Running Hot?

[McCSquare]

"I still am nervous that I might also have a blown head-gasket. "

So am I - for you.

As someone noted in post #5:

Spikes in temperature indication (that can't be attributed to coolant system components) are often caused by combustion gasses in the coolant - due to a head gasket failure.

But on the upside, you have not made any mention of the #1 symptom. H/G failure between the combustion spaces and coolant system will almost always produce white smoke (actually vaporized coolant) at the tailpipe.

Another plus - there hasn't been any noticable loss of coolant - correct?

As far as checking a t-stat for proper operation by just holding it in your hand and looking at it ... I don't know how to respond to that.

I noticed foam in there recently when I was trying to test out a temporary overflow bottle. I'm guessing this is evidence of exhaust gasses in the coolant?

I haven't seen a lot of white smoke, I believe only some steam from water in the pipes when it gets up to temperature.

I just tried applying pressurized air to each cylinder using a valve holder tool. I didn't see any bubbles in the water neck opening. However I have a feeling I'm doing it wrong. Don't I need the cylinder I'm testing to be in the compression stroke for the test to work? In some cylinders I get air flowing straight into the exhaust or back out the carburetor, others hold pressure. I'm assuming I need to be in the compression for the test? Whats the best way to rotate the motor? The harmonic balancer nut? What size is that? I can't see it at all I think I need to do it from underneath the truck.

 

[chengny]

I have a question:
How was the radiator "Flushed" ?
if it was with a garden hose kit,that may well be a waste of time and good water,if,the radiator is scaled throughout the cross flow tubes.
There are some chemicals that may or may not remove those scales,but,the only accurate way to get that job done is to remove the side tanks and run a rod through them,a sort of a flat piece of steel made to just fit the inside of them tubes.
Thats all.

You know what; that's a real good question.

I recently had this happen:

In an effort to REALLY "clean out" the cooling system (of a 350 I had dropped into my truck) I dumped in 3 bottles of Prestone Super Flush, added just enough water to keep everything circulating and drove around for a couple of days...

Oh boy - I certainly got the internal engine passages clean - and everything ended up in the hot (inlet) tank. What didn't get stuck in the tank managed to work it's way into the cross tubes. The radiator is an OEM brass/copper 3 row core unit.

All of a sudden the freaking cooling system was acting like it was possesed and it took me a long time to figure out what was going on.

Took a longer time to reverse flush it to the point where it would actually cool the coolant. It was not really a heat transfer issue - more of a flow problem. You could see the flakes of "flushed" deposits hanging out of the tube ends when viewed through the radiator cap hole.

Try pulling the inlet hose off and using the best flow you can get blast back through the radiator fill hole. See if it improves the situaton.

I can't belive I falied to mention this.

 

[McCSquare]

I did a chemical test for exhaust gasses in the coolant and it was negative. I'm fairly sure I have a leaky radiator. Which explains the lack of pressure in the system. I'm going to order up a new radiator, and while its off replace my accessory belts on the engine.

Thanks for all the tips. I'll update when I get a chance to rip that radiator out.