Part 2: Troubleshooting overheating prob

Maybe the new thermostat isn't working either? Can you try it with no thermostat at all and see what happens? Not a permanent fix, just for diagnosing.

The only other thing I can think of is a blown head gasket allowing hot gasses in to the water. Clogged radiator or other similar problems normally come on slowly not all at once like this.

Steve B.

Hi Steve ...

It has crossed my mind to pull the thermostat, but havent. But now, and based on your recommendation, I will do that.

As a follow-up, I decided to take the car for a drive around the block. As I drive down the street (30-40 MPH), the gauge climbs and I decide to turn from A/C to Heater (blowing to floor) and turn the temperature to HOT. The engine temp gauge continues upwards, then drops a little, then climbs a little higher, then drops a tiny bit, then climbs upwards to red as I return home. I pull in the garage and the engine temp is just in the red, so I turn the car off.

I can hear the water boiling under the hood (radiator). I open the hood and I see the water is pushing out of the radiator and into the overflow tank and out its top onto the floor. I never felt any hot air at my feet (barefooted) when I had the heater on hot. Is this a case of water not flowing through the heater core?

Could this be a case where my original overheating condition caused a blown head gasket, and now the blown head gasket is leaking hot gases into the cooling system and causing an overheating condition? Should I get a dye to check for combustion gases in the cooling system? Do I check compression on each cylinder?

I'm perplexed.

Whenever I've seen that, that means there's air in the heater lines and not coolant.

I think you can diagnose a blown head gasket by reading the plugs, but I know changing the plugs on a 95 Camaro is just a teeny bit of work...

Ray

I wonder if your water pump is turning. I know it's a gear drive but there is no reason that gear couldn't have broken.

After you confirm that the water pump is actually turning and water really is moving through the system then my next step would be to check for exhaust gas in cooling system.

I know the radiator shops have the stuff on the shelf to test for exhaust in the coolant. I don't know if you can get something at the parts store that does the same thing. Plugs are such a nightmare on that engine that I would rather have a root canal than check the plugs and compression.

Steve B.

I have a '95 Fleetwood with the same engine. Needed plugs and wires a while back. If I could find the GM design engineer that was responsible for that nightmare I would love to drive to their house and kick some butt.

Steve B.

[snip]

Better yet, Steve, I wish I could invite the engineer over here to my house and have him/her change the plugs, the rotor and cap, the water pump, among other items.

And even worse than changing the plugs - in order to get to the distributor cap/rotor, one has to remove the air pump, water pump, radiator fan assembly, and crankshaft pulley. I simply can't imagine what the friggin engineer was thinking ... or for that matter, the engineer and the project manager were thinking ?!??!?!?

I can't believe the project manager approved that one, "oh yea, what a great idea - put the distributor on the front of the engine, under and behind the water pump and the crankshaft pulley".

the way I used to check for combustion leaks into the cooling system was to remove the thermostat and water pump drive belt, leave the thermostat cover off, fill the system and start it up and watch for bubbles. That isn't going to work on this cam driven water pump although you will find out if the pump is working :) Other than an exhaust gas sniffer I can't think what you could use.

Hey a quick way to eliminate a lot of possibilities is take off the top radiator hose and see if water's pouring out, that'll tell you the pump and thermostat are working, if you put a garden hose into the radiator to keep it topped up you can make sure it isn't a blockage there either.

You can also sometimes check for bubbles in the cold radiator to identify a blown head gasket/cracked engine

Cannot he apply pressure to the radiator and check for a leakdown--to determine if there is leakage between coolant system and combustion chambers? sam

On Sep 16, 9:44 pm, golden oldie wrote: [snip]

I wonder if any of these items would be helpful:

Maybe "Airlift" or " Combustion Leak Tester" - not sure how to use the Leak Tester - would be nice if they provided more detail on how to use the tool.

Well, the airlift will be helpful in re-filling the cooling system -after- you determine the cause of overheating.

The combustion leak tester works pretty much like the inset picture on the above link... The unit is filled with the fluid that comes in the kit, the unit is placed on the radiator fill and then the squeeze bulb is used to draw any vapors that are in the radiator thru the fluid. If the fluid changes color, combustion gas is present in the cooling system. One needs to be careful when using this tool especially on a vehicle that is violently regurgitating coolant back as you have described yours to be doing. Experience has taught that these things don't work if the amount of coolant entering the combustion chamber is sufficient to snuff any combustion to begin with. (it happens)

Before doing anything else, I'd fit a piece of clear vinyl hose of the correct size to which ever heater hose supplies coolant to the heater core, run the engine and see if in fact coolant is being pumped by the water pump. Sounds like it isn't...

On Sep 17, 8:21 am, aarcuda69062 wrote: [snip]

Excellent idea - I'll give it a go.

Does this suggest that this is a system that *requires* coolant flow through the heater core as part of the cooling system loop? My understanding is that some systems have a valve to control flow to the heater and some must have a constant flow to include a trip through the heater core.

At the time it was heralded as a great idea. I think the opti-spark was originally intended to be a lifetime piece that never needed servicing, and if they sealed it better or didn't put it under the water pump it may have never needed service.

Ray

There is a small coolant hose coming off the throttle body and going to the coolant reservoir. Pull it off, aim it back in to the reservoir and have someone start the car. You should have a good flow of water going through that hose.

I think there is always flow through the heater core but I could be wrong. If you put the clear hose on turn it to max heat high fan just to make sure that coolant should be flowing.

Steve B.

What Steve B said.

"sdlomi2" wrote in news:LQsHi.47885$ snipped-for-privacy@bignews4.bellsouth.net:

I was wondering why nobody had mentioned that yet.

Double check the water pump rotation, the auto parts store may have given you the wrong one.

If they did, it's spinning the wrong way.

cc

1) Because combustion pressure = hundreds of PSI, radiator pressure = 15 PSI. 2) As already stated, the spark plugs are a royal pain to R & R.