New radiator is running colder

[David Kriss]

I have a 2001 Yukon XL with the 5.3 and the towing package. A couple weeks ago, the original radiator split a seam between the plastic and aluminum. I replaced it with an all aluminum one from Amazon (https://www.amazon.com/dp/B07Y7YNFDP?ref=ppx_yo2ov_dt_b_product_details&th=1). After putting the new one in, I noticed that the water temperature wasn't nearly as hot as before. It was one line below the 210 mark before. It was one small line below the big line halfway between 160 and 210 after the change. I replaced the thermostat. The temperature is now right on the big half way mark. Assuming the gauge is linier, the big mark should be 185 degrees and the thermostat is 187 so I think it should be about right. The fact that it used to run hotter makes me second guess myself. The new radiator is 3 row and defiantly thicker than the original. Is this normal with the better radiator? Could the sudden loss of water damage the temperature sensor? The original radiator was pretty dirty on the front. Could it have been not cooling properly? I bought the truck new and I think it always ran close to 210, but it may have creeped up over time and I didn't notice the slow change. It's my wife's truck and I don't drive it that often. I don't mind the temperature being a little cooler but it needs to run hot enough to run properly.

 

[adventurenali92]

Slightly below the mark 210 is correct running temp on the gauge for these trucks. The factory radiator has a valve installed in the top hose that feeds coolant back to surge reservoir that keeps too much coolant from flowing back into the reservoir. A lot of aftermarket radiators, especially the newer aluminum style ones do not have this valve installed so too much coolant flows freely back into the reservoir which causes the truck to not get up to proper running temp. This is more than likely your issue. Pull the hose from the top that runs to the surge reservoir and shine a flashlight over it to verify if there’s a valve installed in it or not. If it doesn’t have one than that’s probably your issue.

 

[OR VietVet]

Just a quick method to see if in fact this is the problem, use a small hose clamp and put on the hose in front of the spout where you reinstall the hose. Then squeeze the hose a bit and drive to see if the smaller hose inner diameter corrects the temp reading. The correct temp reading is just below the 210 mark, just like what @adventurenali92 said.

 

[Marky Dissod]

Just a quick method to see if in fact this is the problem:
use a small hose clamp and put on the hose in front of the spout where you reinstall the hose.
Then squeeze the hose a bit and drive to see if the smaller hose inner diameter corrects the temp reading.
The correct temp reading is just below the 210 mark, just like what @adventurenali92 said.

This seems to imply that one can use this supplemental hose clamp to 'calibrate' the temperature at which one would prefer their truck to operate ... ?

 

[nonickatall]

I had the same problem and i searched for hours. I didnt change the radiator the the thermostat.

Speaking of thermostat, have you checked this? Not that any chunks of the broken radiator ended up in there?

But in my case it was the cooling temperature sensor connector. I pulled it off and put it on a few times to scrape the contacts free, and my temperature has been right since then.

Sometimes you have lice and fleas, as we say in Germany.

 

[nonickatall]

This seems to imply that one can use this supplemental hose clamp to 'calibrate' the temperature at which one would prefer their truck to operate ... ?

No, when the correct orifice is installed, the Temperatur is correct, when everything else of the coolant system is correct.

If the orifice is missing, your car is not geeting warm (fast) enough.

When I searched for my problem I closed the hose, just for test purposes and nothing really changed.

When you close the hose permanent, it can lead into high pressure in the system, which damages your new cooler.

 

[Marky Dissod]

No, when the correct orifice is installed, the temperatur is correct, when everything else of the coolant system is correct.

If the orifice is missing, your car is not getting warm (fast) enough.

When I searched for my problem I closed the hose, just for test purposes and nothing really changed.

When you close the hose permanent, it can lead into high pressure in the system, which damages your new cooler.

Firstly, I'm not thinking in binary terms; closed vs open, correct vs incorrect, OE vs not OE ...
Secondly, I'm not suggesting closing it completely.
I'm suggesting opening it a little more for the summer, and a little less for the winter.

 

[nonickatall]

Firstly, I'm not thinking in binary terms; closed vs open, correct vs incorrect, OE vs not OE ...
Secondly, I'm not suggesting closing it completely.
I'm suggesting opening it a little more for the summer, and a little less for the winter.

From my point of view that makes no sense. Because the variance of that hose is not big enough for adjusting, and whats worse, it bypass your thermotate which keeps the engine longer away from operation temperature, which is bad for your engine and fuel consumption.

If you want to have a different configuration for summer and winter, shade a part of your cooler in the cold time with a temperature resistant material like plastic or tinplate.

Just my humble opinion.

 

[David Kriss]

I had the same problem and i searched for hours. I didnt change the radiator the the thermostat.

Speaking of thermostat, have you checked this? Not that any chunks of the broken radiator ended up in there?

But in my case it was the cooling temperature sensor connector. I pulled it off and put it on a few times to scrape the contacts free, and my temperature has been right since then.

Sometimes you have lice and fleas, as we say in Germany.

I replaced the thermostat and the temperature only rose about one line on the gauge.

 

[blackelky]

I had the same type of thing when I installed a factory aux trans cooler. Trans temp stays around 160 now before it was 180-200 when towing. I wonder if you're engine is really running that cold on a code reader machine.