Interesting thought on oil leaks

[Dojo2000]

<blockquote>quote:</font><hr> Copied from http://home.nycap.rr.com/gbeard1/fourth-genFAQ/4_2u.htmQ: Why has oil coated the underside of my engine and transmission?

A: It's most likely that the seal around your intake manifold is leaking. While it was originally thought to be the intake manifold gasket itself leaking, it's now found to be the sealant being used. The reason is a gasket is only applied to the left and right sides of the manifold while the front and back are sealed with RTV sealant. If the sealant is applied to a surface which isn't clean, the oil will be able seep through. This is why the oil leak is usually found at the rear of the engine (dripping down onto the transmission). It can be easily mistaken for a rear main seal leak. And since the RTV sealant is used on the front of the intake manifold, it's not uncommon to find it leaking there, too. A classic symptom of this intake leak is a rough cold idle. There is a Technical Service Bulletin (#476111) which calls for the replacement of intake gasket with a new and improved one, but that's to deal with a problem of the actual gasket (used on the left and right sides of the intake) laminate burning and causing a foul odor to enter the car through the ventilation system. If you have a 1994 F-Body, you might be able to get your oil leak fixed using this TSB (even though it's for a separate, but closely related problem). Otherwise, you'll have to have the dealer verify the leak which will likely be running black-light dye through the engine. The revised gasket kit is part # 12524653.

Other, less common areas to check for leaks include the oil pan gasket, the oil dipstick tube seal (where it enters into the oil pan), and the timing chain cover seal.<hr></blockquote>

I've got oil coating my oil pan and tranny too. I initially thought it was the rear main seal, but could this be the cause?

[Backfire]

I had those symptoms with my leak. I don't know which engine that post refers to, but on my 94 3.4L the gasket setup is just as described. Two separate pieces between head and intake, with RTV front and back between the block and intake. After I tore everything apart, I cleaned up all surfaces well with acetone. End result is a leak that is no where near as bad but still present :( .

But my symptoms were just as described. Oil running down the pan and on trans. If you investigate a little, you should be able to tell. Clean up the underside real well, and then drive the car for a bit. After, check to see if you can follow the oil back to the source. On mine, the oil was coming down the side of the block, and then running down the converter shield. Plus I could feel it behind the motor if I reached around the back of the intake. It is kind of a pain because you realy can't see anything on the back of the motor, just by feel.

[97firebird]

Yeah, I just had those fixed over the last 2 days. Intake manifold gasket & oil pan gasket. $780!!! [img]graemlins/crybaby.gif[/img]

Apparently, the oil pans are hard to get to with our cars because you have to remove the front crossmember from underneath the engine. And the intake manifold, of course, sits halfway under the cowl. Maybe I shoulda just sucked it up and done it myself, but I guess it's too late ...

[93v6firebird]

well, I have this leak too and Im fairly certain its hte rear main seal... b/c it was there before I took my lower intake off, there was no oil around on the surfaces that meet for the lower intake and the block, AND its still there now and I tightened that lower intake down real good and put on plenty of that sealant...
edit: also the leak is painfully slow, lost a 1/4 of a quart in like 4-5 weeks

[ August 10, 2002: Message edited by: 93v6firebird ]</p>

[TheBlackSwordsMan]

Mine is leaking in a similar place too but you can see oil coming down close to where the oil drain plug is and there is oil all over the torque arm...

Real small leak, about a drop a day I suppose.

[ May 20, 2003: Message edited by: TheBlackSwordsMan ]</p>

[Wicked 3800 V6]

I can almost guarantee you that those TSBs were for LT1s -- they had some serious intake manifold leaks.
And we 3.8's have, hands down, some serious rear main seal leaks.
-Rob

[MustangEater8251]

<blockquote>quote:</font><hr>Originally posted by Wicked 3800 V6:
I can almost guarantee you that those TSBs were for LT1s -- they had some serious intake manifold leaks.
And we 3.8's have, hands down, some serious rear main seal leaks.
-Rob<hr></blockquote>

Yeah the lt1 has lots of intake manifold leaks.


