M998 operating temperature

[Icecold1]

My new to me m998 1987 6.5 runs at 170 or so in the 25 degree weather,seems too cold? It appears the fan runs constantly and unplugging the controller dosent do anything.

so where should I start? With a new t stat? As fan running or not it seems it should run hotter

If a new t stat is in order what temp do I want?

thanks
pete

 

[Bravojmc]

I’m running two grill covers in cold weather to keep mine running at 200

 

[papakb]

Get out your copy of the -20 manual and follow the troubleshooting flow chart for the cooling system. All of this has been covered and well documented in the manuals so that a semi-literate 18 year old Army private can fix complex systems like these. 99% of the troubles your going to have are covered in there. Think of it as a learning experience.

You DO have the manuals don't you?

The system should cycle between 180 and 220 degrees when it's working. The fact that breaking the fan solenoid connector doesn't change anything tells you that the fan is locked up. It could be a bad Kysor-Cadillac solenoid, and bad time delay module a frozen fan clutch or a plugged line somewhere between the power steering pump and the fan clutch.. The flowchart will help you figure out which one is the culprit.

 

[tage]

Get out your copy of the -20 manual and follow the troubleshooting flow chart for the cooling system. All of this has been covered and well documented in the manuals so that a semi-literate 18 year old Army private can fix complex systems like these. 99% of the troubles your going to have are covered in there. Think of it as a learning experience.

You DO have the manuals don't you?

The system should cycle between 180 and 220 degrees when it's working. The fact that breaking the fan solenoid connector doesn't change anything tells you that the fan is locked up. It could be a bad Kysor-Cadillac solenoid, and bad time delay module a frozen fan clutch or a plugged line somewhere between the power steering pump and the fan clutch.. The flowchart will help you figure out which one is the culprit.

yepp yeppp. or the fan system is not working at all "freewheeling"... More likely frozen fan clutch from sitting. You can introduce compressed air into the rubber hose to the fan clutch (not while running) and see the clutch engage/disengage.


Willing to bet you have a good t stat. It's just not getting up to temp.

 

[Icecold1]

Thanks guys,I am new to the m998,only had her a couple weeks.i don't have any manuals.im sure I can dig some up online though.
i thought the temp was cool and the fan seems stuck on so I'll have to see what's up. I'm also new to diesels so I was not sure if they made enough heat idling to get to 200 with the fan on at 20 degrees. It is only getting colder up here in Minnesota

 

[tage]

Thanks guys,I am new to the m998,only had her a couple weeks.i don't have any manuals.im sure I can dig some up online though.
i thought the temp was cool and the fan seems stuck on so I'll have to see what's up. I'm also new to diesels so I was not sure if they made enough heat idling to get to 200 with the fan on at 20 degrees. It is only getting colder up here in Minnesota

TM's are all in the TM section on this website.

 

[twisted60]

Thanks guys,I am new to the m998,only had her a couple weeks.i don't have any manuals.im sure I can dig some up online though.
i thought the temp was cool and the fan seems stuck on so I'll have to see what's up. I'm also new to diesels so I was not sure if they made enough heat idling to get to 200 with the fan on at 20 degrees. It is only getting colder up here in Minnesota

There are free manuals right here for downloading, go to the top of the page and you will see Technical Manuals, have a look in there, download everything for the M998.

 

[porkysplace]

Thanks guys,I am new to the m998,only had her a couple weeks.i don't have any manuals.im sure I can dig some up online though.
i thought the temp was cool and the fan seems stuck on so I'll have to see what's up. I'm also new to diesels so I was not sure if they made enough heat idling to get to 200 with the fan on at 20 degrees. It is only getting colder up here in Minnesota

You can download the TM'S here ;
TM's for the M998 series

A good source on how to use the TM's;
How to use/read Technical Manuals