Help with no heat!!

[SVOeric]

well I been chasing this little gremlin for years..

When I bought the car, I drove it from AZ, in februrary (1999), with no heat. At the time, I just assumed the thermostat was stuck open, since I wasn't getting any reading on the temp gauge.

After I got the car home, I put in a new heater core, (leaking), and a new thermostat. The heat seemed to work after that, but it was summer, and shortly afterwords pulled the engine for a rebuild.

After I got the engine back in, the heat hasn't worked since. I have replaced the thermost 3 times, with the stock temp, and that has made no difference. The engine runs cool in winter (summer too really) normally between the n and o on the gauge.

If I stop the car, and let it sit for a min, with the heat on low, the heat gets good and warm. If I turn the fan up, the heat starts getting cooler. It never really gets cold, but it's not really warm enough to keep the car warm.

Tonight, I stuck my head under the dash on the passenger side, to check the heat/cool cable, to make sure it was moving. It was moving all the way in both directions.

so now I'm nearly at a loss -- The only 2 thing I can think of is
* the water pump, but the engine seems to run cool, so I wouldn't think this is the problem.
* between the time I replaced the heater core, and put the engine back in, something got into the heater core (bugs/mice/whatever) and it has a blockage.

So, this weekend, I'm going to try to flush the out the heater core.

Anyone got any good ideas on anything else I can check ??
I'm driving down (5+ hours) to bama for dyno day weekend after next, and I'd like to have some heat!

[ByteMe]

do u have good air flow coming out of the ducts on high fan? if not there might be a mouse nest in the duct work, i understand for some reason the tbird and the mustangs have a problem with mice getting in there and building nest....kevin

[SVOeric]

nope -- on high, I can blow-dry my hair with it set on vent

[SVOeric]

oops -- it's my 86 1E -- the 85 still don't have coolant lines

I'll search through for the restrictor info. I didn't remember the SVO having one.

[GAboySVO]

Eric,

When I first got my '86, I could hardly get the thing to heat up before I made it to work in the morning. I ended up putting in a 190* thermostat and that seemed to help.

Also, you might want to check to see when the fan is coming on. It might be coming on to soon.

I think Mike has the right idea about not getting enough flow threw the heater core. I don't recall seeing a restrictor in my replacement either. But when the fluid level would get below a certain level, there was not enough flow to the heater core at idle to keep it warm.

Another trick to try is to put the selector in the Max A/C postion with the temp selector at hot. The compressed freon will heat up condesor up front helping to add extra heat to the radiator.

You might want to go to Home Depot and get some of that clear PVC hose and make a temporary connection to the heater core from the water pump to see what kind of flow you are getting.

[SVOeric]

no AC -- big hole in the condenser... I need to just pull the rest of the AC stuff off -- but I'm still debating on fixing it.

You might want to go to Home Depot and get some of that clear PVC hose and make a temporary connection to the heater core from the water pump to see what kind of flow you are getting.

That is a EXCELENT idea...

I used all new replacment hoses, and I don't remember a restrictor either. -- I did some searches.. and havn't found anything yet -- but I'm still looking...

[venomizd93]

Hey if any of you guys have those restrictors left over and don't want them I'll take one. I got rid of mine...dumb dumb dumb....on my cobra. Supposedly a lot of 5.0 heater cores blow out if the restictor is not in the heater hose....I don't want to have to replace my core. I already have to take my who SHO dash out to replace the blend door motor. Rotten bastards

Have you put your hand on the inlet hoes to dee how warm the coolant is???? and if it was the thermo I'd just ake it out and run it to see if that actually was the problem. I would agree that your core or something on the way there is blocked. Good luck

[Otto Man]

Man....
I almost threw all my old hoses out on Monday!
Where is this restrictor? In which hose? Or is it in the heater core itself?
Chris

[SVOeric]

well, I searched, and searched, and I can't find anything about a restrictor, and which hose it is in.

I'm home now, and am about to go work on it.

[venomizd93]

It would be on the inlet.....it restricts flow into the core at high rpms so it won't spring a leak under high rpm stress....supposedly... it's a metal oring, it reduces the hose size.

[Otto Man]

So if I had a new heater core installed (by Ford) it should have this in the inlet and I can toss the hoses?
Chris

[venomizd93]

If you're talking about having it put in at a ford dealer...don't count on it. What they're supposed to do and what they do are two different things. The heater core will not have the restictor in it. Like I mentioned previous it's a small metal piece I think brass that would be in the inlet heater hose near where the intlet to the heater core is. I didn't know what it was when I first changed my hoses on the cobra and I tossed it. Then I read about blown heater cores in 5.0's and wanted it back. I think it may be a discontinued part.

[GAboySVO]

I thought the restrictors were installed whenever you have a high flow water pump installed. Its purpose is to protect the heater core from the greater flow of the performance pump.

I don't believe that the SVOs ever had high flow water pumps from the factory, just the regular 2.3L pump with a larger pilot shaft.

[venomizd93]

You're right on the SVO but stock 5.0's had the restictor at least in 93...must ahve been a lot of warranty core replacements...headaches, headaches, headaches

[KevinK]

Well, when you're done chasing down that restrictor, take a garden hose and flush out the heater core. Then back flush it in the reverse direction. Keep going back and forth until all your get is clear water and good flow. Had the same problem with 60's and 70's Fords.

If you don't get flow, it's time flor a new heater core.