Brrrrrrrr.... It's cold in here!

I'm still thinking pump/circulation problem.
 
I'm with you Tony, Jim, but I would rule air bubble out first, so is very cheap to bleed the system, otherwise it could be loose impeller on the pump, blocked matrix, or faulty valve. So perhaps do the flush first, then bleed the system, then I would pull the pump,and finally look at the valve.
 
zedonist said:
Sorry Andy,

I was in tesco so only half thinking,.
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Cor Zedonist, you really are an addict!! Shopping and posting at the same time!!!;):cool:

M & S
 
zedonist said:
...just driving the trolley, not allowed to touch anything you see...:(
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hehe, my role in Tesco exactly...until we get to the beer aisle:)
 
There is enough flexibiity in the hoses to temporarily by-pass the valve to test.
Remove short hose (valve to heater) - disconnect valve end of hose from block to valve and reconnect to heater.
Not advisable to drive it this way but good enough to test on tick-over which appears to be when your problem arises.
 
Guys, I'll go for air stucked in the heater, first and 2nd the valve controler.
Maybe it's something wrong with the 12 V voltage at idle speed?
Bleeding must be done with all open and ventilation at least 2 and with few violent gas pedals!
If thermostat, gauge will not react in 5 min of running and will not stay straight up all the time.
If w pump with losen impeller, the water will boil instantly.
 
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I understand the thinking behind loose impeller would let the coolant overheat, however it is very common with VAG diesel engines and we can get several cases a year. I have not come across it in a Z3 but I have seen it in a 3 series. The plastic impeller splits around the pump shaft and will drive the coolant when the revs are higher but not at idle.

Tony.
 
In this case , on the 3rd place, the w pump must be taken into consideration; it's more costly, but must be done anyway, as a safety measure.
 
Thanks again guys - a little more info may provide some additional clarity...

When I'm driving along A roads or the motorway and the temp is nice and warm, if I turn the temp dial, it seems to make a change to the temp instantly. So for example if I turn it down to cold, then within a few seconds the air blows cold. If I turn it back to hot - the air blows hot after a few seconds. This tends to lead me to think that it may not be the heater valve but if I can bypass it by disconnecting both hoses coming off it and connecting them to each other so the coolant flows uninterrupted, I assume that if the air blew hot all the time it would point to the valve whereas on the other hand if it made no difference then perhaps something else?

I found this link online too...

http://www.pelicanparts.com/BMW/tec...32-WATER-Heater_Control_Valve_Replacement.htm
 
The test you made is good: it shows the valve controller it's ok.
Now it's only the rpm who plays......I still believe it's air bleeding/ coolant level problem.
In German cars, if you have a list of possible causes for a problem, usually is the simplest one!
 
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Zeti said:
The test you made is good: it shows the valve controller it's ok.
Now it's only the rpm who plays......I still believe it's a air bleeding/ coolant level problem.
In German cars, if you have a list of possible causes for a problem, usually is the simplest one!
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Good morning Zeti. Its 3;07 here and I'm checking in before I go to work. Frankie
 
upstream said:
........... If I turn it back to hot - the air blows hot after a few seconds. This tends to lead me to think that it may not be the heater valve but if I can bypass it by disconnecting both hoses coming off it and connecting them to each other so the coolant flows uninterrupted, I assume that if the air blew hot all the time it would point to the valve whereas on the other hand if it made no difference then perhaps something else?.............
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The suggestion to by-pass the valve was to eliminate it from list of possibles. The fact that the heater blows hot at speed as you have described indicates the valve is not at fault and IMHO that you do not have an air lock or blocked matrix (others may not agree).
As previously suggested it appears to be a pump delivery problem at low engine revs. I would suggest you change the pump as a precaution anyway. If the pump is starting to fail it is much better to change it now.
 
Before drawing a positive conclusion to the fact the temp changes while at speed indicating the valve is working , I would suggest the same test at idle just to verify you get the same temp differences. If the heat is at the same level as previous then the valve is working, using a thermometer to verify temps would be more accurate than simply sticking one's hand in the air flow. HTH JIM
 
oldcarman said:
Before drawing a positive conclusion to the fact the temp changes while at speed indicating the valve is working , I would suggest the same test at idle just to verify you get the same temp differences. If the heat is at the same level as previous then the valve is working, using a thermometer to verify temps would be more accurate than simply sticking one's hand in the air flow. HTH JIM
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Hi,

With the engine warm and the car idling the temperature is only slightly warm. If I start rotating the temperature control, by the time I reach the half way mark I can definately tell a difference in temperature and by the time I have rotated it to the "cold" position - it feels noticeably cold. If I then turn it back in a clockwise direction towards the "hot" setting, at close to the half way mark I can sense a slight difference and at the hottest setting a further slight difference but far from being warm.

At the moment whenever I think about it I seem to find myself flipping between one possible cause and another. Not being very mechanically minded either I suppose I'm trying to be certain about what the cause of the issue is so that I only have to fix it once as I'll most likely have to pay a mechanic to do the work for me.

I suppose this is one of the issues that can arise where you buy a car without a maintenance history. I do have quite a few receipts but I can't see anything for "thermostat" or "water pump".
 
upstream said:
Hi,

With the engine warm and the car idling the temperature is only slightly warm. If I start rotating the temperature control, by the time I reach the half way mark I can definately tell a difference in temperature and by the time I have rotated it to the "cold" position - it feels noticeably cold. If I then turn it back in a clockwise direction towards the "hot" setting, at close to the half way mark I can sense a slight difference and at the hottest setting a further slight difference but far from being warm.

At the moment whenever I think about it I seem to find myself flipping between one possible cause and another. Not being very mechanically minded either I suppose I'm trying to be certain about what the cause of the issue is so that I only have to fix it once as I'll most likely have to pay a mechanic to do the work for me.

I suppose this is one of the issues that can arise where you buy a car without a maintenance history. I do have quite a few receipts but I can't see anything for "thermostat" or "water pump".
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Did you ever check the tightness of the belt driving the water Pump? Frankie
 
My fear proved to be correct...

I just drove around the block to warm the coolant a little and then with it parked (nose upward) on my driveway attempted to bleed the system. A few turns anticlockwise of the bleed screw and the top popped off - leaving the remaining bit in the expansion tank. It's clearly air and water tight but it's not going to help at all with trying to bleed the system so that I can rule that out.

Does anyone know if there is another method that can be used to bleed the system?
 
I did mine like this: car parked, coolant at the level marked on the expansion tank; engine running, temp gauge to middle (thermostat open), heat to the max and ventilation to 2; slightly losen the bleeding screw until coolant and bubbles start to get out; than get in the car and give 2-3 times a short and violent rpm (like 4000 rpm but very short, just push the pedal to the metal and release it immediatelly). Added coolant again to the mark.
And everything was fine after that. I did it until now twice, when changing the coolant every 2 years.
Good luck!
 
Well - things go from bad to worse!!!

I rang BMW to ask if they had a replacement bleed screw. They said yes. "Perfect" I thought so heated a flat head screwdriver, pressed it against the top of the screw (the bit that was left exposed and after it made an indent, cooled it and then used it to unscrew what remained of the bleed screw.

Off I then went to BMW to pick up the replacement. Unfortunately when I bought the replacement home I couldn't get it to screw in. Upon closer inspection, the thread of the part BMW supplied was completely different to that of the original. A trip back to BMW and I receive the explanation that they have none in stock and will have to order the part - expected on monday!

That's pretty much put an end to my plans for this weekend :-(
 
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