket attached to a ½” extension. You may have to tilt the cylinder head and hold it forward to offset the weight of the intake manifold.
21. Torque the TTY Cylinder Head Bolts
Torque down each head bolt to 22 lbs, using a torque wrench with the manufacturer’s outlined torque sequence. Make sure you place white paint dots on each of the bolt heads before angle torquing each bolt at 90 degrees or 1/4 turn. Repeat this task three times for each head bolt for a total of 270 degrees or ¾ turn.
22. Re-Attach the Fuel Injectors
It may be easier to remove each injector from the fuel rail and insert them back into the intake manifold one at a time. Apply a small amount of silicone spray to the injector O-ring to ease the process. Then, press the injector rail against all of the injectors. Two rail retaining nuts can now be screwed on and one rubber tube attached to the intake manifold.
23. Re-Attach Cooling System Components
Re-attach the thermostat housing components, the oil pressure sensing unit, and the EGR valve.
Replace any cooling system-related O-rings, if they appear worn, or apply silicone gasket making material on the outer edges to obtain a good seal.
24. Re-Attach the Intake Manifold Plenum
Mount the intake manifold plenum onto the intake manifold and connect all fittings. Upon completion, attach the throttle body and connect all fittings.
25. Attach the Exhaust Manifold
Install the exhaust manifold with new gaskets. Then, attach the heat shield and torque according to specifications. When you are done, attach the electrical connection for the O2 sensor.
26. Replace the Water Pump
Most new pumps come with a new O-ring. Clean the mounting surfaces and bolt on the new pump, finger-tight. Alternate the torque on the bolts during installation.
27. Install New Timing Belt Components
Ensure that the camshaft and crankshaft paint marks are aligned.
- Install the new idler pulleys. Position the timing belt idler pulley to allow the most slack on the belt during installation.
- Install the new timing belt starting from the crankshaft counterclockwise.
- Move the camshaft sprocket one cog if you're having difficulty slipping on the new belt. Reposition the sprocket after the belt has been installed. Relieve tension from the pulley bolt to allow the belt tension spring to remove belt slack.
- After installing the timing belt, temporarily remove the balance shaft pulley to ease the installation of the balance shaft belt. Use the alligator clip to hold the leftmost part of the belt in place; then with both hands, apply tension to the bottom portion of the belt by turning both shafts inwards. The white marks should be in alignment. If not, then advance to retard the belt position until they are. At that point, you can mount the tensioner bearing with the bracket and nut.
- Attach the balance shaft spring to the balance shaft arm and the spring mount protruding from the water pump. Push down slightly on the balance shaft bearing and let the spring tension allow the proper tension to be applied to the bearing. Tighten the timing belt nut.
28. Attach the Lower and Upper Timing Belt Covers and the Valve Cover
After the timing belt covers have been attached, slide the crankshaft pulley onto the crankshaft. Torque down the crankshaft pulley bolt per the manufacturer's specifications, or use an impact driver.
Apply a little gasket seal silicone on each corner where the valve cover meets the camshaft hump. This will provide a good oil seal.
29. Mount the Distributor Back Onto the Cylinder Head Camshaft
The mounting of the distributor onto the camshaft may be made easier by first removing the distributor cap from the distributor. You have to push down the heater hose while wiggling the rotor to obtain alignment with the camshaft groove. Before installation, make sure the rotor is pointing to the number one cylinder contact point in the distributor cap.
After installing of the distributor, reconnect the distributor cap, thread the spark plugs back into the cylinder head, and connect the ignition wires. Now, place a little dielectric grease inside the spark plug boots to prevent the boots from fusing with the spark plug.
30. Re-Attach the Alternator and the Power Steering Pump
After installation, attach either new or existing belts and tension them according to the specifications.
31. Attach the Side Engine Mount
Job Completion Checklist
You are now done. Here's your final checklist:
- Is the battery connected?
- Does the engine oil need to be replaced?
- Is the engine oil level okay?
- Is the power steering oil level okay?
- Are all tubes and wires snug and secure?
- Is the coolant level okay?
- Is the wheel mounted back on the car?
- Are the jack stands removed?
- Is there any obstruction under the car?
Now, start your car. Let it run for less than a minute, then turn it off. Check fluids.
Restart your car. Check the coolant level again.
Restart your car one last time and let it warm up. Keep a close eye on the coolant temperature. Keep re-checking fluid levels.
Only Need a Timing Belt Replacement?
Only Need a Radiator Replacement?
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
I don't see any oil cooler line's on the original radiator. I bought one and it has two brass fitting for the lines. what do I need to do?
If no oil cooler lines in the original radiator, then keep the plastic caps on the brass fitting of the new radiation and ignore it.