I thought my car was totally f**ked today because upon closer inspection, the steam exiting the exhaust of my newly re-headed car was burning antifreeze...thats not a good thing to have right after a rebuild. It appears that after driving the car 140 miles tonight and stopping it for hours at a time, letting it cool down and heat up 4 or 5 times, that the head gasket seated it self, and no more steam is coming out of the exhaust. That was a terrible couple of hours when I was considering radiator stop leak or pulling the head to figure out what was wrong, but thankfully the car righted itself.

One question...how long do you think I should wait to change the oil? The car was milkshaked before the rebuild, and I never figured out a good way to flush the oil system, so there is probably still residual crap from the old milkshake in the motor (I just added new oil and filter when putting it back together). I used vavoline 10W40 initially, and I have 7 quarts of castrol GTX in my garage, but I forgot which oil was the one with paraffin that isn't good for our motors...are castrol and vavoline both good oils? Thanks.

 

I would change the oil and antifreeze now. You might want to look into the correct procedure to "flush" the cooling and the oil system. If it were my car, I would just replace the coolant, running clean water through the system. Change the oil w/something cheap, run the car for a few minutes, change the oil and filter, and not worry about it. If you had metal particles circulated through the oil, that'd be something different, but in this case I don't suspect it being a problem.
Ahmet

 

To flush the cooling system is easy. Get some Tide (yes the laundry detergent) and mix it with distilled water. Fill the system, run it until nice and hot, let it cool and drain. Rinse and repeat until it comes out nice and white (clear). Flush it a few more times with distilled water only until that comes out clean, then fill with your choice of antifreeze/distilled water 50/50 combination.

As for the oil, change it a few times quickly (500 miles, 500 miles) then don't worry about it. Use normal dino oil for the quick changes. Remember, water will boil out of the oil when it gets hot. Oil gets above 100C (boiling point of water) on a regular basis.

Dal.

 

ribs,

Good to hear you got the beast up and running again.

 

yeah I wouuld do it within 500miles of the rebuild.

 

You'll still be cleaning (probably by removing) the resevoir several times to get rid of the mousse. Took me once a month for 3 or 4 months to get it all. The oil will eventually migrate to the resevoir. Put the tide / very hot water mix in the resevoir in the garage sink and let it sit. Then flush again for a while, and it will flow out.

The oil in the coolant finds lots of hiding places in the water passages, and takes a while to all flush out.

 

I just finished up the same job on a friends car this weekend. It smoked pretty bad for at least an hour but got better with every warm-up/cool down cycle. He estimated that 2 gallons of coolant worked its way through the motor and into the exhaust system before we tore it down (very little in the oil). The 951 exhaust has a lot of low spots before the cat to store coolant so it takes a while to burn out. I can see how it can give you a good scare if you don't expect it.

 

That makes a lot more sense than the head gasket seating itself. It still smelled like coolant (maple syrup) out of the exhaust this morning, but with no smoke. This afternoon, I took a whiff, and all I smelled was unburned hydrocarbons, so I think it got all of the coolant out.

I flushed out the radiator when I had the head off, and I cleaned the f out of the motor's coolant passages, not to mention there was next to no oil in the coolant, just coolant in the oil. I'm pretty sure the cooling system is fine (the half green goop mixed with water looks like it should) but I'll go ahead and change the oil again this weekend, then change it when I re-tension the timing & bs belts in a few weeks. Thanks guys!