Heater Problems

[cargeke]

I'm having trouble getting the heater in my '65 Falcon to put out any real warmth. It's getting cold up here in Chicago and I need the heat. The car is my daily driver and it has a new Mojave heater in it. (Factory heater delete car) The engine is basically stock with a new 180 degree thermostat. I'm wondering if the radiator is working too well. My trip to work is mostly highway, so the radiator is seeing a lot of fast-moving cold air, and my factory idiot gauge barely lifts off cold. (Could be the sending unit.) I'm probably going to try blocking off part of the radiator with cardboard to see if the heat improves, but I'd like to hear anyone elses suggestions.

 

[jamyers]

If your engine isn't getting up to temp, check your thermostat - sounds like it may be stuck in the "open" position. Even with a 160-degree t-stat you should get enough heat to warm your toes. Best way to check one is to put it in a pot of water on the stove with a thermometer and watch for when it opens up (my wife just loves it when I use her candy thermometer for this, she says it gives her cooking such a unique flavor! :roll: )

If that checks out, I'd check the heater return hose to make sure you've got coolant flow. One way is to see if it's getting hot, the 'for-sure' way is to pull it off with the engine running (get ready for some water).

If that checks out, then there's something wrong with the heater itself, either internal airflow or something goofy.

BTW, it really pays to eliminate any non-heater/vent sources of outside air, like around the clutch rod or other holes in the firewall.

 

[wallaka]

Carefully feel of both heater hoses when the car is warming up. With the heater on, both should get equally warm. If one is noticeably colder than the other, you have a blockage in the heater core or hose.

 

[66 Fastback]

Mine had blockage in the heater core. I found remnants of the spring from the lower radiator hose as well as other crud. Now it heats up quickly.
Doug

 

[Eric Rose]

Could be bad seals in the heater box. Also, there were a bunch of leaves and junk in my fresh air vents so I'm sure that stuff could be in the heater box too. I'm going to take mine apart some time this week.

 

[fordconvert]

All good info so far.

 

[cargeke]

The heater is brand new, so I'm thinking it's ok. The hoses were also about the same temperature, but not overly warm. If I get home before dark this week, I'm going to try switching the hose connections on the heater and making sure the thermostat is good. I may have to try a new water pump, if they're not really expensive.

 

[ludwig]

The impeller on your pump may be slipping on the shaft.

 

[jamyers]

I'd think that if your water pump was faulty, the engine would be overheating.

 

[kukm66]

After checking out the hoses as stated above, check for the following info.
Keep in mind that the way this heater setup works is by shutting off all incoming air from the ducts. That is accomplished by the action of the internal door which is controlled by the switch assembly through the use of cables. If any seals are shot or the door is not closing completely, cold air will enter into the chamber and you will not get any heat as it is neutralized by the cold air.

Link:

http://web.archive.org/web/200702071511 ... d4pt1.html

 

[cargeke]

I don't have a stock heater. The car came from Ford without a heater. This is what I'm using: http://www.flex-a-lite.com/auto/html/mojave-heater.html

 

[ludwig]

Bottom line: your heater hoses should be as hot at the hoses to the radiator. If they are only warm, the heated coolant water is not going through in sufficient volume.

I assume the blower fan works and all.

The system is not complex. You have a blockage somewhere or the fluid is not being pumped into the hoses.

Pull one of the hoses and make a loop to the water pump. Do it with the other hose too. If they don't get hot [not just 'warm'], then you have located your problem. If they get HOT and the heater is still not hot, the problem is in the heater core.

 

[69.5Mav]

Check the actual temperature of your coolant by getting a cheap thermometer from the cooking section of your local grocery store. Remove the radiator cap and insert the temp probe. Run the engine and allow the thermometer to reach its peak reading. From your description I suspect that your thermostat may not be sealing up and allowing to much water to flow around it keeping the coolant temp to low. I used to live in chicago, ask me how I know.

Both the block and thermostat housing must be free of any old gasket and compound. Use a scotch bright wheel to clean them up good enough to eat off. Then use a this coating of RTV when you reassemble. A good thermostat with a good seal should deliver coolant close to the thermostats rated temp. Also consider using a 195 thermostat. I did and got a lot of heat from my 72 Maverick when I used to drive from Harwood Hieght to Aroura.

 

[70 grabber]

I agree I would also say with about 95% certainty its thermostat issues.I would also recomend going to a 190 during winter.They are too easy to install not to and you will appreciate the heat up there!!

 

[jamyers]

I'm tellin' ya: Thermostat.

 

[cargeke]

I finally got a chance to work on the car this weekend. Checked the thermostat first Turns out the 180 thermostat I asked for was a 195 that opened at 205. Installed a confirmed 180 stat, and now the temperature gauge holds steady, but still a little cold. The heater hoses get warm to the touch like the radiator hoses too. I might try insulating the heater hoses and see if that helps.

 

[wallaka]

The old cardboard in front of the radiator trick works well if needed...these cars are notorious for poor heat output.

 

[66 Fastback]

Any chance you have air trapped in the hoses or heater core so that they are not moving the coolant they should?

Plumbing wise, is there any difference on a water pump from a heater delete car and a factory heater equipped car. I am just tossing something out there but I don't know the answer. It seems to me that on factory heaters, the heater is plumbed on the bottom side of the thermostat and coolant goes to the heater when the thermostat is closed. Are you plumbed such that you are taking coolant off of the top side of the thermostat or even after it has gone through the radiator? I am only asking since you pointed out it is an aftermarket heater, and you would have had to tee into the cooling system at some point.
Doug

 

[cargeke]

No air trapped in the hoses. Ran the car with the radiator cap off until the thermostat opened. I don't think the water pump is any different. On a heater-delete car, the heater circuit still heats the carb. To add a heater, you just tie into that loop. There is a correct way to hook the hoses up to the heater for the best output. I've tried switching the hoses and it only made the problem worse. Right now I think the biggest problem is there's about 8 feet of heater hose running through the engine compartment. That's a lot of space to lose heat to the atmosphere. I think I'm going to look for some pipe insulation. If that doesn't work, I've got some cardboard waiting.

P.S. Thanks to everyone who posted. My dad and I are pretty good with fixing whatever breaks, but it's always good to have others' experiences to draw on when we're baffled.

 

[gearhead138]

If your car came with no heater were all the water ports just capped off? If so, I would think there might be years of gunk built up in the hose connections (nipples) make sure the water pump connection is clear and the thermostat housing nipple is clear, they can get really clogged with rust from years of no coolant flowing through them. This could restrict the flow and give just warm coolant instead of hot.