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Author Topic:   F-150 Engine Prob
Spi-nex
Dirt Full Roller

Total posts: 70
posted November 15, 2005 09:10 PM  
Ok, the temperature gauge doesnt work and the heater will only kick out half the heat that it used to.

Any ideas on whats goin on?

Thanks for any info!

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Jonathon R. Huston
#81 Factory Stock

b4racing
Dirt Forum Champ
Total posts: 640
posted November 15, 2005 11:18 PM  
blocked radiator, stuck thermostat.

Spi-nex
Dirt Full Roller

Total posts: 70
posted November 15, 2005 11:39 PM  
If the thermostat was plugged, then I dont "think" there should be ANY heat??? Im only goin on a idea here so I will check the thermostat.

I know there is a relay that is hooked to a water temp gauge that goes to the temp gauge on the dashboard, then the other part of the relay goes to the heater that tells it when it can have heat, I "think" thats how it works.

Would a stuck thermostat stop a defroster from working? Cause its still working....I dont know nuttin bout this new technology junk cars lol. I like my nice mechanically orientated engines and cars from teh 60's & 70's

Thanks guys!

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Jonathon R. Huston
#81 Factory Stock

brabbit75
Dirt Full Roller

Total posts: 51
posted November 16, 2005 08:30 AM  
Check heater core, could be plugged, did same thing in my dads ranger, plugged solid, got a different one, works like a champ now. just an idea..

TEAMPCR
Dirt Freak

Total posts: 242
posted November 16, 2005 11:49 AM  
Air pocket.

Spi-nex
Dirt Full Roller

Total posts: 70
posted November 16, 2005 02:14 PM  
Air pocket???

The Flash32
Dirt Maniac

Total posts: 128
posted November 16, 2005 03:26 PM  
I just had the very same problem, the thermostat was stuck slightly open. Showed very low temp. & heater took for ever to warm up.

Spi-nex
Dirt Full Roller

Total posts: 70
posted November 16, 2005 04:59 PM  
Thats exactly what I have. What did you do? put in a new heater core?

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Jonathon R. Huston
#81 Factory Stock

brabbit75
Dirt Full Roller

Total posts: 51
posted November 16, 2005 05:27 PM  
First make sure there isn't an air bubble in cooling system, let it run with radiator cap off for a while, 10 minutes is what I usually do, make sure coolant always stays full in radiator. If that doesnt work, then try a new thermostat , if that doesn't do it, let the vehicle run with the heat on high, open the hood and look at the lines coming off the water pump/intake, going to the heater core, if they start collapsing , then the heater core is plugged. This should fix it, these are most common problems that I've ever encountered.

Spi-nex
Dirt Full Roller

Total posts: 70
posted November 17, 2005 03:25 PM  
OK I did some checking today. The hoses are fine going to the heater, no collapsing.

Radiator coolant level is fine even when running.

Blower gives me all the air I want, just no heat.

I think that a stuck OPEN thermostat would cause this...right??? My theory: If the thermostat is stuck open then the engine never really heats up and the heater cant draw any heat from a cold engine and if the engine is cold then the temerature gauge doesnt have anything to measure either.

Now for my really embarassing question,,,where is the thermostat located on a F-150 straight 6? (Im new at this so bear with me LOL)

Thanks guys

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Jonathon R. Huston
#81 Factory Stock

brabbit75
Dirt Full Roller

Total posts: 51
posted November 17, 2005 05:15 PM  
follow the top radiator hose to the engine. i'm not sure exactly where, but should be close to the motor off the end of the hose

Ego Racing
Dirt Forum Champ
Total posts: 762
posted November 17, 2005 05:29 PM  
The controls on the dash control vacuum from the engine to open and close. These close off the heater core while the temp comtrol is in the cool position or when the AC is on. More than likely the hose to this door is broken or got knocked off or the door is stuck shut. If you get a service manual it will show the location of them and if they have a vacuum booster on them. Yo can check it with a hand held vacuum pump like the type for bleeding brakes.

The Flash32
Dirt Maniac

Total posts: 128
posted November 17, 2005 07:33 PM  
Just change the thermostat, the heater control vaccuum won't be the problem in not making the temp. guage show low temp. When you pull it out, look to see if it is open just a little. If it is, theres your problem!

[This message has been edited by The Flash32 (edited November 17, 2005).]

Ego Racing
Dirt Forum Champ
Total posts: 762
posted November 17, 2005 08:49 PM  
quote:
Originally posted by The Flash32:
Just change the thermostat, the heater control vaccuum won't be the problem in not making the temp. guage show low temp. When you pull it out, look to see if it is open just a little. If it is, theres your problem!

[This message has been edited by The Flash32 (edited November 17, 2005).]


He never said the guage was reading low, he said it didn't work.
Is the guage the typical ford type where there is a 2 inch space in the middle that is "normal" if so what temp is "normal" a 2 inch sweep on most guages is about 100 degrees.

Spi-nex
Dirt Full Roller

Total posts: 70
posted November 17, 2005 09:50 PM  
Its a stock Ford Temp gauge, its about 1 1/2'' across, and the gauge doesnt even come up to the "C".

I think its a thermostat, Ill find out this weekend. Ive never changed one before so Ill just wing it LOL.

Thanks guys.

If you have more info please tell me!

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Jonathon R. Huston
#81 Factory Stock

captain
Dirt Roller

Total posts: 25
posted November 20, 2005 07:20 AM  
The T-Stat is on the front end of the heat at the end of the top radiator hose.

sc1 racing
Dirt Freak

Total posts: 428
posted November 20, 2005 08:14 AM  
when you pull the thermostat out put it in a pan fill with water a put it on the stove top. get a thermometer and put in water and see when it opens. then pull it out and see how long it takes to close.if it is cold where you live loosen rad cap and drive truck around but stay close or have extra water with you. with the cap loose the system wont build the necasary pressure and should heat up quicker. that will tell you if its thermostat or not..

ryan
Dirt Forum Champ
Total posts: 784
posted November 21, 2005 09:12 PM  
On dads 89 f-150 the heater core is very easy to change pull the glovebox and you're almost done. My 97 Jimmy had heating issues where it didn't kick out hardly any heat. We ended up back flushing it and got out a big chunk of sludge and now you have to keep it on low to keep from sweating. We would have just changed out the heater core, but the manual says you have to remove the dash.
Feel all your hoses if they are all hot I would go with the heater core.

Spi-nex
Dirt Full Roller

Total posts: 70
posted December 03, 2005 01:06 PM  
Finially got around to fixing the problem today. And it WAS a STUCK OPEN THERMOSTAT. Pulled it out and the button was all the way out and stuck. Put a new one in and the temperature gauge reads now and I have my precious HEAT back in the truck! Thanks everyone for your input and you guys were right on the money.

Thanks Again

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Jonathon R. Huston
#81 Factory Stock

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