Need help with mysterious major oil leak

[Outrider]

Another update. I see some fresh oil inside the socket head bolts on the top of the a/c compressor. That is under the center front of the passenger side VC. Perhaps I have a leak there, although I don't see any oil around the front of that VC, to either side, where it is visible. If that is the leak, it is covered by the rear metal timing belt cover, but I would have to remove the timing belt and cam pulleys to remove that cover and verify completely.

The problem is that when I removed the upper radiator hose so that I could remove the upper TB cover, some coolant ran down, even though I drained about a quart of coolant prior to removing the hose. Some of that coolant ran down inside the lower TV cover (grrrrrrrrr - not good, and I will pump some air down there with a fan to dry it out), but also that coolant ran down onto where I was trying to look for fresh oil, so now when I see wetness, I have to determine if it is oil or coolant. Not always easy to do.

Another quesiton: If the front crank seal is leaking, it seem that some oil would be on the outside face of the timing belt. Am I thinking correctly? Especially if I am losing a significant amount of oil. It isn't just a little drip.

Here are pictures of what I just uncovered. You can see oil in the sockets of the socket head bolts on top of the compressor in the top 4 pictures. The other pictures were my attempt at showing other aread that were dry of oil. Bad camera angles in some of them. My T4R is up on ramps and I am on a step ladder with a flashlight.

 

[19963.4lsr5]

My guess is the front crankshaft seal. A few months back I blew the one out of my '96 and when replacing it with an oem seal it went in way too easy. Removed the new oem seal and went with Napa seal. This one fit a lot tighter.

I've noticed this when I did the front crank seal on the 96 and also installed a napa seal.


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[BamaDrewski]

Another update. I see some fresh oil inside the socket head bolts on the top of the a/c compressor. That is under the center front of the passenger side VC. Perhaps I have a leak there, although I don't see any oil around the front of that VC, to either side, where it is visible. If that is the leak, it is covered by the rear metal timing belt cover, but I would have to remove the timing belt and cam pulleys to remove that cover and verify completely.

The problem is that when I removed the upper radiator hose so that I could remove the upper TB cover, some coolant ran down, even though I drained about a quart of coolant prior to removing the hose. Some of that coolant ran down inside the lower TV cover (grrrrrrrrr - not good, and I will pump some air down there with a fan to dry it out), but also that coolant ran down onto where I was trying to look for fresh oil, so now when I see wetness, I have to determine if it is oil or coolant. Not always easy to do.

Another quesiton: If the front crank seal is leaking, it seem that some oil would be on the outside face of the timing belt. Am I thinking correctly? Especially if I am losing a significant amount of oil. It isn't just a little drip.

Here are pictures of what I just uncovered. You can see oil in the sockets of the socket head bolts on top of the compressor.

Ok. I was experiencing a leak like this as well. Oil has a way of running and creeping all over the place. I got into a full clean-up and sealing of the cam housings. There, you have to replace the "half moons". Take them out, clean them off (including where they "sit") and replace with new sealant. (A dremel tool with a copper wire brush worked great for this) My issue seemed to actually be the rear "cam covers". They look like thin, black hocky pucks with one side hollowed out. I removed them, cleaned them up and sealed them up good. After I did this, I replaced the VCG's, the spark plug tube gaskets, the PCV gasket (and PCV valve with Toyota OE) and new screw gaskets (for all the screws holding down the valve covers. You also have to "sequence screw/torque" those screws down in a certain pattern to prevent warping the valve cover. Sounds like you did all of these things with the exception of removing the half moons and the rear cam covers and resealing them (Correct me if I am wrong)

Long story short, after I did all this work, no more leaks. Not one drop. From what I could tell my leak was as the rear around the cam covers and one or two of the half moons. Also, I replaced the cam seals/gaskets when I was doing the TB work. Did you replace those?

Also, did you replace your spark plugs? I have had a recent issue when one of mine totally failed and there was a small puff of smoke.....

Forgive all my questions as I can't remember everything in your original post.....

