Engine cooling thermostat in Cat 350

If the engine is running at lower temp look for better fuel mileage when you get back up to normal.
Computer will add more fuel to cooler engine.
Had a Chevy PU (gas) get 2 more miles to the gallon with just thermostat change!
Watch the antifreeze with any animals, it's poison.

Your chassis manual should tell you what the capacity of the cooling system is. You will not need to drain all the coolant but down below the thermostat housing. I would use an 8 gallon Rubbermaid tub. I would think drain about 4 or 5 gallons that would get you down below the housing.

The CAT C10 only has one thermostat but it very big and does not look anything like a car thermostat.

Another thing to consider is if there are booster pumps to move the coolant to the front of the coach. My coach has two booster pumps, one at the engine and one in the front. The pump help get the hot water to the front.
Also some HVAC systems have water cut off valves at the HVAC that can get stuck. Maybe they are stuck closed so no coolant is being allowed in the HVAC unit.

Do you have an accurate way to measure the coolant temperature, such as a ScanGuage or a SilverLeaf? You could also use an IR Temperature gun on the thermostat housing after you warn the engine up. If yours it is like mind you will have to go for a drive to get to operating temperature. Checking the temperature at the housing would give you a better idea of what is going on. You could also use the IR gun in the HVAC unit to determine coolant temperature there.

You just have to drain enough coolant to bring it down below the thermostat area as Brett said above. Most Diesel RV engines have two thermostats. Just be sure that you get the proper ones.

ILVMYGT wrote:
I changed the thermostat in my CAT C10 and don't remembering it being too difficult.

Are there two parts?

It sounds like you have to drain all of the antifreeze first. I need to dig a little deeper and see how much I will need to drain.

I changed the thermostat in my CAT C10 and don't remembering it being too difficult.

I just found a Youtube video. Little more involved than a '57 Chevy thermostat. However, if the cover is easy to access it may not be too bad. Need to do a little more investigating before diving into this.

If you can access the front of the engine (toward the back of the coach) from above or back (side radiator) not much of a job.

Use your engine serial number at a Caterpillar dealer to get the correct thermostat(s) and gasket (some have one, some two thermostats) BTW, Caterpillar calls them "regulators".

Drain off 2-3 gallons of coolant.
Remove old thermostat(s) and gasket.
Pour coolant in housing until full and insert thermostat(s).
Install gasket and housing.

Pretty simple job IF you can access that area which is coach dependent, not engine dependent.

Actuallly, the C7 has two thermostats.
I always had Freightliner change mine.