Coolant Pressure 6.0L Vortec

[adventurenali92]

I agree with @TheAutumnWind , a trans cooler upgrade is definitely the way to go!

 

[millerladam]

Personally, I have never had need to try and find a larger radiator. That being said, a very quick search on Rock Auto, found that the same radiator from spektra is used in the '07 Yukon XL 6.2L 1500, 6.0L 2500 and Sierra 6.0L 2500. The 6.6L D-max Sierra 2500 uses a different radiator. Chances are, that the D-max radiator has more cooling capacity, but should probably bolt in.

You could order one for the d-max from Amazon and see if it fits. If it does, then you have your answer, if not returns are pretty painless with Amazon.

Thank you for the search. For some reason every time I am trying to cross reference one part for one vehicle to another, I can never figure out how to do it. I am a website developer and server engineer but some websites just suck for comparing in my opinion. That being said, it's also funny that you mention the Duramax radiators. I am in the process of rebuilding my LLY (bought a remanufactured one after blowing mine up) and happen to have a brand new radiator sitting in my garage for it. I know the body styles changed but I wonder what the chances of the radiator being the same are? My Duramax is a 2005 3500 body.

 

[Jason_S]

An '05 and an '07 have different part numbers. Doesn't mean that it wont fit or work, but something is different.

 

[millerladam]

Well, the saga continues. So today I replaced the water pump, both belts, and the idler pulley. I proceeded to flush the entire cooling system with distilled water even though the DexCool coolant says tap water is fine. I used approximately 8 gallons to flush the system from everywhere I could until the water was coming out clear. I put everything back together and filled the system with 1 and 3/4 gallons of coolant. I turned the heat on and let the truck get up to operating temperature with the reservoir cap off. I then put the cap on, drove it around the block, came home grabbed a few things and drove to the dealership because when I had it in Saturday they forgot to put the damn clamp back on the intake pipe to the air box (the reason why I don't bring my vehicles to the dealer). While sitting for about two minutes, it moved probably 5 to 10 degrees above normal operating temperature. When I get home, I will let it cool down completely and then check the coolant level. Besides swapping the radiator and replacing the hydraulic fan with electric fans, does anyone have any other ideas of what is going on? Is this normal? The temperature outside today is around 100 degrees with 80% plus humidity and the transmission reached 190 degrees on the way here. I still think there is an issue with the transmission getting to warm when I am not driving it hard or towing.


Any next steps are highly appreciated! Thank you.

 

[TheAutumnWind]

@ 100 degrees ambient I was seeing ~190* trans temps when stock in stop and go traffic.

 

[millerladam]

@ 100 degrees ambient I was seeing ~190* trans temps when stock in stop and go traffic.

Okay, so even if that is normal, why in the hell is the engine getting over 210* sitting at idle for a couple of minutes? On my way home, I stopped and grabbed my toy hauler from it's storage which is about 5 miles from my house and is flat terrain. The engine temperature reached a little more than half way between the half way line and the third quarter line, so somewhere around 220* to 230* with the air conditioning on. I turned the air conditioning off for the half a mile or so which is a school zone and then into my neighborhood. When I did this, the engine temperature dropped back down to around 215* or so, still slightly above the 210* half way mark on the gauge. I am afraid of the truck overheating while towing my toy hauler this weekend. Should I be concerned or should I just tow as much as I can with the air conditioning off, especially up the the grades and just take it easy? The only grade I am concerned about is 9 miles long at a 6% grade.

Thank you!

 

[TheAutumnWind]

Okay, so even if that is normal, why in the hell is the engine getting over 210* sitting at idle for a couple of minutes? On my way home, I stopped and grabbed my toy hauler from it's storage which is about 5 miles from my house and is flat terrain. The engine temperature reached a little more than half way between the half way line and the third quarter line, so somewhere around 220* to 230* with the air conditioning on. I turned the air conditioning off for the half a mile or so which is a school zone and then into my neighborhood. When I did this, the engine temperature dropped back down to around 215* or so, still slightly above the 210* half way mark on the gauge. I am afraid of the truck overheating while towing my toy hauler this weekend. Should I be concerned or should I just tow as much as I can with the air conditioning off, especially up the the grades and just take it easy? The only grade I am concerned about is 9 miles long at a 6% grade.

