I took my valve cover off yesterday to replace my valve cover gasket and fix what I thought was a valve cover leak. The gasket looked fairly new and didn't seem to be leaking, and after further inspection I found a hairline crack on the side of the head on the exhaust side of cylinder 2. Oil has been leaking from this crack since at least February or March and I have daily driven the cruiser for at least half of the that time. I plan on replacing the head with a used one I can get from a guy local to me. What else should I replace while I've got the head off, and what should I look out for? The engine has 234k on it. Thanks in advance for the advice.
Replacing 1FZ-FE Head
- Thread starter Lknmud
- Start date
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I'm sure you've weighed your options, but understand that the used head can form cracks as well at any given time/mileage. Would suck to go through all the while-in-there effort only to suffer yet another cracked head all over again.
Last I checked, Toyota still sells a new head. Gl
Try some searching for head gasket replacement and read through a few of those threads.
There a a few dozen possible things that could be serviced, cleaned, painted, wrapped, repaired, or replaced while the head is off.
@Lknmud : it's a very long list, here's some:
Rebuild head (machine shop) with new valve stem seals. Consider new springs or valves as needed). Might be better off buying a new head
Replace oil pump cover gasket/O-ring and front crank seal if not done yet.
Replace water pump
Replace Thermostat
Replace Heat Control Valve
Replace all heater circuit water hoses including the PHH, bypass hoses, radiator hoses, and paint/replace pipes
Replace fuel filter
Replace all vacuum hoses on the Throttle Body and located under side of intake plenum. Test both VSV's for proper function. You can buy the correct Toyota bulk 3.5mm vacuum hose and cut to fit.
Replace fuel rated hose at top of Throttle body, you will have to cut it off to that the TB off. Cut to fit OEM hose.
Expect to replace the "gas" filter on the top front of the intake plenum (the nipple will break if touched)
Clean valve cover (hot tank)
Replace six spark plug tube seals
Replace PCV valve and grommet
Replace spark plugs
Replace spark plug wires if original.
Replace distributor cap and rotor
Replace distributor housing O-ring
Replace air filter
Clean Intake plenum (hot tank), it will be full of carbon
Clean Throttle Body thoroughly with attention to small vacuum ports.
(need new TB gasket)
Clean IAC valve (need new IAC O ring)
Clean timing chain tensioner
Repair/replace Accelerator Cable (can use two foot long sections of dual wall marine grade adhesive lined heat shrink tubing to go over worn/torn rubber covering)
Repair Cruise control and Throttle Cable as needed (heat shrink tubing)
Replace all hose clamps with the correct OEM clamps or Constant Torque type.
Send fuel injectors out to be cleaned (RC engineering, Witch hunter)
Expect some or all of the harness connectors to the fuel injectors to break, you can order new Toyota connectors
Inspect, repair, rewrap main engine harness, add heat sleeve protection. Ensure harness is hung correctly and not drooping on the EGR pipe.
Clean/replace EGR valve (it will be full of carbon). Some people delete the EGR system if no inspections.
Replace radiator and install new radiator cushions
Replace alternator if original (Denso or Toyota)
Replace/rebuild starter (Denso or Toyota)
Replace water pump (Toyota or AISIN)
Replace fan clutch (AISIN)
Replace Alternator belt idler pulley (Toyota or NTK)
Replace AC belt tensioner pulley
Rewrap any harnesses that having peeling tape (TESA tape 51036 is one option)
While radiator and battery are out check for rust, remove, prime, paint areas uncovered
Replace transmission cooler lines
Some people will pull the oil cooler cover, clean, and reseal with new gasket.
Paint air filter box with a 2k paint and primer (SprayMax) The lid, IME, often will develop rust long before the main box
Replace radiator overflow tank
Probably forgot something but all that should keep you busy
There a a few dozen possible things that could be serviced, cleaned, painted, wrapped, repaired, or replaced while the head is off.
@Lknmud : it's a very long list, here's some:
Rebuild head (machine shop) with new valve stem seals. Consider new springs or valves as needed). Might be better off buying a new head
Replace oil pump cover gasket/O-ring and front crank seal if not done yet.
Replace water pump
Replace Thermostat
Replace Heat Control Valve
Replace all heater circuit water hoses including the PHH, bypass hoses, radiator hoses, and paint/replace pipes
Replace fuel filter
Replace all vacuum hoses on the Throttle Body and located under side of intake plenum. Test both VSV's for proper function. You can buy the correct Toyota bulk 3.5mm vacuum hose and cut to fit.
Replace fuel rated hose at top of Throttle body, you will have to cut it off to that the TB off. Cut to fit OEM hose.
