E9 400 thermostat

[ChesterChop]

Trying to fix things myself. My truck temp is all over.  It doesn't get above 150 if its cool out and will go above 210 when the weather gets hot. The truck is at a shop getting something else repaired now.  I was told to get it warmed up and shoot the radiator with a temp gun to check to make sure it isn't clogged.  Would it do that if the thermostat needed replaced? Looks like there is two on this motor, how hard of a job is that to do? Thanks 

[ws721]

when i had the radiator out of my E9 i changed both thermostats just because i thought i should. However,  the engine would not warm up after that. So i took the Thermostats back to Mack and explained the problem. Luckily for me the service manager happened to walk by and overheard. He suggested putting the old Thermostats back in. Which I did and its been fine. As the service manager said, "Today's parts aren't as good as the old parts.  Make sure its circulating. The Thermostats are available thru Mack. Or were 4 years ago.  Who knows what the new owners have done since. I di have to replace the Thermal clutch fan. But that shouldn't cause it to not warm up in the summer time at least. Good luck

[JoeH]

I've got an endt676 that did more or less the same thing.  Except it doesn't even have a thermostat installed.  It's just a yard tractor used for blowing cement into our silo.  Engine cranks to 1700 rpms to operate the PTO.  We put a solid (fixed) fan on the water pump, now it heats to 155  and stays there.