Hello LS1Tech friends, while I wait for the parts to repair my 4L60E transmission I decided to take advantage of my free time chasing a big giant oil leak in my Tahoe (2WD - street use only). I share this video with you, waiting for your comments on it. The leak is massive.

Tomorrow with daylight I will continue looking for the source of the leak. I'll share all the media to help others with similar problems.

Greetings from Colombia!


-- Update -- 04 / 15 / 2021
Today I made a new video to track the leak. Indeed the VLOM gasket is broken or worn (see video/photos below). This seems to be the main source of the leak, the pressure sensor is still dry, one or two rear main cover bolts have a little oil trail but nothing serious.
Tomorrow I am going to check the driver's side, under the head of the engine I also see what appears to be an oil leak (not coolant), stay tuned.




Old rag with umbrellas to contain the leak

 

Either your oil pressure sensor or the rear cover are leaking. If it were the rear main seal it would be all over the place. If you replace the rear cover, a new main seal is part of it. Sine the trans is out, it would be very easy to replace either or both, and not very expensive even for both.

 

Hey @G Atsma, thanks for your reply. This truck already had those parts replaced a year ago, the rear main seal looks dry (thank God). My main suspect is the VLOM gasket (GM part # 89017690), I've personally checked: the rear main seal, oil pressure sensor and valve cover gaskets, all dry. Apart from the pressure sensor my engine does not have any more sensors with oil circulating at the top, of that I am sure.
The VLOM gasket was the only one that I didn't change last year because I didn't know that it was sold individually. A year ago the leak did not exist and buying the entire VLOM cover ($380+ with shipping and taxes to Colombia ) seemed excessive to me in a preventive maintenance. If the leak is not from this gasket, it would be something more serious such as a cracked block. Tomorrow with more light, brake cleaner, and the flexible camera I will examine the problem carefully.

PD: Sorry for my funny english but isn't my native language.

 

Your English is better than some who live here, but forgot how to use punctuation or complete sentences. Kind of like they skipped everything after 5th grade.... lol

 

Post updated with photo and videos.

 

Have you by chance replaced the head gaskets or had the heads off for any reason? It almost looks like it's leaking out of a bolt hole for #8 cylinder. If that's the case, it is possible there was some residual water in that bolt hole, and the hole cracked from hydraulic pressure during head bolt tightening.

 

Hello @Darth V8r, I have never replaced head gaskets on this truck, but cylinder 8 looks dry. There is oil on the opposite side close to cylinders 5-7, but I think it's coming from the top as well.

The parts arrive next week, once the last oil leak is fixed, I am going to assemble/install the transmission. Starting the truck without the transmission was the best thing I could have done to chase leaks. I don't want to find a drop of oil under the car after the transmission is installed, I'm not ready for that nightmare