breather box?

Jvolvo8501995 · Post by **Jvolvo8501995** » 18 Apr 2025, 08:39

I have a 1995 850 5 speed with 336,000 miles. The only car I ever bought new.
I went thru the carwash and included the under carriage option to get salt and brine off under the car. On the way home it went crazy! Stalling, all dashboard lights on, running horribly, etc.
My mechanic from day 1 said the code came up as mass air meter. He replaced it but it didn't help. I finally had it towed to the Volvo dealership where I got it. They said the code read Breather box.
They also said that it would take lots of labor and as they would take engine parts out to get to the problem hoses and other parts would break or otherwise need to be replaced. They didn't want to deal with it so it's back at my house.
I'm heart broken about it - it was NEVER outside overnight - no rust and great condition other than the front seats which are impossible to replace. (haven't seen any 30 year old seats in great condition...)
Help!

Post by **scot850** » 18 Apr 2025, 08:45

Turbo or non-turbo? Not sure what can go wrong with a breather box that would cause issues with your car.

Are you able to open the breather box and see if you got a lot of water in there and perhaps soaked the air filter?

I'd also look at the distributor in case water got in there.

Neil.

Post by **Clemens** » 18 Apr 2025, 09:54

Correct me if I'm wrong, guys, but shouldn't a problem with the MAF be easily diagnosable by unplugging the MAF? If it runs better than before the MAF is bad. If I remember right, as soon as the MAF is disconnected the ECU uses a base map that can still somewhat make the car run w/o the MAF.

Also: +1 on water in the ignition system/distributor.

One more thought: the big wires to the alternator might corrode over the years, it has happened to others here. maybe they did't like the bottom car wash.

Post by **Clemens** » 18 Apr 2025, 09:57

And, as always if electrical gremlins appear, a bad battery, alternator or the wlectrical part of the ignition switch are possible culprits. This is unlikely after the carwash, though, except maybe the alternator.

Post by **scot850** » 18 Apr 2025, 10:20

The problem is most of the Volvo techs have never worked on cars that old! Most were not even born when they left a dealer.

In their defense, they know the car will likely have crumbly rubber pipes/hoses and parts that may be fragile. It can become a can of worms for them so they basically make up issues that may or may not be correct so you go away.

Clemens has given you the same bunch of suggestions I would have given you. Knowing if it is a turbo or non-turbo helps us as they have different air boxes, although I think it unlikely that it has anything to do with your car's issue unless it got water in it which again I struggle to understand how. The more likely issues are there are some small pipes that run to to airbox that possibly get dislodged or broken with a strong pressure washer.

Neil.

454cid · Post by **454cid** » 18 Apr 2025, 14:34

"breather box" to me, would mean the PCV system, not the air filter, especially when talking about hoses and other parts breaking. Whatever, the dealer did, sounds like it was run a quick scan and throw up their hands, and say I'm sorry.

I'd also look at the ignition, although, an undercarriage wash shouldn't normally cause issues.

Spraying the top of the engine can allow water to drown the plugs, as it fills the plug wells up. I did that myself. A shop vac and compressed air took care of it.

Post by **abscate** » 18 Apr 2025, 18:30

If you can wait reach out to mobile mechanic Robert Spinner and see when he is in your area

This is right up his alley

Post by **scot850** » 24 Apr 2025, 08:34

As your car is a non-turbo (OP PM'd me to clarify), then the only issue they have are a couple of vacuum hoses that can get disconnected. Those small hard pipes had rubber elbows that can rot out, but all that hoses is to stop the cold start valve in the air box operating. The other issue is if the thermostat in that operated the flap has failed open or closed.

In either case, I still struggle to see what that would do to your car. You could jam the flap so it is open if it does not work so you draw only cold air.

I'm starting to think what the other guys have suggested may be the issue in that the PCV (crankcase breather system) may be the issue they meant. You may want to check with the repair shop for clarification. The PCV system has a series of pipes and a part called a flame trap that block with age and require cleaning and in some cases replaced. To do this job requires removing the intake manifold to access the oil separator box on the front of the engine. Some parts will be required like a inlet manifold gasket. There is a write up on how to do this on the website.

Neil.

Jvolvo8501995 · Post by **Jvolvo8501995** » 26 Apr 2025, 07:59

Thanks so much for that info. I'm going to pass it to the mechanic that has worked on the car since day 1.

Vova585 · Post by **Vova585** » 26 Apr 2025, 08:27

I am voting for ignition system. Get yourself a compressor with a long nose attachment and gently blow all components of ignition system: Disconect Wires, plugs, distributor cap, connector to the hall sensor at distributor. Open the hood and let it "air out" on the sun. "Breather box" is only makes sense if you have wet air filter which likely would be replaced either by dealer or your mechanic. Any chance you can post a photo of what dealer provided you? Meaning diagnosed with code....recommend replacing xyz...
Or try this guy he is next to you hopefully

Advanced Level Diagnostics LLC
(732) 962-0503

https://g.co/kgs/SN3T4ic