Steam/smoke from side vent

tiberious1001 · Post by **tiberious1001** » 16 Aug 2020, 04:39

Hello, hoping the expert community can help me out with this.
3 Questions in ascending order of importance;

1) What are the vents/holes that are far left and right of the dash, around the corner of the blower vents, called?,

2) What are they connected to?

3) Most importantly, what would cause steam/smoke to come out of the passenger side of one of these?

I've got the heater core exposed and the passenger carpet back and it doesn't appear to be leaking. Also it does appear to be independent of the blower function. I've just oiled the blower and I'm mid way through repairing the recirculate servo since I've opened it all up. So I've got a fair amount of that side of the dash exposed and can't see anything. I think it gets worse the more I rev the engine and seems to be getting blown out when i do. The air con is working ok, the low speed on the fan isn't working (replaced the fan less than a year ago with a V70 one but broken again, expect another post soon

i turn the air con off when not in motion) but again it appears to not be affected with the air con turned on or off. Tested the pressure of the 134a and it's not going down. The high speed on the fan still works when the engine gets hot. Coolant might have gone down a bit but nothing drastic. I'm one step away from taking the whole dash off. The steam/smoke has a smell but nothing strong, if i would give the smell a description it would be something hot maybe oily. But again the smell is not strong at all and it only comes out of that one hole/vent.

I know i have an issue with the exhaust. Something is cracked but when heated up seals it self back up again, or at least that's what the mechanic said. Something is cracked and the cabin gets some fumes when starting up and reversing out the drive way but after driving it's fine. The cabin air filter was replaced about 6 months ago. That's about all the info i have. I can take photos if it helps anyone.
Thanks.

Post by **abscate** » 16 Aug 2020, 04:57

Many people can’t smell the new coolant so noses aren’t the best diagnostic. Is the coolant level dropping at all? Mark it with a sharpie so you can monitor. Look at the level cold in the morning at the same time for reference

Get that exhaust leak figured out, it’s not safe to have fumes in the cabin

Cookeh · Post by **Cookeh** » 16 Aug 2020, 05:09

Your fan speed issues are down to the resistor, they're a cheap part but fairly inconvenient to access. That being said, if you've got part of the dash apart already then it certainly should be accessible.

Coolant leak from the heater matrix isn't a particularly noticeable leak - it's not something that will empty your reservoir overnight. Definitely mark the level, as abscate recommended.

As for the smoke aspect, given it has a whiff of oil, could this be linked to the exhaust leak? Certainly seems plausible to me. Get that sorted (a must anyway, for health and MOT requirements), and re-assess. Common cracks are in the flex pipe, and the exhaust manifold. Give your mechanic has already investigated this you should be able to find out the exact issue easily enough.

tiberious1001 · Post by **tiberious1001** » 16 Aug 2020, 12:18

Thanks for the replies, as far as coolant loss it looks to me like about a quarter of tank in 8 months or ~3,000 miles. With lock down and no work or travel I've done significantly fewer miles than usual so maybe higher loss than normal. As these things aren't too expensive and I've owned the car for 5 years and more than 50k miles so it might be worth changing the heater matrix anyway. The car is getting close to 300K miles now so anything is possible.

Only thing that mystifies me is why it only comes out of that hole at the side and is seemingly unaffected by the fan. Is that hole even connected to the blower system or is it a separate system?

Post by **scot850** » 16 Aug 2020, 14:32

The vents on the end of the dash are the front side window demister vents to clear the side windows to see the rearview mirrors. They are connected to the vent system and to the 2 outer face vents.

As to why the 'smoke' comes out of there is possibly as it is a small area it may seem that way and are more noticeable. Are the outer vents fully open?

It may be the bearings are bad on the fan and oiling them has caused the oil to heat up and smoke?

Coolant leaks?

Main areas are:

1) Weeping hole at water pump bearing. Usually visible from under the car on UK drivers side.
2) The small radiator or thermostat to header tank pipe leaking at either end.
3) Header tank cracked
4) Failing header tank cap.
5) The coolant pipe that runs from the header tank to the rear of the block leaking at the clamp where it meets the metal pipe.
6) Heater matrix, or matrix 'O' rings.

All of these places will leave telltale residue if they are a problem.

The last place would be any runner hose connection weeping or the radiator ends to matrix section leaking at their joints.

Neil.

tiberious1001 · Post by **tiberious1001** » 19 Aug 2020, 09:16

Everything leading me to the heater matrix. Hopefully that will solve it. To clear up confusion with the fan, the low speed not working on the fan is the radiator fan not the cabin fan, i took the cabin fan out to oil the bearings just because it started to make a squealing noise. The radiator fan is the one i replaced about 9 month ago (with a second hand v70 one) and it stopped working on the low speed again, thinking the steam/smoke might be something to do with the air con running without sufficient cooling.