Coolant Pressure 6.0L Vortec

[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.