How do you air bleed after thermostat change?
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    1. #1

      How do you air bleed after thermostat change?

      Had the thermostat changed back in October, didnt work to well, took ages to get to operating temp. Never overheated though. Called volvo and they just swapped in yet a new thermostat, much the same issue now. Waterpump is ok.

      I was there when they changed the thermostat the second time, noticed they did nothing to air the system, just filled reservoir and sent me on my way.

      Is there not a procedure for venting air in the system?
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    2. #2
      Member EngTech's Avatar
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      Good Question - It should self Purge , but If You suspect Issues I'd give the Top Hose - A - Hand Full of good Hard Squeezes , with Cap Off Reservoir to see Fluid Flow .
      Should be able to Tell by the Feel of the Hose - If there is Coolant in It or Not .

      How much Time to Warm up 5 min. , 10 min. , 20 min. ?___?
      Please Give Miles on Vehicle ?
      Automatic ?
      Last edited by EngTech; 02-13-2013 at 07:39 AM.
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    3. #3
      15+- warm up time, does not heat up under idle only.
      100k km
      Auto

      I`ll check that hose.
      Heard something about parking front up a steep hill, open reservoir, heat on full blast, rev up down and let idle a while.. Might try it.
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    4. #4
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      How do you air bleed after thermostat change?

      It should be heating up by idle only. I am suspecting not an air pocket, but bad or incorrectly installed thermostat.

      An open or missing thermostat will keep an engine from getting to operating temps. An air pocket will cause local overheating in the area around the air pocket. Also, a few temp cycles of the engine will work out air pockets.
      2003 XC70 (mine) | 2005 V50 (hers) | 1995 855 (saved my life ) | 1987 Chevrolet R10 P/U (the mule)
      Volvo P1 Chassis C30/S40/V50 Oil Filler Cap O-Rings for sale - $2 shipped

    5. #5
      Tried warm up on idle, no go. Rev @ 22-2300 for 10 minutes it start pikcing up heat.
      But no real heat until under load. BTW the tempsensor is new..

      How can you, physically, install the thermostat wrong?
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    6. #6
      Find it somewhat odd that to new stats should be bad. Bought 4 months apart.
      Is there, for argument sake a difference/springrate/build in the thermostats between models, engine, diesel, petrol?
      I guess I`m fetching for ideas
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    7. #7
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      How do you air bleed after thermostat change?

      I've seen em installed upside-down in other engines. Not sure in these engines' thermostat housings.

      The difference is going to be in temp ratings to open. Some small manufacturing defect can cause a stuck thermostat.

      What you're describing are exactly the symptoms of a stuck open / missing thermostat. Open or missing means that water is always flowing through the radiator, whether the engine needs cooling or not. In a cold environment when the engine is simply idling, this leads to an engine not coming up to temperature.
      2003 XC70 (mine) | 2005 V50 (hers) | 1995 855 (saved my life ) | 1987 Chevrolet R10 P/U (the mule)
      Volvo P1 Chassis C30/S40/V50 Oil Filler Cap O-Rings for sale - $2 shipped

    8. #8
      I agree but am looking at options.

      found this surfing..

      Another possibility could be with the cooling fan(s).
      Modern cooling fans work off a thermo contact switch.
      The switch can be telling the fans that the coolant is at the right temperature causing the fans to not stay on long enough.
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    9. #9
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      How do you air bleed after thermostat change?

      So while you're at idle, are your radiator fans running? You didn't mention that. Sure, the fans could be running the whole time, but if the rad is cooling the engine too much, the thermostat will close, cutting off flow to the radiator. Causing the engine to warm back up to the thermostat's opening temp (prob 180F).
      2003 XC70 (mine) | 2005 V50 (hers) | 1995 855 (saved my life ) | 1987 Chevrolet R10 P/U (the mule)
      Volvo P1 Chassis C30/S40/V50 Oil Filler Cap O-Rings for sale - $2 shipped

    10. #10
      i had this problem when i changed out the t stat. it may be an air pocket. just drive it for a couple weeks. it might go away. mine did.
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    11. #11
      Junior Member mkd28's Avatar
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      sounds like air. just dealt with this on my jeep after replacing the water pump. I would squeeze the lower and up rad hoses. you will be able to feel any air in the upper one. Although reading your post again, you may have a faulty temp sensor. it seems odd because an air pocket would almost certainly overheat.

