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I'm rehab'ing an 86 I bought a while ago. during the process of fixing all of the vacuum leaks due to aged hoses, I've run into one can't find and suspect is causing a performance issue. I have checked all over the engine bay and all hoses are secure now. This leak is somewhere in the dashboard. I can hear a de-pressurizing sound when the engine is turned off. As well, at around 55mph and under some load, there is a high pitched whistle coming from the dashboard.
The performance hit is a momentary lack of response to change in throttle. I'd like to eliminate this obvious leak before trying to troubleshoot other systems.
I checked the two rubber lines that run the the expansion/vacuum tank under the heater core area. Both of those were in good condition with no cracks. I tried to trace them but quickly get lost in the thight space. I also have the stereo out (mounted up top), so I can see in above the center vents, but the limited visual inspection was a bust.
Never having had to replace the blower motor before, I would rather not take the dashboard apart more than I need to. Any standard gotchas of the vacuum system within the cab?
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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I had the same vacumn leak sound from under the dash when shutting the engine off. Checked the master vacumn check valve under the hood. All seemed OK.
So I disassembled the whole center dash. The leak was not there. And eventually worked my way back under the hood to the master vacumn check valve. which I replaced for $5 from the junkyard. That is all it was.
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This post has been marked as an answer to the original question.
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Where exactly is this check valve located at and what does it look like? I also hear a hiss after shutting off the car; maybe my valve is bad also.
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Mike F - 1984 244 DL - 311,000 miles
Original engine, transmission, drive train, starter
Undergoing reconstructive surgery with POR-15
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It comes right off the intake manifold. As others have described, it sort of resembles an oreo. See below. The photo is an 83 B23F engine, my 86 also has this located above the manifold as well as the 90 B230F I pulled the replacement off of.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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Cool, thanks for the pic! Very helpful!
I looked up check valves on FCP's site and found two. Which one do I need? The description says that it's located right in front of the brake booster.
http://www.fcpgroton.com/index.php?sub_top_menu_item=by_make-by_model-by_year&by_make=78&by_model=1116&by_year=34&category_id=&nodecode=true&search_term=check+valve&do=search
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Mike F - 1984 244 DL - 311,000 miles
Original engine, transmission, drive train, starter
Undergoing reconstructive surgery with POR-15
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Hi Mike,
Looks like you may have found the check valve for the brake booster. Someone posted the link below, but here it is:
http://www.ipdusa.com/Volvo-200/Engine/Heating-&-Cooling/Climate-Control-Check-Valve/p-69-258-261-3910/
Alex
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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Awesome, thanks! I'll add this to my list of repairs once the weather gets warmer.
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Mike F - 1984 244 DL - 311,000 miles
Original engine, transmission, drive train, starter
Undergoing reconstructive surgery with POR-15
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If the car has cruise control there are a couple of places to check for a vacuum leak as well. The one that takes the biggest beating is the one on the brake pedal.
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I believe that the vent controls are vacuum operated - there are vacuum ports at the back of the three buttons that control floor air, defrost and re-circ.
If one of the hoses comes off back there, or if one of the metal ports the hose attaches to fails, you will get that hissing noise.
Try pushing those buttons in different sequences - if the noise changes, you've found the problem.
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I tried switching the vent combinations the other day and it did produce a variety of different pitch hisses. I hadn't thought about checking the connection at the controls and it's not to hard to take off the console bezel. I'll give this a look tomorrow when I finally have some real time to look into this.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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I have an '86 also. That little hose that leads from your intake, through the "oreo" looking oneway valve and into the firewall is likely the culprit. Mine crack a couple years ago, so I cut it off an inch or so from the intake and stuck a stick in it. Driveability problem solved. As for working heater settings? Not so much. I need to get a longer hose...
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I had the inside-the-dash-hiss-after-shut-down. I replaced the vacuum line from the vacuum tank under the heater to the intake. That line gets brittle from heat
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89 240 Wagon 225K, 94 940 190K
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Sounds like the oneway vacuum control valve on the intake manifold is stuck open or bad. When this happens the vacuum in the reservior tank drains. It looks like an oreo cookie and mounted on the intake manifold.
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This post has been marked as an answer to the original question.
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Problem solved! This was the problem part (one way check valve). I was finally able to sneak off to the junkyard today and found a replacement off of a 90 240. No more hissing noises and performance is better. I'll also replace the vacuum line that runs from the check valve to the vacuum tank inside. Upon examination, this hose was resting against the thermostat and had started to deform.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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I tried to locate this part at the local auto parts shops, but no one has it, or at least can't locate it in their computers. I can try the parts yard soon, but would rather have a new part, if it has in fact failed. If anyone knows where I can get a new one, it would be appreciated.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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Just wanted to add that replacing the vacuum check valve on the intake fixed my leak down from the dash area. This thread saved me a ton of work!
I was not in a position to get a factory check valve but found a suitable replacement in the generic "HELP" section parts at the local parts house. It's not a permanent fix but stopped my leaks until I can order the correct part.
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Here is the part:
http://www.ipdusa.com/Volvo-200/Engine/Heating-&-Cooling/Climate-Control-Check-Valve/p-69-258-261-3910/
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Try clamping off or plugging the vacuum line that enters into the passenger compartment (probably behind exhaust manifold) from the intake manifold to be certain that it is the cause of poor performance.
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1980 245 Canadian B21A with SU carb but electronic ignition and M46 trans in Brampton, Ont.
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A took a poor stab at this the past week also. Not having a clamp for this task, I just started the engine and pulled the hose off and plugged it with my finger. To my surprise, idle dropped when the leak was stopped, and rpm increased with the port open. Guess the computer just compensates for the extra air.
I'll probably need to reset base idle since I've fixed more than one vacuum leak so far, so I'll find a more permanent seal at the port (ideally finding the vacuum leak or faulty check valve). Then I can reset the idle and see what the performance is like.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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With carbs, if the idle increases with additional air, that indicates the mixture is a bit rich. So you may be running rich.
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1980 245 Canadian B21A with SU carb but electronic ignition and M46 trans in Brampton, Ont.
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I was successful as plugging up this port on the manifold and the response of the throttle has improved so that I don't have the delay any more. This is good news because it seems like the last vacuum leak in the system.
The initial idle is still low after startup, acting like it might stall out. I'll probably need to set the base idle again, now that all leaks have been found. Also, shifting has become easier as the RPMs don't drop down so much.
Now I just need to determine if it is the check valve at fault or some leak in the cab somewhere.
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'82 245 B21F-MPG-LH 1.0, '83 244 B21FT-K-Jet, '86 244 B23F-LH 2.0
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This doesn't happen to have a turbo and a turbo dash gauge, does it? And I doubt it has cruise control.
Is there a vacuum reservoir under the dash? Some models have one, and the vent-control doors may be controlled by vacuum.
You can open the kick panel and trace any vacuum lines that go to the firewall. Then get a volunteer to move them, or paint some whiteout on the cabin side and pull it slightly out into the firewall side. That way you'll be able to ID vacuum hoses. From there, you may be able to trace them down to their connections.
Good Luck!
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1990 740 Turbo, on its way to stock specs, maybe beyond
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