I'm still in the process of fixing up a 1990 240 GL that had been somewhat neglected the last few years. It's getting a new oxygen sensor soon, and it already has new spark plugs and new transmission fluid, with wires and distributor on the way.

But the car still needs a new mass airflow sensor, and in looking for one, I keep seeing these parts websites talking about needing a new air temp sensor that goes in the air filter box, because without it they will void the warranty on the new MAF. Now this really doesn't make sense to me.

I'm really puzzled about the second air intake this car has that routes the air right through the exhaust manifold. What is the point of sucking in hot air? The metal hose on my car was broken to pieces, so I removed it along with the pieces that mounted it to the manifold, since it wasn't doing any good anyway.

So my question is, how is this all related? Do I absolutely need to get a new hose for the "pre-heated" air intake? Where the heck is this thermostat that goes in the air filter box and supposedly switches from cold to hot air, and what is even the point of that? I thought all cars were supposed to run better on cold air, but I guess I don't know everything....

Please enlighten me in the ways of this strange Volvo design!

Thanks,

Adam

It routes warm air back to the engine when cold to help it warm up faster.IMO it is really not needed.

really only helps in very cold weather. warms up faster. seems like you could use it in winter months.

air mass meter very expensive stuff. get rhe numbers off your old one on top of meter (usually 007) go to a salvage yard and pick one up for approx $75-$100 otherwise will cost you about $400 new. Don't need a new one just one that works. Good luck.

Ok, that makes more sense now. But now I'm wondering if the MAF went out because the pre-heat hose has been broken for a long time and nobody noticed. Or maybe it was that oily crap I found along the bottom of the intake hose AFTER the air filter (I still can't figure out where that came from).

As for getting a different MAF, isn't it risky to get a salvaged part? I would be afraid of it only lasting a couple more years and then dying just like the old one, but maybe I'm wrong. I have found remanufactured ones to replace this one for around $200. That would have it's own warranty and everything. Would that be a better long-term investment?

Thanks for the help, everyone!

Adam

I highly doubt that caused the mass flow to go bad.
It hasn't been proven yet that the hose missing causes it to go bad.

Certain stuff I will go to the junk yard to get and others I won't.

Go and take a look and maybe you might be able to find a new one on a car and save lots of money.

I took my whole configuration out and havn't had problems (in the last two months)