M923a2 coolant system repair

[Hamrick907]

Been digging into the coolant system since my truck started over heating.
Lots of junk in the system. Trying to clean up the radiator with CLR and flush the sysytem.
Found out my fan clutch is bad so gathering parts to rebuild.
Thought I would post some pics.

 

[WillWagner]

Looks like a Freightliner radiator. Was it pushing coolant out of the overflow? What temp did it get to? Gauges are known to be incorrect.

 

[Hamrick907]

Almost exactly the same, the M923 has rounded corners on the radiator.
Freightliner has squared.
No coolant out the overflow but it was boiling when I took the cap off.
Gauge said 235 and then I found out the engine fan had a bad bearing.

 

[Jbulach]

Looks like a Freightliner radiator. Was it pushing coolant out of the overflow? What temp did it get to? Gauges are known to be incorrect.

Will, do you remember? I thought I remember reading about problems with some of the water pumps on the C motors having plastic impeller that break up?

I had a lot of crap in my cooling system, work my truck pretty hard in some fairly high temps, and hardly ever have my fan come on. Not sure what kind of ambient spring temperature in Alaska... just thinking he has other issues as well?

 

[Hamrick907]

Sorry the 5 ton has a square cornered radiator.
Water pump is steel construction and in good shape.
Lots of gunk in the system. CLR seems to be working really good at cleaning stuff up.
Started to take apart the fan clutch and will post pics soon.

 

[Hamrick907]

SUMMER TEMPS AVERAGE IN THE 60'S.
Last year was the first time in my life time that Wasilla hit 90 degrees.

 

[WillWagner]

Early engines had plastic or whatever it was made of but that didn't last long, maybe 6 mos to a year into production. Easy to look at, 2 bolts. Usually if no coolant is pushing out the overflow, not overheating. So if the gauge says 230 and no coolant leaving the radiator, fan not on, not overheating. But he said the fan hub was "bad"....hope he punishes that lil hoodlum!

If the hub is leaking air or friction material is gone, I'd do that first. Also, white vinegar helps get rid of rust.

 

[Jbulach]

Sorry the 5 ton has a square cornered radiator.
Water pump is steel construction and in good shape.
Lots of gunk in the system. CLR seems to be working really good at cleaning stuff up.
Started to take apart the fan clutch and will post pics soon.

Good time to install a coolant filter as well. Mine a year after what I thought was a thorough flush.

 

[Hamrick907]

Coolant filter is on the to do list.
What king of antifreeze do you guys use? Green?

 

[Hamrick907]

Got the clutch tore down.
Bearing 4T-CR1-0868 and 2X bearings 6206LU
Looks to be in good shape for the most part.
Bearing is bad for sure.

 

[frank8003]

Coolant filter is on the to do list.
What king of antifreeze do you guys use? Green?

Does your engine have cylinder bore liners?
What is recommended by engine manufacturer and the TM's for that truck?

 

[Jbulach]

Yes, wet liners. I used cheap green Miles Evercool with SCA precharge in mine.

 

[juanprado]

this thread reminded me to change my filter. Have been using one for maybe 7-8 years. Filter was in my opinion very clean ( 4-1/2 years on it ) in comparison to my first one I changed similar to the one posted earlier.

Don't forget to flush heater core as it is a source of lots of mud also.

I use plain green not hd and for my first 2 coolant filters used ones with dca chemical. Did not have a test strip this time so I just used a plain filter,

 

[Hamrick907]

Thanks for the reminder about the heater core.
Ordered the bearings today off Ebay.
Hard time finding the NTN 4t-cri-0868
I hope I got the right one.
About $100 total.
Clutch pad looks to be in great shape, but there is a little rust.
Had the steel coolant pipes sand blasted, any ideas about the inside of the pipe?
After blasting its just bare metal grey should I paint the inside and if so with what?

 

[WillWagner]

No paint on the inside, coolant will eventually take it off. You can powder coat, that works well.