Radiator Over Cooling

[Calicajun]

Changed out the radiator in my 2013 Tahoe from the stock one to a radiator that allowed me to installed the engine oil cooler lines. The new radiator is an all aluminum core with aluminum side tanks for the trans and oil cooler lines. I have also installed an external trans cooler (it work great).
The two problems I am having now are; the engine temp while driving only gets up to about 170 to 180. If the Tahoe is just sitting the temp will get to 210 degrees and stay there but soon after driving the temp drops. Even towing a 6,000lbs travel trailer for 700 miles the temp rarely made it to 210. The other problem that has started is once every few days the temp gauge stays at zero and a message shows up saying "engine hot A/C turned off". Then if I disconnect the battery for a couple of minutes everything resets and the gauge starts working again and the message goes away.

I had a new factory thermostat installed with the new radiator, so I'm at a lost as to what is going on the Tahoe. The only idea I can come up with is that the thermostat doesn't close all the way allowing water to flow all the time. Are thermostats suppose to stay open a little or close off completely? Anyone have any ideas or suggestions. Or the newly installed oil cooler lines going into the aluminum radiator side tank is cooling the engine oil too much cause a drop in engine temp?

Thanks,
Craig

 

[rockenthebowtie]

Check the connector at the coolant temperature sensor it's located on the driver side of the engine cylinder head in front of the #1 cylinder spark.. might want to disconnect it make sure the terminals on the harness side are not to spread open causing a poor connection... as far as temperature not reaching 210 while driving you do have to take into consideration of the outside ambient air temperature, especially while driving because the ambient temperature will drop more when being pushed through the radiator cooling fins and the aluminum side tanks, aluminum is a very good if not the best heat sink property

 

[Calicajun]

Thanks for the tip, maybe now that engine overheat message will stop showing up.
Sound like good thing to check out. In fact I just went out to check and clean that connector. Don't think it was ever touched when changing out the radiators but then again it is hard to watch everything the shop is doing while they work on a car.


Thanks again,
Craig

 

[rockenthebowtie]

There was a post on here a while back where the guy changed out his spark plugs and started having the same issues I know its a little differnt from your situation but he must of bumped the coolant sensor while changing out the plugs because after I lead him there and*suggested*the same thing as to you it started operating normal again.. wish you the same good luck... oh and yes your very welcome.. Some folks on here sometimes dont realize how far a simple thank you can get you : )

 

[Calicajun]

I did go out and check the sensor, will have to wait and see it that fixed that problem.
I just change out the thermostat, even though the existing one looked good. The Tahoe is now running well within normal operating temperatures. At first I thought it must have been the thermostat but after test driving the Tahoe around some it dawn on me. The shop just put too much antifreeze in the radiator. Okay, so it hit me while I was washing off the driveway from all the coolant that split out while changing the thermostat. To much antifreeze will cool an engine more than it should along with other little problems.
Again thanks for the tip,
Craig

 

[rockenthebowtie]

Ok only just an fyi the cooling system only holds a specified quantity of coolant its not possible to much coolant will cause a cooling system to run cooler however to little coolant will cause it to run above operating temperature and or over heat

 

[Calicajun]

True, I didn't mean it to sound like they put in more than the radiator can hold. I meant they put almost all antifreeze and no water, instead of a 50/50 mix of coolant and water. Though being a manufacturing engineer working with design engineers for the last 27 years, I'm not real sure if they couldn't find a way to put 5 gallons on liquid in a 3 gallon tank.lol

 

[Calicajun]

Update:
Still no luck, thought the problem had been solved but no both problems are still showing up. The engine hot message still comes up every three days or so and goes away after disconnecting the battery. My son had a thought on this problem, he was wondering if the new larger radiator could have less pressure in it due to the larger volume tank and that might be causing a sensor to get a false reading. Are there any pressure sensors or any sensors that can be affected by too large radiator? Still can't figure out why the temperature gauge is reading 170 degrees while driving down the freeway. The temperature gauge does read 210, never any higher, around town. Is there any way to tell what the actual engine temperature is, as I really don't trust the in dash gauge?

