Read that it has to do if you change from conventional not that its Synthetic per se. The molecules are smaller on the synthetic which allow more flow of fluids within seals gaskets etc. That's what I've been told by a few folks. So stick with what you're doing.
rear main seal? (1 Viewer)
- Thread starter bluecruiser
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I got bad advice many years ago to switch to synthetic when I was at about 180,000 miles. I even questioned the guy about it causing leaks. He said that was BS and stop reading the internet. I switched on his advice and within two weeks had a head gasket leak and main seal leak. I fixed the head gasket, but the rear main seal has been slow and I have not fixed it. I am at 310,000 miles now. I have used BlueDevil main seal leak stop and switched back to conventional. Just my experience.
I pulled the skid plate today to grease the front driveshaft and came upon this. I’m going to look further tomorrow and I’m a little afraid to ask but does this look like RMS leak? It’s definitely visible on the skid plate and dripping off the bell housing. This is an 07 Lx470 at 182k.
Indeed that seems the likely explanation assuming that is engine oil and you can’t source the leak back elsewhere.
Mine started almost two years ago at 300k, replaced seal a few months later, leak came right back. Good news, it only leaks about 1/3 quart over 5k miles, so my advice is monitor and not be too concerned.
At least I had new motor mounts and trans mount installed while in there, so not a total waste of labor.
Mine started almost two years ago at 300k, replaced seal a few months later, leak came right back. Good news, it only leaks about 1/3 quart over 5k miles, so my advice is monitor and not be too concerned.
At least I had new motor mounts and trans mount installed while in there, so not a total waste of labor.
Good read through on this thread. Will try that BLUE DEVIL Rear Main Seal leak stopper tomorrow and will update this in two weeks time.
Just an FYI to all of you. I had a very good independent mechanic tell me that it's likely not the rear mail seal on these engines, and rather, the inner oil pan gasket leaking. Apparently this is a very common issue on the Tundra. Not saying it's not the rear mail seal, but it's quite a bit cheaper, and less involved to check the inner oil pan for the leak first.
Good to know, thanks. Going to check that first and monitor leakage for a while. Will report back.
I sure do hope that's what it is.
I used at-205 twice and it's still happening.
No loss of oil between the 5k oil changes.
What is and how can i find the inner oil pan gasket? Is it different from the normal oil gasket?
It would make sense as i had to replace my valve cover gaskets in the beginning of the year and my oil filter housing gasket last week and the rubber was more like plastic.
I had oil show up around the area where transmission meets the engine and I was worried that it was RMS. Had the local Toyota dealer cleaned the engine block and put some dye in the engine oil. Checked it with UV light about 300 miles later and it was all coming from the valve cover gasket.
The aftermarket FelPro gasket set I had installed a week prior to this was the culprit. Fresh OEM valve cover, spark plug tube and bolt gasket later, it is all dry now. Moral of the story is that it could be something much simpler like VCG than something major like RMS.
The aftermarket FelPro gasket set I had installed a week prior to this was the culprit. Fresh OEM valve cover, spark plug tube and bolt gasket later, it is all dry now. Moral of the story is that it could be something much simpler like VCG than something major like RMS.
When I bought my truck I had no clue what the owner used in the engine, I went with synthetic blend for 3 years and now with fully synthetic.
I instaleld a set of flepro valve cover gaskets into my 97 4runner and in 6000 miles, it started leaking again. Since then I learned my lesson and only use OEM seals and gaskets. You can apply a small film of toyota FIPG to the bottom part of the valve cover gasket to make it seal better.
I instaleld a set of flepro valve cover gaskets into my 97 4runner and in 6000 miles, it started leaking again. Since then I learned my lesson and only use OEM seals and gaskets. You can apply a small film of toyota FIPG to the bottom part of the valve cover gasket to make it seal better.
After more research, I can see that there is some minimal leakage from the valve cover gasket and from the oil pan gasket, but I can't see any clear signs that either are making their way down to the RMS area. Below are pics of the passenger side of the valve cover (DS looks similar with weeping at the corners), the front side of the oil pan (facing front of truck, not facing RMS area), and a picture of the bell housing unit.
Question: See first picture. There is a thin black metal piece on the back of the bell housing that appears to be an access door to something. It's held in place by one bolt at its corner, so it seems like you'd loosen it and swing it open if necessary. After cleaning the area, I can push on this black metal piece and watch oil begin to wick down along the bottom edge of this interface. This seems to be clearly where the leak is originating from. What is this?
