Jump to content

2000 sierra 2500 6.0 high engine and transmission temps

cfsierra

By cfsierra
in 2000-2014 Silverado HD & Sierra HD

Recommended Posts

cfsierra Enthusiast

cfsierra

Posted
Posted

truck:

2000 2500 6.0 4.10 rear 4l80e with oil and transmission coolers (oem) 116k hauling 4k lb lance truck camper

 

problem:

engine temp got up to 250 degrees and tranny temp to 250 as well going up a long grade after doing a bunch of cooling system work see below. i've done this grade numerous times with the same load and engine temps never gone above 210; tranny temp no more than ~210-220.

high temps only seen on the grades; on the flats all is normal. Also some different behavior than before work was done-going down the same grade the engine temp cooled down to ~185. it never did that before prior to the work that was done; always 210 regardless of up or down grades.

 

 

so just before labor day i had a local shop do some preventative and long over due maintenance: had them replace the belts, hoses, and flush the coolant. I had never replaced the coolant since i bought it new in '00. well while flushing the system they ran into a lot of sludge and couldn't get it to flow out of the radiator. To get everything to flow properly and ward off any sludge related clogging i replaced the radiator, thermostat, overflow tank/resevoir, and water pump. Replaced coolant with 50/50 dexcool. The shop was instructed to use replacement parts that meet the oem standards; ie no rebuilds.

 

prior to all this work the truck did not have any engine or transmission heating issues with or without the camper. Never got hotter than 210 and always ran at 210 regardless of load or grade.

 

after getting the work done truck ran a good 5-10 degrees cooler ~200 and didn't show any leaks. Took it camping with the camper this past weekend up the local grade (Sherwin Grade) like i've done so many times in the past. however this time i wasn't sure if i was going to make it without over heating. the temp spiked to ~250 half way up (3-4 mile grade @ 6-7%). i have pulled this grade at 60 mph in the past no problem, 2nd gear and 4k rpm. this time i had to slow down to 45 mph to limp it over without over heating. I was even running the heater a full hot; but that didn't drop the engine temp.; perhaps that plus slowing down kept it from actually getting to 260 (red).

 

temps went back to 200 once cresting the grade and on the flats. I drove the truck back over the same grades without the camper and the engine temp never waivered off 200.

 

Any ideas as to what is happening when loaded and going up the grades? Perhaps a bad thermostat, or air in the system? Thermostat seems to be opening at the proper temp when warming up (187). Not sure if the fan clutch is engaging fully or not. I can spin the blades a quarter turn after its up to temp.

 

Taking truck back today to see if something didn’t get installed right and make sure all parts are correct.

 

Any suggestions or ideas would be appreciated. Thanks!

 

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

My reasoning is that it runs cooler than before, but overheats when worked...the thermostat is stuck partially open, and restricting flow when worked.

 

Sent from my SAMSUNG-SM-G900A using Tapatalk

Raptordude Enthusiast

Raptordude

Posted
Posted

Yeah I would say a faulty thermostat. Trucks with no thermostat act similarly. They'll heat up under load but cool down significantly when running down the road normally

 

 

Sent from my iPhone using Tapatalk

cfsierra Enthusiast

cfsierra

Posted
  • Author
Posted

shop replaced the tstat under warranty and replaced the clutch fan as it was leaking. damn near whole new cooling system! hopefully i can load the camper up this weekend and test it out. thanks for all your replays!

ctbailey Enthusiast

ctbailey

Posted
Posted

shop replaced the tstat under warranty and replaced the clutch fan as it was leaking. damn near whole new cooling system! hopefully i can load the camper up this weekend and test it out. thanks for all your replays!

Let us know how it goes with the load on. Maybe I missed it, so if I did I'm sorry, but did you say the tranny was running back down at 200+/- after the coolant swap?

 

Does your trucks oil cooler lines run to a separate oil cooler radiator?

 

 

Craig Bailey

New England

2007 Chevy 2500HD crew

2015 Jayco Jayflight 32BHDS

cfsierra Enthusiast

cfsierra

Posted
  • Author
Posted

Let us know how it goes with the load on. Maybe I missed it, so if I did I'm sorry, but did you say the tranny was running back down at 200+/- after the coolant swap?

 

Does your trucks oil cooler lines run to a separate oil cooler radiator?

 

 

Craig Bailey

New England

2007 Chevy 2500HD crew

2015 Jayco Jayflight 32BHDS

haven't gotten a chance to test it with the camper on yet. hoping to this weekend-will update when i do. i do have a separate oil cooler that came with the truck when i bought it new; part of the towing package.

  • 8 months later...
cfsierra Enthusiast

cfsierra

Posted
  • Author
Posted

its been awhile but an update on this... i just last weekend put the camper on and unfortunately the same problems exist, truck wants to over heat going up the hills but runs perfect everywhere else. this with a replaced fan clutch and a second thermostat (both napa parts) the fan clutch they put on was a napa severe duty which roared all the time during the winter. with the camper on last weekend it was doing fine temp wise then mid way up the canyon the fan clutch disengaged and never reengaged which sent my engine temp to 235 and trans temp to 250! i let the truck cool down and heard the fan clutch reengage, drove down the canyon and tried it again to see if the fan clutch would stay engaged. it did and the temps were fine. the next morning we headed back up the canyon and it stayed engaged and all was fine.

 

So i figured the fan clutch was defective since it seemed to have spotty engagement and replaced it with the standard oem gm fan clutch. install that last week and ran the truck and camper back up the same canyon to see what she would do. Well that resulted in the engine temps climbing to 235 along with the trans going in the same direction all climbing until i aborted and headed home.

