08 Denali engine overheating

[dlr2416]

My 08 Denali will run 210 all day long, but as soon as I hook up my 5000 lbs trailer and start up any hills (even in 65 degree weather) the engine water temp will take off (235+ degrees). I want to know if there is an after market radiator with better cooling abilities or if there is something else I can do to keep the engine temp down.

Any suggestions are appreciated.

 

[sumo]

How many miles in it? How's the level of coolant? Maybe it's time for a coolant system flush.

 

[t.stimpson]

i agree. Flush it and put in new coolant. my 09 has never overheated when towing my camper unless its 90 degrees out and the air is on max.

 

[dlr2416]

125k miles and I have recently flushed radiator and replaced thermostat. Starts to stress me out towing up hills.

 

[sumo]

Possible still have air trapped in the system. Won't hurt to bleed system more

 

[dlr2416]

I've put at least 10k miles on it since the fluid replacement. Is there still a possibility there would be air in the system after that amount of time? The issue is hit or miss. I pulled up a mountain for a few miles in heat on and off the gas on a road with a lot of curves no heat issues, then up a long straight away mountain constant speed and heat starts to climb. I'm so confused as to why this is happening.

 

[2007tahoe]

Is the radiator fan working correctly? if u already changed the thermostat and coolant level is good, the radiator fan would be the next thing i look at. I pulled numerous 5000 lb trailers in 100+ weather with no issue.

 

[AZSCTACO]

I would try "burping" the cooling system. This happened to me before because there was some air trapped in the system. It's a closed system so even though you did it 10k ago, there still could be air in it. See below on how to burp:

http://automotivemileposts.com/garage/v2n15.html

 

[dlr2416]

Is the radiator fan working correctly? if u already changed the thermostat and coolant level is good, the radiator fan would be the next thing i look at. I pulled numerous 5000 lb trailers in 100+ weather with no issue.

I believe the radiator fans are working properly. I have manually check the relays and the fans sound like they are spinning fast when the engine is hot. I recently pulled to the side of the road when it got hot and hear the fans running real hard.

 

[dlr2416]

I would try "burping" the cooling system. This happened to me before because there was some air trapped in the system. It's a closed system so even though you did it 10k ago, there still could be air in it. See below on how to burp:

http://automotivemileposts.com/garage/v2n15.html

I will take a look at the cooling system again. I will try the burping thing. I'm not quite sure how this would work with the closed system but never the less I will try it.

I guess next thing I can try is radiator and pump replacement.

Does anyone know if there is a good aftermarket radiator that cools better than the OEM radiator?

 

[rubicon1976]

My 08 Yukon Denali 6.2L just started doing the same thing last weekend. I was pulling my ~5000lb trailer into the mountains and it overheated to the point where it shut off on me. An hour or so later it started up and seemed to be cooling fine but I noticed pulling up even slight grades for extended periods between CO springs and Denver the temp would start climbing pretty quickly. I've been driving it around Denver all week with no trailer and it has been fine. Did you ever find the problem?

 

[Doubeleive]

swap out your radiator, my opinion is most will get clogged up after 5 years, you can try flushing it and running some chemicals thru it but it might not do much good if you haven't already been doing that annually.
1800radiator has a 1 3/8" radiator with both trans cooling and oil cooling lines (if you are so equipped) if not it doesn't matter it will still work
they have also added a drain **** that GM so thoughtfully deleted
and it has a lifetime warranty
choose #103285 it will fit all 07-13 Tahoe, suburban, Yukon, Yukon xl, escalade, escalade esv. and probably many other full size trucks

 

[gpracer1]

General rule of thumb assuming the thermostat is good and fluid level is full......
Poor cooling at low speed or low load is usually air flow problem.
Poor cooling at highway speeds and under heavier load is usually water flow problem like clogged radiator.

 

[gooffeyguy]

What is the trans temp both when and when not towing?

Sent from my SM-G930V using Tapatalk

 

[muncie21]

Another vote for looking at the transmission side of the issue