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it's cold outside
- Thread starter walshja
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GrahamP
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Just a couple of thoughts, are you running the input hose to the correct i.e. lowest, point in the core? Also is it a crossflow radiator? As I understand it, you have to bleed that system to remove air from the highest point with those.
Your symptons sound like classic lack of water, I've had many old cars in my youth that had water leaks and that is what would happen, the heater would work, then not work. Low water level caused by an air lock would give exactly the same symptons.
Try removing the top hose from your heater core and bleeding through that, another trick is to run the front of the car up ramps to raise it's height relative to the heater then top up the system with the engine running. You may still need to bleed but the air lock should be less severe.
Graham.
Your symptons sound like classic lack of water, I've had many old cars in my youth that had water leaks and that is what would happen, the heater would work, then not work. Low water level caused by an air lock would give exactly the same symptons.
Try removing the top hose from your heater core and bleeding through that, another trick is to run the front of the car up ramps to raise it's height relative to the heater then top up the system with the engine running. You may still need to bleed but the air lock should be less severe.
Graham.
GrahamP
Member
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I've just remembered another trick from my youth 
Get a large plastic soft drinks bottle, cut off the bottom to make a large funnel and jam the neck into your filler, sealing it with whatever seems appropriate. Use this to top up you system with the engine running to give you a head of pressure higher than the heater rad. Combine this with the front up a ramp and you should be able to get rid of all air in the system.
Alternatively find a car in the breaker's with a bleed valve in the heater hose and fit that in your heater O/L hose.
Graham.
Get a large plastic soft drinks bottle, cut off the bottom to make a large funnel and jam the neck into your filler, sealing it with whatever seems appropriate. Use this to top up you system with the engine running to give you a head of pressure higher than the heater rad. Combine this with the front up a ramp and you should be able to get rid of all air in the system.Alternatively find a car in the breaker's with a bleed valve in the heater hose and fit that in your heater O/L hose.
Graham.
RickB
Yoda
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I'd have to find one in my area first.
Is there no way to test or service the thing myself?
Lets say I get it out of the car, see if water flows through it?
If I pour hot water into it shouldn't the whole thing get hot?
If it's blocked then only part of it will heat up right?
Is there another way?
Is there no way to test or service the thing myself?
Lets say I get it out of the car, see if water flows through it?
If I pour hot water into it shouldn't the whole thing get hot?
If it's blocked then only part of it will heat up right?
Is there another way?
RickB
Yoda
Offline
I jacked up the front, my top hose has a connector on it for flushing so I opened the cap and poured coolant into the radiator until it started coming out the flush adapter.
I capped everything off and put the car back on the ground and started it up.
The temp went up to 190F - I took off, drove a couple miles and sat at a red light for a couple minutes. Temp still 190.
Turned on the heater - I could feel a slight warmth.
Drove another mile, dropped off my kid at work then started home.
Turning the heater back on I could feel warm air. Not hot, but warm.
Driving 50 to 55mph home the temp of the air from the defroster actually cooled, the engine temp was steady on 190 the whole time.
I bought that heater core on Ebay for $15.
When it arrives I'll swap it in and see if it makes any difference.
I looked at the picture of the heater in my Haynes manual. For the Midget 1500 the hose from the back of the engine goes to the lower and the hose from the front of the motor goes to the top connector. That's the way mine is connected.
I capped everything off and put the car back on the ground and started it up.
The temp went up to 190F - I took off, drove a couple miles and sat at a red light for a couple minutes. Temp still 190.
Turned on the heater - I could feel a slight warmth.
Drove another mile, dropped off my kid at work then started home.
Turning the heater back on I could feel warm air. Not hot, but warm.
Driving 50 to 55mph home the temp of the air from the defroster actually cooled, the engine temp was steady on 190 the whole time.
I bought that heater core on Ebay for $15.
When it arrives I'll swap it in and see if it makes any difference.
I looked at the picture of the heater in my Haynes manual. For the Midget 1500 the hose from the back of the engine goes to the lower and the hose from the front of the motor goes to the top connector. That's the way mine is connected.
RickB
Yoda
Offline
jlaird said:
Yes, very true.
Today I tried out the theory of the air bubble.
With the system totally full there was not much difference.
Maybe tomorrow I will test flow, using your hose procedure.
I suppose I could connect a hose to the front and see if coolant pumps into a bucket.
Then I'm not sure how to test to see if coolant pumps back into the engine from the heater?
From today's test I know that if I put a cap full of coolant into the high point where my flush connector is a cap full of coolant pours out the top of the radiator (with rad cap off).