smoke coming through vents?

kippster41493 · Post by **kippster41493** » 05 Feb 2016, 09:44

94 850 2.3 When vehicle is getting up to temp. I will smell a burning smell (can't quite tell if coolant or oil) but a little smoke will come through the vents. I'll have the heat on because its winter obviously, the smell isn't constant in fact its only there for a couple of minutes. The smoke will last about 30 seconds or so, I have the windows rolled down at this point mainly because I'll have my 1year old daughter with me in the car. Any ideas where to start?

Post by **rspi** » 05 Feb 2016, 10:29

Is the seal in place along the firewall to seal off the engine compartment from the vent intakes?

kippster41493 · Post by **kippster41493** » 05 Feb 2016, 10:52

I'm not entirely sure where that seal would be? Is it just a rubber gasket along with the top of the firewall? If it is that why would it would be for such a short time? (sorry for the questions, I've never had this happen on any vehicle before)

Post by **dyn blin** » 05 Feb 2016, 14:05

A few thoughts from similar experience

If it's smoke-

Oil on the top the engine under the spark plug cover- if the oil cap gasket is cracking, or the PCV system has a hose loose next to the oil filler neck, it could be burning a spill and causing the odor.

If the PCV system is in need to maintenance, one of the hoses could be cracked or dislodged from the PTC element at the bottom of the turbo intake tube, which could push the gasses where they could come into the cabin through the fresh air cabin filter on the passenger side near the windshield. The PTC element at the bottom of turbo intake tube has a small orifice that may easily get clogged and push back gasses, too

The question on the rubber firewall seal is a good place to look too, but that would simply be a symptom of another problem.

If it's coolant/steam/light-colored smoke coming out the vent:

A failing overflow container cap might cause the smell, but I would imagine the problem would not be intermittent as you describe.

A failing heater core would generally be accompanied by a mess on the passenger side foot well,

Post by **scot850** » 05 Feb 2016, 16:36

A failing seal on the heater core will make the driver's side damp not the passenger side.

Just to be sure it isn't the heater motor, switch it off prior to starting and see if you get the same issue. Once you are moving try switching it on and see if the issue happens again.

Neil.

kippster41493 · Post by **kippster41493** » 06 Feb 2016, 09:30

I'll try to see if it's the motor later when I'm off work. For leaks I do have some oil sitting on top of the cam cover because the PCV hose did need to be replaced, I didn't check the flame trap it self but I'm thinking that needs to be done soon, it's just been too cold and I don't have a shop or empty garage, it has another Volvo torn apart in it ..... Regardless I've checked to see if it was leaking down to the heat shield on for the turbo and it dry back there. If I drive for a bit and no smell/ smoke, is that the motor that needs to be replaced or could that just be because the vents are closed that it's just not coming from the engine bay anymore?

kippster41493 · Post by **kippster41493** » 08 Feb 2016, 10:35

update on this. Didn't have the vents open, didn't even have the fans on. Smoke still came inside the vehicle, noticed it may have even been coming from the back seat area. I know there is an exhaust leak that I'm getting fixed soon (someone cut out the cat and put an over sized pipe and used crush clamps didn't work) Could it be exhaust seeping into the car? Or could it just be from the floor vents in the back because I know even though the fans set to off its never fully off on these vehicles? Same issue, burning smell and smoke for about 30 seconds or so ....

SpeedyPete · Post by **SpeedyPete** » 08 Feb 2016, 21:36

Smoking Vents! The year was 1975 my good friend Richard picked me up for a night on the town in his old mans pride Buick Skylark. We were on our way to pick up the girls and I was diligently rolling doobies on the glove box door. I sparked one up, took a hit then placed it on the dash while I bent over to lick the zigzag of another. Suddenly Richard hits the brakes hard, my head is now stuck in the glove box and the lit doobie on the dash goes down the windshield vent! Oh SHI....! Richard is pissed his dad is going to kill him. I pull my head out of the glove box bleeding and reach over and turn the fan on high cause I don't care how pissed Richard is I am hurting here! It takes awhile but then the smoke starts and it keeps coming and coming and now you can barley see out of the damn car. Richard is screaming like a loon until we both just start laughing. This went on for about an hour before all the smoke cleared. The car reeked, we tried 3 cans of air freshener and sticking a couple of pine sent air freshener trees in the vents to no avail. The old man had our asses for breakfast, lunch and dinner and Richard wasn't allowed to drive the Buick again!

Post by **benpineapple** » 10 Feb 2016, 08:29

SpeedyPete wrote:Smoking Vents! The year was 1975 my good friend Richard picked me up for a night on the town in his old mans pride Buick Skylark. We were on our way to pick up the girls and I was diligently rolling doobies on the glove box door. I sparked one up, took a hit then placed it on the dash while I bent over to lick the zigzag of another. Suddenly Richard hits the brakes hard, my head is now stuck in the glove box and the lit doobie on the dash goes down the windshield vent! Oh SHI....! Richard is pissed his dad is going to kill him. I pull my head out of the glove box bleeding and reach over and turn the fan on high cause I don't care how pissed Richard is I am hurting here! It takes awhile but then the smoke starts and it keeps coming and coming and now you can barley see out of the damn car. Richard is screaming like a loon until we both just start laughing. This went on for about an hour before all the smoke cleared. The car reeked, we tried 3 cans of air freshener and sticking a couple of pine sent air freshener trees in the vents to no avail. The old man had our asses for breakfast, lunch and dinner and Richard wasn't allowed to drive the Buick again!

+1

Post by **benpineapple** » 10 Feb 2016, 08:33

Based on the amount of smoke you're describing, have you been able to see the source of such a significant amount? Tried poking around under the hood to see any potential sources? The cold might help you to visually verify some exhaust leaks.

Does the smoke smell sweet at all? You mention you can't tell if it's coolant or oil.