    12. #12
      Thx.

      I already got a new tempsensor, same condition before and after.. I think it must be air, excact same thing after first thermost swap as with the second.
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    13. #13
      Junior Member Syrup's Avatar
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      If it helps, I did a full cooling system drain and flush last week. The system was bone dry as I used air pressure and forced out remaining water out of the block and radiator.
      After refilling and a 10 min drive, the cooling system burped and needed a top-up.

      Few tips:
      - as mentioned, heater needs to he set to HI
      - park on an incline nose down (expansion tank at the highest point)
      - run the engine with the cap off until the top hose is warm
      - tighten the cap, drive for 10 mins and top off

      Let us know how you go!
      2004 | V70R
      2008 | V50 T5 AWD

    14. #14
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      How do you air bleed after thermostat change?

      Quote Originally Posted by mkd28 View Post
      it seems odd because an air pocket would almost certainly overheat.
      +1! Like I said above...

      I stand by my diagnosis of thermostat open. If its really driving you nuts, get you a cheapo mechanical water temp gauge at an auto parts store and put that in the head.

      If its an air pocket, GUARANTEED you are having local overheating around the air pocket. (there's a reason the block and head are WATER cooled, not air cooled.... It's called specific heat capacity. Water+ethylene glycol cool much MUCH better than air.)

      Just trust me on this one.
      2003 XC70 (mine) | 2005 V50 (hers) | 1995 855 (saved my life ) | 1987 Chevrolet R10 P/U (the mule)
      Volvo P1 Chassis C30/S40/V50 Oil Filler Cap O-Rings for sale - $2 shipped

    15. #15
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      How do you air bleed after thermostat change?

      Better yet, buy a pair of hose pinching pliers and pinch off the upper rad hose. Turn off the cabin heater. If within two minutes after a COLD start, your engine is still not warm, your temp gauge is screwed up, so SHUT OFF THE ENGINE! Leaving this hose clamped will be disastrous if you run the engine too long.

      This will replicate a thermostat's normal behavior.

      I REPEAT, ****** Leaving this hose clamped will be disastrous if you run the engine too long. *******
      2003 XC70 (mine) | 2005 V50 (hers) | 1995 855 (saved my life ) | 1987 Chevrolet R10 P/U (the mule)
      Volvo P1 Chassis C30/S40/V50 Oil Filler Cap O-Rings for sale - $2 shipped

    16. #16
      Member EngTech's Avatar
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      +1 - I'll take - Syrup on that !

      Heater ON for Sure , Cap Off - almost sounds like that forgot to put the stat in the Car .
      I didn't mention the Oblivious .

      Yeah , but No Heat = Engine Not getting Warm .

      I have never had Low Heat from a Volvo.

      Only once on a 122S I bought up North from Florida , it had a 160 stat in It . I quickly took off 2 of the 4 Blades on Fan and added 10 ft of
      Heater Hose to pass behind & Under Dash.
      ** V50 AWD - Handling & Performance Tweaks = New Stance / VW CC - Handling Tweaks - Testing & Porting - Intake Mods
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    17. #17
      I was in the shop, alongside mech when he/we swapped the tstat and tempsensor. It is in there alright.. with the bleedhole upwards..
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    18. #18
      To those that says it will cure itself, it wont. Drove like this almost 3 months after I had the t-stat changed late october 2012
      Had it back in the dealer last week as we suspected faulty t-stat. Put a new unit in, same condition.

      I`m afraid dealer will be looking for a waterpump swap and what have you, if I bring it in the 3 time..

      Another thought, the tempsensor is held in by a lock pin, will this point constitute a air/bleed point, like say if i ease it out whilst running? - which is a pain as the airbox has to come out etc..
      Last edited by goddamnswede; 02-14-2013 at 07:23 AM.
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    19. #19
      Thermostat housing, enlarge picture and have a look at the "rear view" http://www.partsgeek.com/mmparts/the...volvo/v50.html
      The short nossle pointing down, is in fact pointing up when the housing is fixed to the engine, this is the nossle where the tempsensor is located..
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    20. #20
      Member EngTech's Avatar
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      OK, I have to ask - Id the Motor Hot when You put Your Hand on it ?

