Oil pan gasket and pickup tube seal replacement

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Matthew Jeschke

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Replace the Pan Gasket and then see if you still have a leak. RTV is not going to stop a Rear Main Oil Leak.

It was a stupid question for me to ask. I am pretty sure was just the pan now. Looks clean above the pan in the bell housing.

I am curious though some people are using RTV to install the pan gasket. Why do they do that? It has a rubber lip. What is correct?

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Matahoe

Matahoe

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I am curious though some people are using RTV to install the pan gasket. Why do they do that? It has a rubber lip. What is correct?

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Well if you go by the service manual (I use Alldatadiy.com) it tells you to apply a specific sealant at each of the 4 corners where there is a gap from where the front and rear main covers interface with the block. It's a safe bet to follow the service manual for this step. Especially if you see the gaps they are referring to.


From the service manual:

  1. Apply a 5 mm (0.20 inch) bead of sealant GM P/N 12378190, or equivalent 20 mm (0.80 inch) long to the engine block. Apply the sealant directly onto the tabs of the front cover gasket that protrudes into the oil pan surface.

  1. Apply a 5 mm (0.20 inch) bead of sealant GM P/N 12378190, or equivalent 20 mm (0.8 inch) long to the engine block. Apply the sealant directly onto the tabs of the rear cover gasket that protrudes into the oil pan surface.

Here is the equivalent Permatex sealant according to the cross-reference sheet below. Not sure exactly what it is ...but it seems to be more like pipe thread sealant...the stuff you find on sensor threads and such. A bit like pipe dope and a bit like lock-tite. Not sure why they call for this. I used Permatex ultra black RTV gasket maker. It is oil and fuel resistant. Take your pick....but I would use something.


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Matthew Jeschke

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Ah yes i was woundering about that cover. There is a seam there. I think somebody did this job once before on this truck and efd that up. I think this is why it was leaking. They applied rtv all along the back side.

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Matthew Jeschke

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Curious, another guy on youtube is applying a dab of sealant to these waffle shaped corner peices on the gasket then putting it in...cff11ab263b11341beaa43bd9c69d703.jpg5ac9e42300fed271f680961fce306923.jpg

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Matahoe

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All along the back side? Wow. Definitely not reading instructions or trusting the oil pan gasket to do it's job. Again, all we are doing here is just filling in those small gaps caused by the front and rear covers. Once you see the areas on the block corner you will understand.
 
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Matahoe

Matahoe

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Curious, another guy on youtube is applying a dab of sealant to these waffle shaped corner peices on the gasket then putting it in...

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I saw that waffle shape area on my gasket as well. I don't know for sure if those are the areas that match the block. I did apply the RTV on those waffle areas but I may have been mistaken. The instructions do say..."apply directly to the block".
 

Matthew Jeschke

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I saw that waffle shape area on my gasket as well and if i remember correctly I did apply the RTV on those areas. The instructions however do so..."apply directly to the block".
Awesome, yeah that makes since. I imagine that seam would leak. My lt1 I last did this on didnt have the seam like the 5.3L. Not sure why the waffles but appears as though gasket ia designed so.

I have the same black rtv you said you uses. I have always used that. Not sure why gm calla for something different.

Makes me a bit nervous but honestly i am just going to use thr black rtv designed for oil like you used. I think it should work good.

How many miles have you put on your new seal?

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Matahoe

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How many miles have you put on your new seal?

Less than 1000 miles. The Tahoe is our tow vehicle during the summer so it sees little winter use. I noticed on my driveway that I have a small leak..post seal replacement. I messed something up but it isn't a huge leak. Working on that come spring. Too cold right now to want to fix it right. We (Michigan) will be seeing upper 30's in a couple days. I'll run the torpedo heater in my garage, get up under there and take a look. Interesting arctic sub-zero weather we are having at the moment. :)
 

Matthew Jeschke

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Less than 1000 miles. The Tahoe is our tow vehicle during the summer so it sees little winter use. I noticed on my driveway that I have a small leak..post seal replacement. I messed something up but it isn't a huge leak. Working on that come spring. Too cold right now to want to fix it right. We (Michigan) will be seeing upper 30's in a couple days. I'll run the torpedo heater in my garage, get up under there and take a look. Interesting arctic sub-zero weather we are having at the moment. :)
I used to live up in MN. Now am in AZ lol thanks for the help. What do you think you messed up?

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Matahoe

Matahoe

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What do you think you messed up?

It has to be either the oil pan level sensor, crank position sensor, block off plate gasket or ....it could be those waffle areas in question.

I put RTV on them as you know...but they could be way off the mark. Shame on me for not following direction? We will see. I did "eyeball it" Famous last words...right? :(
 

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