2003 Ford F-150 Thermostate is a half and no heat. Then it r

JOHNANDY22

MEMBER
2003 FORD F-150
V8
2WD
AUTOMATIC
80,000 MILES

Replaced thermostate, motor still will run at half on gauge but no heat at all, then The Thermostate will run 3/4 to nearly completely hot Then the Heat will work and the Theormatate will go back to 1/2 or normal.
Water level fine but do hear gurgling noice from heater coil. Truck will run fine and therom at half then when cut heat on no heat. Then after a few minutes the therm will run to nearly completely hot and heat will come out and it goes bck to normal. Just cant understand this. When it first happened I replaced theromostate but didnt fix. Thanks.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,700 POSTS

Based on your description, it sounds like there is an air pocket in the system. Did you bleed the system when you replaced the t-stat? Also, check something for me. With the engine running, hot (normal), and the heater on high (blowing cold air), feel both heater core hoses. Both should be hot. Let me know what you find.

Joe

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Monday, January 4th, 2010 AT 3:43 PM

JOHNANDY22

MEMBER
1 POST

I had the work done at a shop and took back to bleed a valve around the heater core. The gurgling does sound like air in it, is bleading something I can do fairly easy.

Why do you think the thermostate go up so high?
Would it be from air in line around heater coil?
Thanks so much for your reply. Andy

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Monday, January 4th, 2010 AT 11:10 PM

JACOBANDNICKOLAS

MECHANIC
109,700 POSTS

Actually, check near the thermostat housing or on it for a bleeder. Basically, when you open it, air should come out. As far as the temp changes, yes it could be as a result of air in the system or low coolant.

Andy, I'm glad to help. If you have any other questions, please feel free to ask. I'll do my best to answer you. It does get hard via the internet at times, but I give it my best shot.

Joe

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Tuesday, January 5th, 2010 AT 11:02 PM