 

I'm mot sure what's going on. the truck runs fine up the same canyon without the camper and heading down the highway with the camper on doing 70mph in 85* temps no problem. seems if i put a severe duty fan clutch on, at least one that works, would keep temps down. but i never had any cooling overheating problems with this setup until i flushed the system last fall.

 

The truck runs fine, no missing, check engine light is off, so i don't think i've got any gasket leaks, yet at least! One thing i did notice last week with the camper off i stopped at the top of the canyon, after running the truck hard, i popped the hood to listen to the fan. It was late in the evening, kinda dark, and i noticed the passenger side exhaust manifold was glowing red! don't know if that is supposed to do that or not and whether that is a symptom of whats going on.

 

I'm going to call the guys today who worked on it and see what they think. I want to make sure we have all the correctly specced parts, radiator size etc.

 

any ideas?

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

Then I would suspect a undersized radiator or possible blockage somewhere.

 

Sent from my SAMSUNG-SM-G900A using Tapatalk

Raptordude Enthusiast

Raptordude

Posted
Posted

Yeah, maybe your flush dislodged dirt and it didn't come out and got clogged in the radiator or something

 

Do you have a bigger trans cooler?

 

 

Sent from my iPhone using Tapatalk

cfsierra Enthusiast

cfsierra

Posted
  • Author
Posted

thanks for the thoughts guys! ya, could definitely have crud still flowing around in there. taking it in tomorrow.

  • 2 weeks later...
cfsierra Enthusiast

cfsierra

Posted
  • Author
Posted

following up on this. I thoroughly flushed the entire system, then flushed each part of the cooling system individually, engine block (including removing driver side drain plug), heater core, and radiator, reservoir tank, etc. and replaced the water pump, tstat, and radiator with all oem parts, that seems to have fixed the overheating problem when hauling the camper. i suspect the t-stat (both of them) were incorrectly sourced or they simply were not up to oem spec. i think it was not opening up enough, that with a radiator which was not dimensionally adequate and up to oem specs. my temp gauge doesn't move now up or down the grades like before whereas the replacement t-state would allow the truck to cool down to 180-185 on the long down grades.

 

i was quite surprised in the difference in construction between the oem and non oem t-stat, see attached pic. the oem t-stat is on the left. lessoned learned, don't neglect cooling system, use oem parts, and when you want it done right do it your self!

photo-4.JPG

Raptordude Enthusiast

Raptordude

Posted
Posted

Glad you got the problem figured out, but dang! It's a chunk of change to get a factory T stat, waterpump, and radiator! Oh well, smooth sailing ahead

 

 

Sent from my iPhone using Tapatalk

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • KARNUT
      OCI, not when but why?

      By KARNUT · Posted

      It seems fine because it pulls everything out of a hot engine. I’m not going to worry about a thimble full with 5K oil changes with synthetic oil. Every other oil change is at Honda they pull the plug. I watch them through the process. It turns out going to Honda what amounts to their normal oil change intervals.
    • Newduramaxh*ar
      DTC P2C48 auxiliary cooling pump

      By Newduramaxh*ar · Posted

      I tried tapping it.  This might sound like a dumb question, you should feel vibration or some type of noise when it turns on? Can someone please verify? Thank you all!
    • Chuck FB
      first oil change - 2026 2500HD gas

      By Chuck FB · Posted

      I feel better now for my own view point and actions or lack there of towards the dealership service theme reading your post and others. GM corporate is who offers the two free oil changes on the HD trucks and I bought my truck in Feb of 2025 and those oil change offers run out within 2 years I believe and I highly doubt I will be using either one of them. I had asked if I could officially give those free services to another customer ( a friend ) and they said no, its all a GM corporate thing based on the vehicle in question. What that service advisor did however was go into a little story about how such and such customer was denied engine warranty because he had done his own oil changes because then they are not documented ... you see where that goes and so an employee playing the game of scaring the customer into having the service work done there most certainly triggered my thought process. At a later date I did talk to the person who handles warranty claims at the dealership and she said to be sure to document the oil changes and keep receipts for the oil and filter ( coped the receipts from cases of Mobil oil and case of filters I bought from them ) and the vehicles VIN, the date of service, mileage etc and staple that together as a record I would give them if that was ever needed and I keep my own log book for services for each vehicle as well. Oh and about 8 months after I bought the truck the dealer starts calling me to offer a maintenance service since they haven't seen my vehicle show up on their system ... for the mere fee of 300.00 Canadian to change the oil and rotate the tires and a few other minor checks and I declined the offer, I get the call again a couple of months later for the same thing and she could tell I was not interested and she asked if they should take my name off the call list and I said yes, do that !.    By the way did you happen to keep your factory oil filter to open it up and see the surprises inside as I expect some will show up as per the odd little sliver of metal shaving and particles that the filter does trap along with bits of grey silicone sealer that come off of the inside edge of mating surfaces. I have cut open every filter so far on my truck although few miles but have changed the oil often and the second filter was vastly better with very little of anything, that first filter was the unsettling one as I expected it would be. 
    • OnTheReel
      OCI, not when but why?

      By OnTheReel · Posted

      I get why they do this…but man…not ideal. I only extract on inboard boat engines because the drains are buried and even then I hate it because it’s easy to leave a quart behind with that method.   They should market it as an “oil refresh” not oil change!
    • KARNUT
      OCI, not when but why?

      By KARNUT · Posted

      I only get oil changed where I can watch. Valvoline pulls through the dipstick into a see thru glass. When done they show me the dipstick. About the only way they can mess up is using the wrong oil. But that secret wouldn’t stay secret long. Honda uses TQ wrenches on everything. You can watch through a plate glass window. Discount tires does that with tires. Trust but verify. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...