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Hows your heater? What do I need to do for a GREAT heating system?


jrhone

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I have owned the 02 about 5 years.  It NEVER had a hot heater.  Barely got warm if I sat and revved it.  Once moving, it got ice cold.  I manually checked the valve, and actually broke the cable looking at it.  Opened and closed it and it didn't really change anything.  The fan works great.  I bought a heater box with a heater core and I took it to a radiator shop that said it had good flow and no leaks.  It has now sat 3 years.  The heater box in the car has leaks and has zero padding on the flaps so its quite breezy in the car.  The plan is to rebuild the box I got and put it in.  My question is what can I do to get GREAT heat output from the heater in the winter and ZERO heat in the car in the summer.  

 

Should I boil out the heater core?  How about the valve?  How do I know its good?  

 

Any tips on getting the best heater efficiency?

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+ ROASTING. 

 

When the car is at operating temperature and the valve is open feel the inlet pipe to the heater behind the valve.  If it's NOT hot to touch, you aren't getting flow.

 

If it is hot then the doors are suspect.

 

If it's not, burping the system might work.  I've put my car on an uphill incline, opened the heater valve and squeezed the top rad hose a few times (kinda like a pump).  I open the rad cap once the car is cooled to see the level of coolant.  If it's dropped significantly, I top it up.  Might work.

 

I don't think the thermostat makes (much) difference to the heater.  Tell me I'm wrong.

 

Another easy exercise is to drain the block.  The plug is just below the 3rd/4th cylinder exhaust ports.  It may be crudded-up.  Again I'm not sure that would effect the heater.  But it's an easy job, and should be done occasionally.

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The heater in both my '02s kept me nice and warm in more than one blizzard (got so hot we had to periodically open the sunroof to let the warm air out--the thermostat was sticking) and plenty of times in below zero (F) temps, so there's something wrong somewhere.  

 

Things to check:

1.  proper thermostat operation (is it really working?  have you tested it?)

2.  have you cleared any air bubbles from the heater core?  Sometimes it's hard to bleed all the air out

3.  are you sure the heater temperature control cable is connected correctly?  It's very easy to reconnect backwards, so when the dash control is set to hot, the valve is actually closed and vice versa.  Compare yours with an '02 known to be correct.

4.  Are the heater hoses in good shape?  no kinks, no "universal" hoses, but the proper moulded ones?

5.  Observe the temp control cable under the dash; there's a second cable connected to the lever that works backwards from the temp control--it works the air mixer door that's under the main heater air intake so as you turn the heat towards hot, the mixer door gradually closes until on full hot, all the incoming air passes through the heater core.  If that cable is broken and/or the mixer door is stuck open, it can affect heater operation.  

 

Rebuild your spare heater and you should be in good shape presuming you get all the air out of the cooling system and your thermostat is good.   Make sure you have the proper one--the heater used on cars with single barrel carbs has a different heater core from the later ones--small hose nipples that won't work with the heater hoses used on 2 barrel carb cars.

 

cheers

mike

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MAYBE the guts of your heater valve are not turning. 

 

When the engine is off and cold, remove the 2 screws that hold the cover on the heater valve.  With the cover off, test the valve to make sure the core is turning. 

 

If you broke a cable, that's another clue that something is binding or broken.  The good news is it's not a hard or costly fix.

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I don't think the thermostat makes (much) difference to the heater.  Tell me I'm wrong.

 

Not going to tell you you're wrong. I'm probably wrong since the thermostat has been replaced several times but I was focused on the fact that the heater is cooler when the car gets moving and wasn't warm to begin with. I was thinking a stuck thermostat could allow unrestricted flow to the radiator and the coolant would never get warm enough to put out hot air at the heater core.

Obviously not the case here...

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OK...a few things maybe I can rule out.  T-Stats.  I have had a few different ones playing with temps and my electric fan switch to get the electric fan to turn on at the right temp...settled on the standard t-stat.  Yes burped the car every time.  Also had a very good mechanic rebuild the top end and Im confident he burped the system as well.  I'll check the valve operation.  Looking at the valve it looks really corroded and is hard to move.  The temp control cable isn't working but I am manually trying to turn it and its VERY difficult to turn.  Takes a lot of force.  The hoses are all standard 02 hoses except the hoses under the intake manifold.  I think a mechanic connected a hose for a bypass of the intake.  I have always planned on getting the ireland bypass kit for a steel pipe and hose instead of a rubber hose that was used.  i don't think that has anything to do with the heater.  

 

I will check on the air mixer door.  I will also look at the the valve.  All great things to look at.  My feeling is the car has never had good heat so I would think its the heater core or heater valve.  

 

The heater box I got I THINK is a late model one...it has the controls with 4 levers...doesnt the early heater box only have 3 control levers?

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My heater starts putting out heat within a mile of house, so I would say you're not getting any coolant flow through the heater core.

 

 I would recommend checking each small segment of coolant flow.

--  Since the coolant flow heading for the heater begins at the outlet hose fitting at the back of the head, I would start there and make sure that fitting isn't plugged up.

--  Then make sure the hose itself isn't plugged.

--  Then check the heater valve and make sure it opens properly and fully.

--  Then disconnect the heater outlet hose.  Connect-up a garden hose to the heater core inlet or outlet and make sure you're getting good flow through the heater core itself.

--  Then make sure the heater outlet hose isn't plugged.

--  And the hose connection at the water pump.

 

Cheers,

 

Carl

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MAYBE the guts of your heater valve are not turning. 

 

When the engine is off and cold, remove the 2 screws that hold the cover on the heater valve.  With the cover off, test the valve to make sure the core is turning. 

 

If you broke a cable, that's another clue that something is binding or broken.  The good news is it's not a hard or costly fix.

This.

Turn temp to hot, then touch the hoses on either side of the valve. Both should be hot. And Che k to see that the cable is still connected to the valve.

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This.

Turn temp to hot, then touch the hoses on either side of the valve. Both should be hot. And Che k to see that the cable is still connected to the valve.

+1

I vote that Paul and Marshall are correct. My valve stuck in the open position: plenty of heat 12 months of the year! Yours could be stuck in the closed position. One possibility: the temperature cable attaches to a short metal lever that itself is fixed to the shaft of the valve. But many (all?) of these shafts are plastic and the squared-off end of the shaft -- to which that short metal lever is keyed -- simply twists off because the valve itself is stuck. The cable will appear to be working, the short metal lever will move back and forth, but you won't actually be turning the shaft of the valve. I'm not familiar with BLUNT's overhaul kit, but another overhaul kit I used years ago replaced the plastic valve shaft with a brass (or other metal) component, solving this particular issue forever!

Good luck with your heater overhaul,

Steve

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One of the great things about these cars is the heater whether the fan works or not on two of my 4 o2's I had to WD40 (wiggle and loosen it up) the heater valve and manually push the valve in the opposite direction, this resulted in heat...Albeit the cabin controls do not work to close the valve but I'm ok with that....

 

That being said I haven't explored replacing the stuck in the heat direction valve with a valve that closes because I like heat...Living here in the Bay Area..

 

Moral to the story, with a little tender love that valve WILL move..

 

ira

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This.

Turn temp to hot, then touch the hoses on either side of the valve. Both should be hot. And Che k to see that the cable is still connected to the valve.

 

Checked…the hose on the engine side is warm, the hose after the valve ice cold.  n matter which way I turn the valve.  So its safe to assume at least the valve is bad.  My next thought is I wonder if the heater core is good or not.

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