[SWalters]

I have a 2018 Chevy Colorado ZR2 2.8l Duramax. I recently experienced the truck not start after I had driven it to work one morning and after 10 hours it wouldn't start. Initially we diagnosed it as a bad starter. Put a new starter in and had the same symptoms. After lots of testing, we found the 400 Amp fuse from the positive battery cable to the starter cable was blown. The parts store only had a 300 Mega in stock so we put one of those in until a 400 could be ordered. There were no issues for a few days but then I started receiving a message Engine Reduced Power and Engine Overheating Idle Engine; however, there was no reduction in power. The temperature gauge would be at 260 when getting the messages but then it would drop back to to sometimes 190 - 220. After a few miles it would do the same thing. I even stopped and popped the hood and there was no indication the engine was overheating.

When I got the 400 amp fuse in I put it in and then had a new issue. Prior to going to work one morning, I remote started it for approximately 10 minutes and then left for work. I had the defrost on due to frost on the windshield and it wasn't defrosting. I switched to the vents and the air was cold. After the warmup and a 5 mile drive to work the heat never got hot. That night after work the truck wouldn't start again. I checked voltage on the starter side of the fuse and it was 0. I took the 400 off and ohmed it and it was bad. Put the 300 back in, turned the heater off completely and the truck started fine. Each time I go out I make sure the heater is off and it starts fine but the heat still does not get hot. Talking to a buddy he thought maybe there was a preheat system that was tied in with the start system which could be shorted and popping the fuse. I'm at a loss and don't really want to have to go to a dealer. Any ideas would be greatly appreciated.

 

[Coloradorob]

I have a 2018 Chevy Colorado ZR2 2.8l Duramax. I recently experienced the truck not start after I had driven it to work one morning and after 10 hours it wouldn't start. Initially we diagnosed it as a bad starter. Put a new starter in and had the same symptoms. After lots of testing, we found the 400 Amp fuse from the positive battery cable to the starter cable was blown. The parts store only had a 300 Mega in stock so we put one of those in until a 400 could be ordered. There were no issues for a few days but then I started receiving a message Engine Reduced Power and Engine Overheating Idle Engine; however, there was no reduction in power. The temperature gauge would be at 260 when getting the messages but then it would drop back to to sometimes 190 - 220. After a few miles it would do the same thing. I even stopped and popped the hood and there was no indication the engine was overheating.

When I got the 400 amp fuse in I put it in and then had a new issue. Prior to going to work one morning, I remote started it for approximately 10 minutes and then left for work. I had the defrost on due to frost on the windshield and it wasn't defrosting. I switched to the vents and the air was cold. After the warmup and a 5 mile drive to work the heat never got hot. That night after work the truck wouldn't start again. I checked voltage on the starter side of the fuse and it was 0. I took the 400 off and ohmed it and it was bad. Put the 300 back in, turned the heater off completely and the truck started fine. Each time I go out I make sure the heater is off and it starts fine but the heat still does not get hot. Talking to a buddy he thought maybe there was a preheat system that was tied in with the start system which could be shorted and popping the fuse. I'm at a loss and don't really want to have to go to a dealer. Any ideas would be greatly appreciated.

Just a dumb question…… Is there anti freeze in the reservoir tank? Do the rad hoses get hot?
my lower rad hose clamp broke and the temperature gauge actually dropped as the engine got hotter and hotter.

 

[4wheeldriveseats35]

I think there is a TSB for frayed wiring harness behind the engine block near the firewall. I had a lot of trouble getting to mine but what I could see was fine. We both have 2018’s so maybe they fixed it by then.

 

[Garrobo]

Mine was a frayed wire harness under the ac compressor.
39 k miles and out of warranty. $986.00

 

[SWalters]

UPDATE - bigoilbob you were exactly right. The antifreeze reservoir was empty despite the rad hose still getting hot. Put 3/4 of a gallon in and that took care of the issue. I ended up pulling the fuse for the Fuel Operated Heater which appears to be in the same electrical circuit of the starter and haven't had the starter fuse blow anymore. It appears when the temperature is below 36 degrees and you have the heat in the truck set to hi, the Fuel Operated Heaters turns on to pre-heat when you turn the key on. Since I removed that fuse, even with the heater set to Hi and below 36 degrees the fuse no longer blows. Not sure if I will even chase that gremlin as I don't worry about that pre-heating as long as the glow plugs are doing there job for the block I don't care about the inside heat that much. I'll just let the truck warm up a few extra minutes before getting in. Thanks for the comments.