I think I'm going to have to get dynomite to bleed my cooling system. Ever since I bypassed my heater hoses, the temp guage runs insanely hot at 2000 rpm or higher, but cools right back down if I let it idle. I had this problem when I first got the car and had flushed the system, but it seemed to go away on its own after a while. That was before the Highflow pump too. After about 5 miles of driving, if I take it out of gear, let it coast and idle, the temp comes way down (and fast too) and stays at 170. Ambient temps seems to have no bearing. It happens in the morning when it is in the 70's AND in the afternoon when it is in the 90's.

I've let the car idle and warm up in the driveway with the cap off, then rev it and watch the temp climb. At some point, it will launch about 2 ups of coolant clear over the fender and out on the ground. Right after that the temp guage drops. I refill with a few cups, and recap. I've run this procedure twice and the guage still gets past 250 like I described above.

I'm going to try pulling the T-stat and running without one for a bit. Oh , by they way, that stat is a drilled one from Stewart.

Anyone know any other tricks? If this doesn't work I'm getting DYNOMITE! :mad


[Modified by isosceles, 2:59 AM 5/24/2003]

 

Jack thr front end up so the top of the radiator is higher than the engine, then refill as usual. :cheers:

 

If its a blockage your car wouldnt cool down as quickly as it seems too.

Maybe you are putting the water thru the system too fast and its not getting a chance to cool down ?? :mad:

High volume waterpump causing cavitation ?? Maybe headgasket leak pressurising system ??

Bad pressure cap ??

Just my thoughts and hope they help. Ive done my vette about three times recently for a thermostat housing leak and had no probs once its been bled


:cool: :cool: :cool:

 

I know this is a problem on BB's... The upper radiator hose.... Unless it is the correct molded shape and installed so the hose goes around the alternator instead of over it, the high spot will be in the hose and that's where air will go. That will create an airlock of sorts and will cause the system to vent water. It also sound like the thermostat is opening too late. New parts CAN be fualty....

 

I would reconect the heater hoses and use a vacuum valve controlled by the ventilation system to keep you from getting hot air when you don't want it. Jack up that front end and burp your car...

 

Do you have your coolant overflow tank on the car?

 

yes, I have the coolant overflow tank. I am wondering if it is even connected. Here's what I did that makes me wonder:

On suggestions from the posts above, I jacked up the right front of the car. I was able to get an additional 1/2 gallon of water in. Earlier in the morning I had already removed the T-stat. I was thinking that I might be able to add some water through that opening, but it was full to the top.

I ran it pretty hard after about a 3 min ride a 45 (that's usually enough to get the temp to clinb) and I'm happy to say the temps stayed down around 160-170. The car did puke a few ounces of coolant from the overflow hose (thought this was supposed to go to the overflow tank?)when I parked it. I waited a few minutes and restarted it. The temp was up around 190-200, but I'm sure it would come down if I let it run.
So for now, I'll run without a t-stat. I saw a post in Stewart's q&a forum and they actually recommended that to someone.
Thanks for all the input! :hurray:

 

Running without a tstat is just masking the problem. T stats control minimum temp not maximum. Without the tstat it should take longer to get hot but stay hot . I would see if you could get someone to "sniff" your radiator for hydrocarbons with an emissions anylyzer. Sounds like a headgasket.Any hydrocarbon reading over 10ppm is bad. Jerry

 

It is possible for the Thermostat to stick and then pop open at a very high temp... say around 230 deg. That woul do what you describe.

 

First of all you have to make sure that the recovery tank is connected and working. Next you should be seeing the level change as the car heats up and cools down.Then go from there.

 

I'm going to reconnect the coolant recovery tank. I think I've been driving it that way since I bought it last August. I never had a problem except for 220-230 temps at highway speed. When I bought it and first flushed the system, I had the same symptoms I do now, eventually the problem quit happening (that's why I was inclined to think it was air).

Last month I started throwing belts. With only the Alt belt on, I revved the motor and I heard a metallic squeak (not like a belt slipping). The water pump sounded like it was rattling, that's the reason I got a new one and went with Hi-flow to reduce hiway temps.
Right after I installed the pump, all was good, things were running cool. Not until after I bypassed the heater hoses did this latest problem occur.

I'll also have to drive again without the t-stat and see if it pukes anymore coolant. Gee, if I have a bad head-gasket that means I'll HAVE to pull the heads and maybe get a little work done to them..or.... AR MOTOR TIME!! (i wish!) :party:

 

Start your car and run it with the cap off until it is just about ready to boil over. In this time you may see alot of bubbles in the neck. I did this on my 94 today after changing the coolant and it burped and bubbled for about 10 minutes before it came close to a boil over.

I agree with your hunch, it sounds like air in the system.

 

rdrman,
you hit the nail on the head! I have one, but it's the Bubba model AND it wasn't even hooked up. I was assuming that there was a hose UNDER it. This is one of those generic ones that connects through a hose on the top. I was ready to reconnect this one and started another thread asking about the routing of the hose (which should be a no brainer as the tank is supposed to be about 2 feet from the radiatior), Paul79 sent me a pic of what it is supposed to look like and where it is supposed to me mounted. Needless to say, one is enroute from Zip.
I'm sure as the car was cooling it has been sucking air instead of siphoning coolant.

 

Another idea, make sure neither of the radiator hoses are collapsing.

 

Glad you found the problem! The recovery tank and its hose can really cause alot of mistuff with the radiator. Once you start pulling in air it just gets worse and you start looking at more costly problems,ussally overlooking this tank,kinda makes you appreciate the thought that went into the design ;)