Thank you!

I was getting s steady ~220* in stop and go traffic when it was 110* last weekend. Left it idling running the a/c that day and I saw about 200* trans 220* coolant. That is with an upgraded 12x12" transmission cooler, in a recently flushed system with a brand new waterpump.

 

[adventurenali92]

You should always have the air off when towing up a grade. That's kinda towing 101. My 6.0 has been doing the same thing the last week or so with warm temps and driving through the construction zones and stop and go. Warm temps outside, my trans gets to about 190ish and my operating temps get right on the 210 mark. Just take it easy towing your trailer and try not to hammer it.

 

[millerladam]

Thank you for the replies.

I was getting s steady ~220* in stop and go traffic when it was 110* last weekend. Left it idling running the a/c that day and I saw about 200* trans 220* coolant. That is with an upgraded 12x12" transmission cooler, in a recently flushed system with a brand new waterpump.

So it seems like this is pretty normal then? I have thrown probably damn near $1000 at this engine in the last two months and I am sick of throwing money at it and nothing changing. The last item to replace is the radiator and I am thinking about doing it just to get it done. My cost is $155 plus another two gallons of coolant at $10/each.

You should always have the air off when towing up a grade. That's kinda towing 101. My 6.0 has been doing the same thing the last week or so with warm temps and driving through the construction zones and stop and go. Warm temps outside, my trans gets to about 190ish and my operating temps get right on the 210 mark. Just take it easy towing your trailer and try not to hammer it.

Yeah, I understand I should have the air conditioning off when towing a grade, I am just afraid I guess. I don't tow as much as other people as we only use our toy hauler maybe once every couple of month,s and it's the largest trailer I have ever towed. This will only be our fourth trip with it since we bought it back in November but when I bought it I was towing with my 2005 Duramax, which unfortunately ended up having a blown head gasket and I am still rebuilding it. I am hoping to have it done by the end of August, but I don't know if that's going to happen. In the meantime, my Yukon is my tow rig which I traded the wife's minivan in for after blowing up my Duramax.

I guess I will just take it slow and easy. We are traveling at night so the temperatures are cooler, hopefully this will help.

 

[ccapehartusarmyINF.(ret)]

okay your coolant tempshould always stay just below 210 always if it ever goes above 210 something is wrong doesnt matter if your towing idling or just driving
ive got 240k miles on my suburban and here in arizona ive sat for hours running the ac full blast when it was 115 dagrees outside and the temp stayed just below 210 and never budged
now the ac may start blowing warmer air but thats it engine temp stayed the same
now its very important for the cooling system tomaintain 15psi this raises yer coolants boiling temp from 212 to 245 dagrees water boils at higher temp under pressure
every time ive had this issue in the past ad cant seem to located the source of the problem it usually winds up being a leak somewhere it winds up being a tiny and obscure hard to find leak
the affectiveness of your cooling system depends on its ability to maintain pressure roughly 15 psi

 

[adventurenali92]

Your 2500 was designed to be an extremely capable how vehicle. So you shouldn't worry about hauling with it. That being said i think replacing the radiator is a good idea despite the low mileage. Sometimes lack of use is what causes things to wear out when they start getting used on a regular basis again. But through all your updates I haven't seen anywhere that your engine temps are running overly hot. Like redlining. That's when you might have a serious issue.

 

[millerladam]

okay your coolant tempshould always stay just below 210 always if it ever goes above 210 something is wrong doesnt matter if your towing idling or just driving
ive got 240k miles on my suburban and here in arizona ive sat for hours running the ac full blast when it was 115 dagrees outside and the temp stayed just below 210 and never budged
now the ac may start blowing warmer air but thats it engine temp stayed the same
now its very important for the cooling system tomaintain 15psi this raises yer coolants boiling temp from 212 to 245 dagrees water boils at higher temp under pressure
every time ive had this issue in the past ad cant seem to located the source of the problem it usually winds up being a leak somewhere it winds up being a tiny and obscure hard to find leak
the affectiveness of your cooling system depends on its ability to maintain pressure roughly 15 psi

Thank you for your reply. While I don't necessarily disagree, if you're referring to the 2001 Suburban with the 5.3 liter in your signature, your engine is different than mine. Regardless of being a 6.0L, even the 5.3L from my same year is different. The 1500's in my same year have electric fans as one major difference, that goes for the Yukon's, Tahoe's and Suburbans. We're not really comparing apples to apples here, especially considering your truck is 6 years older than mine and there were significant changes in those 6 years.

