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1984 245 Stock Air Cleaner Functionality

Terry1941

New member
Joined
Sep 9, 2020
Location
Federal Way, Washington
Hi all,

I have been working on making out newly purchased 1984 Volvo 245 Gas FI car with 150,000 road worthy. Today I was doing minor maintenance like replacing the air filter. The old one was dark and greasy with no light shining through. In cleaning out the old case before putting the new one back on I was intrigued with how the fresh air intake worked, checking to make sure it wasn't plugged. I found that the spring loaded flap has the fresh air port closed (air temp outside was about 62 degrees). Because unimpressive performance, poor gas mileage, and the greasy condition of the old air filter I was wondering if by chance there was a malfunction with the spring only allowing for air to come trough the manifold tube? Has anyone experience this issue before?

The brass spring loaded pin does move when you push it down and manually opens the fresh air port, but the spring was very strong in favor or keeping the warm air tube open?

We have had the car for about a month. The first tank of gas, with about 75% town driving, logged 200 miles, is this normal? I know these were not high MPG cars, but I was hoping for a little better than that. Replacing the plugs - cap- and rotor are next.
 
Failure of the air box thermostat is common. It should close off the warm air @ ~60?F on a FI car. From your description it sounds like it's bad. It's a cheap fix but it can be difficult to compress the spring enough to replace it.

The bad news is that if it's been bad for a long time there's a good chance it cooked the MAF. Good replacements are hard to find and/or expensive for LH 1.0. The good news is that the connector for the MAF can be repinned and you can use the more common MAF and ECU for LH 2.0.
 
Where would you find parts to replace the thermostat and how would you know if the MAF sensor is bad? The car runs smoothly. is there someplace that repines and provides the upgrade?
 
The thermostat is available from most any online retailer as well as the dealer. You could probably even pick one up at a local independent repair shop.

IPD is a popular place to buy Volvo parts.

https://www.ipdusa.com/products/5451/103083-volvo-airbox-thermostat-valve-calorstat-1266826

Poor millage and rough running are typical symptoms of a bad MAF. You can repin the connector yourself. It isn't difficult to do. Once done all you have to do is change the MAF and ECU and they plug right in.

Here's a thread on how to do the upgrade. It's LH 2.0 - LH 2.2. My mistake.

http://forums.turbobricks.com/showthread.php?t=246934
 
You can just rip the flapper out and grab a rubber pipe cap from the hardware store to cover up the hole, if you don't mind the car losing a tiny bit of originality. Might wanna throw a new o2 sensor into it and see if that helps with the running issue.
 
I like the idea of just taking the flapper unit out, but do you think there would be any cold weather issues? I read in one of the threads that the fuel injected models were designed so that the pre-heat closed when the temperature reached 60 degrees and they didn't run well below that on cold air (cars designed for Sweden). It can get cold here in the Tacoma Washington area while temperatures most of the year float around the 50's & 60's, it can still get well below that at times. Unfortunately our warm weather season is very short.
 
The flapper is just there so it heats up faster and has less emissions on cold mornings. You won't hurt anything by removing it although you may have to drive around a bit longer before getting it smogged in the winter.
 
You can just rip the flapper out and grab a rubber pipe cap from the hardware store to cover up the hole.

Yes, do this.

I like the idea of just taking the flapper unit out, but do you think there would be any cold weather issues? It can get cold here in the Tacoma Washington.

It will have an almost negligible impact on the amount of time it takes for the engine to warm up. The airbox mod will also minimize the chance of damaging the Air Mass Meter.

The flapper is just there so it heats up faster and has less emissions on cold mornings. You won't hurt anything by removing it although you may have to drive around a bit longer before getting it smogged in the winter.

Yes. And we no longer have smog testing in Washington state, so that's no longer a concern.
 
You wanna keep the preheat hose if you need to get a visual emissions inspection. (Cali) However, you do NOT want the thermostat broken (stuck open), routing hot air into the airbox.
 
I can confirm that closing up the flapper does not cause any cold weather issues. My DD has that mod and hasn't had any problems in winter here, in temperatures down to -20 deg F.
 
Easier still is to put a small hose clamp around the brass thermostat body which forces the flapper closed always.
Keeps the preheat hose look for visual inspection and always pulls cold air from the snorkel.
 
Another easy upgrade is to unsnap the four legs of the plastic thermostat bracket from the air box. Then use the open hot air intake for a second cold air intake that enters from the hole in the right headlight panel. The engine didn't seem to mind. No issues with cold weather affecting the mass air sensor.
 
Another easy upgrade is to unsnap the four legs of the plastic thermostat bracket from the air box. Then use the open hot air intake for a second cold air intake that enters from the hole in the right headlight panel. The engine didn't seem to mind. No issues with cold weather affecting the mass air sensor.

That's a cool idea!
Just make sure that if you live in an area that gets lots of rain that you cap the hole from the preheat hose or run it up higher.
If you don't it will snorkel water right into the engine driving through high water!
 
I read to do that here. I think it was the smokey100 guy that wrote about it. For the end coming through the sheet metal hole I used the right angle stock 240 turbo elbow with the horn removed. I aimed it toward the radiator. So it's been ok but if I hit really deep water then it would be a problem.
 
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