Heater blowing cold air

tez · Oct 18th, 2006, 16:59

Hi All - me new to this although had a 740 GLE for ten years now - brill car!
BUT as it was a bit chilly this morn I put the heater on but it blew cold even after a half hour journey. Cannot see any water leaks anywhere - have topped up the expansion bottle. Could this just be the thermostat stuck? Cannot see any signs of leaks anywhere.

James A · Oct 18th, 2006, 18:03

Maybe, but it could very well be an air lock. Have you replaced the coolant recently?

Oct 18th, 2006, 18:10

replace all the coolant turning the blower to full and hot leave it running as you replace the coolant. Check the thermostat for operation and replace as necessary.

Charlotte

alsner · Oct 18th, 2006, 18:12

Hi, just a thought but remove the plastic cover from underneath the steering column and look for the heater valve next to the clutch pedal, move the heat control and see if the cable is connected properly. If the arm goes down then that is the valve opening as it should if it doesn't move check the cable attachment.

See pic on this thread

http://www.volvoforums.org.uk/showthread.php?t=22070

Ali

rogerthechorister · Oct 18th, 2006, 20:03

A friend of mine had a similar problem but he did not know where the fresh air vents in the footwells were, and his were open - he'd just bought the car!

Rich 264 · Oct 18th, 2006, 23:19

Had same problem a while back. I tried flushing the heater matrix (disconnected pipes from back of engine where they enter bulkhead, stuck hosepipe on) but that didn't work. Replaced thermostat, original was 92degree but GSF supplied 88degree, eventually got a 92degree but didn't make much difference. Viscous fan was "wooshing" all the time, indicating the coupling had failed and was no longer slipping when it should: i replaced this and not only did the car warm up a lot quicker but it saved a lot on fuel and released a lot of power.
I had already checked the water valve in the foot well, it was working but also slightly wet, water loss was not significant but i thought it could be letting in air bubbles and air locking so i replaced this. Made a slight difference but not much. I also replaced the expansion bottle cap, as these are important for keeping the coolant at correct pressure, and at 20yrs old i think it must have been shot. When i fitted the new one i had water leaks everywhere for the first few trips!
Eventually i spent best part of an afternoon high pressure flushing, back flushing, flushing and back flushing, and you guessed it, flushing again!
Hey Presto!!
I've had roasting hot air for the last 12mths, just as hot as any 240! I have never found the 740 heat/ventilation system to be a patch on the 240, but it's red hot and it does the trick. When i finish work at 2am and the cars iced up thats important!
Rich

Chris1Roll · Oct 19th, 2006, 22:23

Mine was the same, a four hour drive to london and back in March, and my hands were almost frozen to the wheel.

Tried bleeding it, worked a little bit till i switched it off again, then I was back to cold again.

So i disconnected both the hoses and backflushed it for about half an hour with a hosepipe, loads of lovely gunky stuff came out. Result! Lovely and toasty!

Oct 18th, 2006, 16:59	#1
tez tez Last Online: Nov 6th, 2016 15:08 Join Date: Oct 2006 Location: horsham	Heater blowing cold air Hi All - me new to this although had a 740 GLE for ten years now - brill car! BUT as it was a bit chilly this morn I put the heater on but it blew cold even after a half hour journey. Cannot see any water leaks anywhere - have topped up the expansion bottle. Could this just be the thermostat stuck? Cannot see any signs of leaks anywhere.

Oct 18th, 2006, 18:03	#2
James A VOC Member Last Online: Jul 16th, 2014 10:52 Join Date: Dec 2003 Location: Volvograd	Maybe, but it could very well be an air lock. Have you replaced the coolant recently? __________________ 2002-2003: 1988 240GL manual saloon - Nameless 2003-Date: 1990 740SE automatic estate - The Volvo 2009-2014: 1997 V70SE 2.5 10v manual estate - The Volvo 2 aka TV2 2014-Date: 1992 940SE Turbo automatic estate 'Wentworth' - The Wentworth

Oct 18th, 2006, 18:10	#3
charlotte001 Guest Location:	cold air replace all the coolant turning the blower to full and hot leave it running as you replace the coolant. Check the thermostat for operation and replace as necessary. Charlotte

Oct 18th, 2006, 18:12	#4
alsner In Volvo limbo Last Online: Aug 4th, 2013 03:26 Join Date: Feb 2006 Location: At home View Photos By: alsner	Hi, just a thought but remove the plastic cover from underneath the steering column and look for the heater valve next to the clutch pedal, move the heat control and see if the cable is connected properly. If the arm goes down then that is the valve opening as it should if it doesn't move check the cable attachment. See pic on this thread http://www.volvoforums.org.uk/showthread.php?t=22070 Ali __________________ Volvo History 1990 745 GLE (10 months) 1989 745 Turbo (16 months) I will return to the fold when the time is right. *It's Just a Ride* Bill Hicks

Oct 18th, 2006, 20:03	#5
rogerthechorister Rogerthechorister Last Online: Dec 16th, 2023 02:15 Join Date: May 2006 Location: Rochester	Is it the heater? A friend of mine had a similar problem but he did not know where the fresh air vents in the footwells were, and his were open - he'd just bought the car!

Oct 18th, 2006, 23:19	#6
Rich 264 Pinball Wizard Last Online: Feb 6th, 2013 00:53 Join Date: Dec 2002 Location: cheshire	Had same problem a while back. I tried flushing the heater matrix (disconnected pipes from back of engine where they enter bulkhead, stuck hosepipe on) but that didn't work. Replaced thermostat, original was 92degree but GSF supplied 88degree, eventually got a 92degree but didn't make much difference. Viscous fan was "wooshing" all the time, indicating the coupling had failed and was no longer slipping when it should: i replaced this and not only did the car warm up a lot quicker but it saved a lot on fuel and released a lot of power. I had already checked the water valve in the foot well, it was working but also slightly wet, water loss was not significant but i thought it could be letting in air bubbles and air locking so i replaced this. Made a slight difference but not much. I also replaced the expansion bottle cap, as these are important for keeping the coolant at correct pressure, and at 20yrs old i think it must have been shot. When i fitted the new one i had water leaks everywhere for the first few trips! Eventually i spent best part of an afternoon high pressure flushing, back flushing, flushing and back flushing, and you guessed it, flushing again! Hey Presto!! I've had roasting hot air for the last 12mths, just as hot as any 240! I have never found the 740 heat/ventilation system to be a patch on the 240, but it's red hot and it does the trick. When i finish work at 2am and the cars iced up thats important! Rich

Oct 19th, 2006, 22:23	#7
Chris1Roll Senior Member Last Online: Yesterday 21:51 Join Date: Aug 2006 Location: Cannington	Mine was the same, a four hour drive to london and back in March, and my hands were almost frozen to the wheel. Tried bleeding it, worked a little bit till i switched it off again, then I was back to cold again. So i disconnected both the hoses and backflushed it for about half an hour with a hosepipe, loads of lovely gunky stuff came out. Result! Lovely and toasty!

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