Chevy and GMC Duramax Diesel Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter #1
Since the colder weather my LML seems to be running cooler then usual. Not sure if the t-stats are bad or it’s normal for cold weather. According to my edge CTS engine temps are between 160-170. Air temp has been in the 20’s at night and 30’s during the day here in New York. Last week I did a 6 hour drive to Vermont and temps were in the teens at night. Truck ran below 160 at certain times even when climbing decent hills. I put a grill cover on for a few miles and the truck was running at 195 within a few mins which it never runs that hot. It also made the truck think it was 55 degrees outside even tho it was 30
 

·
Premium Member
2012 3500 hd srw
Joined
·
374 Posts
IMHO 160 is to low. I changed mine when it started running 170 in 30 dregree Temps. Heater worked faster milage increased .5 mph.
 

·
Registered
Joined
·
78 Posts
Stats more than likely and are pretty cheap and easy diy if you dont know when they were replaced last. They dont seem to last like they should. I saw that same type of scenario just a bittttt cool in the winter (from upstate NY as well). Plus not enough heat for my liking. New stats and sticks 180* or so and such better heat.
 

·
Registered
2017 GMC Denali 2500HD, 3.5" Rough Country Lift, 305/55R20 Yokohama Geolandar A/T
Joined
·
1,134 Posts
Winter cover will fool the temp sensor. I think it mentions that in the owner's manual, if I remember correctly.

195° isn't a problem for your truck, but I wouldn't want it going over that all the time running empty.

Were you pulling a trailer when you had these temps?

You should change your thermostats. The truck should sit right around 185-188° running around on the highway unless it's really cold out.
 

·
Registered
Joined
·
2,581 Posts
Thats about the temps mine ran when the T-stats went out (120k mi)
 

·
Registered
Joined
·
6,263 Posts
Sounds like it needs thermostats (there are 2). It's really not that uncommon to need to change them.
Shouldn't need grill cover at the temps posted.

The temp sensor behind the grill is used for the ambient temp displayed by the truck.
The diesel uses a a temp sensor in the passenger side mirror for ambient temp. (gas engine does not have the mirror sensor)
 

·
Registered
Joined
·
523 Posts
A couple winters ago I put on the winter grill cover. I found things appeared to get too hot under the hood and I would almost smell a "burning" smell after the elevated idle finished. That winter, the temperatures would range from 0C to -35C. Just too much of pain to remove/reinstall the cover, so I haven't used it since. No issues.

Sent from my SM-G960W using Tapatalk
 

·
Registered
Joined
·
523 Posts
I also was advised to use GM/AC Delco thermostats and not aftermarket by my diesel mechanic.

Sent from my SM-G960W using Tapatalk
 

·
Registered
Joined
·
281 Posts
I used the Mishimoto thermostats in my 11, winters in Alaska need more heat than the GM thermostats provide. Factory thermostats are only 170/175 degree, if it’s really cold out, the truck will only get to 168-170 or so. I used the 190/195 set and even in -40 weather, truck would run 187 or so.
 

·
Registered
Joined
·
523 Posts
Cool! Didn't even know these existed.

Sent from my SM-G960W using Tapatalk
 

·
Registered
Joined
·
6,263 Posts
Hmmm....
always thought that the oem thermostats were one that starts to open at 180 and the other starts at 185.
 

·
Registered
Joined
·
281 Posts
might be, I just plugged the factory numbers into one of the parts store interchanges and that was the temps that they showed for the interchange.
 
1 - 13 of 13 Posts
Top