Good Afternoon Ladies and gentlemen...... can any of you guys or gals help me??? i have a 1970 P6b ive been having problems with overheating and no hot air entering the car via the blower...... any suggestions? also can anyone tell me what the mixture control switch on the top of my manifold does?..... thanks all....... oh the heater matrix seems to have hot water passing thru it!!!!! weird????
mixture control sensor
- Thread starter CobRov
- Start date
CobRov said:
Overheating can be down a to a lot of things including timing, binding brakes, blocked radiator, etc.
Heater problem could be flaps not working properly, foam eroded from the flaps or heater rusted out below as mine was.
Got a picture of the mixer control switch - haven't the foggiest what that is?
Richard
Dave3066
Well-Known Member
CobRov said:
That's usually a sign of lack of coolant in the system but as you think there is coolant running through the heater matrix then it's obviously not that.....have you checked the coolant level?
quattro said:
Richard
Don't the heater flaps allow cold air in to mix with the warm air? So if the foam is eroded all you would get is hot air provided there is coolant in the matrix....
I could be wrong of course :?
CobRov said:
Might you be referring to the otter switch on the top of the inlet manifold near the front, it has a wire coming vertically out of it? If so this detects when the coolant has reached a particular temperature and tells you via an orange light above the clock, although your 1970 car will be a series 1.....I think..... and I don't know where the corresponding light would be :? . Lets you know to put the choke back in.
Dave
Overheating on an S1 P6B? Mmm. Where to start is a bit of an open book, but here's my attempt!
First off check that the thermostat has a bleed hole in it - sometimes with a small "jiggle pin" through it - so that some water can circulate even when the thermostat is shut. If there isn't one, check the thermostat is the correct temperature and does work, then simply drill one! The hole should be at 12:00 when installed in the engine.
Next, have the hose off the triangular metal bloc between the carburettors - colloquially known as the carburettor tower. Then have a good poke around in there with a small screwdriver or similar and satisfy yourself that the coolant passages in the manifold are not blocked. Prove by verifying you have an enthusiastic stream of water come out of there when you top up the system.
Verify that the pump is circulating coolant energetically - have a hose off and run the engine.
Then you're on to the radiator. If it is elderly and or visibly damaged or blocked, then time for a refurbish. Don'y buy off the web etc, take it to your local radiator shop and get them to recore it. BUT have a three row core instead of the existing two row.
The P6B is known to be marginal on cooling - it doesn't take a great deal wrong to upset the system. So another thing we all tend to do is to fit a coolant header tank. Use the search facility with that phrase and there'll be lots of info come up. A header tank allows the radiator to run just a tad fuller and you get perhaps another 1/4 inch of radiator doing some work at the top. And you don't ever have to worry about topping it up again!
All of the above presumes there's nothing wrong with the engine. Clearly if you have a head gasket starting to go, the timing is out, or the carbs badly set, then this will stress the cooling system further.
Chris
First off check that the thermostat has a bleed hole in it - sometimes with a small "jiggle pin" through it - so that some water can circulate even when the thermostat is shut. If there isn't one, check the thermostat is the correct temperature and does work, then simply drill one! The hole should be at 12:00 when installed in the engine.
Next, have the hose off the triangular metal bloc between the carburettors - colloquially known as the carburettor tower. Then have a good poke around in there with a small screwdriver or similar and satisfy yourself that the coolant passages in the manifold are not blocked. Prove by verifying you have an enthusiastic stream of water come out of there when you top up the system.
Verify that the pump is circulating coolant energetically - have a hose off and run the engine.
Then you're on to the radiator. If it is elderly and or visibly damaged or blocked, then time for a refurbish. Don'y buy off the web etc, take it to your local radiator shop and get them to recore it. BUT have a three row core instead of the existing two row.
The P6B is known to be marginal on cooling - it doesn't take a great deal wrong to upset the system. So another thing we all tend to do is to fit a coolant header tank. Use the search facility with that phrase and there'll be lots of info come up. A header tank allows the radiator to run just a tad fuller and you get perhaps another 1/4 inch of radiator doing some work at the top. And you don't ever have to worry about topping it up again!
All of the above presumes there's nothing wrong with the engine. Clearly if you have a head gasket starting to go, the timing is out, or the carbs badly set, then this will stress the cooling system further.
Chris
Dave3066 said:
hmmm.. .possibly
I would have thought though, that when the heater was set in the 'cold' position, some air could pass through the matrix and heat up causing a warm draught, but when set to the 'hot' position some of the air wouldn't be diverted through the matrix leaving it only just warm, and if exasperated by holes in the heater body or a weak fan, would leave you cold.
I could be wrong too 8)
If I had been bothered to rebuild my heater instead of bunging it back in, I would have known more
Richard