Pan Gasket Leak

[535678]

I've checked numerous times since installing a brand new cork gasket on an ATF pan to ensure it wasn't leaking. Three out of four times I check it is bone dry under there. The only time a leak begins to form is in the hours AFTER bringing the car home hot -- after driving an hour or more. In other words, you won't see any leak when you arrive home after a long drive. You have to let it sit in the driveway three or four hours for the leak to develop.

The leak is consistently very small. One drop every time and it never falls to the driveway. Wipe it off and as long as the engine stays cool or warm, the leak won't come back.

I'm going to torque the bolts down a little tighter. Is this type of leak normal with a cork gasket, especially a very fresh one?

 

[Chris142]

Should not leak. Did you straighten the pan out where the bolt holes are?

 

[Azeem]

No,it's not normal to leak period.

Some aftermarket Transmission pan gaskets which come as ATF kit with the filter are flimsy and better off re-use the OE if it's not torn up.

 

[535678]

The gasket was OEM from the dealer. I tightened the 18 bolts starting in the middle and working outward in a clockwise pattern toward the edges.

It's possible I didn't torque the back end bolts enough, but even so, I don't understand how it leaks only part time the way it does. Why wouldn't it seep out while the car is being driven and the ATF fluid is just as hot or hotter?

 

[Trav]

Gasket compression. Cork gaskets sometimes need a few tightenings before they hold torque.
Be careful with cork gaskets they like to spread out. I use a very small 1/4" ratchet holding it in the palm and just snug them with turning force.

Warm it up and go over it a couple of times, it may take a while for the gasket to "set".
A torque wrench is basically useless on these kind of gaskets.

 

[SteveSRT8]

Where did you find a cork gasket? I have a hard time believing those are still out there!

Normally you reuse the factory gasket, it is generally superior.

As Trav said, it's a "feel" thing. You over tighten and they leak, same if under-tightened...

 

[punisher]

Chris142 brought up a really good point: Make sure the pan is straight. They usually bend around the bolt holes and you don't get proper compression on the gasket. By the time you tighten the bolts enough to stop a leak, the gasket has start to split.

 

[mechanicx]

Not sure what application it is, but is there a chance it has a pan bolt hole that is through and not blind that's requires thread sealer on the bolt?

 

[SteveSRT8]

Originally Posted By: punisher
Chris142 brought up a really good point: Make sure the pan is straight. They usually bend around the bolt holes and you don't get proper compression on the gasket. By the time you tighten the bolts enough to stop a leak, the gasket has start to split.


Good point. Many times a cheap stamped pan is already bent when you took it off!

 

[demarpaint]

Originally Posted By: SteveSRT8
Originally Posted By: punisher
Chris142 brought up a really good point: Make sure the pan is straight. They usually bend around the bolt holes and you don't get proper compression on the gasket. By the time you tighten the bolts enough to stop a leak, the gasket has start to split.


Good point. Many times a cheap stamped pan is already bent when you took it off!


+1 Or gets bent in the process of taking it off.

 

[Doog]

I always use a really thin coat of RTV on both metal edges and on the bolt threads when doing any oil pan gaskets. Never any leaks.

 

[bdcardinal]

Originally Posted By: SteveSRT8
Where did you find a cork gasket? I have a hard time believing those are still out there!

Normally you reuse the factory gasket, it is generally superior.

As Trav said, it's a "feel" thing. You over tighten and they leak, same if under-tightened...


Some OE gaskets are cork. Although a lot of times the same trans used cork fro a certain number of years, and then there was a running change to elastomeric. For some Ford transmissions this is true and both the cork and elastomeric gaskets are still good numbers.

 

[SteveSRT8]

Originally Posted By: Doog
I always use a really thin coat of RTV on both metal edges and on the bolt threads when doing any oil pan gaskets. Never any leaks.


OK, great for you.

I never use ANYTHING on mine and they don't leak either...

 

[bdcardinal]

Originally Posted By: SteveSRT8
Originally Posted By: Doog
I always use a really thin coat of RTV on both metal edges and on the bolt threads when doing any oil pan gaskets. Never any leaks.


OK, great for you.

I never use ANYTHING on mine and they don't leak either...


+1, always install gaskets dry unless the FSM states otherwise.

 

[mechanicx]

Originally Posted By: bdcardinal
Originally Posted By: SteveSRT8
Originally Posted By: Doog
I always use a really thin coat of RTV on both metal edges and on the bolt threads when doing any oil pan gaskets. Never any leaks.


OK, great for you.

I never use ANYTHING on mine and they don't leak either...


+1, always install gaskets dry unless the FSM states otherwise.


+2. You might get away with using RTV or gasket sealer on a cork or paper gasket, but I wouldn't do it. But sometimes there are one or two bolt holes that call for sealer or RTV on the bolt threads.

I think the cork gasket are usually cork/rubber, but I prefer rubber gasket or even paper.

 

[535678]

Today my routine was similar to yesterday. Drove the car for two hours straight, got back at 2:30pm.

By dinnertime it had cooled down, and there was only trace amounts of ATF but not enough to form a drip. I just tightened the bolts so we'll see what happens tomorrow.

 

[535678]

Okay, so I originally thought the pan gasket was leaking. I did tighten it down a month ago and while the ATF drops seem to be fewer, that may be explained by something else based on where the leak is appearing. I don't see how ATF could flow out of the pan and pool in that spot without more spatter.

What you see pictured is the extent of the leak after three weeks without wiping it off. No drips on the driveway either. This is a very, very slow leak and as I explained before, it starts leaking AFTER bringing it home hot and allowing it to sit for a few hours.

We've never touched that bolt before. Outside of a couple oil changes, it's never been to an auto mechanic since it was built. I've done all the other maintenance myself. Why the edges of the bolt are slightly deformed is a mystery.

After taking these photos I did attempt to tighten it. Couldn't find the torque spec in the service manual so by hand I did 1/32 to 1/16 of a turn. I'm afraid to go any tighter.

 

[yonyon]

That orange sealer is from the factory??? I would be tempted to get an aluminum or copper gasket to stick under the head of that bolt.

 

[535678]

Originally Posted By: yonyon
That orange sealer is from the factory??? I would be tempted to get an aluminum or copper gasket to stick under the head of that bolt.


Yes, orange sealer from the factory.

Around the bolt there seems to be less. I wonder if they failed to evenly apply it?

 

[GSCJR]

Is it me? Or does that washer built-in to that bolt head look deformed.