No heat, core flushed. What is the thermostat o-ring P/N?

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I did the rear heater removal. I had no heat before and after rear heat removal.

I also replaced every single coolant hose on the entire truck 2 years ago. Every single one....

If I have an obstruction then it's one of the hardlines.



While i have you all here, what position should the heater valve on the fire wall be in for heat? Want to start ruling out all these things.
 
I'll try to remember to check the heater valve when I get home if someone else doesn't chime in first.

How did you flush the core? I ran muriatic acid (VERY carefully) through mine until crud stopped coming out. This alone boosted the vent temperature from 120F to 150F.
 
Pulled heater core 2 years ago out of truck. Ran pool acid through it diluted with water until the flow was good. Lots of rusty stuff came out.
 
Randy88FJ62 said:
Pulled heater core 2 years ago out of truck. Ran pool acid through it diluted with water until the flow was good. Lots of rusty stuff came out.
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This right here makes me believe that there is another rust obstruction. I believe for the heater valve that when it is on full blast the top should be pulled UP. With what you have been saying, I am thinking another heater flush is in order prior to pulling the t-stat. Does the upper hose going to the valve feel hot when your truck is up to temp?!
 
I have not checeked or touched hoses when truck is warm. On the list after a drive.
 
I think I agree with greg that you may be looking at another flush. You don't just want to get sediment out, you also want to break up any scale that's lining the inside of the core. Scale will act as an insulator even if you still have good flow. Your acid may have been too dilute. When I did mine I used full strength muriatic acid (30% or so). It can be done without pulling the heater core, you just have to be really careful to contain the acid and flush the core thoroughly when you're done.
 
I'm pretty sure the core is good. If there is a blockage it it elsewhere.
 
I have this same issue, front heater blows barely warm air while the rear heater blows smokin hot air.

Just pulled my thermostat to check it and everything looks good there - except a couple bolts I broke in the process. Upper hose felt plenty hot too, so I'm not really sure what the problem is.

I think my next step is to attempt to flush the heater core. Never done this before, is it pretty easy?
 
Took me years to figure out the valve on the fire was was stuck in the cool position lol. Some wd40 on the sliding pin heat works great. Little things make a huge difference huh?
 
bentonrover said:
Took me years to figure out the valve on the fire was was stuck in the cool position lol. Some wd40 on the sliding pin heat works great. Little things make a huge difference huh?
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That is actually a really REALLY good suggestion. Wonder if that is my problem, that the valve just isnt completely opening... Will throw some penetrant on there and let it sit for a couple days while I work on other things..
 
I just work it up and down. Take the cable off. That actually goes to the temp adjust. I couldn't believe thats all it was. You can take it out and clean all the crap that probably stuck in there. Good luck
 
My issue is different, but started with no heat in the cab. Changed thermostat with prerequisite breaking of bolts. Now I'm in process of replacing the water pump. A pic in progress, is all this really necessary? I'm used to Chevy or jeep water pumps that are a 1-2 hour job.

IMG_20170131_180046.webp
 
Vandyfan said:
My issue is different, but started with no heat in the cab. Changed thermostat with prerequisite breaking of bolts. Now I'm in process of replacing the water pump. A pic in progress, is all this really necessary? I'm used to Chevy or jeep water pumps that are a 1-2 hour job.

View attachment 1393179
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waterpump job kind of sucks... many people do forget about the rubber washer in the thermostat housing.....
 
Elbert said:
waterpump job kind of sucks... many people do forget about the rubber washer in the thermostat housing.....
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Just had my thermostat out and did not see any rubber gasket in there. Maybe they didn't have it in the 2h diesel HJ60's? Or maybe the previous owner didn't put one in?
 
Aloha Jen said:
Just had my thermostat out and did not see any rubber gasket in there. Maybe they didn't have it in the 2h diesel HJ60's? Or maybe the previous owner didn't put one in?
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don't know...since I don't have a diesel, if the thermostat housing is the same design then its very common to be an issue. Go look on the sor web site to see if teh parts diagram shows a "rubber o ring or washer"... if so then you know ...at least on the gas burners there must be 50 posts a year...related to the no heat issue.
 
Aloha Jen said:
Just had my thermostat out and did not see any rubber gasket in there. Maybe they didn't have it in the 2h diesel HJ60's? Or maybe the previous owner didn't put one in?
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Here's the parts fiche diagram for the 2H. It doesn't show a thermostat gasket ("o-ring") like the 2F has. The diagram for the 3B doesn't show one either. The P/N table in the parts fiche just has a single entry for the thermostat gasket for the 2F.

2H thermostat.webp
 
Elbert said:
don't know...since I don't have a diesel, if the thermostat housing is the same design then its very common to be an issue. Go look on the sor web site to see if teh parts diagram shows a "rubber o ring or washer"... if so then you know ...at least on the gas burners there must be 50 posts a year...related to the no heat issue.
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bhk said:
Here's the parts fiche diagram for the 2H. It doesn't show a thermostat gasket ("o-ring") like the 2F has. The diagram for the 3B doesn't show one either. The P/N table in the parts fiche just has a single entry for the thermostat gasket for the 2F.

View attachment 1426999
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Thanks, looks like i don't need one!
 
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