Also, looks like you are running green coolant from the photos. Our rigs tend to dislike the green stuff. If you have the time and money (now or eventually) I would recommend a coolant flush (Thermocure is great) with distilled water and replace with Toyota RED and distilled water. Good luck man and stay positive. If there is an answer to be had, it will probably be on this forum!

 

[JRZEE2000TR4LTD]

Another update. I see some fresh oil inside the socket head bolts on the top of the a/c compressor. That is under the center front of the passenger side VC. Perhaps I have a leak there, although I don't see any oil around the front of that VC, to either side, where it is visible. If that is the leak, it is covered by the rear metal timing belt cover, but I would have to remove the timing belt and cam pulleys to remove that cover and verify completely.

The problem is that when I removed the upper radiator hose so that I could remove the upper TB cover, some coolant ran down, even though I drained about a quart of coolant prior to removing the hose. Some of that coolant ran down inside the lower TV cover (grrrrrrrrr - not good, and I will pump some air down there with a fan to dry it out), but also that coolant ran down onto where I was trying to look for fresh oil, so now when I see wetness, I have to determine if it is oil or coolant. Not always easy to do.

Another quesiton: If the front crank seal is leaking, it seem that some oil would be on the outside face of the timing belt. Am I thinking correctly? Especially if I am losing a significant amount of oil. It isn't just a little drip.

Here are pictures of what I just uncovered. You can see oil in the sockets of the socket head bolts on top of the compressor.

Ok, get about 5 cans a brake cleen spray it everywhere you see wetness.
Even spary it down where the CS is. Even though it is somwhat sealed there it should find a way out. Might be able to just loosen the bolts that hold that cover on and back it off against the dampener. Not sure though as maybe the dampener will be in the way of some of the bolts which I think it is. If you had some compressed air that would be the way to go.

No need to take off the inner timing belt cover. It really looks like it might be running down the back side of that inner cover from the VC cover. There's a gap there where some wiring runs. Spray that whole area down with Brake Kleen and get it nice and dry then start up the truck and watch that area on top of the AC compressor. My money is on your Passenger side VC gasket (or cover if it's cracked) by looking at the pictures

 

[19963.4lsr5]

If you can't see oil under the cam pulley running down the block I doubt it's the cam seal. When the 97 crank seal leaked it just filled the skid plate with oil. Didn't blow all over the place.

When I do valve cover gaskets I retorque them multiple times. Until their all tight and stay that way. I'd pull the passenger VC and seal the half moons properly and buy new grommets for the VC bolts and do it again following the torque sequence in the manual.


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[Outrider]

Ok. I was experiencing a leak like this as well. Oil has a way of running and creeping all over the place. I got into a full clean-up and sealing of the cam housings. There, you have to replace the "half moons". Take them out, clean them off (including where they "sit") and replace with new sealant. (A dremel tool with a copper wire brush worked great for this) My issue seemed to actually be the rear "cam covers". They look like thin, black hocky pucks with one side hollowed out. I removed them, cleaned them up and sealed them up good. After I did this, I replaced the VCG's, the spark plug tube gaskets, the PCV gasket (and PCV valve with Toyota OE) and new screw gaskets (for all the screws holding down the valve covers. You also have to "sequence screw/torque" those screws down in a certain pattern to prevent warping the valve cover. Sounds like you did all of these things with the exception of removing the half moons and the rear cam covers and resealing them (Correct me if I am wrong)

Long story short, after I did all this work, no more leaks. Not one drop. From what I could tell my leak was as the rear around the cam covers and one or two of the half moons. Also, I replaced the cam seals/gaskets when I was doing the TB work. Did you replace those?

Also, did you replace your spark plugs? I have had a recent issue when one of mine totally failed and there was a small puff of smoke.....

Forgive all my questions as I can't remember everything in your original post.....

Also, looks like you are running green coolant from the photos. Our rigs tend to dislike the green stuff. If you have the time and money (now or eventually) I would recommend a coolant flush (Thermocure is great) with distilled water and replace with Toyota RED and distilled water. Good luck man and stay positive. If there is an answer to be had, it will probably be on this forum!

It may very well be the half moons that I just left in place. I wasn't aware those needed to be re-sealed. I'm pretty sure the VC gaskets themselves aren't leaking. Maybe I knocked a half moon during the VC replacement process and broke the seal.

