|
700/900 Series General Forum for the Volvo 740, 760, 780, 940, 960 & S/V90 cars |
Information |
|
Volvo 940 only blowing cold airViews : 2624 Replies : 50Users Viewing This Thread : |
|
Thread Tools | Display Modes |
|
Mar 16th, 2021, 15:51 | #1 |
Member
Last Online: Feb 1st, 2022 10:11
Join Date: Mar 2015
Location: Hampshire
|
Volvo 940 only blowing cold air
Hi - 1992 Volvo 940 GLE estate - non-turbocharged, no air conditioning, B230F engine. The air vents are only blowing cold air at the moment. Would be interested in suggestions to address this.
Caveat - the car has been sitting around unused since the start of the pandemic. I've run it up and down my driveway a few times, but it has been on SORN. I recently taxed, insured it and it scraped through its MOT. I've only used it for a couple of short local journeys however. It could just be the case that the stone cold engine really just hasn't had a chance to warm up? The manual heater temperature control can be twisted between a third from cold, and fully hot. It cannot be twisted to the fully cold position. I remove the trim from under the steering column and i can see the cable moving the heater control valve. Prepared to replace the heater control valve if need be. There is no coolant leak or coolant smell, so I'm assuming the heater matrix is ok. Fans work as expected on all speed settings, so I assume the blower motor resistor is ok. Would it be a good idea to remove the coolant hoses, and either replace or give them a thorough flush with a hosepipe (if I can get them off their fixtures without splitting the rubber)? There are two hoses going into the bulkhead from the engine block, followed by, I imagine, further hoses going to the heater control valve in the cabin. Is there anything else to think about here? If I need to replace these hoses, will the Volvo take a relatively standard fit, or are they hard to come by? Thanks! |
Mar 16th, 2021, 15:52 | #2 |
Member
Last Online: Feb 1st, 2022 10:11
Join Date: Mar 2015
Location: Hampshire
|
Alternatively, I'm guessing, thermostat needs replacing?
|
Mar 16th, 2021, 16:16 | #3 |
Premier Member
Last Online: May 3rd, 2024 20:53
Join Date: Jul 2012
Location: Lenzie
|
If you have no leaks around the heater control valve I would leave that well alone
__________________
V70 D5 SE Geartronic 215bhp Saville Grey 2012MY 940 LPT Manual 1996 740 SE 1990 |
The Following User Says Thank You to griston64 For This Useful Post: |
Mar 16th, 2021, 18:02 | #4 | |
Premier Member
Last Online: Feb 11th, 2023 20:32
Join Date: May 2010
Location: Blyth, Northumberland
|
Quote:
The two hoses are shaped and difficult to source. Q1. Is the temperature gauge working? If it is, does it move to vertical (about halfway) after just a mile or so, or does it loiter cooler than that? Q2. Is the radiator top hose getting hot? If it does, does it do this quite suddenly after idling the engine for a while, or does it just warm up gradually? If either or both of these apply then I would suspect the thermostat. If you intend to replace the thermostat I suggest that you check whether you are able to loosen the nuts of the thermostat housing as they can be stubborn. If they are stubborn, give them a couple of doses of releasing fluid for a day or two before attempting to remove them. They should be flange nuts and the nut part is quite shallow.
__________________
Ian. Since 2005: 1992 Volvo 940 estate 2.0L. Manual. Daily driver and workhorse. Last edited by Ian21401; Mar 16th, 2021 at 18:08. Reason: Amend text. |
|
The Following User Says Thank You to Ian21401 For This Useful Post: |
Mar 16th, 2021, 20:31 | #5 | |
Premier Member
Last Online: Yesterday 23:33
Join Date: May 2012
Location: Lakenheath
|
Quote:
Also worth checking your viscous coupling on your cooling fan isn't siezed as that will increase warm up time.
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
|
The Following 2 Users Say Thank You to Laird Scooby For This Useful Post: |
Mar 17th, 2021, 11:46 | #6 | |
Senior Member
Last Online: Aug 30th, 2023 18:22
Join Date: May 2015
Location: Fordingbridge
|
Quote:
I had this issue around this time last year and replacing the thermostat and giving it a good flush through sorted it. It's still not mega hot but it's pleasantly warm on a cold morning. I find it takes 20 minutes to get a good amount of heat out of the heater. Just remember that the centre vents above the controls only deliver cold air - you only get warm air from the vents near the mirrors and from the floor vents. You mention that the heater control can't be turned all the way cold, that's odd. It's just a simple mechanical connection to the HCV. Just wondering out loud if the HCV has worked loose slightly and rotated in its housing?
