440 Has always ran too cool.

[Sasquatch]

I am doing everything I can to try and get this engine to run closer to 200 degrees.  It has ALWAYS been a cool motor, running about 170-175 which is too cool.  I swapped out the 180 degree thermostat for a 195 before this trip and the temperatures did go up, to only 180-189.  I always used the proper skirted thermostats.  Even down here pulling hills at 65 in near 80 degree weather she just does not warm up.  I even tried blocking off half the radiator with cardboard for a stint, and that only gained me about 3-5 degrees.  What am I missing?

[cook elandan]

What kind of gauge are you using. can you trust it.

[Sasquatch]

I use two. The dash gauge and the digital one that is part of the fuel injection kit I installed. They both read the same.

[Rickf1985]

Do you have a heater return line that runs back to the radiator? That would provide constant flow from the radiator.

[Sasquatch]

I think that may have something to do with it.  I need to track how they run.  I know they split and one link runs to the water heater (nice for hot water on the road) and the other to the heater box.  I will track down how they flow.

I made it to Tucson this afternoon where I will be for the next week before heading home.  The 195 degree thermostat made a small difference in temps, but not much at all.  I expected more.

It is not a huge deal.  I am splitting hairs here.  The coach ran fantastic.  I averaged between 7 and 8.8 mpg running hard and bucking major headwinds all the way here it seemed.  Cant complain.

[Rickf1985]

I have the same setup on my 89 Chieftain and my gauge runs low but I don't believe the gauge since the fan clutch kicks in regularly.  I need to put in an aftermarket gauge. Plus I am running a 454 Chevy, completely different animal. But if you have a high flow though those heater lines, even if you are not using the heater, you are still using water that is flowing through the radiator and bypassing the thermostat. I find it hard to believe that a 440 would run that cool. Most people would pay lots of money to get that to happen!

Just curious, when you start it up cold and then let it warm up you should be able to see the thermostat open by a drop in the gauges. At what temp does this drop occur?

[Sasquatch]

I'll take a photo of the front end of this Executive sometime and post it.  Some coaches you wonder how any air gets into the radiator at all, but not on this one.  It is a ram air scoop that rams all the air it can grab into the entire core of the radiator unobstructed.  And the radiator itself is massive.  I even pulled off the mechanical fan and clutch and went to an electric fan off of a 90's era Ford crown vic (or something, I cant remember).  The only time that fan kicks in is if it is really hot out and I am idling in traffic.  If the coach is moving at anything above a snails pace there is enough air being forced through the radiator that the temp just falls back to 'normal'.

I see what you are asking for about the temp drops.  Logic would dictate that you could watch the temps rise, then when the thermostat opens and cold water is allowed back into the engine from the radiator they would momentarily drop until things stabilize.  This does not occur on my rig.  One of a couple of factors could be coming into play:  1, the thermostat opens slow enough that the fluid transfer is not enough to drop the temp gauge even momentarily.  In a perfect world this is ideal as to not shock the hot motor with cold air running into it. 2, Your theory about the heater hoses "preheating" the radiator may also be a factor.

It is probably a combination of both in this rig.  I did test both the old and new thermostats on the stove wired with my Omega Digital Thermocouple to see where they opened and watch as they opened/closed.  The 180 began opening at 175 and would not fully close until the temps cooled down to 168.  The 195 began to crack open at 187 and was fully open at 196.  As the water cooled, it did not fully close until 184 degrees.  This is all within spec for mechanical thermostats.

Again, I know I am splitting hairs and the motor is running fine.  These type of noggin stumpers are fun to analyze, discuss, and try and figure out.  I am trying different things to try and maximize the efficiency of this coach while still being able to drive a brick at 60-65 mph. It is a challenge, and fun for me.