Car heater, too hot or too cold - SV650.org

L3nny · 27-10-16, 10:09 AM

The heater on my BMW 320D E91 doesn't get hot unless you put it on the highest 28 degree setting which is then too hot.

Anyone have any ideas what could be wrong?

27-10-16, 08:14 PM

What year is that, at a guess your thermostats have failed

L3nny · 28-10-16, 07:54 AM

It's 2010, if the thermostat had failed I'd expect it not be be getting hot at all.

ophic · 28-10-16, 03:00 PM

No, I think they work on the principle of max heat until ambient temp (indicated by thermostat) hits the required value. But the highest setting just ignores the thermostat and pumps out max heat permanently.

andrewsmith · 28-10-16, 05:41 PM

Could be worth checking the cabin filter. Fixed the issues I had the heating and cooling performance on my car.

They do rely on an air flow to perform properly and the engine temperature

Sent from my D2303 using Tapatalk

L3nny · 02-11-16, 04:40 PM

Had the car serviced last month and they replaced the cabin filter then. I pulled it out anyway and had a look and it does look pretty new.

I've also been monitoring the coolant temperature using ter Torque app on my phone and a Bluetooth OBD adapter. It's sat a a constant 80-85c.

maviczap · 03-11-16, 07:38 AM

Could be the thingy that takes the heat from the coolant to your heater is gummed up. Can't remember what its called, but a mate had a similar problem on another car.

Red ones · 03-11-16, 09:30 AM

How accurate is the outside air temperature sensor?
They don't just give a nice little display for the driver, but also determine whether any hearing or cooling is needed for the cabin (and also determine fuel air ratio for the engine amongst other things)

Sent from my iPhone using Tapatalk

ophic · 03-11-16, 10:58 AM

Quote:

Originally Posted by maviczap

Could be the thingy that takes the heat from the coolant to your heater is gummed up. Can't remember what its called, but a mate had a similar problem on another car.

Heater matrix?

Mark_h · 03-11-16, 11:07 AM

It'll not start blowing in anger until the heater is significantly hotter than the current inside car temp. Prior to that it will blow but not hard. Around the heater control area you'll find a little (about the size of a micro SD card) grill with a fan behind it. This is where it samples the cabin temp. When mine was clogged with fluff it went a bit weird so give that a clean out.

My old BMW had a heatsink controller for the fan motor. This failed and then the fan was either off or very very on. This was a right bugger to get to but once swapped out all worked fine. Not sure if the newer BMWs still have these or where they live. BMW forums refer to these as Hedgehogs.

Oh and also on the 5-series you set target cabin temp with one control but can also set the dash vents to blow hot and/or cold regardless of the cabin temp. May be worth checking you've not got the dash vents set to cool while trying to lift the cabin by 15degrees.

27-10-16, 10:09 AM	#1
L3nny Member Mega Poster Join Date: May 2008 Location: MK Posts: 2,109	Car heater, too hot or too cold The heater on my BMW 320D E91 doesn't get hot unless you put it on the highest 28 degree setting which is then too hot. Anyone have any ideas what could be wrong? __________________ 2015 GS 1200 Adventure

27-10-16, 08:14 PM	#2
AlexAdams Guest Posts: n/a	Re: Car heater, too hot or too cold What year is that, at a guess your thermostats have failed

28-10-16, 07:54 AM	#3
L3nny Member Mega Poster Join Date: May 2008 Location: MK Posts: 2,109	Re: Car heater, too hot or too cold It's 2010, if the thermostat had failed I'd expect it not be be getting hot at all. __________________ 2015 GS 1200 Adventure

28-10-16, 03:00 PM	#4
ophic Member Mega Poster Join Date: Jan 2004 Location: Whyteleafe Posts: 3,395	Re: Car heater, too hot or too cold No, I think they work on the principle of max heat until ambient temp (indicated by thermostat) hits the required value. But the highest setting just ignores the thermostat and pumps out max heat permanently. __________________ Silver SV650SK3, Fuel exhaust

28-10-16, 05:41 PM	#5
andrewsmith Member Mega Poster Join Date: Apr 2010 Location: Newcastle upon Tyne, Just south of salad dodging country Posts: 7,750	Re: Car heater, too hot or too cold Could be worth checking the cabin filter. Fixed the issues I had the heating and cooling performance on my car. They do rely on an air flow to perform properly and the engine temperature Sent from my D2303 using Tapatalk __________________ RIP Reeder 20/07/1988 - 21/03/2012. Always missed squire!!! Every year we meet old friends, gain some new ones, lose old ones and you always remember them all. “Live as if you were to die tomorrow. Learn as if you were to live forever.” Mahatma Gandhi

02-11-16, 04:40 PM	#6
L3nny Member Mega Poster Join Date: May 2008 Location: MK Posts: 2,109	Re: Car heater, too hot or too cold Had the car serviced last month and they replaced the cabin filter then. I pulled it out anyway and had a look and it does look pretty new. I've also been monitoring the coolant temperature using ter Torque app on my phone and a Bluetooth OBD adapter. It's sat a a constant 80-85c. __________________ 2015 GS 1200 Adventure

03-11-16, 07:38 AM	#7
maviczap Member Mega Poster Join Date: Mar 2007 Posts: 9,096	Re: Car heater, too hot or too cold Could be the thingy that takes the heat from the coolant to your heater is gummed up. Can't remember what its called, but a mate had a similar problem on another car. __________________ We're riding out tonight to case the promised land Make everyday count RIP Reeder - Jolly Green Giant and comedy genius

03-11-16, 09:30 AM	#8
Red ones Member Mega Poster Join Date: Jul 2003 Location: Hertfordshire Posts: 1,422	Re: Car heater, too hot or too cold How accurate is the outside air temperature sensor? They don't just give a nice little display for the driver, but also determine whether any hearing or cooling is needed for the cabin (and also determine fuel air ratio for the engine amongst other things) Sent from my iPhone using Tapatalk

03-11-16, 11:07 AM	#10
Mark_h Member Mega Poster Join Date: Aug 2005 Location: Fleet, Hampshire Posts: 2,448	Re: Car heater, too hot or too cold It'll not start blowing in anger until the heater is significantly hotter than the current inside car temp. Prior to that it will blow but not hard. Around the heater control area you'll find a little (about the size of a micro SD card) grill with a fan behind it. This is where it samples the cabin temp. When mine was clogged with fluff it went a bit weird so give that a clean out. My old BMW had a heatsink controller for the fan motor. This failed and then the fan was either off or very very on. This was a right bugger to get to but once swapped out all worked fine. Not sure if the newer BMWs still have these or where they live. BMW forums refer to these as Hedgehogs. Oh and also on the 5-series you set target cabin temp with one control but can also set the dash vents to blow hot and/or cold regardless of the cabin temp. May be worth checking you've not got the dash vents set to cool while trying to lift the cabin by 15degrees. __________________ Don't want to be the quickest; don't want to be the best; just want to be the one having the most fun. XL125Varadero -> Curvy SV650N-Y -> SV1000N-K3 -> Multistrada 1200s Twin-tastic stuff. Minister for Sustainability *Aliquid prudentissimus delectabiles et intelligentes in adamasset lingua.* Last edited by Mark_h; 03-11-16 at 11:13 AM.

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