Currently have the thermostat mod with the 180° stat in. Normally idle and cruise around 176-183. Accelerating sometimes drops below 170 for a short time. Hasn't gotten below freezing yet but that won't be long. Should I install a 190° to increase the temps in the winter or am I fine with staying with the 180°?

 

I have an inline setup here in Chicago. I run a 195 in the winter months and a 180 the rest of the time. I normally see engine temps in the high 190's to 203 when running the 195 t-stat. It keeps the cabin nice and toasty when the temps outside are zero or -20. This year winter has been mild and in the high 30's / low 40's. I could easily have left the 180 in and been just fine. When that temp dip happens the first thing I always do is swap out the 180. It makes a big difference when the bitter cold hits.

 

I have a 2003 with an inline thermostat which will throw a code if the engine takes too long to heat up, so I switch from a 180 in summer to a 195 in winter for that reason if nothing else.

 

QQ on this as well.

I went with the 185 deg inline option. Problem is, it's working too well I think.

I'm in the Colorado mountains and the past week or so has seen morning temps in the single digits. I have a 20 minute drive and the engine temps never get above 120. I figured it was just a stuck tstat, but that isnt the case. Any other ideas? I was thinking of going to the 190 deg option, but not sure that would make a difference since I can't even get it to 185... Would it make that much of a difference as these guys are saying?

 

If you are sure the thermostat element is not stuck, then the 195 will probably help. In the winter at very low temps the heater core will remove a lot of heat from the coolant, if you put the HVAC on recirculation it will heat up faster and remove less heat from the engine, allowing the thermostat to come in to play.

 

Are you getting decent heat? If not, l'd swap thermostat. Face it, no matter what brand you buy anymore...there is a great deal of premature failure. And this is no knock on the upgrade supplier, he doesn't make the parts...so he has to work through the same issues. Anyhow, if you have decent heat, could be temp sensor. If not, then bumping it up may help remedy the issue.

We're heading for a cold snap here and it's crossed my mind about changing to a 190°. We've only had temps as low as 24° and see 165° when this happens...and she sets a code shortly afterwards.

 

Yes you should

 

Why do you say it's not a stuck thermostat? What did you do to confirm that?

A "stuck thermostat" more typically means a thermostat is stuck closed and it does not open, causing overheating. In the case of your truck, it sounds to me as though the thermostat is stuck open, the equivalent of having no thermostat at all.

A normally operating thermostat would not open until its specified temperature is reached. If the thermostat in your truck was operating properly, there's no way it would stay at 120° with no coolant circulating to the radiator, even with the ambient temperatures you state.

 

The only time I ever had a failed t-stat (not LR) it failed open.

 

Thanks for the responses all.

Yeah, mln01, I guess I was confused by the terminology. What I was trying to convey is that it seems to function normally. I took the housing apart the other day to check. I see what you mean though and it's not stuck - open or closed.

To answer the other questions, no, I am not getting decent heat at all. This is what has me worried.

The temp gauge does fluctuate, but never goes above the top of the blue mark. I think the plan is to switch to a 190 deg and see if that makes a difference. I'm trying to figure out if that would be the only explanation for what I am seeing, or if there is something besides the tstat that I should be worried about.