Heater issue

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Dec 8, 2009 | 08:03 PM

DiscoTruck

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Heater issue

I hope someone can help me. I've searched the site and haven't found anything for 73-79 trucks. In a nutshell, I have heat, but it is barely warm. coolant level is full, blower works fine. I have a 79 F250 4x4 w/351M manual trans. original low mileage truck, with all emissions intact.

Dec 8, 2009 | 09:07 PM

montana_highboy

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From: Big Sky Country

Could be a stuck thermostat.

Dec 12, 2009 | 10:22 PM

cathode

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Quote:

Originally Posted by DiscoTruck

With the truck warmed up and running, pop the hood and grab the two heater hoses running to the passenger side of the firewall. If they're cool or just luke warm, you may in fact have a stuck thermostat and the truck isn't getting up to temp. If at least one of the hoses is very warm to the touch, you probably have a plugged heater core. Hot water is getting there, but not flowing through the core and you get no heat.

3 different cores for these trucks, 1 standard, 1 high-output (usually labeled as "Hi Output" on the heater controls in the dash) and 1 for A/C trucks. They're all ~$35 at Napa. About a 1.5 hour job (for the non A/C trucks) to swap and you'll be happy with the results. I just did this on my 79 F250 the day before yesterday. It's good to have heat!

Dec 16, 2009 | 06:29 PM

DiscoTruck

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Cool, thanks, I'll do that tonight.

Dec 16, 2009 | 08:49 PM

Greyman

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If it's plugged you can disconnect both hoses and back flush the core. I did this on my core. Air gun in the hose and blow it out into 2 liter soda bottle. You can see what comes out and when to stop. Worked great after.