Engine Overheating

Tiny
JOJO15
  • MEMBER
  • 2003 CHEVROLET IMPALA
  • 168,000 MILES
Hello Im having a bad time with my coolent system. I have changed just about everything the water pump, thermostat, radiator, intake manifold, and 2 elbow joints located under the intake manifold. I have blow my head gasket but had it fixed.
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
FREEMBA
  • EXPERT
Have the cooling system pressure tested (make sure they remember to check the heater core along with everything else). This check should include checking the radiator cap!

During the system pressure test, a good system (with no leaks) should hold pressure for 2 minutes or more. The cap should do the same.
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
JNICOLE79
  • MEMBER
  • 2003 CHEVROLET IMPALA
  • 190,000 MILES
I have replaced the radiator, water pump, thermostat and thermostat sensor. My car goes to the hot side and turns off soon after starting to drive. It has plenty of water in it. It does not steam. I do not know what is wrong. Also I have had the head gaskets checked they are good. And when I push on the gas I hear a grinding noise. Please help me!
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
KEN L
  • ADMIN
Hi, does the engine seem hot? I am thinking it could be the engine temperature sensor or loose connection at the sensor which would cause the problem. Do you have a manual sensor like this?

Www.2carpros. Com/articles/how-to-use-an-infrared-temperature-meter to see if is really overheating?
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
NATESSBCS10
  • MEMBER
  • 2003 CHEVROLET IMPALA
Engine Cooling problem
2003 Chevy Impala 6 cyl

I have changed the water pump do to leakage now the car wants to heat up over 200 easy. But I can turn on the heat and it cools down, however when I turn on the ac it cools down alot faster like a steady drop to 160 -170
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
Check cooling fan may not be coming on with engine temp but does with AC. Check out fan relay and temp sensor.
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+1
Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
NATESSBCS10
  • MEMBER
Hasnt been long maybe 5 months replaced the relays for the fans and 1 of the fans also. Are you talking about the sending unit on the radiator or the temp gauge?Or is that the same one?
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
ECT located near coolant outlet left rear engine
Do fans come on with engine temp?


https://www.2carpros.com/forum/automotive_pictures/198357_Graphic_107.jpg

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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
NATESSBCS10
  • MEMBER
Yes the fans come on however they go alot faster with the ac on. Also I didnt bleed the air out of the lines looking to that now. My heat inside the car doesnt seem to be as hot as it should either.
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-1
Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
TONIS
  • MEMBER
  • 2003 CHEVROLET IMPALA
Engine Cooling problem
2003 Chevy Impala 6 cyl Automatic 100000 miles

just chgd thermastat, since that, heater puts out proper heat when idling, then cage drops down to 140 when driving, and gives out a little heat. Had a coolent flush. Still no chage
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
BLACKOP555
  • EXPERT
Sounds to me like you may have put in too cold of a thermostat, try to put in a higher temperature rated thermostat.
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Wednesday, August 1st, 2018 AT 7:51 PM (Merged)
Tiny
DP978
  • MEMBER
  • 2002 CHEVROLET IMPALA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 93,000 MILES
I bought this car in January of 2009 and since then it has been overheating constantly. Thankfully I don't need to drive it everyday, but I have put a hefty sum of cash into the vehicle and was hoping someone could give me the best prognosis for my problem.

First note - In the winter the car barely overheats, I assume due to the weather outside.

When does it overheat -
After 40 minutes of driving 65 mph +
Stop and go traffic
Idling

What I have fixed/done -
New thermostat/Radiator fan/Multiple Heater core and Radiator line flushes/had Head gasket checked, came back negative

Other symptoms -
The heat in the car will stop working and I will get a heater core flush hopefully to allieviate backed up hot air, not sure if this can cause overheating

After flushing out the radiator it appears to help, but uncertain, most machanics say that there is build up and sludge, one said it was rust piling up in the lines (is there something I can buy to get rid of the rust?)

The coolant can be murky, but does not smell like oil

Whats next -

I just don't know what it could be anymore, flushes seem to work, but that could be the introduction of new coolant into the system and very temporary. Could it be the intake manifold, which I read is bad on this model car, how would I check that?

Any other suggestions?

Thanks!
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
KHLOW2008
  • EXPERT
Hi DP978,

Thank you for the donation.

When overheating occurs and the radiator fans do not stop after starting, then the cooling efficiency is poor. Possible causes are :

1. Weak water pump.
2. Clogged radiator, normal flushing would not help, you need to remove the raditor to get the core internal lines cleared.
3. Bad thermostat. It is not opening sufficently.
4. Cooling fans not working.
5. Insufficient coolant in system.

