96 GMC Jimmy coolant temp?

[darkred87T]

Hi,
I might have posted a thread a while back about this. A freind form work has a 96 GMC Jimmy and his mechanic told him it needed a heater core. Heat comes out of the vent but only luke warm.

He brought it over today for me to take another look at. He drove about 40 miles before he got to my house giving the car more than enough time to warm up. I looked at the tempurature guage and it was only reading about 155-160. Granted, it is pretty cold today but my Grand Am and other cars Iv'e driven usually hang out just over 200 degrees despite the coldest of days. I'm thinking he just needs a thermostat. What do you guys think?

 

[SFITurbo]

Try back flushing the heater core with a garden hose, same thing happened to my friends...full of sludge.

 

[darkred87T]

Thanks I did that twice for him already. It seems to flow O.K.

He says it gets a little better but I still don't think the thermostat is working.
The heat doesn't start to get hot in my car until the temp goes over 170 or so. His truck doesn't even reach 170 degrees.

 

[TR Custom Parts]

If the heater core flows well than it sounds like the t-stat is hung open. Cheap and easy to fix.