Expect to replace the "gas" filter on the top front of the intake plenum (the nipple will break if touched)
Clean valve cover (hot tank)
Replace six spark plug tube seals
Replace PCV valve and grommet
Replace spark plugs
Replace spark plug wires if original.
Replace distributor cap and rotor
Replace distributor housing O-ring
Replace air filter
Clean Intake plenum (hot tank), it will be full of carbon
Clean Throttle Body thoroughly with attention to small vacuum ports.
(need new TB gasket)
Clean IAC valve (need new IAC O ring)
Clean timing chain tensioner
Repair/replace Accelerator Cable (can use two foot long sections of dual wall marine grade adhesive lined heat shrink tubing to go over worn/torn rubber covering)
Repair Cruise control and Throttle Cable as needed (heat shrink tubing)
Replace all hose clamps with the correct OEM clamps or Constant Torque type.
Send fuel injectors out to be cleaned (RC engineering, Witch hunter)
Expect some or all of the harness connectors to the fuel injectors to break, you can order new Toyota connectors
Inspect, repair, rewrap main engine harness, add heat sleeve protection. Ensure harness is hung correctly and not drooping on the EGR pipe.
Clean/replace EGR valve (it will be full of carbon). Some people delete the EGR system if no inspections.
Replace radiator and install new radiator cushions
Replace alternator if original (Denso or Toyota)
Replace/rebuild starter (Denso or Toyota)
Replace water pump (Toyota or AISIN)
Replace fan clutch (AISIN)
Replace Alternator belt idler pulley (Toyota or NTK)
Replace AC belt tensioner pulley
Rewrap any harnesses that having peeling tape (TESA tape 51036 is one option)
While radiator and battery are out check for rust, remove, prime, paint areas uncovered
Replace transmission cooler lines
Some people will pull the oil cooler cover, clean, and reseal with new gasket.
Paint air filter box with a 2k paint and primer (SprayMax) The lid, IME, often will develop rust long before the main box
Replace radiator overflow tank
Probably forgot something but all that should keep you busy
Last edited:
- Thread starter
- #6
Thanks, I'm going to clean it up and have a machine shop check it out so I know its in good shape when it goes on. I'm also going to be doing some cooling system upgrades in the near future hopefully to prevent anything like this from happening again. Unfortunately a new head from Toyota is a bit out of budget for me right now, especially being an unexpected cost.
@Kernal gave you the complete list. From my recent experience, there are two areas to inspect wile the head is out (of course, you want to clean the throttle body and upper/lower intake housings):
1. All the coolant/heater system hoses behind the head. Inspect and replace if a) any appear damaged, or b) they appear to be original. They are much easier to replace while the head is out.
2. Power steering pump and high pressure hose. Inspect and replace the hose if it is wet, inspect and rebuild the pump if the rear end is wet.
There are four sensors on the front driver's side of the head. Be very careful when you disconnect them. The engine harness connectors for two of the three electrical sensors are still available, the A/C cutoff switch harness side connector is not. Be very careful with that one when you disconnect it.
The two knock sensors will likely break and so will the engine harness side connectors. All of this is available new. It's not the end of the world if they break.
The six engine harness side injector connectors are also points to watch when disconnecting the harness. Spray all connectors liberally with CRC plastic safe contact cleaner before you disconnect them (you'll need at least six cans). All the injectors and connectors are still available if you damage them, but he injectors are very expensive. Take extra care when reinstalling the injectors; the upper O-ring on the injector into the fuel rail is especially an area to watch. That's the seal for the fuel. If you tear one (I did) it'll leak fuel all over your new repair.
FWIW, I removed the head with the engine in the truck. I will never do that again. It's so much less work to pull the engine than worry with the head getting it in and out. If you try to remove the head with the engine installed, you will need either a) and overhead lift (crane/hoist) and then you'll have to remove the hood, or b) you'll have to have an engine hoist with a 2-ft extension on the boom (the commercial ones won't reach) or remove either the bumper or outer passenger fender to reach the head.
In any case, the front end (at least) will need to be up on jackstands and you'll want to remove both front wheels.
1. All the coolant/heater system hoses behind the head. Inspect and replace if a) any appear damaged, or b) they appear to be original. They are much easier to replace while the head is out.
2. Power steering pump and high pressure hose. Inspect and replace the hose if it is wet, inspect and rebuild the pump if the rear end is wet.
There are four sensors on the front driver's side of the head. Be very careful when you disconnect them. The engine harness connectors for two of the three electrical sensors are still available, the A/C cutoff switch harness side connector is not. Be very careful with that one when you disconnect it.
The two knock sensors will likely break and so will the engine harness side connectors. All of this is available new. It's not the end of the world if they break.
