Hi
I recently acquired my first e30, 316i touring, and the heater is only blowing cold air. Any suggestions on how to test what is wrong with it and how to fix it. It is my daily so would like to get this sorted ASAP.
Thanks
Heater only blowing cold
Moderator: martauto
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German-Whips
- E30 Zone Camper

- Posts: 1157
- Joined: Wed Jul 14, 2010 11:00 pm
- Location: Berkshire
Do you find that the temperature gauge of the car rises past the half way mark whilst sitting in traffic or whilst idling?
If so, then it could be an air lock in the heater matrix which would need to be removed.
Or, if i remember correctly, there are 2 pipes which enter the bulkhead on the passenger side of the car, sometimes these are "shorted" to stop coolant from getting to the heater matrix if theres a leak in the area.
Worth checking those 2 pipes are correctly routing around the heater matrix.
If so, then it could be an air lock in the heater matrix which would need to be removed.
Or, if i remember correctly, there are 2 pipes which enter the bulkhead on the passenger side of the car, sometimes these are "shorted" to stop coolant from getting to the heater matrix if theres a leak in the area.
Worth checking those 2 pipes are correctly routing around the heater matrix.
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blazed
- E30 Zone Newbie

- Posts: 201
- Joined: Sun Mar 27, 2011 11:00 pm
welcome to the wonderful world of E30 ownership!
this should help you:
http://www.e30zone.net/e30zonewiki/inde ... oubleshoot
the wiki on here is brilliant just takes a bit of getting used to the search.
this should help you:
http://www.e30zone.net/e30zonewiki/inde ... oubleshoot
the wiki on here is brilliant just takes a bit of getting used to the search.
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Brianmoooore
- E30 Zone Team Member

- Posts: 49360
- Joined: Mon Jan 10, 2005 11:00 pm
The two pipes in the engine bay that connect to the heater stub pipes on the bulkhead lie most naturally if they are connected the wrong way around. Check that the one from the back of the cylinder head goes to the bottom stub, and the one from the 'tee' hose goes to the top.
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Jazakius
- E30 Zone Newbie

- Posts: 17
- Joined: Mon Feb 11, 2013 11:00 pm
Hi
Thanks for all the feedback.
I have checked and the pipes are connected right and the temp gauge never rises above just over quarter.
When the car is warm there is warm air coming through the feet setting but if I switch it to the face setting the air is cold. Fan works on every setting (1,2,3 and 4).
Thanks for all the feedback.
I have checked and the pipes are connected right and the temp gauge never rises above just over quarter.
When the car is warm there is warm air coming through the feet setting but if I switch it to the face setting the air is cold. Fan works on every setting (1,2,3 and 4).
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BenHar
- E30 Zone Addict

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- Joined: Sun Jul 11, 2010 11:00 pm
- Location: Reigate, Surrey
If the heater temperature comtrol is set to half way it should blow hot at your feet and cool out of the upper vents.
It should be hot from all vents when the control is turned fully clockwise.
This is controlled by flaps moved by the temperature control. Maybe some of the cables have broken?
If it is a 325i or 320i the temperature gauge should sit just above the quarter mark all the time the engine is warm.
Ben
It should be hot from all vents when the control is turned fully clockwise.
This is controlled by flaps moved by the temperature control. Maybe some of the cables have broken?
If it is a 325i or 320i the temperature gauge should sit just above the quarter mark all the time the engine is warm.
Ben
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Brianmoooore
- E30 Zone Team Member

- Posts: 49360
- Joined: Mon Jan 10, 2005 11:00 pm
The temp. gauge on a M40 engine should lie right on the centre mark. If your gauge only reads a quarter, it's likely you either have a faulty thermostat, or the wrong (80 degree) one fitted.
Air distribution in the cabin is controlled by a mechanical flap in the heater box, connected to the lever by a Bowden cable. If you take off the panel above the driver's knees, you can just about see the heater box end of the cable to see if everything's working correctly.
Air distribution in the cabin is controlled by a mechanical flap in the heater box, connected to the lever by a Bowden cable. If you take off the panel above the driver's knees, you can just about see the heater box end of the cable to see if everything's working correctly.
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mikemike
- E30 Zone Newbie

- Posts: 82
- Joined: Mon Oct 27, 2014 11:00 pm
hi from mike , same problem with mine , found it was the bowded cable was at fault