      If it isn't You shouldn't even be driving it in this Cold - If bot up to Temp - in the Engine Bay .

      Could be a Bad stat - Have Volvo replace it for Free - It's Defective .
      ** V50 AWD - Handling & Performance Tweaks = New Stance / VW CC - Handling Tweaks - Testing & Porting - Intake Mods
      A Garden Gate will Last You a Life Time . http://s261.photobucket.com/user/Eng...0Trim%20%20etc

    21. #21
      Drove the car to full heat, needle @12 o`clock. Set car on incline, reservoir top point. Cabin heat on full blast. Opened cap on expansion tank. Left on idle.
      Squeezed both lower and top hoses for about 5 minutes. Hoses felt hard, fillled with fluid.
      Had a look at tempgage, it had dropped down 1,5 point.

      I could easely hold my hand on the top alu part of engine, 30 + seconds..
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    22. #22
      Tried disabling AC to see if it had any effect, no go.
      Talked to volvo dealer, they have forwarded a mail to volvo tech dept, awaiting answer come monday.

      Ohh btw, the engine is hot to touch when tempneedle is @12 ocklock, not so much after it drops down a point or two. My previous post mentioned i can touch it without issue, that must have been with heat at 10 ocklock
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    23. #23
      Still combatting this issue.
      Does anybody know if the radiator fan should be running when the car is cold. Or should it just run when close to operating temp?
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    24. #24
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      How do you air bleed after thermostat change?

      If you have the front defrost setting on (which engages the air conditioning compressor) then yes the e-fans can be on when engine is cold. Otherwise, mine doesn't...

      But like I said earlier... If the thermostat is functioning properly, and the engine is cold and running, there should not be an appreciable amount of coolant flowing through the radiator. So if the fan is running or not, the engine will get warm. Once the engine warms to a certain temp, the thermostat will open and allow coolant to flow through the radiator. Once the engine gets to a certain higher temp, the temp sensor should trigger the e-fans to come on.

      This is a generalized description of how it SHOULD happen on most cars. The only thing I don't know for sure are the Volvo-specific set points for the fans and t-stat.
      2003 XC70 (mine) | 2005 V50 (hers) | 1995 855 (saved my life ) | 1987 Chevrolet R10 P/U (the mule)
      Volvo P1 Chassis C30/S40/V50 Oil Filler Cap O-Rings for sale - $2 shipped

    25. #25
      My fan is on regardless of defrost setting. Automode on ac and the fan is on from the get go.
      Got word back from Volvo tech sweden, they suspect the ac is overfilled. To much pressure and the fan kicks in early to cool condenser..

      Measured low side to 400kPa and high side peak to 1700kPa. The peak is just as the compressor kicks in and pressure drops to +-1100kPa as it equalizes.

      Dunno if this makes any sence.. it didnt to Volvo, meaning they dont know the pressures. When they do ac service, they empty system and fill by weight, not pressures.

      Also had them update ac software. No refrigerant was added or taken out. Will let cool over night and see if SW update made a difference.


      Ac sort of makes sence to me, I had the system serviced at volvo june last year. When summer was over i noticed the slow heat up condition. Thus took it in to dealer in october and had the thermostat changed, and again in february along with temp sensor.

      Seems my issue started with the ac service..

      Anyway, as soon as car is started, the radiator fan kicks in 16%. And stays there, regardless of temp, ambient or engine.

      Mechanic will sent our findings back to volvo tech but from a bit of googling, the pressures seems alright..
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN

    26. #26
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      I know I am a little late on this, but has anyone checked for water flow through the heater core? Just my $.02

    27. #27
      I am off for work the next 2 weeks. Gave the keys to my new friend at volvo dealer. He will take it home and let sit over night and do his diagnosis in due time. Meaning no charge - hopefully.
      At least it wont distract him from other work in the shop.

      This morning commute to kindergarden, I pulled over when dash heat needle was at 10 oclock or 2 markers on meter i dash if you like.
      Opened hood and felt the engine, warmish. Then checked the lower radiator hose, right side seen from front - as close to the rad as possible. It was hot, corresponding to the heat i felt on the engine.
      2005 V50T5/GT/StageI/Forge CBV/KN
      1997 855R/Auto/StageII/Forge CBV/KN