Another white smoke question.

[Adam N.D.J.]

Mine is a little different though. Kinda interesting that other people have the same problem as me though. Ok, here's the details:

 

1989 GL SPFI, first thought it was a head gasket. Checked the coolant with a block tester, no combustion gasses in the coolant. Compression test turned up #1 170 #2 160 #3 145 #4 155. Leak down turned up nothing. Did a pressure test on the cooling system, found it leaked down 13psi in about 30 seconds. At this point I'm thinking it's the intake gaskets. Put a set of gaskets in it, (found the old ones were rock hard, some evidence of leaking). Filled the cooling system, and started it up. It's still puking out coolant through the exhaust, and still looses pressure pretty fast with the tester on it.

 

So here is where the big question comes in, do the SPFI heads suffer from "THE CRACKS" like the turbo heads are so notorious for? Cause I'm starting to think that that may be the problem with this one. Thanks for the help.

[Subarian]

The SPFI heads have single ports, not the twin ports of the MPFI turbo heads. That doesn't mean that they can't crack, but they're not any more likely to crack than carbed motors.

 

You might be able to pull the spark plugs and look for coolant in the cylinders while you're doing your pressure test. That would give you an idea if it's maybe a head gasket.

[Adam N.D.J.]

Ya, had the spark plugs out during the coolant pressure test. Before I changed the intake gaskets there was steam coming out #3 (which was on the intake stroke at the time, hence my conclusion for that fix). But now, after the gasket change, I don't get any steam from any of the cylinders.

I'm thinking that my conclusion of the cracks is a little more the way to go now. I started up the motor, then opened the radiator cap, and put my hand over the exhaust pipe, pressurizing the exhaust, and coolant started puking out of the radiator. Guess I'll just have to pull the heads. Tomarrow. Time to go home now.