I have a mysterious oil leak. no leaking from any seals, engine and undercarriage is dry. Radiator coolant is clean(also loosing coolant, Thermostat bolt hole maybe) no blue smoke out tailpipe.( I don't have cats).

I have AC delco pcv valve in drive side valve cover going into manifold. I also have a rubber hose going from passenger side valve cover to Throttle body. Is it possible that oil is getting sucked into TB and that is where my loss is coming from?

I have a 1991 GTA. 350 TPI

My coolant is clean and I am also losing it. I had to make bolt in thermostat larger due to breaking a bolt in there wondering if that is loss.

Idle drops from 650 to 550 occasionally followed by black smoke but aside from that car runs great.

any Ideas?

 

Do your header tubes, or Ypipe look white? If so you could have a bad head gasket. (maybe)

Has the motor ever bin overheated?

Coolant: may be that bad bolt hole.
Oil: may be a bad intake gasket.

 

I have oil loss through my pvc but I am not sure how to stop it. My routing is the same as yours

 

do you have oil walking up the dipstick ? How is the oil preasure?

 

joejoe

Headers are not white

Never overheated. never been past the 210 mark. (195 thermostat)


D's89IROCZ

After changing oil pressure is good going from 30 - 50 area, slowly but evenly goes down as I lose oil. That's how I found out.

By walking up the dipstick I assume you mean oil staying on the dipstick while off. I will check that and get back to you.

Thank you

 

my 305 ( when it had bearing issues) would have oil comeing right up the dipstick . It would even push it out a bit( too much preasure)

 

Loosing oil and coolant on a 350 TPI, i'd take a good close look at the intake manifold gasket. These cars were NOTORIOUS for leaks there. And since the engine is at a slight angle it runs down off the back of the engine. It can even appear to be an oil filter leak if it's leaking enough and gets down far enough.