Caterpillar C-12 thermostat assembly question

[Mattymatty]

Basically, I just need to figure out how this diaphragm fits into the thermostat housing.
When I was changing out the thermostats in my Freightliner, two of these diaphragms fell out of the housing, and I can't seem to figure out how they're supposed to go back in.

 

[Truck Shop]

I personally have never seen anything like that, maybe some others have.

 

[Joe H]

Looks like a piece of an old thermostat. An old something, what I don't know.



Leave it out.

Joe H

 

[Truck Shop]

Should be sealing rings for stats in bottom of housing.

 

[HeavyMetalRepair]

That looks like an AFRC diaphragm off of a different engine. Can you post a pic of where exactly it came from?

 

[Truck Shop]

That looks like an AFRC diaphragm

Reminds of A model pump diaphragm or retarder.

 

[Mattymatty]

That looks like an AFRC diaphragm off of a different engine. Can you post a pic of where exactly it came from?

It just sort of fell out of the bottom of the bore after I took the thermostats out.
I imagine it was sitting in there something like this, but I'm not sure.

 

[Truck Shop]

Below the sealing ring, what the heck? Call Cat with engine serial number for complete
parts list of thermostat housing, or better yet maybe @Nige can provide it.

 

[HeavyMetalRepair]

Interesting, is your freightliner an over the road regular ol semi truck or a special application truck?

 

[Nige]

Below the sealing ring, what the heck? Call Cat with engine serial number for complete
parts list of thermostat housing, or better yet maybe @Nige can provide it.

Sorry, my computer she done broko.

 

[Truck Shop]

Only thing I can find in exploded view, supposedly C12.
*

 

[Nige]

That’s pretty much a standard temperature regulator installation. A lip seal in the housing and the regulator installs into the seal.

 

[Mattymatty]

It seems that these diaphragms aren't in the parts list at Cat. Also they don't seem to be in any of the housings that I've seen in pictures and videos.
That makes me think that they're not necessary, and I should put the thermostats back in without them.

 

[Truck Shop]

It seems that these diaphragms aren't in the parts list at Cat. Also they don't seem to be in any of the housings that I've seen in pictures and videos.
That makes me think that they're not necessary, and I should put the thermostats back in without them.

Correct.

 

[Nige]

I wonder if someone put them there in an attempt to get the engine to run warmer by reducing the coolant flow.? If so it would be a strange way of going about it when you could simply swap the water temp regulators for some rated at a higher temperature.

 

[DustAndRay]

I'd just put the new stats in without those diaphragms and keep an eye on your temp gauge for the first few runs. If it holds steady where it should, you're good. At least now you know the last guy had some "creative" maintenance habits lol.

 

[HeavyMetalRepair]

I wonder if someone put them there in an attempt to get the engine to run warmer by reducing the coolant flow.? If so it would be a strange way of going about it when you could simply swap the water temp regulators for some rated at a higher temperature.

That was my assumption. I’ve seen washers welded inside the upper radiator tubes before. Blocking the front of the radiator seems like the easiest solution for that.

 

[Truck Shop]

Blocking the front of the radiator seems like the easiest solution for that.

These issues--is where the old shutter system or weather front worked well. I remember
drivers complaining of heating problems in late spring then finding a piece of cardboard
in front of rad.

 

[BC Placer gold]

Our old International with a L10 (ex-highways plow truck) has a shutter system. Seems to still function as designed.