my cat is smoking

[jedicocheese]

After running about 10 mins, smoke starts rolling from under the heat shield on top of the cat converter. I have a new exhaust from the cat back and no smoke comes out the tail pipe.
Yesterday i removed the new exhaust and the cat didn't smoke at all. i thought that if if was clogged, it would smoke either way?
Any ideas what might be causing this?
It will start to smoke if it runs at idle for about 7 mins or if i drive it down my driveway and back.
I thought it might be an oil leak because there was some oil on the heat shield, but that has since burned off and now it appears the smoke is coming from under the heat shield.
would the muffler cause enough back pressure to make something in the cat smoke?
thanks
J

[mutant]

You didn't say what year SVO you have.
If it's an '86 the gearbox rear seal can leak and drip onto the cat.

[jedicocheese]

yeah, it's an 86. i thought that too, but the smoke seems to be coming from under the heat shield on top? also, why would it not smoke with the exhaust off from the cat back?
this is giving me such a headache. I've had the car almost a year now and haven't driven it once and i SO want to drive it and let the turbo kick in....

Thanks
j

[Rob Hughes]

Does it look like this?