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Replacing Cat C9 Thermostats

Yahoo Message Number: 88079
I'm looking for advice/help from someone who has changed out the 2 engine coolant thermostats on a Cat C9 (2006). I got the top of the housing off, the old gasket cleaned off the housing, and the new 'normal looking' thermostat that mounts into the housing on the engine reinstalled just fine. However, the larger thermostat that mounts into the top of the housing has me baffled - I cannot get the thermostat out of the housing. Is there a special trick to removing the thermostat?

Regards,

John

'06 Inspire DaVinci #51905

Re: Replacing Cat C9 Thermostats

Reply #1 –
Yahoo Message Number: 88087
John, Last year I changed out the thermostats in my 2005 Inspire with the Cat C-9 engine. As I recall, they both just pop out. The big thermostat has a bit of a tight fit but it will pop out with a little prying.
Good Luck,
RJ

2005 Inspire #51264

Re: Replacing Cat C9 Thermostats

Reply #2 –
Yahoo Message Number: 88088
As I recall, when I suggested a thermostat change with my last service, my local CAT service center told me a thermostat chance was not needed until 100,000 miles.

Jay

05 Inspire 51457 C-9

Re: Replacing Cat C9 Thermostats

Reply #3 –
Yahoo Message Number: 88089
John

Just replaced both of mine - C9 400 hp - 2005 year
No secret to removing the 'larger' stat - "just use a bigger hammer / screwdriver / grips!!" - take care with the housing 'face' when you 'lever'
The 'top' of the larger stat sits 'snugly' inside a hard rubber seal in the housing - the seal should also be replaced at the same time - this part also can be difficult / needs persuasion to remove
As neither part is to be re-used - they can be 'butchered' to remove
Once out of the top housing I cleaned up the mating surfaces of the seal in the housing with wire wool before driftig the seal back in - sorry I cannot remember the drift size but it was 'large'
On s different note - Appears my gasket was also 'gasket sealed' on both sides as well - so I resealed both sides to avoid the potential for leaks upon reassembly
Also worth checking that the 'ball bearing' in the small bypass valve in the housing is still free - only costs 'cents'

I have our housing bolt torque settings somewhere
We have decided to make the 'stat' replacement a routine service item as although we appeared to change nothing / found nothing amiss when replacing the stats - the dash heat and engine are now much quicker getting to temperature (so there was clearly something amiss - we did not bother to check the operation of the individual stats given the relatively low cost of replacement items)

If you need further info - you are welcome to pm me

Ian S.

2005 Allure 430 Hood River #31321
Cat C9 - 400hp - #9DG02935

Re: Replacing Cat C9 Thermostats

Reply #4 –
Yahoo Message Number: 88108
Many thanks to Jay and Ian. I have never been adverse to the concept of Use a Bigger Hammer, but I like to be sure that I am not ruining the parts I need in the process. I used a piece of wood to protect the face of the housing and proceeded to pry out the stat with a pair of Linesman pliers. Worked like a champ. Now to go complete the job.

Regards,

John

'06 Inspire Da Vinci #51905

Re: Replacing Cat C9 Thermostats

Reply #5 –
Yahoo Message Number: 88122
John

Did your thermostats go bad? I purchased the two to carry with me in the event of failure after I learned that the smaller one is not widely stocked.

Dan 2006 Allure 31348

Re: Replacing Cat C9 Thermostats

Reply #6 –
Yahoo Message Number: 88132
Not to my knowledge. However, the temperatures were starting to run a little higher than they had been in the past and since they were 7 years old, I decided that they could be acting up a little. I haven't used the coach since I finished changing them (yesterday) so I don't know if it did any good. Since I was doing oil change, etc., figured it was just as easy to go ahead and change them.

Regards,

John

'06 Inspire Da Vinci #51905