I haven't recently replaced the spark plugs. They don't have many miles on them, though. Probably less than 20k miles.

I did replace both camshaft seals. I always to those and the front crank seals when I replace a timing belt.

I need to replace the VC bolt grommets, which I also failed to do. I doubt that is the cause of my leak, though. And I need to replace the PCV valve. I think that may possibly be the cause of the white smoke.

It's starting to look as if several small problems are turning this into one big problem. That can be quite typical. I really don't think this is just one simple thing.

Regarding the coolant, I was afraid of changing the type, so I used at least the same color, for that reason. I really don't want to get into total flush/replace thing, because if I don't get all of the old stuff out, then I am mixing types, which I understand can cause real problems.

 

[BamaDrewski]

It may very well be the half moons that I just left in place. I wasn't aware those needed to be re-sealed. I'm pretty sure the VC gaskets themselves aren't leaking. Maybe I knocked a half moon during the VC replacement process and broke the seal.

I haven't recently replaced the spark plugs. They don't have many miles on them, though. Probably less than 20k miles.

I did replace both camshaft seals. I always to those and the front crank seals when I replace a timing belt.

I need to replace the VC bolt grommets, which I also failed to do. I doubt that is the cause of my leak, though. And I need to replace the PCV valve. I think that may possibly be the cause of the white smoke.

It's starting to look as if several small problems are turning this into one big problem. That can be quite typical. I really don't think this is just one simple thing.

Regarding the coolant, I was afraid of changing the type, so I used at least the same color, for that reason. I really don't want to get into total flush/replace thing, because if I don't get all of the old stuff out, then I am mixing types, which I understand can cause real problems.

Please check the rear cam covers. Also, with respect to changing coolant, the Thermocure (At WalMart) does a great job. I used it on a 5VZFE Tacoma that never had the coolant changed with 202K miles. I drained the coolant, added the Thermocure and distilled water and ran for about 20 minutes (including turning on the heater on HOT to get the heater core cleaned out). The gunk that game out looked like black coffee. I drained again, ran only with distilled water and repeated this three times. The third flush, the water was clear. Also, I have a friend who is a Toyota Master Mechanic. He said they actually had a "autopsy" of a 5VZFE engine running the green stuff and one running the red. He said the internals of the engine with the green stuff looked terrible. Apparently lots of white, gummy globs of aluminum corrosion. He said it was absolutely evident the green stuff did not do well in the 5VZFE. I guess it depends on how long you want to keep and run your rig however.......mine has 306.5K on it now and I intend to run it until it falls apart - probably in another 300K...LOL

 

[JRZEE2000TR4LTD]

Please check the rear cam covers. Also, with respect to changing coolant, the Thermocure (At WalMart) does a great job. I used it on a 5VZFE Tacoma that never had the coolant changed with 202K miles. I drained the coolant, added the Thermocure and distilled water and ran for about 20 minutes (including turning on the heater on HOT to get the heater core cleaned out). The gunk that game out looked like black coffee. I drained again, ran only with distilled water and repeated this three times. The third flush, the water was clear. Also, I have a friend who is a Toyota Master Mechanic. He said they actually had a "autopsy" of a 5VZFE engine running the green stuff and one running the red. He said the internals of the engine with the green stuff looked terrible. Apparently lots of white, gummy globs of aluminum corrosion. He said it was absolutely evident the green stuff did not do well in the 5VZFE. I guess it depends on how long you want to keep and run your rig however.......mine has 306.5K on it now and I intend to run it until it falls apart - probably in another 300K...LOL

Those cam plugs are where mine was mainly leaking too. Highly suggest replacing them IF you're going to take it apart again. With that being said, I don't think those are the main issue here as the oil leak is in the front somewhere and when those cam plugs leak it runs down the back back of the motor, onto the bellhousing, making you think it's a rear main seal leak.
No way that kind of oil leak goes forward.

