Hey everyone. I won a contest with Mishimoto and was awarded a thermostat for my Vehicle. My MR2 didnt even have an engine at the time so I optioned for one for my Ram with the Hemi.

According to their website (http://www.mishimoto.com/chrysler-30...tat-05-13.html) the OEM Dodge thermostat is set at 203* and the Mishimoto opens up at 180*. My Ram has never gone above halfway but i've heard that Dodge's tend to run hot without showing it.

I drove my Ram for about an hour tonight and i've even towed trailers with a load for 8 hours and have never seen it higher than this (below).

So I guess my question is if anyone has history with lower degree thermostats on these trucks. I just moved to Las Vegas so I definitely have warm weather to look forward to. Not sure how sensitive the Hemi's are to operating temperatures.

 

I'm curious about the statement that Dodges "tend to run hot". Was that in reference to the Hemi engine or Dodge vehicles in general? Either way, it sounds like bunk.

Thermostats do not control how hot an engine runs. They open at a specific temperature for proper performance. Back when I had my 1997 Ram I had a mystery issue of it running hot and blowing coolant through the overflow. A lot of people kept telling me to run a cooler thermostat, as if that would somehow magically fix the issue. I found a shop that could test the coolant and, sure enough, there were traces of carbon gasses which meant a head gasket leak. When under load, the gasket had just enough of a gap between the head and the block that it would move, thereby allowing exhaust gasses into the cooling passages. The exhaust gasses being injected into the cooling system is what caused my blowing coolant issue.

OK, back to your question. The manufacturers test their vehicles in the harsh desert conditions to ensure cooling systems function properly. A vehicle that is running hot is doing so because: A) it's towing a load which is causing the engine to run hotter due to the extra work; B) a clogged or undersized radiator; C) a faulty thermostat (not opening all the way, or not at all; D) a worn water pump (impellers degraded due to age); E) an incorrect water pump (counter-clockwise pump in place of clock-wise pump or vice-versa).

Unless your truck has been reprogrammed with a tune, there is no reason to run anything other than the stock thermostat for your application.

 

Going that cool, you will likely see performance and fuel mileage issues. As stated these engine's are tested for optimal running temperature.

 

That's about where my temp gauge rides.

SJ03