Question: See first picture. There is a thin black metal piece on the back of the bell housing that appears to be an access door to something. It's held in place by one bolt at its corner, so it seems like you'd loosen it and swing it open if necessary. After cleaning the area, I can push on this black metal piece and watch oil begin to wick down along the bottom edge of this interface. This seems to be clearly where the leak is originating from. What is this?
You can remove that access plate, and clean the area thoroughly. It's purpose is to allow access to the flexplate bolts in the event you have to pull the transmission or engine. I have a very similar leak, so I'll be doing the same investigation soon.
Upper oil pan gasket would likely mean pulling the front diff; which is better than pulling the transmission, but not that much better.
I'd definitely start with the valve cover gaskets, to start. And work your way down.
NorCalFJ100
SILVER Star
Anyone from this thread attack any of these potential leak sites? Rear Main or Upper Oil Pan?
Mine leaked when I bought it. (170k) The leak never changed through 2 valve cover replacements, one felpro one OEM.
After 50k more miles it finally started dripping on the floor.
I took the rear main retainer and the front oil pump/retainer off for both crank seals and both O rings behind both retainers.
I resealed both pans, retainers, new flex plate and bolts, new timing belt tensioner and a new belt. Among other things.
My seals were all original grey fipg.
I noticed a significant oil pressure increase on the dash gauge.
My gauge would be close to one quarter all the time. Now it flutters around half at anything above 900 rpm. This wasn't because I was loosing a ton on the ground. I never really added oil between changes. I don't go over 5k with that.
I think the o rings are important, and overlooked.
I did not order the 350$ reseal toyota kit. But everything is in there. I just looked to see if the o rings were there, they are.
I just didn't need most of that stuff as it's been done already.
After 50k more miles it finally started dripping on the floor.
I took the rear main retainer and the front oil pump/retainer off for both crank seals and both O rings behind both retainers.
I resealed both pans, retainers, new flex plate and bolts, new timing belt tensioner and a new belt. Among other things.
My seals were all original grey fipg.
I noticed a significant oil pressure increase on the dash gauge.
My gauge would be close to one quarter all the time. Now it flutters around half at anything above 900 rpm. This wasn't because I was loosing a ton on the ground. I never really added oil between changes. I don't go over 5k with that.
I think the o rings are important, and overlooked.
I did not order the 350$ reseal toyota kit. But everything is in there. I just looked to see if the o rings were there, they are.
I just didn't need most of that stuff as it's been done already.
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NorCalFJ100
SILVER Star
Did you do all that work when you did a timing belt swap? I swapped my belt a few months back. That was a big job. I'd hate to dive that deep again. But this little leak is pesky and I'd love to get rid of it...
NorCalFJ100
SILVER Star
Yikes. Can some of this work be done with the engine in the truck still? Or does the TCase and/or trans need to come out at minimum?
my opinion,, all of it can be. Minus the separation of the transmission.
It can be done properly and fix leaks that way also. Read the other rear main seal threads, there aren't a lot, and the oil pan threads, oil pump and front crank seal also. I wouldn't mess with the pans unless there was a provable leak or engine was upside down. Pan redo is almost free at that point minus the pick up gasket and I think an o ring. The inside fipg squeeze out is breaking off already into the crank void on all these cars. Think what you will about that.
People have done them without removing the engine and been fine I'm sure.
I think doing the rear and front is pointless without taking the oil pump and rear retainer off also for those orings. unless there is no leak. I bet 90% the people out there with quoted rear main seals aren't real rear main seal leaks. Valve cover gaskets, or oring under the retainer or retainer seal to the upper pan most likely. I don't really buy the vc gasket idea unles you swipe the inside of the bell housing and it's clean. Everyone should look under the black cover plate before giving someone 2k $ for work.
I'm not a mechanic, don't take my word for it.
manual link. https://lc100e.github.io/manual/
It can be done properly and fix leaks that way also. Read the other rear main seal threads, there aren't a lot, and the oil pan threads, oil pump and front crank seal also. I wouldn't mess with the pans unless there was a provable leak or engine was upside down. Pan redo is almost free at that point minus the pick up gasket and I think an o ring. The inside fipg squeeze out is breaking off already into the crank void on all these cars. Think what you will about that.
People have done them without removing the engine and been fine I'm sure.
I think doing the rear and front is pointless without taking the oil pump and rear retainer off also for those orings. unless there is no leak. I bet 90% the people out there with quoted rear main seals aren't real rear main seal leaks. Valve cover gaskets, or oring under the retainer or retainer seal to the upper pan most likely. I don't really buy the vc gasket idea unles you swipe the inside of the bell housing and it's clean. Everyone should look under the black cover plate before giving someone 2k $ for work.
I'm not a mechanic, don't take my word for it.
manual link. https://lc100e.github.io/manual/
