[DeTomaso] oil leak questions

Christopher Kimball chrisvkimball at msn.com
Sun May 2 18:28:00 EDT 2010


FYI: 

I did some investigation earlier today, and here is what I found:

1) the hose going to the valve cover has a lot of suction, so that probably isn't the problem.

2) while idling, I took the engine up to 4000 RPMs and notice the mechanical oil pressure gauge I installed was registering 85 pounds, dipping back to 80 when I increased the RPMs beyond 4K.  People tell me on a new engine that's OK, but it sure seems high.

3) After 10 to 15 minutes of running the engine between 2000 and 4000 RPMs, I took a look under the car and oil appeared to be beginning to seep from not just the drivers' side corner of the pan where the gasket appears torn, but along most of the driver's side edge of the oil pan.  There were no drips anywhere because I hadn't run the car for very long, but the seepage was definitely visible.

4) by the way, that's the side of the oil pan on which there is a bend in the outer edge flange on the pan itself where, clearly, the engine was dropped or lowered on something which connected with the edge of the oil pan, bending the flange (and probably warping it sufficiently to cause the pan not to seat correctly).

5) but here's the interesting part:  in the light of day, and with the help of a flashlight, I was able to see that the edge that's seeping was sealed using not only the cork gasket, but also gray silicone rubber of some kind.  This leads me to believe that perhaps the mechanic damaged the oil pan, and then tried to cover his tracks by removing it, squirting a bunch of silicone where he had caused the problem, and then hoping it would hold until the car and I got home.  On the other hand, maybe that's just how oil pans are normally installed.

I can't remove the oil pan at the moment, I can only lower it until it hits the frame.  I'm not a mechanic, either, so doing anything myself with the rear main seal is out of the question until my Pantera fund has increased.  The rear main seal isn't leaking much, so I don't feel any real rush to dive into that, but I would like to try and get the oil pan leak resolved.  My fear is that the reason the oil is leaking through the existing gray silicone is that the pan is damaged more than just a silicone injection can fix (I've seen some women that fit that description...!)  Therefore, I might go to the trouble of lowering the pan, cleaning the surface as much as I can, re-sealing it with RTV, only to have the same problem happen again.

Ah, the joys of owning a classic Italian sports car...  (although, come to think of it, it's the American part that's being the problem!)

Thanks for your continued help and advice.  I hope to see many of you in Reno.

Sincerely,

Chris
#3846






Chris, if the engine is pretty new, the pan gaskets shouldn't 
have bonded to the engine yet. FWIW, I always oil one side of the pan 
gaskets and contact-cement the other (your choice of surfaces). After 
2-3 years, I can still drop the pan without tearing a gasket and no 
leaks. And as JT said, mis-idexing the neoprene seal ends fixes most 
rear main seal leaks. 

Complications arise if -A- the rear main is still running a rope seal- 
used by OEMs up to the mid-'70s and sold by some auto parts stores even 
today, and -B- if the seal surface on the crank is damaged or machined 
wrong. This last is seen on some cheaper stroker cranks but not OEM. 
FWIW, the upcoming June POCA newsletter issue has a two-part main oil 
seal article series- front & rear, with photos of what's involved. 
Cheers- J DeRyke 		 	   		  


More information about the DeTomaso mailing list