Cat C9 engine: Thermostat(s) replacement

Not a bad idea after removing the old gasket to use a sanding block and some wet-dry 400 grit sandpaper to "dress" the mating surfaces. Just put paper towel in the thermostat housing to so metal gets in.

This will tell you very quickly if both surfaces are true.

I have always called Caterpillar with my engine serial number, and they have been very responsive. I too needed to replace two thermostats in our C7, called Cat got part numbers for thermostats and gasket. Our local truck repair center had them in stock. I installed, but have a leak. Called Cat to discuss installation procedure. Cat said I did it correctly. I ordered two more gaskets that will be in tomorrow. Possibly I didn't get all the old gasket off the block and top cap. Bought a scraper from local auto supply, and I will try again tomorrow. One suggestion I received was to drain about 2 gallons of coolant before beginning and then just before installing the thermostats add the coolant until you can see the level where the thermostats are installed. This will prevent an air bubble that can create temperature sensing problems and proper cooling.

KenandCarolW wrote:
I am reluctant to call a Cat dealer to determine the numbers, then shop around for price. (Don't hesitate to upbraid me if you think I need it.) Can anyone help?

Just go to the Caterpillar dealer with your engine serial number for the thermostats (called regulators) and gasket.

Saving a buck or two and overheating an engine would be poor economics.

Ok, we have come to plan “D”

Sauer Sundstrand says part# 41236 is not a valid part number.

I am having my son drive here with the truck

We will move the motor home to this guys shop

We will pull the trailer home.

He will remove the pump and carry it around to try and find parts.

The shaft will be replaced with a grease-able shaft.

This year’s racing season is over.

This will remove the pressure of being stranded, and allow us to fix it correctly

When I used to do the maintenence on local school buses I tried after market themostats.They did not last nor perform as well as OEM from Cat.

Just my two cents worth. dave