With a diagram and instructions from the FAQ, I set out this afternoon to inspect and clean the flame trap on my newly purchased 1992 240 station wagon. After about 20 miutes I finally deducted the location of the flame trap and the three hoses that fit to it. It took some wiggling and stretching, but I was able to get all the hoses off and the hard plastic spaghetti strainer part out of the trap. I cleaned everything out (the hoses weren't very clogged) and re-installed everything. Excitedly, I started the engine to do the jiggle test. I unscrewed the oil fill cap and much to my dismay, there was jiggling! I pushed down and pulled up on the cap and I did feel negative pressure pulling down slightly on the cap. Is everything ok or is some jiggling normal? Any suggestions on what else could be going wrong?

Also, where is the PCV valve located?

This is really bizarre. A lot of people say that the plastic caps jiggle, but my 87s both suck the plastic caps down TIGHT. The 90 240 isn't bad, and it has actually gotten better somehow. Actually my highest mileage car was the best with the jiggle test. Until it bit the dust in an accident.

Also, did you pull out the little bronze nipple on the intake manifold and clean that out too? I had to use a drill bit, mine was so crusted with junk when I got it. It did make a big difference.

Jiggle test??

Bronse nipple??

I have 168K on my '89 240 and I have replaced the flame trap several times( the original was a metalic piece that is replaced with this white plastic piece. What and where is this bronze piece?

And review this jiggle test that I am ignorant to.

Thanks

The flame trap has three hoses. One goes to the big plastic intake hose. One more goes to the engine block, and the third, small hose goes to a little bronze nipple right on the intake manifold. At least poke something through that to clean it out. It is usually very dirty. I always put a thick piece of wire through the little hose because it gets clogged pretty easily as well.

Got It. That's right at the throttle body, yes? thanks i will check it.

I did not take the intake manifold nipple off, but I did poke a nail through it to see if it was clogged up. It seemed like everything was free and clear. Should I go back and remove it to make sure?

Just hold your finger over the end (the end going to the flame trap assy.) to sense for vacuum at idle. It should suck. If not, check the hose for blockage, and then the brass fitting.

Be sure the plastic nipple on the trap assembly is clear.

You can usually clear the fitting with a chunka coathanger wire or little screwdriver or drill bit. The hose costs a quarter.

Don Foster (near Cape Cod, MA)

It might depend on idle RPM. +/-50 or 100 rpm could create a mechanical resonance with the cap, promoting more "jiggle," whereas if your engine is slightly off this rpm, the vacuum may prevail.

Don Foster (near Cape Cod, MA)

Wow, Don.

I never thought of that!

Uh oh... I smell another 240 project day starting :)

Chris --

I think the best thing is an actual measurement. I do this using a modified oil cap and a special low-pressure differential gauge called a "Magnehelic." These meters come in different ranges (0-5 inches of water works well) and are often on eBay for a few dollars.

A pressure (or vacuum) equal to 1" of water is the amount of vacuum needed to suck water up a straw 1". Roughly 27" of water equals 1.0 psi.

However, a simple manometer can do a fine job instead of the meter. You can use water in the manometer (which gives you a direct reading in "inches of water"), or substitute motor oil, which only requires that you compensate for the difference in density.

Don Foster (near Cape Cod, MA)

Chris, I'm manufacturing a version of an old breather system checker that Perfect Circle used to make. Its very simple to use. If the little ball goes one way, you've got vacuum, if it goes the other, you've got pressure. You should have slight vacuum regardless of engine speed. If you want to see a picture of my tool, check out our web site @mercymotive.com

P.S. I've made an early and a late version of the tool. Some web servers haven't updated our photos. The old style looks like a hockey puck with a clear tube on top, the later version is a laminated deal with a semi-circle channel in which the ball moves. Either kind works great. Chris Bogue

Around 1986, Volvo switched oil filler caps. The ones on the earlier cars were metal, newer ones are made of plastic. Your oil filler cap is too light for the jiggle test to work properly.

If the flame trap is clean and the real main seal is not leaking, you really have nothing to worry about. How many miles on the car?

The car only has 69,000 miles. Where is the rear main seal located? I have not checked it yet. Is it under the car, where the transmission connects to the engine?

You are correct about the location of the rear main. Park the car on a clean spot on your driveway at night. If you come out the next morning and see a puddle of oil under the car then you know there is a leak.

Considering the very low mileage of the car and the information in your last post about how clean your flame trap was I think your rear main should be good for a long time. It will last anywhere from 150-200K depending on how good the maintainence is.

Another way to keep things in good shape is to use synthetic oil. Flame trap accumlation is virtually eliminated, engine wear is reduced, mileage will go up maybe 1-2 MPG, your significant other will love you more, etc.

My engine has 246K on it with 15K on the rear main. I started using synthetic when the seal was changed. I had a lot of varnish on my camshaft that was gone when I changed 2500 miles later. Mobil 1 or Amsoil are the preferred oils, there is a wealth of information in the archives.