2021 silverado 3,0
overheating issues
Thanks for the detailed post…
How about giving us as much info as you can so maybe we can help a little…
I guess you meant a 3.0L diesel engine??
How many miles on the vehicle, is it out of warranty??
When does it overheat? in stop and go traffic or on the highway at speed??
Do you have a check engine light (CEL) on??
Have you checked your coolant level??
If you don’t help us, we can’t help you…
3 Likes
2021 3,0 LM3 deisel
72.000 miles
Started noticing it in November of last year, Went to pick up an outdrive for my boat about 200 mile trip. While on the NJ Turnpike i noticed my temp up around 240 and came back down,
Pulled over and let it sit for about 30 minutes and continued on, went up and down the whole trip. When i got back that afternoon i had to put in almost a gallon of antifreeze.
Since then i had put in about half a gallon. last week i had a antifreeze smell and noticed it was down about a quart.
Took to the dealer and they said i need 2 new radiators?
Sorry, TYPO error
LM2. that bulletin NHTSA is for gas motors
Engine running hot, cooling system very low, added coolant and repeat. Eventually the cooling system was inspected for leaks, radiators are leaking, are they damaged? What caused the leaks?
Many late model turbocharged engines have a liquid cooled intercooler. This reduces the length of air intake piping to the intercooler, compared to a grill mounted intercooler. The benefit is less turbo lag.
There are two coolant reservoirs, there must be two radiators.
Looks like your 3.0 has a main radiator AND an Auxiliary radiator… Looks like the main rad calls for 8.5 hour labor and the aux rad calls for 3.5 hours labor but the labor for the aux rad is included in the main rad labor… plus the evac and recharge of the AC system…
Looks like you have 3 choices, either do it yourself or pay someone else a lot of money to repair it for you, or just keep doing what you are doing and hope it doesn’t blow the head gasket and then you might have to take out a 2nd morgue to afford that repair…
3.0L Eng Main
Includes: R&I Bumper Assembly. Includes: R&I Grille Assembly. Includes: R&I Grille Shutter. Includes: R&I Transmission Oil Cooler. Includes: R&I Auxiliary Radiator. Includes: R&I Air Cleaner. Includes: R&I Cooling Module. Includes: R&I Cooling Fan Assembly. Includes: R&I Air Conditioning Condenser. Includes: Drain and refill Cooling System. Includes: Check and adjust Transmission Fluid level with fluid temperature within parameters. DOES NOT include Air Conditioning System recover, evacuate and recharge.
8.5 hours labor…
Found this video… If all true, I’d be dumping this vehicle asap… 40-50 hours for a problematic cam sensor?? ummm no… lol
Seems sort of unusual you’d have two defective radiators on a 3 year old truck. hmmm … Why does the shop think the coolant loss problem is the radiators? Are they seeing visible coolant leaks from them? If so, what part of the radiators? Do you see any puddles of coolant in the areas under both radiators? Is any coolant dripping on the ground underneath the truck? Do you drive your truck on gravel roads quite often, where a rock could be thrown up from the road and hit the radiators? Do all the under-engine shields remain in place?
In any event if the radiators have holes in them, they have to be replaced. Can you think of any other option?
No signs of leaks anywhere, mostly all highway miles, i do go on the beach with the truck in the summertime but no gravel or stone roads.
there is a intercooler 3way valve to help both radiators cool the turbo and send the antifreeze to the proper places when needed, i have read and seen people having issues with them. I asked the dealer to confirm the valve is good and not having any issues. There are no lights on the dash or codes that come up… The dealer said to replace both radiators it would be 2000.00 dollars. i do have an extended warranty on the truck through GM but of course it doesnt cover the radiators. GM is currently on national back order for the smaller one,( Probably because of manufacturing defects). I asked the service advisor, So if i spend 2000.00 on radiators are you sure the problem is fixed. He said that is what the lead tech said, not me. Its hard for me to believe both radiators could be bad and at the same time, and not a bypass valve, sensor, or thermostat,ECT…
what ever happened to the old radiators from the 60’s and 70’s, never had to replace one of them
One of them remains in my early 70’s Ford truck. The manufacturers seem to prefer aluminum radiators now, presumably b/c they are lighter and less expensive. They don’t seem to be as robust though.
No experience w/your truck’s cooling system, but I’m guessing the tech’s thinking is that while in the process of replacing both the radiators they’ll find the actual problem. The alternative would be to tell you it will cost $2000 in labor to diagnose the problem. Either way it seems like it is going to cost you $2000. At least w/the current plan you’ll end up w/new radiators.
Visit the service department and ask to see the leaks. While you are there you can inspect the valve, sensors and thermostat for leaks. Post pictures of the leaks here so others can understand what a leak looks like.
You don’t want to wait for engine damage and warning lights to illuminate, the temperature gauge indicated a problem that needs to be corrected.
Do you think the tech diagnosed the leak over the phone?
im going to have to get the radiators replaced no matter what, i should be able to ask the chevy service department to give any parts replaced since im paying for them… I should be able to see a sign of a leak through the coils or stain from them leaking. i did a pressure test and nothing leaked. Although the new trucks have so many sensors and valves im not sure if everything in open while testing. I had to wait a day from my service date because the Chevy diesel mechanic was not in on my scheduled day.and they could not find and issue till he came in the next day.and said it was the radiators
It seems like a good idea with these symptoms to do a simple check to make sure that the engine oil and transmission fluid are both coolant-free. Maybe the tech took photos of the leaks? If not yet, something you could request.
i have, no moisture in anything
Watch for Dexron sludge, me I would go to an independent and get peak global or similar when replacing whatever is leaking.
While looking online I came across a couple of people with your vehicle and similar problem. it seems they had a small crack at a weld in the EGR. It made a very small leak. not enough to see any dripping on the garage floor. 0ne dealer pressure tested the vehicle overnight and the pressure dropped. and then after that they found the problem. I am not saying it is your problem but, it might be a spot to check out.
Liquid cooled egr on diesels? Heard there was a way to fix that.
The most puzzling question is why did two nearly new radiators fail at the same time? Could be just a coincidence, but that seems pretty unlikely. hmmm … well a a severe over-pressure incident could have damage both radiators at the same time I suppose. The cooling system has a pressure control valve that is supposed to prevent this sort of thing. Suggest to also ask your shop to double check it is working correctly. If the pressure increased very rapidly, the pressure control valve might not be sufficient to relieve the pressure quickly enough. Do you recall anything like that occurring?
Both cooling system caps failed?
What would a driver observe from the driver’s seat that would be an indication of high pressure?
Steam, coolant temp gauge readings.