Truck running cold, coolant question
 

So after I replaced all that stuff in my truck a few weeks ago, I keep getting P 1281 - engine too cold too long. I have run a 180* T stat the last year or so with no problems even in the dead of winter (for Texas anyway). I replaced the T-stat and coolant temp sensor when I pulled the intake that last time. I tested the T-stat for accuracy and it opened at about 182. Started throwing a code so I replaced it with the same brand I initially had and tested that one as well, still a code. So I replaced the coolant temp sensor with a different brand, and I still get the code. After 2 T-stats that have been checked and 2 coolant temp sensors, I think the problem is something else.

Here's the question: Would antifreeze that is too diluted with distilled water cool better to the point that I can't get the truck up to temp? does antifreeze retain heat better than water? Do they make a tester for concentration levels? Maybe I just need to drain a gallon and replace with pure Ethylene Glycol.

Suggestions welcome.

RE: Truck running cold, coolant question
 

Anti-freeze that is over diluted with water would run hotter. if you've got a 180* t-stat that could potentionally cause the truck to run cool. I know most people have no issues with them but others have lots of problems. You may not have enough water in there. I would try draining hal a gallow and adding half a gallon of water.

If that doesn't work, it could also be a problem with the PCM and how it's reading the coolant temp. Try getting the genuine mopar sensor. And if that isn't your problem, just return it or sell it to someone else.

RE: Truck running cold, coolant question
 

There are concetration testers out there. looks like a small version of a baster with 4-5 balls inside. 5 bucks at your local autoparts store. should be a problem with running full antifreeze levels though.

RE: Truck running cold, coolant question
 

THe problem is more than likely the 180 thermostat. Your old one may have been maintaining 185 or so and not causing the code to be thrown, while the new ones are causing it. I cannot run a 180 as it throws the code everytime I install one.

RE: Truck running cold, coolant question
 

are you drilling a hole in the t-stat to let air escape ? that could be slowing down the warm up. if so, try one w/o the hole.

can you find your original one out of the trash ?

RE: Truck running cold, coolant question
 

I would think that diluted coolant would run cooler. Water boils at 212 degrees, antifreeze raises that to 270+. The lower the concentration, the lower the boiling point. It takes something like 540 Kcals to transform liquid to stream which takes energy in the form of heat out of the system. While our system isn't reaching 212*, some amount of water is super-energized at a lower temperature and this is why you start to see steam from a kettle before it actually boils. Under pressure this further raises the boiling point. But water jackets tha touch heavily heated areas will still absorb a lot of energy.

My question is better suited by knowing this. What retains heat better, Water or Ethylene Glycol?

Turkeyhunter, you may be right about the T stat, I never did check the original and might have just gotten lucky. I might have blown some chunks out of my radiator when I flushed it and am getting better cooling than I'm used to. Or maybe the new water pump is more efficient?

RE: Truck running cold, coolant question
 

All i know is that water cools better than anti-freeze, but its highly corrosive and eats blocks and water-pumps. Try mixing a little more anti-freeze into the mixture so it holds more heat.

Also remember that straight anti-freeze will freeze when not dilluted with water

RE: Truck running cold, coolant question
 

here's another thought - did you recently remove your superchips ? i'm thinking that hypertech and (maybe) superchips alter the pcm programming to accept the 180. the hypertech programmer actually comes with a 180 t-stat. they wouldn't provide that if it set off the cel.

RE: Truck running cold, coolant question
 

Eh, I could be wrong. Wouldn't be the first time...

I still think it's the 180* t-stat. But again, I could be wrong.