I've got a 2008 Western Star 14L with a cab heat problem.
When sitting an idling (cold winter days) at up to 1000 or so....engine temps will still drop to 130-140. Of course, then my cab heater temps also drop to a point where it feels like lukewarm air coming out.
It's a big bunk so it starts to cool off in there quite a bit.
When driving down the highway, it will rarely kick on the fan with the engine temp usually hovering around 185-190 and the cab heat will get warmer but still not great... especially when it's a cold Saskatchewan winter day (even with a full winter front).
It's always had this problem but I've just learned to live with it. But I have drivers in it and they don't like driving it...lol
It had a new head put on a few months ago so I don't think that's the issue...as its been like this for years. So I was going to change thermostats to see if that will help.
Not sure what's in there right now...but which would be the best temp thermostat to keep engine warmer and cab heat hotter??
Cab heat issue
Discussion in 'Trucks [ Eighteen Wheelers ]' started by skman, Dec 2, 2022.
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austinmike Thanks this.
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zinita17601 Road Train Member
- Aug 19, 2010
U may have two separate issues,a bad thermostat and a bad heater valve.ducnut, skman, austinmike and 1 other person Thank this.
Sounds like one of the two thermostats is stuck open.skman and austinmike Thank this.
What temp thermostat would you recommend?
It doesn't get crazy hot here in the summer, no mountains to climb...but it does get cold in the winter
Espressolane Road Train Member
- Nov 21, 2009
It does sound like flow to the heater cores is restricted.
Sounds like a winter front could help out.
uncleal13 Road Train Member
- Apr 9, 2009
I had a 2013 4900SF, first two winters here in Saskatchewan cab was cold, side windows would frost up going down the highway, would only clear when stopped.
Third winter I unhooked the cab heater hose off the heater control valve to flush out the heater core.
I happened to glance at the port of the valve and saw that it was mostly closed, only open about 1/8”. I knew my cab setting was full heat. I double checked and confirmed it was selected hot.
I got looking at the valve. The arm were the control cable was attached was mounted into a hole that was too far from the body of the valve so it had lots of leverage but didn’t rotate the valve very far.
I drilled a hole into the arm about half way down and installed the cable.
It was now harder to turn the control knob, but the valve now would rotate fully open.
After that the cab was roasting hot, and the windows stayed clear.Rideandrepair, ducnut and skman Thank this.
It’s common for engines to lose heat, when not doing work. All that can be done is to bump the idle even more or add an auxiliary bunk heater.
I agree with the others, you definitely need to be looking for heater control valve issues and plugged heater cores. I’ve experienced both. With a truck that old, if the heater cores have never been changed, they need to be.
slim shady Thanks this.
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