However, I do understand the water boils at a different temperature when under pressure. When I started this journey the cooling system wasn't holding pressure which is why this thread was originally started. Now, the system builds and holds pressure as far as I can tell. Where the upper radiator hose wasn't getting hard before, it is now, but not lock a rock hard. I am not doubting at this point that it could definitely be the radiator, especially since that's the only thing I have yet to replace. I am hoping our trip this weekend goes well and if everything works out and we make it back without any major issues, I will look at replacing the radiator next weekend to see if this issue stops.

Thank you again!

 

[TheAutumnWind]

Thank you for your reply. While I don't necessarily disagree, if you're referring to the 2001 Suburban with the 5.3 liter in your signature, your engine is different than mine. Regardless of being a 6.0L, even the 5.3L from my same year is different. The 1500's in my same year have electric fans as one major difference, that goes for the Yukon's, Tahoe's and Suburbans. We're not really comparing apples to apples here, especially considering your truck is 6 years older than mine and there were significant changes in those 6 years.

However, I do understand the water boils at a different temperature when under pressure. When I started this journey the cooling system wasn't holding pressure which is why this thread was originally started. Now, the system builds and holds pressure as far as I can tell. Where the upper radiator hose wasn't getting hard before, it is now, but not lock a rock hard. I am not doubting at this point that it could definitely be the radiator, especially since that's the only thing I have yet to replace. I am hoping our trip this weekend goes well and if everything works out and we make it back without any major issues, I will look at replacing the radiator next weekend to see if this issue stops.

Thank you again!

Have you done a leak down test? Probably not a bad idea at this point. Should be able to rent a tester from a local autoparts store.

 

[millerladam]

We are back from our camping trip, came home yesterday. Overall, the truck did pretty well. Better than I had expected. The first part of the trip is mountainous and has a couple of decent hill climbs. The engine never got hotter than around 235* and the transmission stayed around 200* with an outside ambient temperature in the upper 70's and low 80's. The second part of the drive was another 50 miles of which is mostly grades with one grade being 6% for 9 miles or more. I ended up having to pull over approximately 2 to 3 miles into the 9 mile climb because the temperature reached right round 240* and I didn't want it going any higher than that. At this point, I let the engine cool all the way down to normal operating temperature before I resumed my travels and wasn't able to pull the hill at more than 20MPH. After this, the engine never moved from normal operating temperature the rest of 30+ mile drive, including up the rest of 9 mile hill.

On the way back, most of it is down hill except for one major grade which I have driven this setup up before however, this time it was warmer outside and I had my side by side in my toy hauler. This particular grade is also 6% and is approximately 6 miles. I turned the heat on full blast and rolled the windows down (which my three girls and wife absolutely hated) and the engine never got warmer than 235*. All of this was after I replaced the water pump, both bolts, the tension pulley and flushed the entire cooling system with about 8 gallons of distilled water. I did notice that the upper radiator hose was quite hard and holding pressure without a problem.

Let me ask this now. I have always been told to never turn off a vehicle that is warmer than normal operating temperature. Unfortunately, I made this mistake last year in November and I am pretty sure that added to by Duramax "blowing up". Is it OK to let the vehicle cool down and then shut it off once it gets back to normal operating temperature or should I let it run for another few minutes before shutting it off? Also, I have noticed that if the engine is at normal operating temperature and I shut it off, if I turn the key a few moments later, the temperature gauge shows that the coolant temperature has actually gone up. Is this normal in this truck or is this a sign that the radiator needs to be replaced or that there is another underlying problem?

