Why do you think it is overheating? Is it based upo the dashboard gauge?
Did you install an OEM ACDelco unit, or an aftermarket (Chinese) one?
Overheating After Radiator Replacement
My 2005 Impala (base 3.4) has a new engine and transmission. We recently noticed a very big coolant leak, and found the radiator was cracked.
We replaced the radiator, thermostat, and rad cap, and now having running hot/overheating issues. We have bled the air, but still no luck. The car can idle for a long time and will remain at the half-way point (which is still hotter than its normal operating temperature). As soon as we hit the road, it jumps up to 3/4 and stays there.
The heater blows hot air fine, and we are not noticing any other issues. The thermostat opens and none of the hoses are visually externally collapsing.
Where do we go from here?
We replaced the radiator, thermostat, and rad cap, and now having running hot/overheating issues. We have bled the air, but still no luck. The car can idle for a long time and will remain at the half-way point (which is still hotter than its normal operating temperature). As soon as we hit the road, it jumps up to 3/4 and stays there.
The heater blows hot air fine, and we are not noticing any other issues. The thermostat opens and none of the hoses are visually externally collapsing.
Where do we go from here?
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Why do you think it is overheating? Is it based upo the dashboard gauge?
Did you install an OEM ACDelco unit, or an aftermarket (Chinese) one?
Yes, we are basing it off of the dash gauge. Radiator is an aftermarket one, unfortunately.
Either plumb in a known good gauge or buy a infrared thermometer.
Pat
Pat
Are the fans coming on? They run at three speeds: both at ¼, one a full (the other off), and both at full.Yes, we are basing it off of the dash gauge. Radiator is an aftermarket one, unfortunately.
When the gauge gets up past halfway, stop and open the hood, and check what state the fans are in. You want to see that they are both running at full speed.
If there's a wiring problem, such as one fan not connected, or a relay problem - there are 3 relays which control the fans - then, when the fans are supposed to be running at one speed, they may be running at a lower speed or off, which would allow the temp to rise some.
That said, when the gauge is at ¾, it's still in the safe operating area.
One other thought, what temp rating does the new thermostat have?
Doug
.
Yup, both fans are running. The thermostat rating is 180.Are the fans coming on? They run at three speeds: both at ¼, one a full (the other off), and both at full.Yes, we are basing it off of the dash gauge. Radiator is an aftermarket one, unfortunately.
When the gauge gets up past halfway, stop and open the hood, and check what state the fans are in. You want to see that they are both running at full speed.
If there's a wiring problem, such as one fan not connected, or a relay problem - there are 3 relays which control the fans - then, when the fans are supposed to be running at one speed, they may be running at a lower speed or off, which would allow the temp to rise some.
That said, when the gauge is at ¾, it's still in the safe operating area.
One other thought, what temp rating does the new thermostat have?
Doug
.
The only other thought I have is water pump. You've replaced most everything else. But I would also follow the other suggestions and try to get a good read of the temp to compare with the gauge before you do that.Yup, both fans are running. The thermostat rating is 180.
Doug
.
We replaced the water pump today, and it’s still replicating the exact problem. Gets to half while idling and shoots up to 3/4 as soon as it drives. One other thing I noticed was the half of the top radiator hose closest to the rad is cool, but the half closer to the engine is hot (but not as hot as the bottom hose). I thought it was because of the fans, but it’s actually like air temperature cool.The only other thought I have is water pump. You've replaced most everything else. But I would also follow the other suggestions and try to get a good read of the temp to compare with the gauge before you do that.Yup, both fans are running. The thermostat rating is 180.
Doug
.
Please stop wasting money! Please do some diagnostics. You have a computer to get some easy information, please use it glean some ideas. Please use the idea that I suggested above. The infrared guns can be had for $20 at harbor freight and home depots have them for ryobi around $25 IIRC
Open the radiator cap slowly when the car reaches operating temp. Then look into radiator to see if it's flowing through cores. The thermostat was it replaced just because it was in the process along with the radiator? or was it part of the shotgun part process?
My avatar a few years back as part of basic maintenance I replaced all hoses and thermostat. Then some time afterward noticed that the hot light would come going down the road at 55 mph plus. Did the same process above and found that when bring the RPM up the flow should increase. I did not even at 4k. Aha thermostat is not opening all the way. The unit that failed was a USA made Robert Shaw. I did not have the time to return the faulty unit in for warranty and bought a china made unit from parts plus. That one has been working great for several thousand miles.
Pat
Open the radiator cap slowly when the car reaches operating temp. Then look into radiator to see if it's flowing through cores. The thermostat was it replaced just because it was in the process along with the radiator? or was it part of the shotgun part process?
My avatar a few years back as part of basic maintenance I replaced all hoses and thermostat. Then some time afterward noticed that the hot light would come going down the road at 55 mph plus. Did the same process above and found that when bring the RPM up the flow should increase. I did not even at 4k. Aha thermostat is not opening all the way. The unit that failed was a USA made Robert Shaw. I did not have the time to return the faulty unit in for warranty and bought a china made unit from parts plus. That one has been working great for several thousand miles.
Pat
Thankfully the water pump was on warranty, so it didn’t cost anything. I’ve been reading online and is suggesting the thermostat (which was replaced as part of the process, not afterwards). I will be getting something to check the temperature of the coolant tomorrow. Tough with only one car now and two people with jobs that are 50+ miles apart.Please stop wasting money! Please do some diagnostics. You have a computer to get some easy information, please use it glean some ideas. Please use the idea that I suggested above. The infrared guns can be had for $20 at harbor freight and home depots have them for ryobi around $25 IIRC
Open the radiator cap slowly when the car reaches operating temp. Then look into radiator to see if it's flowing through cores. The thermostat was it replaced just because it was in the process along with the radiator? or was it part of the shotgun part process?
My avatar a few years back as part of basic maintenance I replaced all hoses and thermostat. Then some time afterward noticed that the hot light would come going down the road at 55 mph plus. Did the same process above and found that when bring the RPM up the flow should increase. I did not even at 4k. Aha thermostat is not opening all the way. The unit that failed was a USA made Robert Shaw. I did not have the time to return the faulty unit in for warranty and bought a china made unit from parts plus. That one has been working great for several thousand miles.
Pat
I winder if the DexCool was mixed with green? If so, you are making cement in your cooling runs everywhere. When you replaced the coolant/radiator, did you notice any gel looking substances in there? DexCool loves to gel when exposed to air (bad radiator cap) and mixed with green coolant. Plus, knowing the temperatures in places is helpful too.
No green has been in this car, and all the coolant looked watered down and thin, not gel-like. We haven’t touched it in a few days because it’s been non-stop pouring rain. Hopefully tomorrow.I winder if the DexCool was mixed with green? If so, you are making cement in your cooling runs everywhere. When you replaced the coolant/radiator, did you notice any gel looking substances in there? DexCool loves to gel when exposed to air (bad radiator cap) and mixed with green coolant. Plus, knowing the temperatures in places is helpful too.
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