__________________
'93MY Volvo 940SE 2l Petrol Manual non-a/c "Valhallarama" |
|
The Following 2 Users Say Thank You to kiloran For This Useful Post: |
Mar 17th, 2021, 20:23 | #7 | |
Premier Member
Last Online: Feb 11th, 2023 20:32
Join Date: May 2010
Location: Blyth, Northumberland
|
Quote:
Re the heater control: As you are able to see the HCV you should be able to see where the wire core of the control cable is connected to the HCV lever by a clip. Release the clip and check whether you have full movement of the HCV lever and the heater control knob. Then move both to fully hot and reconnect the cable and check whether you have full movement hot to cold. If that doesn’t work disconnect them and move both to fully cold and check for movement. If this also fails then you will have to accept a compromise and reconnect appropriately.
__________________
Ian. Since 2005: 1992 Volvo 940 estate 2.0L. Manual. Daily driver and workhorse. Last edited by Ian21401; Mar 17th, 2021 at 20:28. Reason: Amend text. |
|
The Following User Says Thank You to Ian21401 For This Useful Post: |
Mar 17th, 2021, 21:21 | #8 |
Member
Last Online: Feb 1st, 2022 10:11
Join Date: Mar 2015
Location: Hampshire
|
Thanks all for your excellent advice.
I have concluded it is almost certainly the thermostat that needs replacing. The water temp needle did not reach 50% after the decent run I made last night. It hit about 30% where it 'loitered' for the remainder of the journey. New Volvo original thermostat and gasket ordered. Will also drain, flush and replace the coolant. HCV not turning to cold - I will remove the driver's side steering column trim and check whether it is correctly seated in its housing. Will also remove the clip and try the test Ian21401 suggests. Glad I've managed to get the car running as it should again. It is a majestic, incredibly comfortable, glacially slow old bus and I adore it! |
The Following 2 Users Say Thank You to McGandalf For This Useful Post: |
Mar 17th, 2021, 23:16 | #9 | |
Premier Member
Last Online: Yesterday 23:33
Join Date: May 2012
Location: Lakenheath
|
Quote:
When you come to do it, invest in something like Comma X-stream Flush for the cooling system and add it as per the directions on it. If it says run it at a fast idle for 20 minutes, take it for a half hour drive instead. Once you're home and it has cooled somewhat, remove the 'stat housing and the old 'stat. Refit the housing then remove the top hose from the radiator stub. Use your garden hose in the open end of the top hose, if you have a Hozelock type fitting it should fit snugly inside the top hose. Turn the water on for the hose and leave it running. This reverse flushes the system with the old stuff exiting via the radiator stub at the top. Usually takes about half hour to get it running clear, once it is running clear leave it 10 minutes or so more to ensure it really is clear. Turn the hose off and remove it from the top hose. Remove the bottom hose from the bottom of the rad to drain off excess water from the rad and block and then refit - having a new Jublee clip for it is a wise move as they often rust. Once the bottom hose is secure, add 5L of concentrated Ethylene Glycol antifreeze. The exact figure for 50/50 mix is something like 4.8L, can't recall it exactly and it's as close to 5L as makes very little difference. Fit the new 'stat, note the seal sits around the edge of the 'stat ont on it or under it - there is a groove inside the seal to let it sit around the 'stat. Ensure the recess in the head and 'stat housing are clean and smooth, use some silicone grease in the groove and smear some on the outer parts of the seal too and fit, ensuring the jiggle valve is at the top if it has one. Refit the 'stat housing and top hose to the rad. Top up the expansion tank with fresh water (remember you already have enough antifreeze in so water is fine), refit the cap and squeeze the bottom hose several times to help move the air to the top. If the level drops in the tank, add more water to the "MIN" line and squeeze the bottom hose a few more times. Repeat until squeezing the bottom hose doesn't result in further drop of the level. Refit the cap and take for a drive, ensuring you get it up to temperature and that the heater works, no leaks etc. Return home and park it facing uphill and leave to cool until the following day then check and top up the level to the "MIN" mark if needed. I've used this method for decades on a variety of cars and it works. Whatever you do, don't be tempted to buy OAT coolant, doesn't matter how good the salesman says it is, it will destroy your engine. If some idiot has previously used OAT coolant (usually red or orange) then you have other problems and could be the cause of your lack of heat. Hopefully they haven't though!
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
|
The Following User Says Thank You to Laird Scooby For This Useful Post: |
Mar 18th, 2021, 12:29 | #10 | |
Member
Last Online: Feb 1st, 2022 10:11
Join Date: Mar 2015
Location: Hampshire
|
Quote:
Comma X-Stream Flush seems to be no longer available though - Evapo-Rust C715 Thermocure looks like a good alternative. Have ordered a new thermostat - when it comes I'll run through the steps you suggested. I have a suspicion the coolant in the car might never have been changed in all its 29 years. It is the right colour though (blue/green, if you can still call it that). |
|
The Following 2 Users Say Thank You to McGandalf For This Useful Post: |
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|