2000 S70 SE Base Air Intake Flap Topic is solved

[scot850]

This is a long known issue with turbo P80's in cold climates. It gets worse with age as the oil from the turbo leaks into the intercooler. Bit like fat in heart arteries! When the warm air in the engine cools the moisture in the air condenses in the intercooler and freezes the channels closed preventing the engine getting enough air to power the car. I have seen the intercooler rubber hoses sucked almost flat!

Years ago in countries like Sweden you used to be able to buy a clear plastic plate that fits over the grille and reduced the airflow to prevent this happening. Unfortunately these have been unavailable for many years.

I have used zip-ties and cardboard behind the main grille intakes and this has worked well. Have to remember to remove it above about +5C though!!

Neil.

[MoVolvos]

This is a long known issue with turbo P80's in cold climates. It gets worse with age as the oil from the turbo leaks into the intercooler. Bit like fat in heart arteries! When the warm air in the engine cools the moisture in the air condenses in the intercooler and freezes the channels closed preventing the engine getting enough air to power the car. I have seen the intercooler rubber hoses sucked almost flat!

Years ago in countries like Sweden you used to be able to buy a clear plastic plate that fits over the grille and reduced the airflow to prevent this happening. Unfortunately these have been unavailable for many years.

I have used zip-ties and cardboard behind the main grille intakes and this has worked well. Have to remember to remove it above about +5C though!!

Neil.

Since our summers are much warmer than winter is cold I decided to block it off from the outside just in case the flapper is not functioning. Prefer cool air from the front of the engine than hot air from the exhaust manifold.
Aluminum foil over Rockwool left over from garage wall and attic insulation. I doubled the amount in the picture.

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[MoVolvos]

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UPDATE: Blocking the tube caused a P0171. Removed the restriction and code went away. Decided to remove the entire tubing and leave the air inlet open to engine compartment rather than draw air from the exhaust manifold.
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[abscate]

I don’t think I’ve seen one of these malfunction except for the vacuum lines pop off the thermal switch in the air box. I live in an icing type state so I keep mine stock. I did have slow speed running on the T5 ice up my ETM once , right about 30F and in slow city traffic. Once I got up to 45 mph winter driving the boost heat cleared it up

[scot850]

For cold weather there is the cardboard piece zip-tied behind the grille. Just remember to remove above about +5C.

Neil.

[454cid]

For cold weather there is the cardboard piece zip-tied behind the grille. Just remember to remove above about +5C.

Neil.

I've just tried that on my 99 since I need a new thermostat and I'm waiting on Fedex. There's not much room to get cardboard in there nicely on a turbo. I ended up just putting it on top of the horns, so much air is still going around it, I'm sure.

[scot850]

If you zip-tie the cardboard to the back of the grille you stop more of the cold air. You still get cold air fed up from the lower air guide but it reduces the amount/speed of the cold air allowing the car to warm up quicker. It is not perfect but it helps up here at -30C and below!

Neil.

[MoVolvos]

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Is there an air temp sensor in the air box and if how does that affect engine management?
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[454cid]

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Is there an air temp sensor in the air box and if how does that affect engine management?
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It's more like a temperature sensitive valve for vacuum. It doesn't affect engine management at all outside of determining where the air comes from by controlling whether or not the air motor/servo/diaphragm gets vets vacuum or not.

This is of course assuming you have the same design I do (in my 96)..... I think some cars may have been different.

It looks like a tiny sardine can with two vacuum ports that stick through to the outside of the air box top.

[abscate]

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Is there an air temp sensor in the air box and if how does that affect engine management?
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The MAF has a built in temperature sensor to report temperature compensated air flow, at least in the 1999 MAF.

I think this is also true for earlier MAF. the Bosch part number MAF data sheet will tell all.