 

[JRZEE2000TR4LTD]

It may very well be the half moons that I just left in place. I wasn't aware those needed to be re-sealed. I'm pretty sure the VC gaskets themselves aren't leaking. Maybe I knocked a half moon during the VC replacement process and broke the seal.

I haven't recently replaced the spark plugs. They don't have many miles on them, though. Probably less than 20k miles.

I did replace both camshaft seals. I always to those and the front crank seals when I replace a timing belt.

I need to replace the VC bolt grommets, which I also failed to do. I doubt that is the cause of my leak, though. And I need to replace the PCV valve. I think that may possibly be the cause of the white smoke.

It's starting to look as if several small problems are turning this into one big problem. That can be quite typical. I really don't think this is just one simple thing.

Regarding the coolant, I was afraid of changing the type, so I used at least the same color, for that reason. I really don't want to get into total flush/replace thing, because if I don't get all of the old stuff out, then I am mixing types, which I understand can cause real problems.

No way you "knocked" the half moons loose. Where, if any place did you put sealant when you did the VCs?

 

[BamaDrewski]

Those cam plugs are where mine was mainly leaking too. Highly suggest replacing them IF you're going to take it apart again. With that being said, I don't think those are the main issue here as the oil leak is in the front somewhere and when those cam plugs leak it runs down the back back of the motor, onto the bellhousing, making you think it's a rear main seal leak.
No way that kind of oil leak goes forward.

Agreed the rear cam covers might not be the issue but a comprehensive check of everything while in that area will provide a lot of peace of mind moving forward. I took my time doing all the aforementioned work. Took me about 3 days as I wanted it done right and not have to do it again anytime soon. I am sure the OP did things right but like many others, I never knew about the half moons and rear cam covers until many years after owning my rig and reading LOTS AND LOTS of forums and articles. Let's call it "cumulative learning...."

 

[JRZEE2000TR4LTD]

It may very well be the half moons that I just left in place. I wasn't aware those needed to be re-sealed. I'm pretty sure the VC gaskets themselves aren't leaking. Maybe I knocked a half moon during the VC replacement process and broke the seal.

I haven't recently replaced the spark plugs. They don't have many miles on them, though. Probably less than 20k miles.

I did replace both camshaft seals. I always to those and the front crank seals when I replace a timing belt.

I need to replace the VC bolt grommets, which I also failed to do. I doubt that is the cause of my leak, though. And I need to replace the PCV valve. I think that may possibly be the cause of the white smoke.

It's starting to look as if several small problems are turning this into one big problem. That can be quite typical. I really don't think this is just one simple thing.

Regarding the coolant, I was afraid of changing the type, so I used at least the same color, for that reason. I really don't want to get into total flush/replace thing, because if I don't get all of the old stuff out, then I am mixing types, which I understand can cause real problems.

Here's a write up that shows where you use the FIPG (although he didn't need to use as much as he did in that one picture)

http://www.toyota-4runner.org/3rd-g...cover-gaskets-true-write-up-**pictures**.html

 

[Outrider]

I will replace the cam covers, once I identify them. From memory, I don't recall exactly what they are. Not the half moons, I presume.

When replacing the VC's, I put sealant only at 4 places on each - where the gaskets when up and over the cams - at those sharp corners. I put a good-sized dab of black hi-temp RTV at each of the 4 places on both covers.

I was hoping to have a "Tada - there it is"! obvious moment of clarity here as I was taking stuff apart and studying things. It probably is the cam covers, and I am just going with the best guess here, and will keep hoping the problem is solved. Once all of the residual leaked oil has either been cleaned off or finally all dripped off, and it stops leaving oil on my basement floor, then I will finally know that the problem was solved. Until then, I will just keep hoping.

My daughter is a new veterinarian. I told her that finding and solving a mysterious animal issue is extremely similar to doing this kind of work. To solve them, you have to know how things work and behave, study things, and very often the only thing you can do is go with your best guess. The only real difference is that vehicles generally do not heal themselves.

On the coolant issue - that is for another time. I have to stay focused on this. One thing at a time. I am old and my cluttered brain can't keep everything sorted. Plus - that isn't an emergency issue (yet). But I will look into that later.

