radiator cap hissing

[LMP]

..I think you should try to measure the voltage at pin C
www.avigex.ca/xport/tps3.jpg with key ON, you should measure voltage on the "wiper" while somone slowly presses throttle down to floor. YOu should measure a continuously rising voltage from about 0.5 to 4.5 volts. If you have only near 0 and then 5v all of a sudden, this means the resistance track is cut in 2 pieces and then you need a new sensor.

[53bruce]

Just had a Oldsmobile 3.1 that did VERY simular things... start it up, ran very great until it got hot, ( and thats the key thing, it HAS to be HOT)then big burps of bubbles in the overflow tank!
turned out to be a snapped cylinder head bolt between 2 of the front cylinders...
As you mentioned, no antifreeze in the oil, but when the car was parked facing up hill, it seemed as though there was a fair amount of water coming out the exhaust. If you really want to prove it, put in flouresent dye into the antifreeze, then for sure you will see where its going. The cold air you feel in the heater is because once the cylider leaks exhaust gas into the cooling system, the bubbles will give you cold air out the heater.
Sorry. I think that despite what the service station says, its broke in a bad way. if the oil isnt contaminated, it may be worth saving

[timguyli]

Well it seems to be running on coolant wise... I have not tackled the tps problem yet due to the snow, and the fact that since i needed to get back and forth to work i had to put my Geo metro on the road. I have run it for about an hour in my driveway and no bubbles.. no over heating so far.... maybe its fixed?

[timguyli]

ok. Now it seems theres liquid..coolant? dripping down the block near where the block and Tranny meet. Its hard to see where cause the exaust manifold blocks it.

[LMP]

You have had new gaskets installed all around...heads and manifold..so if if leaks significantly and looks as it is coolant, I would consider removing the valve covers and checking the head bolts are properly torqued...there is always an unwanted and unexpected possibility that the gaskets have settled a little and the bolts could reveal as undertorqued now. Alas, this is not very interesting after all of what you have been through.......

[timguyli]

IS IT POSSIBLE THAT ITS FROM THE tHERMOSTAT HOUSING OR MAYBE THE TUBE THAT RUNS AROUND THE FRONT OF THE ENGINE?

[LMP]

A definite possibility. These items have been displaced and stressed and that can have had that result on piping and other gaskets.

[timguyli]

The mechanic said its oil. Most like;y from the rear main seal. Im thinking it might be the oring for the distributor cause i see some oil by that also.

[cdru]

Originally Posted by timguyli

The mechanic said its oil. Most like;y from the rear main seal. Im thinking it might be the oring for the distributor cause i see some oil by that also.

The oil shaft o-ring is notorious for leaking on the 3.1 and 3.4 engines. If you look under the throttle body, you will see a silver cap about 1.5" in diameter. This is the top of the shaft. On older engines with a distributor, this is where the distributor would be. The o-ring on our engines wasn't designed for hi temp/pressure conditions and it deteriorates. It seeps oil because one of the main oil lines flows right through there, so it's under higher pressure then where other places might be. It should always be replaced when the manifold is removed as it's easy and takes about 5 minutes. An oil leak here would drip down the tranny and appear to me a main seal leak. Any reputiable mechanic that has worked on several of these engines should know that...a GM dealer definitely would know it.

You may be able to get to it by just removing the throttle body. If not, then at least the upper manifold/plenum gets removed. Remove the bolt holding the clamp down. Then use a pair of channel lock pliers to pop it straight out. On mine, it stuck so I had to use a small pry bar on the channel locks (not underneith) to pop it up. My o-ring was completely dry and brittle, cracking easily. Reassemly is reverse of removal. You can also put in a paper gasket under the cap to help prevent future leaks in case the o-ring fails again. Just use a gasket from an earlier engine that did have the distributor. Sorry I don't know the part number.

[timguyli]

Are you saying I dont have a distributor? Then whats holding the cap up?

[LMP]

.....as suggested in CDRU post, yours is one of these "older engines with a distributor".... lol