Thanks,
Craig

 

[Gear Head]

Same exact problem with my 2002 - 5.3 - temperature gauge sits at 165-170 degrees while driving down the highway at 80MPH. Baffling me! I replaced the radiator over the summer (same one), flushed the system and replaced the deathcool with green - added a new temperature coolant sensor and a new thermostat - no luck in getting the operating heat back to the 185 mark on a constant basis.

Any suggestions would be greatly appreciated

 

[Calicajun]

Gear Head,
Did you add engine oil cooling lines with the new radiator?

 

[Gear Head]

No - I replaced the radiator with the same one (obviously a new) with no oil cooling and no transmission cooling lines.

 

[Calicajun]

Mine replacement radiator is a double cooling core with engine oil cooler lines. The old radiator already had trans cooler lines.
I just tried (some engine oil still on my hands) disconnecting the oil cooler lines and did a test drive. The engine temp gauge still read lower than I think it should but didn't get as low as before by about 10-15 degrees. Still too low and I don't understand why the temp drops so much and stays low while driving on downhill or on flat roads.

 

[Calicajun]

It been suggested to me that sometimes when changing a radiator that pockets of air get trapped in the engine block. That running the engine up to operating temperature with the radiator fill cap off will remove the air pocket/bubble. So far this is the only thing I have left to try that makes any sense to me, so I will give it a try and see what happens.

Any other suggestions are welcome,
Craig

 

[Kunihiro]

From your initial post, correct me if I'm wrong, but if the vehicle is in motion, the temperature appears to be fine, but sitting at a stoplight or for some other reason, the engine temp appears to rise? Is this correct?

What type of fan are you using? Electric or pump driven?

Here is why I ask. when I had my 71 Camaro, I installed an aluminum "Be Cool" radiator to my custom built motor. The motor would be nice and cool while the vehicle was in motion, but as soon as I stopped at a stop light or something, the engine temp would begin to rise. This radiator system utilized a dual fan set up. One fan was utilized just for the motor and the other fan kicked on when I turned on the A/C.

As it turned out there was a small gap that encompassed the entire electric fan shroud. So, when stopped, the fans would suck air through this small gap between the radiator fins and the fan shroud, which obviously was on the motor side of the engine compartment, thus not allowing cooler air through the radiator fins. The fix was to have a small piece of aluminum to seal the gap, thus allowing the fans to pull air through the radiator and not behind it.

Just my thoughts, since you installed an aluminum radiator....

 

[Calicajun]

From your initial post, correct me if I'm wrong, but if the vehicle is in motion, the temperature appears to be fine, but sitting at a stoplight or for some other reason, the engine temp appears to rise? Is this correct?

What type of fan are you using? Electric or pump driven?

No, just the opposite, if the car is sitting still the temp will reach normal operating temps. When driving down the hwy the temp gauge drops to 165-175.

 

[Kunihiro]

No, just the opposite, if the car is sitting still the temp will reach normal operating temps. When driving down the hwy the temp gauge drops to 165-175.

ah,,,ok....thanks for clarifying.

 

[BlessedHellRide]

was this a dealer install, what was the cost? thanks

 

[Calicajun]

was this a dealer install, what was the cost? thanks

No, this was done by an after market shop.

 

[Metaldrgn]

The only thing I could see that could effect this is the thermostat. If it's working properly your engine shouldn't get below 205 or whatever it's designed for while driving. I have a Yukon and Tahoe and it's the same for both even down to -27 F.

 

[Metaldrgn]

I did go out and check the sensor, will have to wait and see it that fixed that problem.
I just change out the thermostat, even though the existing one looked good. The Tahoe is now running well within normal operating temperatures. At first I thought it must have been the thermostat but after test driving the Tahoe around some it dawn on me. The shop just put too much antifreeze in the radiator. Okay, so it hit me while I was washing off the driveway from all the coolant that split out while changing the thermostat. To much antifreeze will cool an engine more than it should along with other little problems.
Again thanks for the tip,
Craig

Antifreeze is actually less effective at transferring heat than just water so your engine would just run hotter. As the name implies it's also used in lower temperatures to prevent freezing and in general to prevent corrosion/rust I believe.

Did you change the thermostat or someone else? There's the possibility that you got a shady mechanic that didn't actually change it out and just pocketed the money if someone else did the work.