This seems like a really weird problem but our heater only works when the car is actually moving. Whenever I stop (motor is running of course) at a crossing the air cools down immediatly. Does anyone have an idea what could be wrong? Any hints would be very appreciated.

cheers

M

 

How does the heat do when you are at a stop but you raise the engine rpm up to 2500 or so??

 

Sounds like it could be fluid level, water pump orbelt.

Make sure you check the easiest first, being the water level.

 

Thanks a lot for your suggestions to further diagnose the problem (I just keep forgetting to rev the engine at crossings ).

@ginman: What water level are you talking about? I don't have an ac in that cat so there isn't any fluids involved with the heater I think, or do you mean the actual water level in the engine cooling system?

thanks

M

 

So the heater output does get warmer when revving the engine? Losing heat only when idling at low rpm is pretty much a guarantee that you poor coolant flow/volume. Try turning your heater fan offwhen at an idle, let engine idle for a couple of minutesand then turn on fan to 3 position quickly. If you get a brief burst of warmer air followed by cooling off rather quickly then you have poor coolant flow thru the heater core. At an idle there is just not enough hot coolant flowing thru the core to keep up with the cool air flowing thru it so core cools off quickly.
Loss of coolant flow and not having any overheat or running hot problems would point to a heater core restriction. If engine is also running hot at times then would be looking at a water pump problem or restriction elsewhere in the engine.

 

@babyhuey Yes! It has nothing to do with the car actually moving. As soon as I rev the engine the heat comes back immediatly.

Hmmmm - I just went outside to check the coolant and guess what the coolant dip stick indicator doesn't show anything -> practically empty! So I will try to fix the coolant tomorrow and see if the heater issue still exist... would be a bit embarassing if it would've just been the fluid level (guess I now know which fluid level youre talking about ginman). Well in any case thanks a lot and I 've learned a thing or two about my car today! It's a 323 from 93 and works pretty good otherwise - just a tiny oil leak but thats all.

 

Radiator top has cracks in it.

I have found the problem why my coolant fluid was practically empty. It's the non metal radiator top piece (see photo) which has a crack in it. Now my question to the more experienced in this forum: Can I go about this myself or do I have to go to the workshop and buy a new part? Or is there a way to fix that with glue or similar, I guess any kind of fix will have to withstand a certain amount of pressure and heat.

Anyway, here some pics of the problem.

1. With cold motor and cleaned the crack is clearly visible.
2. Close up of the crack.
3. With motor running for ~1 minute.



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