03 Tahoe oil leak

Bigtrite · Oct 3, 2024

I’m chasing an oil leak on my Tahoe. It drips about 2-4 drops every night. I thought it was the oil cooler block off plate but now I notice it on the rear oil pan bolts on both sides. It doesn’t look like it’s the pan, I pulled the inspection plate and it doesn’t look like it’s the real main seal. What do you guys think

justirv · Oct 3, 2024

Bigtrite said:
I’m chasing an oil leak on my Tahoe. It drips about 2-4 drops every night. I thought it was the oil cooler block off plate but now I notice it on the rear oil pan bolts on both sides. It doesn’t look like it’s the pan, I pulled the inspection plate and it doesn’t look like it’s the real main seal. What do you guys think View attachment 439669

That oil cooler block off plate is a horrible design, cheap warped metal that I've replaced gaskets on a few times... a billet replacement works well. Good to hear it doesn't appear to be the rear main seal. How many miles on your trans? If neither of these (apparently), it's possible it could be the valve covers at the rear (both of mine leaked simultaneously). Also the oil pressure sensor is up there. Mine's an '02 Z71 for reference.

OR VietVet · Oct 4, 2024

Oil sender, valve cover gaskets, intake manifold or that crap oil cooler block off that needs a billet plate instead, like @justirv said. You can use an oil leak dye and a blacklight.

Bigtrite · Oct 4, 2024

justirv said:
That oil cooler block off plate is a horrible design, cheap warped metal that I've replaced gaskets on a few times... a billet replacement works well. Good to hear it doesn't appear to be the rear main seal. How many miles on your trans? If neither of these (apparently), it's possible it could be the valve covers at the rear (both of mine leaked simultaneously). Also the oil pressure sensor is up there. Mine's an '02 Z71 for reference.

Mines an 03 z71 with 208k miles. I believe it’s still the original trans and everything. I’ll try using a mirror today and see if I can see the rear of the valve covers and that sensor. I’m also going to try and see further into the hole at the rear main seal. That’s my main concern. Anything else that would be leaking would be a lot cheaper to fix other than the rear main

strutaeng · Oct 4, 2024

Please read through this recent thread: https://www.tahoeyukonforum.com/threads/baffling-oil-leak.150783/#post-1914303

RMS leak is hard to pinpoint. The only side of the flexplate is the part that you can see, stays clean. The backside takes the oil drip and flings it into the bellhousing, but it's hard to see the actual leak source.

The oil dye is going to be your best friend here as @OR VietVet suggested.

Good luck.

justirv · Oct 4, 2024

I agree with @OR VietVet and @strutaeng with their approach. Reason I ask about your trans is the possibility (or probability) of it being near end of "normal" servicible life. If it is the RMS, I'd hate to fix that, then have the trans fail soon after. If it's a minor leak, maybe wait. Just a thought.

03 Tahoe oil leak

Bigtrite

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OR VietVet

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strutaeng

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