befuddled by overheating
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 7,708
Likes: 266
From: indy indiana
befuddled by overheating
this isnt a vette.Its my kids grand am.Bring it over says I,thanks dad ,says she. its a quad 4,95 grand am. have replaced the thermo stat,still over heats.then replaced water pump,still over heats. then pulled thermo ,put on stove,works fine.flushed radiator twice,back flushed engine while thermo was out of car.still overheats. there was some rust and crap in the coolent...is why i back flushed. No leaks,cap is holding pressure.no smells,no bubbles,no discoloration in oil. However...before i back flushed the heater would put out hot air untill it started to overheat,,then cool air.now it just cool air all the time.I firmly believe it isnt a head gasket problem but damned if i know what to do next.Pride and stubborness is now come into play...cant let daughter think her "old man" has failed and cant even find the problem. Any ideas? i was thinking that little bits of rust was blocking the flow thru the radiator once it was started,but doesnt look that way now. When this started,the side of the radiator that took water from the engine block was hot,as was the hose...the "inlet side wasnt..the hose nor the radiator half.( side to side outlets).Today,neither hose was hot,not was the radiator,but the engine sure was.Help.
Instructor
Joined: Jun 2006
Posts: 140
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From: Bergen, Norway
Overheating blues
Too often I find cars with cooling systems full of contaminated coolant or just plain tap water. Over time the radiator (and heater core) will get a layer of crud on the inside without necessarily blocking the cores. This layer will isolate the hot water on the inside from the cooler air on the outside, in other words- no or little heat exchange. It may be necessary to either have the radiator professionally cleaned or maybe just get a new replacement unit at your local autoparts store. Refill the system with fresh antifreeze and water 50/50%. I even like to use distilled water for this. Also make sure radiator fan operates correctly, if electric it should turn on at the preset temp. and switch off again when temp. is low enough. I would also consider replacing all heater hoses & radiator hoses if they aren't replaced recently.
Good luck from Norway!
Good luck from Norway!
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From: Cape Cod, Mass.
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Is the fan coming on? These newer cars are programmed by computer to come on at a given temp. If the fan doesn't come on, the car will continue to heat up.
Safety Car
Joined: Dec 2004
Posts: 4,876
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From: Jersey Shore Exit 98
Originally Posted by Jack60
Just a guess, too much air in the system???? 
Jim
Le Mans Master
Joined: Nov 2000
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From: Going too fast over the hill. Iowa
Originally Posted by ghoastrider1
...before i back flushed the heater would put out hot air untill it started to overheat,,then cool air.now it just cool air all the time.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 7,708
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From: indy indiana
Originally Posted by Jims79
I have the same problem on a 67 GTO. Changed the thermostat twice all the fluid and the car runs at 210 & goes up to 230 240 at stop lights. Once I start driving it goes back down to 210 215 but I would like to run cooler all the time. Someone told me I had air in the system which I could because I replaced top & bottom hoses. How do you remove the air from the system? Also I was thinking of running w/out a thermostat is that a bad thing.
Jim
Jim
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Melting Slicks
Joined: Jul 2004
Posts: 2,452
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From: Scottsdale AZ
my process
I live in scottsdale AZ, hot it is!!!!
If you have water circulation then usually the radiator is junk, they go fast around here especially those OEM units that maybe have not had distilled water only. I like to remove the top hose and flush the block while the engine is running, then do it again then do it again. If you have colant flow its the radiator which is so coated with crud there is no thermal transfer. If your headgasket is blown, it will blow compression into your coolant passages and then blow the radiator cap off, or it will suck coolant into the combustion chamber. Is this an iron block and aluminum head engine with copper headgasket? beware not using good coolant and distilled water, in fact water is the best coolant the red sutff is just for freexing weather.
If you have water circulation then usually the radiator is junk, they go fast around here especially those OEM units that maybe have not had distilled water only. I like to remove the top hose and flush the block while the engine is running, then do it again then do it again. If you have colant flow its the radiator which is so coated with crud there is no thermal transfer. If your headgasket is blown, it will blow compression into your coolant passages and then blow the radiator cap off, or it will suck coolant into the combustion chamber. Is this an iron block and aluminum head engine with copper headgasket? beware not using good coolant and distilled water, in fact water is the best coolant the red sutff is just for freexing weather.
Race Director
Joined: Feb 2004
Posts: 14,984
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From: CT
Originally Posted by capevettes
Is the fan coming on? These newer cars are programmed by computer to come on at a given temp. If the fan doesn't come on, the car will continue to heat up.
Exactly, if the fan doesn't come on when it is supposed too the temp rises very rapidly. It pegs the gauge in a short period of time
Instructor
Joined: Jun 2006
Posts: 140
Likes: 0
From: Bergen, Norway
Purpose of antifreeze
Keep in mind antifreeze's purpose is not only to keep the coolant from turning into ice in sub-zero temperatures but is also designed to keep the internal parts of the engine etc. cooling passages free from corrosion, it lubricates the waterpump seals and rises the boiling point compared to clean water. Too much antifreeze is not good either, follow the manufacturer's recommandations or use 50/50. If the temperature rises at traffic stops but goes down again at cruise speed it could be a sign of either missing/bad fan shroud or bad fan clutch if installed. Sometimes the radiator-fan has incorrectly distance from the radiator or fan shroud. If you have a shroud only the front half of the blades should go into the shroud.
Last edited by Joys; Jul 5, 2006 at 03:30 PM.
Melting Slicks
Joined: Nov 2002
Posts: 2,460
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From: Wheaton IL
If your radiator isn't hot and the engine temp is way high you either have a blockage (bad thermostat counts as a blockage), bad water pump, not enough coolant, or some kind of air cavity in the pump.
That means coolant isn't flowing through the radiator. Like other's I'm going to guess that a bunch of crud is built up somewhere.
Brian
That means coolant isn't flowing through the radiator. Like other's I'm going to guess that a bunch of crud is built up somewhere.
Brian
Le Mans Master
Joined: Jul 2000
Posts: 8,506
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From: Calhoun, GA_______ Let It Rock
Does it overheat on the interstate ? In town ? Both ? I had a new 1989 IROC that would overheat on the interstate. The airdam/spoiler under the front end was suspose to direct airflow to the radiator and was mis-installed or something. It wasn't directing the flow of air at speed, causing it to overheat.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 7,708
Likes: 266
From: indy indiana
thanks for all the tips/help/suggestions.
thanks guys. I went back at it today. Flushed from the front,then the back,and did it all over again. Then went to auto zone,bought some radiator flush stuff,,,ran it for 15 minutes,flushed everything again,ran it 15 more minutes,flushed it again. then drove to auto zone again,and bought the 5 hour flush stuff. the car drives great now,,,still starts getting hot at red lights tho.Feel like i am on the right track.anything above10 or 15 mph and temp stablizes in the right place. whew...you guys were right on that suggested the crud.Radiator seemed to flow ok,think its in the block where all the crud is.proably both,,going to have it pro flushed tomorrow. tahnks again,,,,daughter still looks up to dad..chuckle.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
You are probably looking at the DexCool mud problem. Exposed to air it turns to a sludge that plugs things up and is difficult to remove. GM had TSBs on this. As well that engine had head gasket problems.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 7,708
Likes: 266
From: indy indiana
Originally Posted by paul67
You are probably looking at the DexCool mud problem. Exposed to air it turns to a sludge that plugs things up and is difficult to remove. GM had TSBs on this. As well that engine had head gasket problems.
