Another overheating thread

[twobjshelbys]

I've been watching this with great interest.

Overheating Issues, Perplexed

but I think this is not the same problem.

My CSX with a Roush 427IR has very erratic temperature. My problem occurs a medium amount of time after starting. I thought it was an air bubble because the top of thermostat housing to radiator link was above the radiator fill cap. I'd purge and fill and then it would lock up again. Erratic temperature swings from 78C to 110C, with some brief spikes to 120C. So I put on the expansion tank to get the high point above the engine. This morning when I check the tank it was dry - after having filled it almost to the top - and on the way to work it spiked up again. By the time I got to work the oil temp was about 100c and the water temp was down to 60c. That doesn't make any sense.

It did the same thing on the way home - although oil temp only got up to about 90 yet the water went up to about 90 and then back to about 80 (it's a 160F thermo) but was back around 60. I even turned off the aux fan - no radical temp change.

When I parked the car and let it sit for about 15 minutes both oil and temp gauges were at about 85C.

Tonight my best friend and mechanic checked the overflow tank and it was a little below the baffle plate but still not as much as I had put in. I'll check it in the morning when it is "cold" which will probably be about 65F ambient.

One of the things I've noticed are wildly erratic temp swings. It will move from 110C to 80C in several seconds. It makes me wonder about the temp gauge, but I have no way of verifying this.

I would expect the oil and water temps to be pretty close and change on driving conditions. The oil temp now will stay about 90 and go to 110, but the water jumps all over the place.

I'd thought about the lower radiator hose collapsing but the elbows are hard tubing and of course I can't see them when tese events happen.

When it isn't moving it is pretty good - gets to about 90 max and stays between 80-90.

Expansion tank shows the thermo opening. I drilled 1 hole into it - that what was recommended - but I see people putting up to 4.

Any ideas?