Oil leaking from exhuast flange

GoldenMotor.com
Jun 2, 2015
78
0
6
Marlton, New Jersey
I just cleaned out the stock exhaust pipe and replaced the gasket with an aluminum one. I cleaned and sanded the pipe flange and now it's leaking a small amount of oil from the flange. I remember seeing a good post from Tom about this but I couldn't find it when I did a search. Would really appreciate the link or any other ideas about this problem. Thanks,
George
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
George,
The steel flange is usually warped due to the welding process. A metal gasket will work well but the flange and the mating gasket surface on the cylinder must be absolutely flat.

Clean the flange and then use a magic marker or machinist dye and 'paint' it. With a sheet of sandpaper laying on a flat surface, like glass or something as flat, rub the flange over the paper a couple of times and you'll quickly see where the warp is and what needs to be done to sand or grind it flat.

You can check the mating gasket area on the cylinder but as a rule they've been machined pretty good from the factory. It's the exhaust pipe flange that's usually the culprit.

Tom
 

Slogger

Member
Sep 8, 2014
544
4
18
nohio
If all else fails you can use a bit of high temp gasket sealant. I didn't think it would work, thought it would cook out. It didn't. I used Permatex Copper stuff. It's orange.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
make sure the flange is really flat by hammering, then filing - next time use a fiber gasket as the metal ones lose their filling material pretty quickly