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?

 

[Doubeleive]

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?

OEM if you can get one reasonable, rockauto usually has good prices, I would stay from cheap ones they tend to be more trouble than they are worth, I bought mine from 1800radiator paid probably as much as a oem one would have been but I got a lifetime warranty and it was a smidge thicker than a oem one, if you have a local radiator shop they usually can swing a good price for oem or a quality brand name we have one here where I live they only sell radiators they don't do installs so they are more commercially priced they mostly sell to the repair shops who in turn mark them up.

 

[Geotrash]

The behavior that you’re describing is normal on these rigs in my opinion. I have both a 2007 and a 2012 Denali, and pull a 3000 pound trailer often. On a hot day, going uphill at low RPM, my temperature gauge creeps up to between the 210 mark and the one above it. Happens on both rigs. I’ve read a lot about towing with these things, and others have said the same. The only thing that keeps these things cool pulling a trailer in hot weather is an aftermarket transmission cooler. Seems to help both transmission and coolant temperatures.

Keep in mind that the boiling point of a 50/50 mix of antifreeze and water at 12 psi cooling system pressure, will be 259°F so there is plenty of margin built into the cooling system even if the temperature creeps up over the 230 mark.

Also, 5w-30 is what you want, especially pulling in hot weather.


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[Klewis]

The behavior that you’re describing is normal on these rigs in my opinion. I have both a 2007 and a 2012 Denali, and pull a 3000 pound trailer often. On a hot day, going uphill at low RPM, my temperature gauge creeps up to between the 210 mark and the one above it. Happens on both rigs. I’ve read a lot about towing with these things, and others have said the same. The only thing that keeps these things cool pulling a trailer in hot weather is an aftermarket transmission cooler. Seems to help both transmission and coolant temperatures.

Keep in mind that the boiling point of a 50/50 mix of antifreeze and water at 12 psi cooling system pressure, will be 259°F so there is plenty of margin built into the cooling system even if the temperature creeps up over the 230 mark.

Also, 5w-30 is what you want, especially pulling in hot weather.


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Agreed. I have 2011 Denali XL with the 6.2 liter and going uphill for long stretches even without a trailer my engine temps are above 210 but never more then 235. When towing it won’t get above 235 on the hills. It freaked me out at first.

Just got back from Yosemite and my trans temp hit 241 with no trailer!! I have the trucool ready to install this weekend.

I already installed the 700w fan and am also looking to upgrade my radiator as well.

Let me know if you find a good radiator upgrade.

 

[thompsoj22]

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?

ACDELCO RockAuto, Stay oem as much as possible. Heating up with 4k lbs behind you is bound to happen, what is the trans temp?

 

[thompsoj22]

Agreed. I have 2011 Denali XL with the 6.2 liter and going uphill for long stretches even without a trailer my engine temps are above 210 but never more then 235. When towing it won’t get above 235 on the hills. It freaked me out at first.

Just got back from Yosemite and my trans temp hit 241 with no trailer!! I have the trucool ready to install this weekend.

I already installed the 700w fan and am also looking to upgrade my radiator as well.

Let me know if you find a good radiator upgrade.

JMO, consider a bigger alt DENSO 6860 220 amp and install a 1.9 inch overdrive pulley. That 700 watt motor draws 55 amps to go to high speed and at an idle it may cause problems, also run a "new" 7 blade fan on that motor for max cooling effect. I have to think somthing is not right to hit 241 trans temp without towing? stick to ACDELCO oem radiator. do you have the dual fan setup? and if so which side are you running the 700 watt motor? My opinion is you want the 700 watt motor and 7 blade fan on the drivers side as this is the coolant "hot return" and you want to pull as much heat as possible as quickly as possible. Feel free to disregard all of these tid bits as useless info!, just how im controlling heat on our 08 xl1500 6.2 143,000k

 

[Doubeleive]

hmm, the one only time my temp ever even budged was at 8000 feet 70 degrees outside and doing about 95mph for a extended period and that was with 700w fans a fresh radiator and trucool 40k, (trans temp stayed at 165) on both my 00 and my 03 I replaced the radiator when they started to budge over the normal center line and they both stopped doing it with the new radiator installed.

 

[bill1013]

If you have the bucks see if an all metal one is available. My Tahoe had an aluminum core, but the ends were high impact plastic with the core wrapped around the plastic ends. Trouble was the plastic weakened over time, from the heat, and it eventually cracks or splits at the seem or right at the filler neck below the cap seat. I ended up getting the OEM part as the all metal one was $900 and it would take about a week to ship it out here. I used my Tahoe as a daily form of transportation and couldn't wait. Plus, they had plenty of the OEM radiators and I think they were only $250. Big difference! But in the end...it's all up to you. Hope this helps!

Bill1013

 

[OR VietVet]

There are some options, I would have to look for them but will let you, of companies out there that make custom all aluminum radiators. They will bolt right in.

 

[Klewis]

There are some options, I would have to look for them but will let you, of companies out there that make custom all aluminum radiators. They will bolt right in.

I’ve been looking around online to find reviews on Cold-Case Radiators. They look good but some reviews indicate that fan shroud won’t fit back on without modification. Close to pulling the trigger on one

 

[Joseph Garcia]

If you go with the project scope of replacing the radiator, I'd highly recommend replacing all rubber hot water hoses. I recently had a heater hose blow out on me, and was not a pretty sight. I ended up replacing all of them, and they were all labeled with the original year of manufacture for the truck.