What Material Should I Use for the Oil Pump Gasket? - JeepForum.com

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post #1 of 6 Old 11-30-2009, 05:11 PM Thread Starter
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What Material Should I Use for the Oil Pump Gasket?

So, I posted here a little while ago about my oil pressure taking a couple seconds to move from zero whenever I started my Jeep cold. I was told that this was normal, and not to worry about it.
I haven't been worrying until today, when it occurred to me that when I had my oil pump out a few weeks ago, I may have compromised the seal on the gasket where the pump meets the block. This thought was corroborated when I started my Jeep and listened. I heard a hissing (sucking?) noise for a second or so, and then it stopped right as the oil pressure gauge moved up.
So, I think that the failing gasket is allowing air in, and the oil is draining back down the pickup tube when the Jeep sits for a long time.

Anyway, I'm planning on dropping the pan again and replacing the gasket.

So two questions: First off, does my analysis of the noise sound correct?
And more importantly: What is the best material to use for a gasket? Will grey RTV work, or should I use that paper-type gasket material maybe? I would just buy the gasket if I could, but it seems it's not available unless I buy an entire rebuild kit for $30.


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post #2 of 6 Old 11-30-2009, 05:35 PM
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The oil will always run back down the pickup tube when you turn the engine off, there's no check valve on the pump suction.
I would use a thin paper gasket, as opposed to RTV.
I don't know about the hissing (if no gasket, it may be caused by pressure, not suction since those mating surfaces are on the pump's discharge), but I do know the oil pressure gauge takes a second to come up on any vehicle I've ever owned.

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post #3 of 6 Old 11-30-2009, 05:56 PM
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hissing you've definitely isolated to the oil pan? because the tb hisses for a second or two at start up before the iac gets to the proper position.

my oil pump doesn't have a gasket and they have a drain back valve in the block, not the pump.

'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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post #4 of 6 Old 11-30-2009, 08:09 PM Thread Starter
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I have not, in fact, isolated the hissing to the oil pan. I just made an assumption based on the fact that the hissing seemed to cease at the exact same time that the gauge started moving.

So, the gasket on the oil pump isn't really an important sealing point? I notice you have the 318, is there a difference between the pump setup on that and the 4.0?

Oh, and TB is for Throttle Body, right? I The 4.0 has direct injection, would there be some other apparatus that would hiss for a second or two at startup?
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post #5 of 6 Old 11-30-2009, 08:42 PM
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The IAC makes a hissing noise upon start up. There's no gasket between the block and the oil pump. It's not a crucial sealing point, so the two machined surfaces do just fine. Some high performance engines with high volume/pressure pumps use a copper gasket, but that's it. You wouldn't want a regular gasket there because if it were to blow out, you would be left with a gap for oil to escape.

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post #6 of 6 Old 11-30-2009, 09:05 PM Thread Starter
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Mine has a gasket, looks like the usual paper stuff. So I thought perhaps for some reason a good seal was necessary at that point. But I won't worry about it if it's non-crucial, it's starting to get cold around here! Not a good time to rip into my engine if it's not necessary.

Thanks once again for the help, gentlemen!

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