New to me 2011 Yukon Denali

[KyleSM]

This car is awesome. The thing heats up under load though. Hauling a 4k lb trailer on the freeway, uphill on a hot day at low RPM gets the engine heating above were it usually sits. Performs better at high RPM, and has no issue at lower speeds, say 45 mph and bellow.

The oil change tag says 5w-30 was put in. I see 5w-20 is recommended.

Also, it appears an aftermarket air-intake has been installed.

Could the oil heat up like that? I see thicker oil heats up an engine, but as it gets hot it should get thinner.

Where should I start troubleshooting?

 

[Doubeleive]

WELCOME, how many miles on it?

 

[KyleSM]

160 000

 

[KyleSM]

I got no ECM codes, and noticed that the oil cap says 5w-30.

 

[OR VietVet]

Welcome to the forum from Oregon. I would check to see if there is any blockage at the a/c condenser and radiator that would block air flow across them. Basics first. Do you have maintenance records? How old is the thermostat? Coolant clean?


We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.


If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.

 

[KyleSM]

Turns out the ECM readout is lower than the one showing on the dash. Just a bad gauge maybe.

 

[Doubeleive]

Turns out the ECM readout is lower than the one showing on the dash. Just a bad gauge maybe.

Maybe but at that age and mileage it may be beneficial to at minimum flush the cooling system and use citric acid to clean it in the process, personally at this point I would flush it real good and then yank that old radiator out and put in a new one and while you are doing that replace the heater hoses and T's that split at the firewall those are well known to break off after being aged.

 

[KyleSM]

Maybe but at that age and mileage it may be beneficial to at minimum flush the cooling system and use citric acid to clean it in the process, personally at this point I would flush it real good and then yank that old radiator out and put in a new one and while you are doing that replace the heater hoses and T's that split at the firewall those are well known to break off after being aged.

Is this a common fix or issue? I like the idea of a new radiator, but would like to diagnose if possible. I'm thinking it may be a sensor issue. If the radiators get gunked up after so long than I could just do that. The only other one I've replaced was cracked and leaking, in obvious need of replacement, that was not an easy swop on that Volvo S70.

 

[Doubeleive]

Is this a common fix or issue? I like the idea of a new radiator, but would like to diagnose if possible. I'm thinking it may be a sensor issue. If the radiators get gunked up after so long than I could just do that. The only other one I've replaced was cracked and leaking, in obvious need of replacement, that was not an easy swop on that Volvo S70.

You can swap a 00-14 radiator in about 30 minutes, not hard at all, if you plan on doing your own maintenance you may want to invest in a clone tech2 for troubleshooting things just like this.
it's possible it could be a gauge problem but the gauge is not going to be perfectly in sync with the actual temp anyway, if it works properly just driving around normal and only heated up when towing or if it starts to get hot just idling on a warm day or with the ac on and idling that is a pretty good indicator that the cooling system needs a little tlc.

 

[KyleSM]

Prices aren't bad. I'll do a little research and probably grab one. Do you recommend any brand in particular? Is there such a thing as a high performance radiator?