I have a 95 pontiac trans am that overheats I replaced the water pump, both fan motors, the thrmostat and the radiator it continues to overheat any ideas of what else it could be

10

Asked by Sep 30, 2012 at 03:49 PM

Question type: Maintenance & Repair

20 Answers

6,675

Have you checked or replaced the radiator cap? It might not be holding pressure.

1 out of 1 people think this is helpful.
10

Yes I replaced it because the radiator had a whole in it

1 out of 1 people think this is helpful.
6,275

Sounds like you may not have all the air out of the system then....

4 out of 4 people think this is helpful.
9,415

Make sure the air dam for the radiator is still there. Make sure there are not any leaks anywhere. The missing air dam or a leak will both cause the car to overheat.

1 out of 1 people think this is helpful.
31,015

Michael's right sounds like you "curbed" it. In a case like that the car will run in the driveway all day long without over heating but as soon as you start driving it the temp climbs. Once the car hits a certain speed the fans stop working. Whoever honestly thinks a bad radiator cap will cause a car to overheat needs to sell their tools. Let me guess auto zone told you that. The only think the radiator cap does is raises the boiling temp of the coolant. It has NOTHING to do with the temperature nor is it capable of changing the temperature.of the coolant.

2 out of 2 people think this is helpful.
9,415

Not entirely accurate John.. The radiator cap controls pressure which in effect raises the boiling temperature. A faulty cap will cause the coolant to boil more quickly and dependent on the temperature outside will cause the car to overheat (even driving down the road). Had it happen more than once. A leak in the coolant system will have the same effect. My bet on this problem though is that someone did not re-install the air dam and for the Firebirds it is a necessity.. :-) Trust me on that.. I learned the hard way.. LOL

3 out of 3 people think this is helpful.
6,675

John, if you knew what you were talking about, it would be great. If you think that a radiator cap that is deficient on spring tension, would not cause an "over heating" problem, then you are the one that should seek different employment "dude" ! The reason that there is a pressure cap, is to increase the boiling point. Any good mechanic or anyone schooled in this, knows this. The boiling temperature of a fluid increases when pressure is increased. I'm trying to provide helpful information, at the simplest level, at the cheapest price. All I did was ask a question. What you did, is just annoying. There is no statement here when the car overheats, running down the road nor other. Even if there was, if you don't keep the pressure in a cooling system on a vehicle, it can overheat at any point, driving or not.

2 out of 2 people think this is helpful.
9,415

John, A radiator cap has several functions. (1) It keeps the cooling system sealed from outside contaminants. (2) By keeping pressure on the cooling system, it raises the boiling point. (3) The radiator cap allows coolant to go to the expansion recovery tank when coolant gets hot, expands, and pressures increase. (4) As the system cools down, it allows coolant to return to the engine from the expansion recovery tank. A bad radiator cap can cause the engine to overheat at lower temperatures. This will cause the coolant to boil over to the expansion tank.

2 out of 2 people think this is helpful.
9,415

Drive your car (or truck) around for a day without the radiator cap. Let me know how that turns out :-)

31,015

I would have no problem driving around with the cap only 1 click down to where the system can't build pressure. What about the systems that have a sealed and pressurised reservoir? The cap has 1 job and as long as the rest of the system is functioning properly and your less than 1500 ft above sea level there will be no issues. 195°F is the hottest any engine should ever get, if its getting hotter than that then there is an issue somewhere that needs to be fixed before it becomes a serious issue. As for the pressure raising boiling point, it works both ways, that's how evacuating a refrigeration system removes any moisture.

6,675

Michael, you are the King in my book. Thanks for the backing here! I'm 46 years old, and have been a mechanic/technician for for 25 of them. If you want to count "backyard/shade tree mechanic".,... it would be another 6 years added on.

9,415

John.. Older SBC engines usually ran around 215 for normal operating temp. Absolutely nothing wrong with them, that is just how hot they ran. I have owned so many GM cars.. I can give so many examples. Like.. My brother currently has a LT1 in a 95 Formula. Runs 210-215 in the summer months. This is common. ***And since I am done arguing... A bad radiator cap will cause the engine to overheat. I have found numerous articles to support my claim.. And none to support yours ;-)

2 out of 2 people think this is helpful.
6,675

John, most caps that are sold (USA), are designated at about 14-15 psi (cars, not diesel). Don't care what elevation you are at (I'm at about 570 above sea level). It's still the same cap that they issue anywhere in the USA. This person didn't state where they are. So I don't know where you are going with this? Grasping at straws to save your credibility? One click down to reduce pressure, really? Anyone that drives in the USA, with a standard equipped modern vehicle, shouldn't have to adjust for anything (Mountains or other) And yes, you would be wrong. If it doesn't hold the pressure, it surely will overheat . The pressure is what keeps it from boiling over.

1 out of 1 people think this is helpful.
31,015

Exactly no one should have to adjust and that's why vehicles are built the same and the boiling point of a proper 50/50 mix is 223 so like I said if your cooling system is boiling over there is an issue that a radiator cap will only mask. SBC at 215 and no vapor lock issues. Pft okay!!!

6,675

Nope John, that's why they have sensors, and the computer adjusts for altitude. Your too young to know this, and I was too young to experience this. An old mechanic friend of mine told me how you get through the Rocky Mountains long ago. You would have a guy at the bottom lean out the mixture for the higher elevations. At the other side you could get a guy to rich up the mixture (days of carburetors), I wouldn't expect that you might understand that. I grew up in the days of carburetors that switched to fuel injection. I also had a knack for computers and electronics (Thank my brother for that). Now, I'm not as smart as I would like to be, but I'm not stupid either. So given the time I put into this field, stop knocking a veteran down, Please.

1 out of 1 people think this is helpful.
6,675

John, You are the greatest mechanic of all. By best to you and your partner. Wink-Wink. Glad your not touching my vehicle.

2 out of 2 people think this is helpful.
10

I don't see any thing leaking I was told it might be a head gasket how much does it cost to replace and what is a air dam never heard of that

6,425

the air dam is on the bottom of the radiator.. a black 4" fin to scoop more air to the radiator on the underside of the car. http://ls1tech.com/forums/attachments/chevrolet-camaro-1967- 2002/64328d1147270499-air-dam-final_lowleft.jpg

1 out of 1 people think this is helpful.
9,415

As Jason mentioned, it is a fin attached under the car to scoop air into the radiator. It is used on cars that do not have grills. Just look to make sure it is still attached. You would have had to have removed it to replace the radiator, just make sure it was re-installed. You can find them online by just Googling it.. (ex: http://www.ebay.com/itm/93-02-Camaro-Firebird-Trans-Am- Lower-Air-Dam-Deflector-NEW-GM-/380459620920#vi-content )

1 out of 1 people think this is helpful.

IT SOUNDS LIKE IT COULD BE ONE OF TWO THINGS ,HAVE YOU CHECHED FOR A PLUGED HEATER CORE, ORTHE EXTREAM IS A CRAKED CYLINDER HEAD.MADORE

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