 

[BamaDrewski]

Those cam plugs are where mine was mainly leaking too. Highly suggest replacing them IF you're going to take it apart again. With that being said, I don't think those are the main issue here as the oil leak is in the front somewhere and when those cam plugs leak it runs down the back back of the motor, onto the bellhousing, making you think it's a rear main seal leak.
No way that kind of oil leak goes forward.

Looking at the photo the OP took of the inspection plate being off, it looks like there is oil running down the back somewhere. (See pic with red circles)

 

[Outrider]

Here's a write up that shows where you use the FIPG (although he didn't need to use as much as he did in that one picture)

http://www.toyota-4runner.org/3rd-g...cover-gaskets-true-write-up-**pictures**.html

That explains a lot. Thanks.

 

[JRZEE2000TR4LTD]

I will replace the cam covers, once I identify them. From memory, I don't recall exactly what they are. Not the half moons, I presume.

When replacing the VC's, I put sealant only at 4 places on each - where the gaskets when up and over the cams - at those sharp corners. I put a good-sized dab of black hi-temp RTV at each of the 4 places on both covers.

I was hoping to have a "Tada - there it is"! obvious moment of clarity here as I was taking stuff apart and studying things. It probably is the cam covers, and I am just going with the best guess here, and will keep hoping the problem is solved. Once all of the residual leaked oil has either been cleaned off or finally all dripped off, and it stops leaving oil on my basement floor, then I will finally know that the problem was solved. Until then, I will just keep hoping.

My daughter is a new veterinarian. I told her that finding and solving a mysterious animal issue is extremely similar to doing this kind of work. To solve them, you have to know how things work and behave, study things, and very often the only thing you can do is go with your best guess. The only real difference is that vehicles generally do not heal themselves.

On the coolant issue - that is for another time. I have to stay focused on this. One thing at a time. I am old and my cluttered brain can't keep everything sorted. Plus - that isn't an emergency issue (yet). But I will look into that later.

Those are the correct places, PLUS over top of the seams where the half moons rest and on the cam plug cap (But you didn't take that off)

Could the VC gasket gotten slightly out of place when you placed the cover into position?

Are the "cam covers" you are referring to be the cam plugs? 1 on each head on the back.

 

[Outrider]

Looking at the photo the OP took of the inspection plate being off, it looks like there is oil running down the back somewhere. (See pic with red circles)

I will study that more closely, but I think that is just oil that ran or was blown back from gravity/airflow. I think it is only on the bottom, and not on the now-exposed aluminum face under the inspection plate. But I will study it more.

 

[Outrider]

Those are the correct places, PLUS over top of the seams where the half moons rest and on the cam plug cap (But you didn't take that off)

Could the VC gasket gotten slightly out of place when you placed the cover into position?

Are the "cam covers" you are referring to be the cam plugs? 1 on each head on the back.

Entirely possible a VC gasket got pushed out of place, as I was wiggling the covers through a bunch of junk to locate them. But I don't see any oil coming out from under the VC's anywhere (the areas I can actually see).

Yes - I meant cam plugs - not cam covers.

 

[JRZEE2000TR4LTD]

Looking at the photo the OP took of the inspection plate being off, it looks like there is oil running down the back somewhere. (See pic with red circles)

Yes but it's also in the front. If the oil leak were solely the cam plugs it would not be in the front on his AC compressor. The plugs could be leaking too though but it's definitely not the main source of his leak now.

 

[JRZEE2000TR4LTD]

Entirely possible a VC gasket got pushed out of place, as I was wiggling the covers through a bunch of junk to locate them. But I don't see any oil coming out from under the VC's anywhere (the areas I can actually see).

Yes - I meant cam plugs - not cam covers.

And there was no oil trails under your camshaft seals?

The areas that you can see the VC gasket are right above the exhaust manifold correct?

 

[BamaDrewski]

I will replace the cam covers, once I identify them.

The cam covers are at the rear of each valve body. They are held in with a "bridge" with two bolts. You have to remove the two bolts, remove the "bridge" and you can reach in and grab the covers and pull them out. Clean up the grooves they sit in and clean them up as well. Use FIPG to reseal and torque to factory specs.