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Discussion Starter · #1 · (Edited)
Miles: 250k
Problem: Car overheats

What my dad and I have done to the car:
1. Replaced Intake Gaskets.
2. Changed Coolant.....Twice
3. Replaced Thermostat....Twice
4. Flushed Radiator
5. Had Radiator acid dipped to clean it.
6. Water Pump Replaced.

What we have found: We have replaced parts and the coolant is flowing like it should but the car is still over heating...we have two things left to try then the car is going to get scrapped if it does not work.. thing 1. Replace the CTS and 2. See if the coolant is getting suck somewhere in the heating system because the pipe leading to the heater core was hot but the return pipe was cold

Any ideas on what else it could be?
 

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Discussion Starter · #3 · (Edited)
How quickly is it overheating? Did you bleed the cooling system?

Pat
Sitting idle Under speeds of about 30-40MPH it does not overheat it stays at about 170 to 180 but anything over 40 and it climbs in to the red in about 30 seconds and yes we have bleed the cooling system.
 

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Discussion Starter · #4 ·
We took it in to a shop and they said the head gaskets were fine on it but if they were wrong would it be worth it to fix the car since it would be a 1,500$ repair? The car in great working order is only worth 1,600$ and we have already spent 300 in parts and I bought 2 new tires for 230$ and I bought The car for 600$ it so I am in deep with this car already.
 

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Napa sells a combustion test kit. That will tell you whether head gaskets are good or not

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Personally, I would not put $1500 into a 12 year old car with 250k miles. That is a LOT of miles for a call like this. Might even be cheaper just putting a junkyard engine it instead.

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If you did the intake gaskets the heads are much farther into the tear down. I do head gaskets on 3.4s at least 6x a week. Here in my area head gaskets would run you maybe 40$ both sides and head bolts maybe 50$ or so...you wouldnt need to buy a kit considering you just replaced intakes....reuse them. But before jumping to conclusions make sure head gaskets are the issue

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Discussion Starter · #8 · (Edited)
If you did the intake gaskets the heads are much farther into the tear down. I do head gaskets on 3.4s at least 6x a week. Here in my area head gaskets would run you maybe 40$ both sides and head bolts maybe 50$ or so...you wouldnt need to buy a kit considering you just replaced intakes....reuse them. But before jumping to conclusions make sure head gaskets are the issue

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I will be getting the kit to make sure but the shop we took it to said the heads were fine. We are going to replace the Coolant temp sensor first and flush the heater core to see what comes out of it considering the guy that did the Radiator said it was very clogged.
 

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I will be getting the kit to make sure but the shop we took it to said the heads were fine. We are going to replace the Coolant temp sensor first and flush the heater core to see what comes out of it considering the guy that did the Radiator said it was very clogged.
yeah a coolant flush wouldn't hurt especially given you were told it was very clogged. there may be some debris in the system causing a clog that is not allowing fluid to pass freely about the system. for 100 bucks it's not a bad place to start....and at least then you'll know you have new fluid in the system.
 

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If your savvy with a ratchet, 6 inch extension and a 13mm socket you can do this flush yourself for about 25-30 dollars in supplies and an hour of letting the car run with the cleaner in the cooling system.. Go to autozone( i say autozone because they are the only ppl to carry the yellow mix- all coolant). Youll need 1 gallon of the mix all yellow and yes its full strength, small tube of black rtv, peak radiator cleaner/flush and a peak radiator tee kit. All will run approximately 25-30$.

1. Drain your cooling system through radiator drain then close after drained.

2. Remove your thermostat from the housing and reinstall the housing with black rtv to seal it up(leave thermostat out of the system. Give it about 10-20 mins for rtv to seal

3 add water and flush to radiator until its full. You wont have to worry about air as the thermostat is out so water should flood the block quickly. Run the car for maybe an hour with the flush.shut off your car after all said and done equip your tee into the heater core line( either will work) hook up a water hose to the tee, open radiator cap and drain plug and start your car with the hose filling the system while also emptying it at the radiator..the hose should force all gunk and blockage thru and out. Once the water runs clear and clean you should be able to completely drain the system, close her back up and add your gallon of mix all

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Discussion Starter · #12 ·
So we replaced the Coolant temp sensor and that helped a bit but it red lined on us again after two days so we just put the Blue Devil Head Gasket stuff in it as the last thing we are going to try....every other part of the cooling system and anything that could cause overheating has been looked at.
 

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So we replaced the Coolant temp sensor and that helped a bit but it red lined on us again after two days so we just put the Blue Devil Head Gasket stuff in it as the last thing we are going to try....every other part of the cooling system and anything that could cause overheating has been looked at.
When it red lined, were you sitting still, or moving? How fast?

I'm wondering if you don't have an intermittent relay on the cooling fans. Did you swap out any fan relays in all this?

Doug

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Discussion Starter · #14 ·
When it red lined, were you sitting still, or moving? How fast?

I'm wondering if you don't have an intermittent relay on the cooling fans. Did you swap out any fan relays in all this?

Doug

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Moving at interstate speeds and no we have not switched out fan relays.
 

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Moving at interstate speeds and no we have not switched out fan relays.
If it's pegging the needle at highway speeds, it's probably not a fan issue - interstate speed pushes lots of air into the engine compartment (ie, thru the radiator) even when the fans are off.

I'm thinking it's either a temp sensor issue (sensor or wiring), or you have a sticky thermostat. I know it's new, but you have the symptoms of one that's stuck.

If there's a temp sensor issue, I would expect you to see the temp needle jump to the red state. Do you recall - were you watching the needle - when it went into the red? Did it jump? Or climb into the red? If it moved smoothly, even if quickly, I'd say the temp sensor / wiring is good...which brings us back to a stuck thermostat.

I know it's a PITA - I just put a thermostat in one of my 2002 Impalas - but I'm thinking the next step is another thermostat, barring you selling it :(

Doug

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Discussion Starter · #16 ·
It was a smooth climb in to the red. We replaced the temp sensor a few days ago and that helped a bit and we have a fail safe thermostat in it so it should be flowing even if it is stuck.
 

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Discussion Starter · #17 ·
As per previous posts the car did have alot of sludge in it and when we were putting in the blue devil the car was spitting up coolant with particle in it. I am thinking about once again draining coolant and disconnecting hoses and running water though the Block and Radiator and heater core again to try to flush more of it out. I really want the car to work out but if it keeps overheating ill have to sell it to someone that has the time and money to show it some Extensive TLC
 

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It was a smooth climb in to the red. We replaced the temp sensor a few days ago and that helped a bit and we have a fail safe thermostat in it so it should be flowing even if it is stuck.
I agree, a fail safe would stick open.

As this point, you're down to only a few things left to try.

Check the wiring on the new sensor. You say the new sensor "helped a bit". I'm wondering if you have a broken sensor wire that is intermittent. Can you pull the wire out of the loom and inspect it?

Has the cooling system been pressure tested? Are you seeing any coolant loss?

Maybe try another shop, perhaps a radiator shop. Give them the history of what you've been thru. Maybe they can ID the cause of the needle pegging.



Doug

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Discussion Starter · #19 ·
We had the radiator cleaned at a radiator shop and he said the overheating should stop or slow down after it was done which is has alittle bit but its still doing it, With the car still spitting up dirty coolant should i just keep replacing coolant till its clean? Or is Coolant with particles in it normal?
 

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Discussion Starter · #20 ·
Also if this helps when the car is red lined and i turn the heater on the air that is blown in to the cabin of the car is cold.
 
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