skelly1

I got my old 85 vette back from my father in law. I sold it to him 10 years ago. From the looks of the coolant, I don't think it was changed since I owned it. I drove it a couple days to work with no incident. Then day 3 on the way home it started to overheat. I pulled over and let it cool off and that's when I noticed what the coolant looked like because it was boiling over. Limped it home and got a new radiator since that sounded like the typical plugged radiator situation where the car won't over heat around town, but a long uphill drive and it overheats. So, I replaced the radiator and T-stat yesterday, flushed it and filled it up with clean coolant and water. It still overheats according to the gauge anyways. I haven't driven it yet. After I replaced everything and was waiting for the t-stat to open up, I was monitoring the gauge at idle. It got up to 191 and then the t-stat opened up, I finished filling the radiator and put the cap on, and the gauge read 178 and stayed there for about 5 minutes at idle. Then I ran up the RPM to about 2500 while sitting in my garage and it slowly started going up to about 200 at which point I shut it off. The main fan is running all the time by the way, which I'll have to fix later. Edit: The AC was on so the fan is probably supposed to be on all the time.

My experience tells me that the water pump may have self destructed or the head gaskets are blown. I didn't see any bubbles in the coolant while it was running indicative of a combustion leak and the oil fill cap does not have any milky oil on it. That's about all I have to indicate a combustion leak. We used to use a smog machine to sniff the fumes coming out of the radiator fill to see if there was a combustion leak but I'm fresh out of smog machines because I don't work in a shop any more.

So, I want to pull the water pump next to look at it. How much of an effort is that job?

Another question I have is is there more than one coolant temp sensor? I spotted one on the side of the left head. Is that the only one? If it's suspect could that be the reason my fan's running all the time? Does the dash gauge use the same sensor?

Thanks all for any help and comments.

Cruisinfanatic

whats wrong with 200?
Drive it. If it gets to 240, then something else is wrong

oldalaskaman

yup

c4cruiser

Look up under the opening behind the front license plate. Is there all sorts of debris and dirt that is covering the A/C condenser? Air has to go past that in order to get to the radiator for cooling. I'll bet that there are all kinds of debris between the condenser and the radiator.

You can use a garden hose to push stuff out from the radiator fins The upper radiator shroud is not that hard to loosen so that you can get a shop vac hose between the two units and vacuum out the junk.

Hard to say if the WP is toast. Do you hear any metallic noises when the engine is idling that would indicate bad bearings? It's possible that the impeller is shot. Take the pressure cap off and start the engine. Once the t-stat opens, you should see coolant circulation. That would indicate a good WP.

And after sitting for so long, it's entirely possible that there is still gunk from the old coolant in the engine and may be blocking coolant flow in some areas. I would flush the system again and refill with just water. Drive the car for awhile then flush again. Do that one more time and refill with a good 50/50 mix of coolant and distilled water.

skelly1

There was a lot of debris between the radiator and condensor. I took all that out when replacing the radiator. I will drive it tonight to see if it overheats on the road. Thanks! BTW I don't hear anything coming from the WP.

skelly1

I drove it tonight about 20 miles on some uphill roads. It consistently ran at about 190-195F. When I got to the turnaround point after a pretty good uphill hard run I stopped and let it idle. It went from 198-212 and then I took off and went back. It quickly went down to the normal moving 190-195. Am I good here guys? I'm kindof paranoid here. It seems like it gets pretty warm when it's not moving. I'm running the AC the whole time, which shouldn't matter IMHO. I'd like to cross this problem off the list and move onto some of the other issues. Thanks!

RedLS1GTO

I don't see what it is that you are worried about. 212 is not overheating, not even close.