Did an OEM rebuild. Machine shop decked the block, milled the head, and installed a new Cometic head gasket.

First startup the car was smoking white and spewing coolant out the exhaust.

I pulled the exhaust manifold and saw pools of coolant on the exhaust port of all 4 cylinders, which makes me think the leak is on the intake.

I pulled the throttle body and saw that the inside of the intake manifold was coated with coolant.

My first though was the IAC valve leaking into the intake, but I filled the IACV with pressurized water and worked the flap back and forth. No water seepage into the throttle chamber.

Then I thought I had mixed up a coolant line and a vacuum line and feeding coolant directly into the intake, but I checked all the lines. The only vacuum lines are PCV valve, brake booster, EVAP, and cruise control.

I don't see any coolant line going directly to the intake manifold.

The intake manifold gasket is brand new and I don't see any coolant seepage on them. I assume it's air tight.

I'm stumped. If anyone has any suggestion please let me know.

I think the coolant is getting into the intake somehow since coolant is coming out of all 4 cylinders?

I'm going to do a leakdown test tomorrow but I doubt it will tell me much since coolant is getting into all 4 cylinders and the intake manifold itself.

 

did u run a bead of rtv around the coolant passage running through the manifold and block? it must be leaking rite there.

 

No, I did not. Am I supposed to? I didn't see any mention of RTV on the intake gasket in the FSM.

I used a Fel-Pro intake gasket from Advance Auto Parts.

That passage seeping through the intake gasket would put coolant in all 4 cylinders?

 

there is not really any other way for coolant to get in but from the tb where the iacv is. u can bypass them and loop the hoses or find a tube to clamp the hoses together and try that to see if it goes away. coolant should not have any way of seeping into the tb though. it isn't recommended to put it there but it is safe measure just like old chevy intake manifold gaskets used to leak its just a peace of mind and extra assurance.

 

Thanks for the tip.

I can't think of any other way unless the shop completely botched the head gasket installation.