As for oil leaks, I had a valve cover, fixed that easily. You guys also may want to consider changing the drain plug, it was causing me some leaks, I changed it and stopped instantly the little seal on the plug wore out on my stocker, it was a less then $8 part if I rember right form autozone.

[gregmondro]

are you guys sure that this is only for LT1s?

I had my rear main seal fixed when I had my transmission overhauled, and they also replaced the oil pan with a brand new one.

Last time I changed my oil, there was oil under the pan when I had my rear main seal leak, but i'm almost positive that it isn't the rear main seal (since it was fixed not too long ago - 6k miles ago).

[mjparme]

This is a timely topic for me because I just got my car back from the dealer where they replaced my oil pan gasket. I bought the car last October with 33K on it and this is the first problem I have had (just rolled 40K). It appeared to be either coming from the oil drain plug or the oi pan gasket. With some dye the dealership service department determined it was the gasket.

When I bought the car (GM certified used vehichle) I got the $2,300 3 year/36 month extended warranty (bank wouldn't give me financing without it) so the repair was covered. However, if I didn't have the warranty the repair would have cost me $393!!! The parts totaled $55...what the hell were they charging for labor!?!?

Of course if I didn't have the warranty I would have done it myself (or at least attempted to). But still $393 to replace a $11 part seems like highway robbery. (The gasket was $11, the $55 came from other parts associated with the repair. If I was the one paying for it I would have questioned them).

[Dojo2000]

<blockquote>quote:</font><hr>Originally posted by mjparme:
This is a timely topic for me because I just got my car back from the dealer where they replaced my oil pan gasket. I bought the car last October with 33K on it and this is the first problem I have had (just rolled 40K). It appeared to be either coming from the oil drain plug or the oi pan gasket. With some dye the dealership service department determined it was the gasket.

When I bought the car (GM certified used vehichle) I got the $2,300 3 year/36 month extended warranty (bank wouldn't give me financing without it) so the repair was covered. However, if I didn't have the warranty the repair would have cost me $393!!! The parts totaled $55...what the hell were they charging for labor!?!?

Of course if I didn't have the warranty I would have done it myself (or at least attempted to). But still $393 to replace a $11 part seems like highway robbery. (The gasket was $11, the $55 came from other parts associated with the repair. If I was the one paying for it I would have questioned them).<hr></blockquote>

If I'm not mistaken the engine needs to be pulled (at least partially lifted) and/or the k-member needs to be dropped to be able to take the oil pan off, so it doesn't sound like an easy task to me.

[gregmondro]

<blockquote>quote:</font><hr>Originally posted by Dojo2000:


If I'm not mistaken the engine needs to be pulled (at least partially lifted) and/or the k-member needs to be dropped to be able to take the oil pan off, so it doesn't sound like an easy task to me.<hr></blockquote>


yeah, it's not that easy to get to. the only reason I had my rear main seal replaced was because I was getting my transmission redone, so there was no point not to get everything done all at once.

[Dojo2000]

<blockquote>quote:</font><hr>Originally posted by gregmondro:



yeah, it's not that easy to get to. the only reason I had my rear main seal replaced was because I was getting my transmission redone, so there was no point not to get everything done all at once.<hr></blockquote>

Yep, I had them replace my leaking rear main seal when I had clutch replaced on my old transmission. It's only like a $10 part and since they had the tranny off anyways they didn't charge me extra labor.

[NSolano]

Had this fixed for $650 here in Chantilly, VA. Oil gasket and trany gasket replaced. New oil pressure sensor, and new sealant for the oil pan and tranny pan. I have checked underneath the car every week after that and I have found a little bit of tranny fluid there, but nothing serioius, the mechanic said that it should be fine unless the rear main seal is leaking, but I dont feel like thats an issue since my car has a smooth idle and everything seems fine.
go get it fixed by a private mechanic, dont let th dealership rip you off.