Coolant should not be mixed, ie. Different brands in the system can cause clogging.

If the coolant is murky, it means the system could be clogged somewhere or has a lot of contaminants in it. One of the best way to check fior clogging and the condition of the coolant flow is to remove the thremostat and run the engine. If you can see the coolant flowing fast in the system then the water pump should be ok.

Let the engine run and replace the coolant with water to clear out any contaminant. Repeat a few times, each time allowing the water in system to heat up, which will then be able to clear the contaminants. A good radiator flush would help. It would be best to do the flushing over a period of a few days (without the thermostat to check if it is the cause).

Once the water in the system loooks clean, you can proceed to replace with coolant if it is not overheating.
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
DP978
  • MEMBER
Thank you for the response -

Can I ask a couple simple follow ups - I am by no means a mechanic or gifted when it comes to anything cars.

Just a few weeks ago I got both 1. A radiator flush and 2. My Coolant drained and replaced (so there should be no issue of mixed coolant brands).

After a couple of drives the coolant under the radiator cap is green with lots of specks of brown (does not smell like our) which a am assuming is rust or something that is making it murky.

Although I am not sure I would know how to 'remove the thermostat', I would want to check the flow of coolant, but how would I go about seeing if the coolant was 'flowing fast' or not? (Would I undo the radiator cap and see if anything flowed in there?)

Also, regarding your last paragraph about flushing it out with water, how would I go about replacing the coolant? Would I let the coolant spill out the radiator cap and pour in water in replacement? Or would I drain the coolant sommeplace else and put in water as it runs?

Edit: Should the fans come on immediately when the AC is turned on? It appeared that they were not turning, they are visible from the back of the radiator, correct? (The car was running at 220 f at this point)

Thanks for your help, I will definately be able to donate more once I am closer to some sort of answer.
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
KHLOW2008
  • EXPERT
The brown specks are an indication of contaminants and it could be rust or other foreign materials.

As to the overheatng, if the cooling fans are intermittently coming on and off, it could be caued by the Body Control Module or the charging system. There was a service bulletin out on this problem so I would suggest testing/checking if the cooling fans are working correctly as you have done the flushing so many times before.

Get the charging system tested to see if it is good.

The cooling fans should come on when the AC compressor is running. For some models there might be a slight deley at initial startup.

To flush with water, you would need to drain the coolant ut and refill with water.

To remove the thermostat, you would need to remove the thermostat housing located in fron of engine.
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
FRANKIE8991
  • MEMBER
  • 2000 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 120,000 MILES
First I have replaced the water pump and thermostat. And the water temp would get real hot then all of a sudden it would drop down to cool then it will go back up then back down. What could cause this. Thanks Frankie
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Air in the cooling system.
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
GREY-HAIR
  • MEMBER
  • 2002 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 170,000 MILES
1 1/2 years ago had the head gaskets replaced, they were the cause of overheating. Now it's overheating again. The water pump and thermostat have been replaced, the lower radiator deflector is missing. When I drive the car it will go to 210-220 I will then park and let it idle temp does not come down until I turn on the A/C the fans kick on and the temp comes down to normal. When the car was cold I drained some coolant out so I could see the first row of the radiator. With the cap removed I started the car when it got to normal temp I could see good flow out of the top row of the radiator. If I start the car and let it idle for at least a half hour it will run at normal temp never getting hot
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
Hi grey-hair. Welcome to the forum. Sounds like a problem with the coolant temperature sensor if the radiator fan doesn't turn on without having to turn the AC on. To verify the lack of a fan is causing the overheating, next time it runs too hot, turn the heater on maximum hot and fan on high. That will act like a small radiator.

Also check for multiple fan relays in the fuse box under the hood. Some cars have a low and a high speed relay and some have one for just the radiator fan and another that runs both the radiator and the AC fans. A fast test for relays is to switch two indentical ones around to see if a different circuit stops working.

Some vehicles, minivans in particular, use an electronic fan relay module with multiple inputs. That would also be a likely suspect.

Caradiodoc
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)
Tiny
GREY-HAIR
  • MEMBER
I just drove it 50 miles on the highway at first it was ok then comming back it ran at 210. Shouldn't ram air at 80 mph be sufficent airflow to keep it cool? Just now I ck'd the temp sensor and it has 5 vdc to it and through the sensor I see an open circut, I only had one fault and that was po420 I replaced the downstream o2 sensor and cleared the fault. If the temp sensor is bad shouldn't that show as a fault?
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Wednesday, October 24th, 2018 AT 1:29 PM (Merged)

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