The six engine harness side injector connectors are also points to watch when disconnecting the harness. Spray all connectors liberally with CRC plastic safe contact cleaner before you disconnect them (you'll need at least six cans). All the injectors and connectors are still available if you damage them, but he injectors are very expensive. Take extra care when reinstalling the injectors; the upper O-ring on the injector into the fuel rail is especially an area to watch. That's the seal for the fuel. If you tear one (I did) it'll leak fuel all over your new repair.
FWIW, I removed the head with the engine in the truck. I will never do that again. It's so much less work to pull the engine than worry with the head getting it in and out. If you try to remove the head with the engine installed, you will need either a) and overhead lift (crane/hoist) and then you'll have to remove the hood, or b) you'll have to have an engine hoist with a 2-ft extension on the boom (the commercial ones won't reach) or remove either the bumper or outer passenger fender to reach the head.
In any case, the front end (at least) will need to be up on jackstands and you'll want to remove both front wheels.
I don't know. I did the head gasket job with it in the car and it wasn't that bad. The hardest part was honestly getting to the bolts that hold the two halves of the intake together and pulling back the wiring harness, which you would have to do if you removed the engine. Everything on top is easily accessible. Got a buddy to help me lift it up and out. Left the hood it place. It really wasn't that bad.
You had an easier time than anyone I've spoken to; mine was typical - the hoist wouldn't budge it until I persuaded it with my very large rubber mallet. The rear four headbolts, especially the rearmost two, were a PITA to get out and put in.
And those undermounted intake bolts are no problem when the truck isn't in the way.
And those undermounted intake bolts are no problem when the truck isn't in the way.
I removed the upper intake. Left the bottom half in place. That'll give you something to lift from on the driver side. That'll help break the seal. Once it was broken it lifted out. It was definitely heavy though. Yeah, the upper intake bolts were a pain in the butt.
@Kernal and @Malleus gave very good pointers. I will just add that you'll likely want to replace, and not reuse, the head bolts. IIRC, I used the supra or ARP style bolts. My memory is a bit murky because I did all the work in the driveway with, like @jsloden, the engine very much inside the vehicle (although I did remove the hood and put up a tailgating canopy as a makeshift garage).
There was much wailing and gnashing of teeth during that process. Although, from a pure wrenching standpoint, it wasn't that difficult. Take some stuff off, replace some, then bolt it all back on.
There was much wailing and gnashing of teeth during that process. Although, from a pure wrenching standpoint, it wasn't that difficult. Take some stuff off, replace some, then bolt it all back on.
IIRC, the intake can be unbolted from the head, then simply pulled back away from the head and held there with a motorcycle strap while you pull and replace the head. Not worth messing with pulling the harness wiring through and risking cracking ancient wires.
We have done quite a few with the engine still in place. If the wiring harness is in bad shape we replace it on OBD 2 rigs. On OBD 1 they are NLA, so we do whatever repairs needed. We are just finishing up on a 93 with a TRD supercharger.
This style of socket made getting the head and manifolds on/off while in the car no problem.
Sure, some of it is awkward, but I'd swap the head in the car again if called for.
Every situation is different but for my own it was much easier to pull the head with the engine in place. Picture a slightly sloped, uneven parking space with no room for a hoist and no way to roll it around anyway, etc. I've enjoyed working in well equipped shops in the past but compromised the garage/workshop space on the current house 
I've worked on much more challenging projects than removing/replacing the head on the 1FZ and that may be why I didn't find doing it in place to be that big of a deal. Those harder projects got me in the habit of breaking the work down into manageable chunks (learned the hard way). If I had a shop with room I'd probably have pulled the engine but not to save time on the head work, to allow more extensive updates. If I had a shop with a lift... etc. etc.
I'm sure that many/most of the folks recommending pulling the engine to do the HG have done plenty hard mech. projects, etc. and I know that their recommendations have good merit. I share the above to encourage folks like me that need an alternative approach because they don't have the facilities/space to pull the engine but could benefit from a DIY head gasket replacement.
We all have different lifting/carrying capabilities but I didn't find the head to be that heavy and with some prep/planning you can create landing places for it so that you can safely move it one step at a time into position without as much risk of mishap or gasket damage/etc. That way you can get into the right position to lift and move the head through each part of it's trip and avoid being overextended, off balance, etc. which could quickly make the head impossible to manage. On install an extra set of hands to lift/guide the front-end of the head while you manage the rear and the actual alignment/placement could be helpful.
As mentioned above you can leave the lower intake and harness where they are and just pull them back to remove the head. I did this and then after the head was out of the way I cut the chunk out of the lower intake that allows the harness to then be left while I removed the lower intake for cleaning. Cutting the lower intake with the head in place would be harder. Make sure you keep the alu pieces out of the block.
