2015 Yukon Denali XL- engine seized, no warning lights, gauges read no

ZakA · July 11, 2017

First time poster, long time GMC customer. 2015 Yukon Denali XL 63,000 miles 4wd. Got in the vehicle to take my family out to dinner on July 10th, 2017. Less than 1/2 a mile after driving I noticed the idle wasn't right and felt a slight shudder. I slowed down and looked for a place to pull over. About 10 seconds later the truck stopped running and I pulled over to the side of the road. There was no warning lights on and all gauges showed the correct temps and readings. I tried to start the truck and it turned over but didn't start. After that initial attempt the starter would not turn the engine over. My first thought maybe the battery was dead and that caused the truck to stop running. Hooked up jumpers and no difference. Had the vehicle towed to our local dealer Watson Chevrolet in Tucson.

After the dealer removed the pulleys and tried to turn the block by hand they called to inform me that my Yukon had overheated and seized the block. I was shocked to say the least! Apparently there has been a light leak in the radiator that was not noticed by me or their service department. The dealer is taking the stance that since the radiator was not covered by power train the repairs to the motor will not be covered. My stance is that the vehicle never had a low coolant warning or even showed a change in the engine temp that was out of line. The temperature gauge read normal the entire time and no warning lights or messages ever came on.

5 weeks prior I had the truck into the same dealer trying to resolve a hard shift problem. They replaced the valve body on the transmission and the temperature sensor for the transmission. Apparently the transmission sensor was not displaying the correct temp and needed to be replaced.

The dealer wants me to authorize a tear down to see what the cause was. It is apparent that the radiator leak was the cause of the overheating but I had no indication that is was low on fluid or that it was overheating. The dealer can't tell me if they find that the warning system or gauges were not functioning properly that the warranty will cover the rebuild of the motor. I am looking for advice on how to proceed.

Edited July 11, 2017 by ZakA

Dnt · July 11, 2017

Very unfortunate for you man it sure is strange that NO check engine or low fluid level lights came on. There have been a lot of trucks that had the radiator slow leaks but this is the first time that I have heard of one being driven until it locked the engine up. I guess you are at the mercy of the dealership. Maybe they would be willing to check the low coolant level sensor etc for proper operation and if shown to be bad they would be willing to present a case to GM on your behalf for a warranty engine?

I had a 2009 truck that was a notorious oil burner and I still do not fully trust GM to build a 100% trouble free vehicle.I am the guy at the gas pump holding up the gas line with the hood up checking fluid levels at EVERY gas fill up.. I almost fell over one day when a fella walked over and asked me what I was doing. He said he never knew that you open that front panel that way LMFAO

Bangback · July 11, 2017

Very unfortunate for you man it sure is strange that NO check engine or low fluid level lights came on. There have been a lot of trucks that had the radiator slow leaks but this is the first time that I have heard of one being driven until it locked the engine up. I guess you are at the mercy of the dealership. Maybe they would be willing to check the low coolant level sensor etc for proper operation and if shown to be bad they would be willing to present a case to GM on your behalf for a warranty engine?

I had a 2009 truck that was a notorious oil burner and I still do not fully trust GM to build a 100% trouble free vehicle.I am the guy at the gas pump holding up the gas line with the hood up checking fluid levels at EVERY gas fill up.. I almost fell over one day when a fella walked over and asked me what I was doing. He said he never knew that you open that front panel that way LMFAO

According to my 2017 Chevrolet Suburban Owners manual, you are doing the right thing. On page 412 for the Maintenance Schedule, in the upper right hand corner of the page, it says that you are required to, at each fuel stop, check the engine oil level.

ZakA · July 12, 2017

Update- Just received a call from the service manger. The lifter spring on the #4 cylinder gave loose and fell into the cylinder. This would explain the lack of any error codes or the motor overheating. The motor didn't have the chance to send any error codes because it seized almost immediately.

The panic and uncertainty was induced by a service tech that was over zealous on pinning the failure on a leaky radiator. The motor was not "bone dry" as he insisted. The dealer is ordering a new motor and will be installing it under warranty.

Dnt · July 21, 2017

That is great news thanks for following up, very few people do that and most threads like this just twist in the wind with no resolution ever posted....

seamus2154 · July 27, 2017

Good news! BTW I too have the 2015 Denali and there is a TSB on a leaking radiator!!! I had mine replaced under warranty and is a known issue. They also change the thermostat as it cycles too often stressing the radiator.

That is a pretty unusual issue for a 63K car or truck?? Has this been known to be an issue on this new LT based motor?? The spring is in the valve cover and to come loose means a broken cap or lock then dropping the valve which will total the motor.

torres24 · December 3, 2019

i have a 2015 1500 denali 6.2 engine, just last week engine went out on me, took truck to dealer engine has to be replaced, luckily warranty still covered a whole new engine, truck only has 62k miles no prior warning of anything wrong just gave out one me. a year ago transmission temp. sensor/harness was also replaced at that point truck only had 53k miles on it.