overheat in the Arizona desert

ruswin

Registered User
I've been driving a 93 5-speed around Phoenix since 1995 with relatively no overheating problems. Recently I bought a 95 auto for my wife. On the hotter days at highway speeds the car is definately getting above "norm". (Notably higher rpm's as well 85mph in the 5-speed = 2100 / auto = 2500+) When I stop the car, air is bubbling back into the overflow causing a low coolant condition upon start-up. I have read a couple threads about the importance of the plastic air dam. Tha car I bought has almost no airdam left (worn down?) I just replaced the radiator cap but I still would like to find out what else can be done to keep a stock SC cold when the heats above 100'.


SCCOA... there is a god!
 
When was the coolant last changed, and has it had regular maintainance? If its been a while, do so again.

The airdam is said to make a significant difference in cooling, but I think there is more to your problem.

First, ensure that there is enough coolant in the resevoir. If it is boiling over, this is a sign of a pressure leak allowing the coolant to boil at engine temperature. The light is based on a sensor which detects level of coolant.

Next, make sure your thermostat is working correctly and your low & high speed fans are working. There is 1 fan in the '93, and 2 in the '94.

In your climate, it may also be beneficial to add a solution with an increased quanity of water, such as perhaps 60/40 (water coolant). Water has a greater heat transfer rate than coolant. Just be aware not to use too much, as coolant raises boiling temperature & prevents corrosion.

There are additives which increase cooling available, such as Redline water wetter. And as TbirdSCFan said, running the A/C will engauge the low speed fan, which is useful for low speeds when the intercooler doesn't have a chance to work.
 
Go to Autozone and have your radiator cap Pressure tested. Most cars use a high pressure cap to raise the boiling point of the water in the antifreeze. When the water boils it turns into vapor which evaporates and does not remove any heat from metal it passes over. I would try the cap first along with a cooling system flush. The thermostat will not make much of a difference at all unless the fan switch is modified to come on at a lower temp.

There is a company called ECS (Evans Cooling Systems) that makes very good cooling products. Their coolants contain no water at all, so you never have overheating problems from vapor. The boiling temperature of their coolant is 370-375 degrees. The down side to normal cooling is that you have to have the high pressure to keep the water from boiling and that also puts more stress on all the system components. The NPG coolant has no water in it, so it can run at almost no system pressure. At colder temperatures water will freeze and expand, which is why engines have freeze plugs. The NPG Propolyne glycol shrinks and becomes a gel. It also eliminates system corrosion and water pump cavitation ( which is a problem on 94-95 models). And their Coolant never evaporates so you never have to add anymore. They say their test car has over 200,000 miles on it without ever having to add a drop of coolant. They do not say if it has ever been flushed.

They also have hi flow water pumps, radiators and cooling fans. You could check with them to see if they have anything for the SC.
 
I went to a lower Tstat and it didn't help. Went to a larger radiator and it didn't help. Turning on the airconditioning helps a bunch. When all else fails, you can always get a chip tuner that turns the fan on at a lower temperature ... speaking of the fan, perhaps there is a problem with one of your fans??

Paul
(6 weeks to go??)
 
After hearing air hissing around the radiator cap, I replaced the radiator cap. I can't tell if it worked right now because I'm in So. Cal and it is rather cold here now.

Both fans are working but, one is a puller and the other is a pusher. The main "puller" fan comes on first then the smaller "pusher" fan comes on a few degrees later. I am having the coolant changed out now but I think it "looked" pretty good.

It's not a low coolant condition until I shut off the motor and the coolant overflows back into and over the top of the overflow. Of course I top it off after it cools.

Someone wrote another thread about using an airdam from a different vehicle.
Would a larger airdam effectively direct more air to the huge gap between the center of the bumper and the radiator. (See photo)Compared to my 93 the 95 front end seems to have more available surface area. Where can you find the plastic piece (airdam) except in junkyards?

I'm having my mechanic purge the system and replace the themostat. What exactly should I use. I heard that Robert shaw? makes a 180 that works the best.

As far as the fan switch turning on the fans at a lower temp, is that a chip thing or what?
 

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It sounds by your first post that you are merely low on coolant. If air is bubbling out then there is air in the system. You have to top off the overflow (and make sure it doesn't leak) after it cools.

It takes several cycles to purge all the air from the system. It's like bleeding your brakes if you let the container run dry you have to start all over again.

You can also use the bleeder located next to the thermostat housing.


The thing that always bothers me about most of you guys that add a cool fan switches, lower thermostat, wiring your fan to run all the time, and these Band-Aid fixes is that the car came from the factory and cooled just fine. That means that something has changed to make it to the point that is no longer cools.

It could be that the rad is plugged, a collapsed lower rad hose, belt slipping (loose tensioner or glazed belt), insufficient airflow through the rad, or any of a number of causes, but the problem needs to be addressed instead of putting some JB weld here and there and calling it good.

Jeff


Ruswin, this is not directed at you but just the band-aid brand in general.
 
