Leak diagnosis (1 Viewer)

[Bighead]

I have a recently acquired 97 with ~89k miles that has developed a leak I noticed this morning after a drive. I wiped it off with a white paper towel and it appears to be oil due to the color but I am not positive.

After doing some searches, I am seeing references to rear main seal or upper pan arch seal leaks. Based on the photo below can anyone point me to the areas to look at to determine the issue.

The first pic has the fluid circled and the second is a different angle after wiping it down.

 

[Fj80oregon]

What else do you need to know? You are correct that’s it’s either the rear main(not common) or the upper oil pan very common. It could possibly be the valve cover gasket if the back of the engine is covered in oil above the pans.

Upper oil pan arch seal renew

Oil pan arch seal project I tackled re-sealing the famous arch seal this weekend. This project is a little involved but fairly straight forward. While I had the engine raised, I took the opportunity to replace the motor mounts. I'm an ameteur so I'm sure there're more efficient ways to do...

forum.ih8mud.com

 

[Bighead]

Thanks for the reply and the link. I am admittedly an 80-series novice and wanted to make sure I was on the right track.

I wanted to know about any other places to look that would help isolate the issue to one or the other or something completely different. Since I posted the pic no other fluid has shown up in that location as it’s been sitting. I did find a couple of fresh streaks on the front half of the oil pan.

EDIT: Well, after looking at that link that arch seal is going to be a nut roll.

 

[Kernal]

Large oil leaks up front (1FZFE) are often from the Oil pump cover gasket (usually the biggest leak) then the distributor O-ring and valve cover gasket. Rarely the front crank seal but that is replaced when the harmonic balancer is out of the way for the oil pump cover gasket replacement. Also, rarely there may be a small leak/seep from the timing chain cover with a quick fix not requiring removal of the cover.

For the rear leak you can pop the plastic inspection cover out of the bell-housing then using a mechanics mirror or fiber optic camera go in, up and look forward at the rear crank seal and rear arch of the upper pan. They're very close together (one over the other) so it can be difficult to determine where the leak started from.

You can clean that area off (spray something up in at the rear arch/seal area that won't harm rubber seals) then run the engine, go back and look again to try to determine where the leak started from ----

If it helps, many of us have run our 80's for years with a small seep in the rear, no big deal. Changing engine oil type/viscosity may make a difference.

 

[Bighead]

Large oil leaks up front (1FZFE) are often from the Oil pump cover gasket (usually the biggest leak) then the distributor O-ring and valve cover gasket. Rarely the front crank seal but that is replaced when the harmonic balancer is out of the way for the oil pump cover gasket replacement. Also, rarely there may be a small leak/seep from the timing chain cover with a quick fix not requiring removal of the cover.

For the rear leak you can pop the plastic inspection cover out of the bell-housing then using a mechanics mirror or fiber optic camera go in, up and look forward at the rear crank seal and rear arch of the upper pan. They're very close together (one over the other) so it can be difficult to determine where the leak started from.

You can clean that area off (spray something up in at the rear arch/seal area that won't harm rubber seals) then run the engine, go back and look again to try to determine where the leak started from ----

If it helps, many of us have run our 80's for years with a small seep in the rear, no big deal. Changing engine oil type/viscosity may make a difference.

Thanks for the info.