I don't believe there is a head gasket problem or anything else because, as I have stated, I am not losing coolant. Period! I have never lost coolant except one day when the outside temperature was 115* and I let the truck idle with the air conditioning off and the temperature climbed up to 235*, but this was also before I replaced the coolant surge tank, the surge tank cap, and the upper and lower radiator hoses.

Lastly, I finally received an e-mail back from GM but they just requested additional information such as my phone number and the dealer involved (which there really hasn't been one involved except the one that did the transmission flush) so I will be replying to them today.

Thank you!

 

[Jason_S]

The temperature going up after the engine has been turned off for a few minutes is normal. You basically lose coolant flow through your engine when you turn it off, but the engine is still hotter than the coolant so it will continue to shed heat into the coolant until you start it back up, or the engine radiates that heat into the air. Your entire engine does this not just your coolant.

I forget if you replaced your thermostat. A thermostat not fully opening, could give you similar symptoms. You could try boiling your current one to see if it opens fully, but you will need to look up the specs on how far it should open because I forget. Or for the same effort you could just get a new one, boil it to make sure it opens as it should and slap it in.

Not sure which part of the country you are in, but if you are in dogwood or cotton wood country, I would look inside your grille to see if maybe your condenser and radiator are plugged up with the stuff. Dunno why I didn't think to suggest it earlier. If your AC blew cold, until you turned the heat on, but didn't blow crazy cold until it blew warm air, then your condenser is probably getting enough air flow. In which case, the only major part of your cooling system that is has not been replaced is your radiator.

Your transmission temps sound fine for your load`. I forget where the temp sensor is, but I want to say it is in the pan. The flow path for your trans cooler should be trans -> trans cooler -> trans "cooler" in radiator end -> trans. Done this way, you are helping to pull additional heat from your radiator and keeping your transmission fluid from running too cool.

 

[millerladam]

I hate to resurrect an old thread however, my problems still persist for anyone else having the same issue I am. The only thing I have not done is a proper pressure test which will be on my list shortly. Over the winter (we've had a mild winter here in AZ), the truck, while sitting at idle, still gets over 210*. I am still concerned. At this point, the entire cooling system has been replaced (thermostats 3 times, radiator, water pump, hoses, coolant reservoir, reservoir cap, etc) with no change.

 

[TheAutumnWind]

I hate to resurrect an old thread however, my problems still persist for anyone else having the same issue I am. The only thing I have not done is a proper pressure test which will be on my list shortly. Over the winter (we've had a mild winter here in AZ), the truck, while sitting at idle, still gets over 210*. I am still concerned. At this point, the entire cooling system has been replaced (thermostats 3 times, radiator, water pump, hoses, coolant reservoir, reservoir cap, etc) with no change.

Interesting. Head gasket is definitely good? I cant believe you threw that many parts at it without pressure testing the system.

 

[millerladam]

Well, just over 3 years later and guess what... yup, I still have the same problem! Absolutely everything in the cooling system has been replaced, the AC compress was recently replaced as well as the AC idler pulley / tensioner and water pump (again) as well as the thermostat and I still have overheating issues at idle. But hey guess what, it's a known issue on the Yukon XL 2500 with the 6.0L and mechanical fan. But does GM do anything about it? Absolutely not! There used to be a company that made bolt on supercharger kits that also made an kit for adding two pusher fans but unfortunately, they no longer sell the kit. I am half tempted to find a fan or two that I can install and either put on a rocker switch or just let them run all the time, even in the winter. I would be interested to hear from anyone else that has this same problem. I cannot imagine that I am the only person that owns a 2007 Yukon XL 2500 4x4 that is absolutely bone stock that is having overheating issues that seem to get better when I turn off the AC.

 

[79jasper]

If not going electric fans, I would go with a different fan clutch. When replacing one at work, they asked a/c? Severe duty? This was a 2500 gas engine. Maybe you got a light duty version?
Personally, I would just go electric fans.

Sent from my SM-N960U using Tapatalk

 

[mikeyss]

Have you ever hooked up a tech2 or any scanning device to make sure the gauge is reading correctly? The tech2 will tell you the exact temp of the engine, I believe the gauge is more of a dummy gauge and not accurate.