Airbox thermostat failure...

[akitawagon]

Hey Kelvin,

Thanks for the info on the airbox thermostat. The flap/door on my airbox intake was stuck partially open so I was still getting my 30 plus miles/gallon, unlike the major mileage/performance loss you had with it fully closed.

I did the "dowel pin" modification last week to hold the door open more and it felt like another significant step up in performance with more air getting in. So with the K&N air filter, the QBM timing change and air box, my '93 is performing a lot better than when I first got it. It's not a turbo, but this does give NA cars more options.

Now I just have to figure out the fluttering and squeeking noises I have (no relation to the airbox change).

[Pauloil]

where is this part on fcpgroton site?

[kelvin6]

If you must obtain a new part:

http://www.fcpgroton.com/volvo850fuelsystem.htm

It's $28.00.

I never said anything about actually replacing it after removal . I said jam it with some sort of spacer so that the damper would open up permanantly to the cold air side.

I'm still so happy about how this car performs now without it that i have no intention of replacing the thermostat...

[ccgaudette]

Mostly have to say is "me too" -- including about 2 mpg better efficiency.

I found the thermostat about 7 weeks ago. While inspecting it, it started to ooze a metallic slurry. So I just removed the whole thing, including the flap. With the weather here at 65-85

[akitawagon]

I think if your car is operated in moderate temperatures most of time (and you don't over oil the K&N filter), opening up the airbox damper/flap is not going to do any immediate damage to your to MAF sensor.

I checked my NA wagon the other day to see if the thermostat was dead and found that the damper door was stuck in the fully open position, like someone epoxied it. One of the intake piping tabs was broken also so it looks like someone didn't want to bother replacing the thermostat. I guess this explains why my wagon always seemed to have more overall power than other NA 850s I've driven.

My wagon has been driven mostly in California with some snow trips in Washington and Lake Tahoe and hasn't ever had any problems or codes with the MAF failing. I've never monkeyed with the airbox before other than replacing filters and the car hasn't been to any other service place for almost two years, so I can say that I've most likely driven for two years or more with the airbox flap fully open. The K&N filter was added about a year ago.

I do not know what our friends that experience the sub zero temps will see though. They may need to have a working thermostat.

[hausmeister]

Does anyone know at which temps it should switch from cold to hot air intake?

[billofdurham]

Check this thread: [url https://www.matthewsvolvosite.com/chat/p ... ght=airbox[/url]

Bill.

[luketrash]

I drove 290 miles before refueling during this holiday trip. I'm in Iowa and the temperature was 40-60F. I got 25mpg doing about 75-80mph all the way from my place to Omaha, and then city driving in Omaha. So not too bad for a used Volvo in need of the AutoRX treatment.

[MadeInJapan]

That's about what I get with combined driving. Even the little bit of driving in the city pulls the total MPG's down.

[strungtight]

This sight has been incredible. Since picking up my repossessed 1993 850 GLT sedan with 108,000 miles on it from some mad Russian in Pittsburgh, I have pegged the cold air flap open in the airbox, replaced the radiator and hoses, replaced the thermostat, plugs, oil, and tranny flush all on my own thanks to this site.

With the cold air flap permanently open, does the O2 sensor do anything? I noticed the O2 sensor is much easier to get to on the 1993 and I need a new one but I wont replace it if I dont need to. I have the codes for fuel trim and it just looks shot but I dont want too spend any more money than i need to at this point.

My PCV system parts will be arriving soon. Are there any DIY guidelines for this project on this or another site?

Thanks