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Overheating - possible reasons? by yellowstone
Started on: 01-11-2004 07:05 AM
Replies: 11
Last post by: Dslice on 01-12-2004 05:47 PM
yellowstone
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Report this Post01-11-2004 07:05 AM Click Here to See the Profile for yellowstoneSend a Private Message to yellowstoneDirect Link to This Post
I have an overheating problem. When driving the car heats up to about 1/4 of the coolant temp dial and stays there for a while. Then, while in traffic, it starts moving to more than 1/2 the dial until the fan comes on. Then it will quiver and stay there, more or less. If I switch on the A/C it will quickly go back to 1/4 of the dial.
If I go on-highway and drive 80+ (this is Germany) it will start to go up and up even if the A/C is on.

What are the possible reasons? I have no kinks in the coolant pipes, no air in the system, my termostat works fine...

Thanks

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lurker
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Report this Post01-11-2004 08:59 AM Click Here to See the Profile for lurkerClick Here to Email lurkerSend a Private Message to lurkerDirect Link to This Post
i'm no expert but i hear that turning the AC on forces the fan on. if turnng on the AC solves your problem then i'd have to guess there's something wrong with the switches or wires that control your fan. as for the highway speed issue, i'd guess youve got a flow restriction issue, maybe your radiator needs a flush? let us know what you find.

[This message has been edited by lurker (edited 01-11-2004).]

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Phil86SE
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Report this Post01-11-2004 12:09 PM Click Here to See the Profile for Phil86SEClick Here to Email Phil86SESend a Private Message to Phil86SEDirect Link to This Post
My guess would also be an air flow problem. It sounds like there just isn't enough air flowing through the rad to cool things down.

hope this helps

-Phil

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Fierobruiser
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Report this Post01-11-2004 12:55 PM Click Here to See the Profile for FierobruiserClick Here to Email FierobruiserSend a Private Message to FierobruiserDirect Link to This Post
Belt slipping? Does your voltmeter go down as the temp goes up?

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TaurusThug
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Report this Post01-11-2004 04:25 PM Click Here to See the Profile for TaurusThugClick Here to Email TaurusThugSend a Private Message to TaurusThugDirect Link to This Post
there might be a bag or something between the a/c condenser (i think thats whats there) and the radiator. that could solve your problem.

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silver86se
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Report this Post01-12-2004 12:39 PM Click Here to See the Profile for silver86seSend a Private Message to silver86seDirect Link to This Post
hi check under the car to see if you have the air dam ...
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CC Rider
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Report this Post01-12-2004 12:51 PM Click Here to See the Profile for CC RiderClick Here to Email CC RiderSend a Private Message to CC RiderDirect Link to This Post
I believe it's an air flow issue due to the body kit. You could be creating a pressure zone under the front hood. The solution I like is at this post toward the bottom of the first page. Camero door vents installed under the hood behind the headlight assembly.

http://www.fiero.nl/forum/Archives/Archive-000001/HTML/20030204-2-026101.html

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1987 Trans Am
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Report this Post01-12-2004 01:16 PM Click Here to See the Profile for 1987 Trans AmClick Here to Email 1987 Trans AmSend a Private Message to 1987 Trans AmDirect Link to This Post
Also check your coolant level. At times a person can loose coolant through the head gaskets causing your engine to overheat. The coolant would then go into your oil. If you think that this could be a possibility, drain just about a cup of oil and see it if really is ONLY oil that comes out of there. I knew of a guy who had the same problem and ended up ripping the block down to replace the head gaskets on his own. Sorry if this scares you but it is a possibility.
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Pyrthian
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Report this Post01-12-2004 01:29 PM Click Here to See the Profile for PyrthianClick Here to Email PyrthianSend a Private Message to PyrthianDirect Link to This Post
on mine, that is normal. The thermostat is at about 1/4 on the scale, and the fan switch is at about 1/2 on the scale. The A/C swicth forces the fan on. If you want the fan to come on earlier, you will need a lower temp fan switch. Unfortunatly, most lower temp fan switches are at lower temps than the stock thermostat, so the fan will be on almost all the time. If you're not hitting 3/4 to red on the scale, your not actually overheating, just running hot.
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Carrolles
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Report this Post01-12-2004 01:46 PM Click Here to See the Profile for CarrollesClick Here to Email CarrollesSend a Private Message to CarrollesDirect Link to This Post
I have a 195 degree thermostat and a 200 degree fan switch. That combination works great in my 85SE v-6 and my 85GT.

As far as overheating at highway speed I'd look at airflow. If you are missing the small black air deflector underneath the nose you will have overheating problems at highway speeds.

Good luck,

Carroll

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Indiana_resto_guy
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Report this Post01-12-2004 01:46 PM Click Here to See the Profile for Indiana_resto_guyClick Here to Email Indiana_resto_guySend a Private Message to Indiana_resto_guyDirect Link to This Post
Fierobruiser has a good thought in this, "Belt slipping? Does your voltmeter go down as the temp goes up?"

As well as TaurusThug when he said "there might be a bag or something between the a/c condenser (i think thats whats there) and the radiator."

CC Rider believes "it's an air flow issue due to the body kit. You could be creating a pressure zone under the front hood. The solution I like is at this post toward the bottom of the first page. Camero door vents installed under the hood behind the headlight assembly.
http://www.fiero.nl/forum/Archives/Archive-000001/HTML/20030204-2-026101.html "

All very good suggestions. I'm guessing this is a new issue on an already been driven body modification so we can put CC Riders thought on the back burner for now.
Double check your belt and fluid as 1987 Trans Am has suggested. A question, how old is the water pump?
If three or more years old or a lot of kms it may be time for a new one.
Check your hoses and make sure none are collasped and blocking off or restriction the flow of coolant.
I was having similar problems with an 86 GT and the radiator was partly clogged up. Another radiator fixed it.

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Dslice
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Report this Post01-12-2004 05:47 PM Click Here to See the Profile for DsliceClick Here to Email DsliceSend a Private Message to DsliceDirect Link to This Post
First thing off change the thermostat, they're cheap here in the states. I wouldn't imagine them being to spendy there. I think there $13U.S.
Like mentioned above, check coolant and that your water pump flowing enough coolant through the lines. Some aftermarket water pumps have plastic impellers that seperate from the shaft, or slips enough to fail in pumping the right volume of coolant.
Make sure coolant lines are good, this includes the heater core. The cooling system needs to operate under pressure. If There is a leak anywhere, like the heater core or radiator cap, it will cause air to enter the system when the car cools and to boil over prematurely.
Make sure noting is blocking the radiator. Check temp sensors, there are two I believe on for the gauge and the other for the fan/ecm. Make sure realys are ok.
Worst case is a head gasket, but thats last resort. Minnesota is alot like Germany, climate wise, maybe a tad bit warmer there. Your Fiero's should be running nice and cool in cold weather. At 30F, is that 0C, maybe get a little warm in trafiic but open road you should cool right down.

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