A couple of quick points in this discussion:

1) Turning on the A/C (which turns on the low speed fan) ONLY helps if you are below about 48mph. It does not help at highway speeds and would actually be worse at highway speeds because of the added heat load.

2) I'm one of those guys who put in the manual low speed fan switch. I did not do it because I was having cooling problems. I did it because I don't like the way this system was designed that forced the engine to raise to 222F before kicking on the cooling fan - that's all. I simply manually turn it on at a lower temp thus narrowing the operating temperature range of my engine. I'm not trying to fix a problem other than inherent design problem. The other inherent design problem is the lousy air flow into the radiator provided by the body design on these birds.

Jon
 
Someone wrote another thread about using an airdam from a different vehicle. Would a larger airdam effectively direct more air to the huge gap between the center of the bumper and the radiator. (See photo)Compared to my 93 the 95 front end seems to have more available surface area. Where can you find the plastic piece (airdam) except in junkyards?

The air dam mod utilizes two air dams from a Pontiac Grand Am. They cost somewhere around $20/ea., or cheaper if you get them from an online discount dealer site.

I don't have the link, but it is pretty easy to do. The first one sticks up into the engine compartment while the second sits in a normal position- they are sort of inverted against one another. A few extra holes must be drilled either into the dam or into the bumper cover where they mount. It will sit a tad lower then the stock one, but it is well worth the extra cooling! It took me less than 30 minutes to install when I did it.
 
ruswin said:
After hearing air hissing around the radiator cap, I replaced the radiator cap.
That should help with the loss of coolant which is sounds like you're having. You should check around the water pump also. I had a sloowww leaking WP for a year or more, always seemed to be low on coolant. I had to eventually replace it and my coolant system is holding every drop now.
It's not a low coolant condition until I shut off the motor and the coolant overflows back into and over the top of the overflow. Of course I top it off after it cools.
Are you saying that the bottle overflows? If its overflowing its probably the radiator cap especially if the temperature gage is normal.. Otherwise, after one or two times, it should stabalize and when the car cools, it shouldn't drop below the lower level in the coolant bottle or rise over the upper level.
Would a larger airdam effectively direct more air to the huge gap between the center of the bumper and the radiator. (See photo)
That's a pretty big gap; you might want to look a other cars.
As far as the fan switch turning on the fans at a lower temp, is that a chip thing or what?
Yes.
 
Thanks for the help... I'm begining to think I am missing a body piece under the bumper. A different thread showed a pic of the underside of the 94-95 but it lacked detail. Can someone take a pic of the bottom of their 94-95 from the same angle as my pic is?
 
I am having cooling issues at freeway speeds as well here in Arizona. I would be interested in seeing a pic of someones air dam.
 
on mine when the headgasket leaked compression into radiator and pushed enough coolant out to run warm there were no other symptoms but running warm i stopped and checked oil and i saw water in there
i dont believe the air dam missing could cause overheating
 
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I dont have a digital cam now with me but you ARE missing a piece...this piece that you are missing was loose on my 94 and i just bolted it back to place. With out this air dam you pretty much get no air redirected up to the radiator hence your higher temperatures. The airdam 'mod' where you use one or two (I used one, some people use two) GM airdams only works on the early model SC's because of the way the bumper is shaped, i did this to my 89 and it made a hughe difference, specially at high andn medium speeds. I still get higher temps on my 94 even with a 160* thermostat so I think im going with the manual switch route until i can get an EEC tuner or a chip to have the fan come on at lower temps.
 
NEVER MIND...disregard my last post. AFter walking outside barefoot to doublecheck I noticed that you do have the air dam...its the black piece on you bumper. Fromthe angle of you pic I just thought that it was too big of an empty space, but thats the way it is
 
Changing your thermostat won't lower the temperature. Start looking for the other problems in your cooling system before going the manual route.
 
mine runs way under the n on the guage if im cruisin at 75 degrees out thats still original radiator 207 k till i stop in traffic it may go to almost half on guage then fan kicks on then if i move a while 5 min it goes back down below n thats with air off
 
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Air Dam: I had a 19xx Jensen Healey that would overheat. I purchased an air dam from an aftermarker supplier in Arzonia and wala the overheating problem was gone. Of course I purchased the air dam after doing eveything else, even replaced the radiator.
 
HHHHHHHHHOOOOOOTTTTTTTTTTT

I THOUGHT THIS MATTER WAS CLEARED UP...............I GUESS NO ONE READ THE OTHER POSTS...... CUT THE #14 WIRE BY THE IRCM..........4 IN OUT.........ALSO GUT OUT THE STAT & INSTALL.............1/ 2 IN WASHER IN CENTER BEND THE MEDAL TABS TO HOLD IT IN AFTER REMOVING THE COOPER PLUG,,,,,,,,,,,,,,ALSO THE # 17WIRE CAME BE HOCKED UP TO A SWITCH THAT GOES TO GROUND TO RUN THAT ON THE HIGH SPEED SIDE....................USE THE SEARCH ON TECH FORUM TO FINE OUT MORE........FAST FREDDIE:cool: :cool: :D :D
 
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