While checking the air filter on my new (to me) 98 S70 (non-turbo), I made a couple of observations. First, on the back side of the air box near the top, there are 2 small nipple fittings coming out of the back. Neither one had anything attached to it. There were 2 small open hoses there; one white with a black rubber elbow and another smaller one with a hard plastic tip. The latter was broken off and a piece appeared to be on the top fitting, so my assumption is that the white tube connects to the bottom one. What are these lines for, is that the correct placement, and does anyone know what the broken one is called (or part #) so I can order a new one?

Second thing I noticed is that the inlet hose connecting the intake fitting on the front of the car to the damper fitting on the air box was not fully connected. I've played with it, and it just doesn't seem to want to connect properly. From some reading I've done, it seems like this damper should allow cold or warm air to enter the box depending on temperature. If this doesn't fit tightly, what's the result? Is it something I should replace? Other threads seemed to indicate that if the damper wasn't working, performance and mileage would suffer as the engine always draws hot air vs. cold.

Thanks!

 

Check this link out to see placement of tose two tubes https://volvoforums.com/forum/showth...ight=hose+tube. There is pic attached in my post #4

 

Thanks or the reply. Mine, like yours, broke off at the elbow of the hard black piece. It does appear to be a vacuum line to the thermostat on the air box. After doing some research, it appears that many people bypass this thermostat to ensure a cold-air feed to the engine. I may do this myself, would would negate the need for the line anyway.

Any tips or things to watch for when taking the air box out?
Is there a preferred method of disabling the thermostat, or is it just safer to replace it (just in case)?

I live in VA, so in the winter, it gets moderately cold at times.

Jeff

 

Taking air-box off is strait forward, disconnect all tubes and hoses and Maf connector.
It appears that older models have thermostat and newer have vacuum operated valve.
Many people claim that by fixing to only cold side, they got better gas millage and eliminate pinging. Downside to this they reported is longer warm-up time in cold weather.
When I checked mine it worked properly so I just put it back together.
More on this you can read here

 

I went ahead and glued mine back like you did. Definitely the best option I think. I looked at the picture from your post #4; is it correct that taped connection goes on top while the white goes on the lower? One post I found by a supposed Volvo tech indicated the white was supposed to be on top. Frankly, I don't know what the order was on mine.

 

Yes, taped connection goes on top while the white goes on the lower.