C1 front oil pan LEAKING!

[Larry P.]

I pulled the pan and replaced the gaskets and rubber seals. It still leaks between the oil pan and timing cover. What did I do wrong? I started it about 4 hours after I replaced the pan. Does the sealer need more time to set up?
Frustrated!
LP

[Greg S.]

Re: C1 front oil pan LEAKING!

Possibly you used the wrong front gasket. Newer replacement pans use a slightly larger radius at the front. Been there done that.

[Mike M.]

Re: C1 front oil pan LEAKING!

most service replacement or generic pan gastket sets come with both the early and later front and real pan seals and most sets include an illustration on how to determine which pair of seals is appropriate for the pan being used. simply straight edge the pan at its front and rear concavities and measure the distance from the bottom of the straight edge to the lowermost portion of the pan. then read the enclosed illustration and pick the appropriate seals. good luck, mike

[John O.]

Re: C1 front oil pan LEAKING!

Hi Larry
The gasket cement does not need time to set up.
Are you sure it's the oil pan. I had the same problem on my 1956 chevy. I replaced the gaskets and still had leaks up front. After some close observasion.It turned out to be the seal in the timing chain cover where the harmonic balancer goes through.When rust or what ever gets on the balancer and the engine is running, it wears the rubber seal out fast. I changed the seal and cleaned the balancer real good. No more leaks. Try to check for oil coming from the seal if you can. Oil has a way of looking like it's leaking from the wrong place the way it splash's around.If thats not the problem, try adding some gasket cement at the corners of the pan and where it contacts the timing cover.Another thing I did was, I purchased a one piece gasket for the oil pan.It has steel grommets at each hole so you can't over tighten. And it's reusable.It works great.

Good Luck.....John

[Joe L.]

Re: C1 front oil pan LEAKING!

Larry-----

Set the pan upside down on a flat surface. Measure the distance from the center of the front pan seal radius to the flat surface. If the dimension is 2-1/4", then you have the original style pan. This pan requires a 0.22" thick fron seal (GM #3887151). If the measurement is 2-3/8", then you have the later replacement style pan which requires a 0.41" thick seal (GM #12337940).

The GM gasket SET for the original style pan is GM #14079400. The replacement style pan requires gasket SET GM #14079399. I don't really recommend either of these, though. I recommend the Fel-Pro 1 piece gasket. For the original pan, this is Fel-Pro #OS-34509T. For the replacement pan, it's #OS-34510T.

As has been mentioned, the problem could also be the front crank oil seal OR the harmonic balancer seal surface. If the harmonic balancer seal surface is worn (i.e. grooved as a result of long service in contact with the seal), it absolutely WILL leak. To correct this, you must do one of 3 things:

1) Install a new balancer and seal, or

2) Install a repair sleeve on your old balancer snout and install a new seal, or;

3) Install a special new seal which has a displaced seal surface. This places the seal against a "new" and "fresh" surface of the balancer snout.

If your balancer surface is ok and the leak is coming from the front seal instead of the pan seal, then you have one of 4 problems:

1) A worn front seal, or;

2) A seal incorrectly installed or installed without sealer in the cover-to-seal interface (most new seals don't require the application of sealer, though, since the sealer is pre-applied which you can tell if the perimeter of the steel seal shell is "painted" green or red), or;

3) You've used an incorrect seal. The correct one is GM #10243247 or equivalent, or;

4) Your front cover is distorted from improper seal installation. If the front cover is distorted enough in the seal cavity area, it may be "irreversible" and "terminal".

[Larry P.]

Re: C1 front oil pan LEAKING!

It is definately coming from between the bottom of the timing cover and pan.
It only leaks when running. It ran for 200 miles without leaking. It started after I jacked the engine to fix the water pump. I used a board under the pan to spread the weight, but must have stressed something. It ran with no leaks for about one hour. It's the deep pan and I believe it's original.
It's frustrating after 7 years to have everything else ready and running and driving perfect and I can't fix the leak.
LP