Heater will not work

MRCOOLITWV

MEMBER
FORD E-SERIES VAN

1993 econo conv. 302 engine. Front and rear heater. New radiator, new front heater core, new thermostat, new water pump. New radiator cap. 100k miles.

I cannot get either front or rear heater to work. The front heater will make a small amount of heat. I checked everything that I know. When blower is on low speed there seems to be some heat, on high the temprature goes down. Same with rear heater. Seems to be a water flow problem, but I cant single it out.

My mechanic installed all these new parts and then gave up. Said he had no idea

5 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

Does it have heater control valves? Could be a blend door under the dash not moving all the way to hot. Might even be a controller problem at the dash. Do the heater hoses get hot?

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Monday, October 29th, 2007 AT 6:18 PM

MRCOOLITWV

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3 POSTS

Nope, it does not have a heater control valve. It has a flap for the front heater that works fine and the rear heater is just a core with a fan.

I'm a A/C and comerical refrigeration tech., So I should be able to answer your questions.

The heater hose to the front core is hot, the return is luke warm. Remember, new core in front.

The heater hose to rear core is hot, the return is warm.

If you do not run the fans, the cores will eventualy get hot, but as soon as the fans go on, the cores go cold.

Also installed new water pump.

Prety soon I will have a new van, one part at a time.

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Monday, October 29th, 2007 AT 7:07 PM

2CARPRO JACK

MECHANIC
11,533 POSTS

Flow problem. The hot water is sitting in the cores, and like the little radiators that they are, the water is being cooled down when the air blows across them

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Tuesday, October 30th, 2007 AT 7:51 AM

MRCOOLITWV

MEMBER
3 POSTS

Ok, Thanks for your responses Jack. But ya gotta help me out here. I knew comming into this session that I had a flow problem. I just have run out of places to look for it. If you might give me some idea where to look or if you need to know where I have already looked, I can provide that info.

You better hurry, the price of gas is going through the roof and the mileage this thing gets, 15 on a good day, I'll not be able to drive it to you for you to fix. Just kidding.

Thanks, Brent

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Wednesday, October 31st, 2007 AT 5:13 AM

2CARPRO JACK

MECHANIC
11,533 POSTS

Have you tried starting the van with the feed lines in a bucket or such to see what kind of flow you have to them. Maybe debris from prevoius work has caused the restriction. Does the engine run at the normal temp? Sorry BTW didnt mean to insult your intelligence, half the time it is something simple being overlooked.