A board from fender to some point on the engine can be used to lay on and get much more comfortable access to areas around the firewall/etc. while you are working.
Plan to pull the intake/air filer/battery box/ etc. to make work easier but I didn't end up pulling the radiator and it didn't impact my work. I did put a piece of cardboard over the fins to protect them and I pulled the shroud to make changing the oil pump seal, front main seal, etc. easier.
I didn't remove the hood to pull/reinstall the head but it may have made things a little easier at times. I was working outside and wanted to keep things covered whenever I wasn't actively working so the hood was an asset as was covers for the block, wd40, etc.
I've worked on much more challenging projects than removing/replacing the head on the 1FZ and that may be why I didn't find doing it in place to be that big of a deal. Those harder projects got me in the habit of breaking the work down into manageable chunks (learned the hard way). If I had a shop with room I'd probably have pulled the engine but not to save time on the head work, to allow more extensive updates. If I had a shop with a lift... etc. etc.
I'm sure that many/most of the folks recommending pulling the engine to do the HG have done plenty hard mech. projects, etc. and I know that their recommendations have good merit. I share the above to encourage folks like me that need an alternative approach because they don't have the facilities/space to pull the engine but could benefit from a DIY head gasket replacement.
Similar experience to mine.Every situation is different but for my own it was much easier to pull the head with the engine in place. Picture a slightly sloped, uneven parking space with no room for a hoist and no way to roll it around anyway, etc. I've enjoyed working in well equipped shops in the past but compromised the garage/workshop space on the current house
We all have different lifting/carrying capabilities but I didn't find the head to be that heavy and with some prep/planning you can create landing places for it so that you can safely move it one step at a time into position without as much risk of mishap or gasket damage/etc. That way you can get into the right position to lift and move the head through each part of it's trip and avoid being overextended, off balance, etc. which could quickly make the head impossible to manage. On install an extra set of hands to lift/guide the front-end of the head while you manage the rear and the actual alignment/placement could be helpful.As mentioned above you can leave the lower intake and harness where they are and just pull them back to remove the head. I did this and then after the head was out of the way I cut the chunk out of the lower intake that allows the harness to then be left while I removed the lower intake for cleaning. Cutting the lower intake with the head in place would be harder. Make sure you keep the alu pieces out of the block.A board from fender to some point on the engine can be used to lay on and get much more comfortable access to areas around the firewall/etc. while you are working.Plan to pull the intake/air filer/battery box/ etc. to make work easier but I didn't end up pulling the radiator and it didn't impact my work. I did put a piece of cardboard over the fins to protect them and I pulled the shroud to make changing the oil pump seal, front main seal, etc. easier.I didn't remove the hood to pull/reinstall the head but it may have made things a little easier at times. I was working outside and wanted to keep things covered whenever I wasn't actively working so the hood was an asset as was covers for the block, wd40, etc.
I've worked on much more challenging projects than removing/replacing the head on the 1FZ and that may be why I didn't find doing it in place to be that big of a deal. Those harder projects got me in the habit of breaking the work down into manageable chunks (learned the hard way). If I had a shop with room I'd probably have pulled the engine but not to save time on the head work, to allow more extensive updates. If I had a shop with a lift... etc. etc.
I'm sure that many/most of the folks recommending pulling the engine to do the HG have done plenty hard mech. projects, etc. and I know that their recommendations have good merit. I share the above to encourage folks like me that need an alternative approach because they don't have the facilities/space to pull the engine but could benefit from a DIY head gasket replacement.
I removed the hood for ease of access. It means you can stand in the engine bay to lift the head off.
Mine had a crack in as well after having the engine rebuilt. So far it’s been running fine with no issues just a small oil leak . The crack was in the front between cylinders 2 and 3 where the cooling line bolts in. Not in critical area such a cooling port or anything so no rush on fixing.
One thing I did was buy Alum Bond from Amazon to put on the crack to help some of the leakage. One guy on here laughed at it and said it was ghetto JB weld. After reading a review where someone fixed their Kawasaki crankcase figured I would give it a shot. Followed the instructions and and went on pretty easily. Since the crack went all the way up to gasket I knew stoping all the oil would not be feasible because I was applying it the outside. After a couple days the oil stopped leaking as much.
Now 6 months later, I have been amazed to find no more oil leaking. I’m probably just gonna leave it until the head gasket needs replacing.
Last edited:
- Thread starter
- #19
This is the same exact place that mine is leaking. I might do the same thing to help give me some time to save up and get all new Toyota parts and replacement hoses, but not as a permanent solution.
Some more info on the head crack if you are interested.
Hairline Cracks In Cylinder Head -- Advice Please!
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