2013 Tahoe engine temperature fluctuations

[Dave McLean]

Hey everyone...I’ve been hunting around looking for some help, and can’t seem to find what I’m looking for. If there’s a link, feel free to point me in that direction. Anyway...

My 2013 LTZ seems to have some cooling gremlins I can’t figure out. I’ve had it for three years and the temp has been rock solid 210 - regardless of the outside temp, towing, etc. Now it will creep up to 230, usually in traffic or slow. High speed fans then cut in and the temp goes down. No dash lights or over temp yet. Has happens at speed, but not so often. Almost seems like it’s a delay and the fans should come on earlier?

Fans come on with AC as expected and I tested all three relays and they “click” as advertised. Not throwing any codes and coolant is good - changed it couple of years ago (now 45K total miles). Is there something else I can try to troubleshoot? Thermostat?

Hoping to get some ideas before I take it to the shop or start the “replacing parts” diagnosing technique.

 

[Doubeleive]

Hey everyone...I’ve been hunting around looking for some help, and can’t seem to find what I’m looking for. If there’s a link, feel free to point me in that direction. Anyway...

My 2013 LTZ seems to have some cooling gremlins I can’t figure out. I’ve had it for three years and the temp has been rock solid 210 - regardless of the outside temp, towing, etc. Now it will creep up to 230, usually in traffic or slow. High speed fans then cut in and the temp goes down. No dash lights or over temp yet. Has happens at speed, but not so often. Almost seems like it’s a delay and the fans should come on earlier?

Fans come on with AC as expected and I tested all three relays and they “click” as advertised. Not throwing any codes and coolant is good - changed it couple of years ago (now 45K total miles). Is there something else I can try to troubleshoot? Thermostat?

Hoping to get some ideas before I take it to the shop or start the “replacing parts” diagnosing technique.

sounds like the most likely scenario is the radiator is not working as efficiently as it once did, replacing the radiator will likely resolve your issue, you can try flushing it and using some citric acid (radiator flush) but it may be too late for that it really depends on what your maintenance schedule has been, I always flush mine annually (regardless of miles) and use the radiator flush each time in the process. I have had the same issue you are reporting happen before on previous vehicles and replacing the radiator with a new one resolved the issue completely.
as long as you are not having to add coolant or seeing it get hot pretty much all the time then it's the radiator. if it was running hot all the time then I would lean more towards the water pump, and if it was loosing coolant then you would be looking for a leak.

 

[Foggy]

It sounds like your LOW speed fan operation is not working correct..
The low speed should come on about 220* ish , then the high speed will
trigger about 230* ish IF the temps keep increasing
Both fans will always operate at the same level: off, low or high

Or you could have a bad temp sensor. Bad thermostat. Coolant Leak causing
a low coolant situation and/or air in the cooling system.
A bad pressure cap on the tank will also cause gremlins

Lots to chew on, yes...

 

[avalonandl]

How many miles and what about water pump. They tend to go bad.

 

[Dave McLean]

How many miles and what about water pump. They tend to go bad.

Thanks everyone. Good ideas. I only have 45K miles and flushed may two years ago?

I’ll check the fans again. While I just used the dash gauge, I think the low speed came on about right. The temp sensor should be pretty easy and cheap to replace.

I’ll keep everybody posted on my progress.

 

[Dave McLean]

Um, well...I ah... figured it out. Seems my coolant was low . Sometimes ya just miss the obvious. Odd it was that low, so I'll keep an eye on that. Thanks!!

 

[avalonandl]

Those LS pumps will leak fluid thru a weep hole on the back side....