Hello All,

Well, this occurrence was completely unexpected and surprising. IJust had the throttle cable replace as it snapped before christmas. I went out of town and had a friend pick car up from my mechanic for me. I just got back into town two days ago. My friend had told me about a week and a half ago that the volvski was leaking oil. They were adding 1/2 a quart every couple of days. And trying not to drive the thing as best they could.

SO, I get it back and granted, I have not looked underneath and examined the engine or underbody at all yet, but with just a flashlight I can see that the rear of the engine block is moist with oil, one both the passenger and driver's side. Oil light was on also, put a full quart in it and it went off.

I plan on examining the underbody tomorrow in depth. After I do this I will come right back with more info. I am praying it is a oil breather box problem, as that is one thing I have not done on my brick yet and have been meaning to.

Thanks for any info and I will have some more concrete info tomorrow.

One thing that is kinda perplexing though, is that I took off the flametrap apparatus and found it to be clean inside and free of crud. I am not sure if this means the breather box/oil separator is clean also or if I should take this off and clean it out while I'm in that area.

No, the breather box can be clogged and the flame trap clear. Or vice-versa. The breather box usually takes longer to clog than the flame trap.

BTDT - Based on my personal experience, I had the cam plug blow out on me too... I'd go ahead, pull the breather box and clean it or replace it with a new OEM Volvo box only. Otherwise you might have other seals blow out from high crankcase pressure.

If you choose to do so, you can test the breather box. Here's how:

Remove the flame trap and the hose below it that connects to the breather box. Stick a long hose on the nipple. Remove the oil cap. Blow through the hose, and using your other hand, feel for air flow through the oil cap opening. If you feel air the box is clear.

Personally, I'd still do the breather box unless you find a restriction somewhere else in the PCV system. Have you tested all the hoses and the nipple on the intake? I had a slow rear main seal leak that I successfully stopped after I replaced a flame trap hose I thought was clear. That little .60c hose saved me big bucks. Save yourself the headache, replace anything in the PCV system that isn't new or close to new.

Thank you very much everybody for the advice and knowledge. I'm getting the replacement parts this week and going to fix it the coming weekend. I plan on taking off the breather box and cleaning it out as best as possible. My breather box hasn't been replaced or cleaned out as long as I've had the car(5+ yrs). I will have a backup breather box on hand just in case.

While I'm going to be taking the valve cover off, I'm thinking of taking off the air intake manifold also to get easier access to the breather box. Just poking around in there it seems pretty isolated and hard to get at without taking intake manifold off.

"While I'm going to be taking the valve cover off..."

You don't need to take the valve cover off to install the cam plug.

In my earlier post above there's a LINK to how I did it, as well as a picture of a simple retainer to keep the plug in place.


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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks, was looking at that post. Will examine thoroughly

You should be able to blow air through the flame trap hose going to the oil separator. The cam plug could just be old and failed due to age.
Dan

I usually check that the flame trap isn't clogged by starting the engine, then undoing the oil filler cap and just placing the cap gently back on top of its hole. There should be just a little suction if all is well. If the flame trap is clogged the cap won't sit on the hole, but will keep being pushed out a little. This test doesn't work on a very worn engine, because blow-by will cancel out the positive ventilation.

Well, couldn't get to it yesterday. Was only able to get it to the place I'm going to work on it at. Had to work the rest of day.

Today I wil have the results. Did see yesterday that the muffler was blown out. Knew something was wrong in that the car sounded alot louder than normal. The muffler was very old and most likely needed to be replaced. It pretty much sheared apart at the center. Its still hanging on but the metal is totally bent out indicating an explosion from within.

Il will post pics soon

Going to check cam plug and rear of engine as best I can from underneath.

"Going to check cam plug and rear of engine as best I can from underneath."

You check the cam plug from the top of the engine, just reach around the back of the head and feel for a 2" diameter hole or very oily area.
Dan

Thanks Dan for the advice,

I reached my hand back there and there is a 2" diameter indentation back there. THen inside that indentation in the center is a hole that seems like 1/2" diameter or so. I can feel inside the hole that there might be threads or something.

Just turned car on and ran it. It's obvious this hole is the problem. Air is coming out when car is on and a little oil shot out onto my hand also.

I'm looking in the Bentley bible and I'm having some problems finding a detailed schematic of this rear cam plug. But I beleive this is the problem.
Haven't check it yet but I have a hunch the breather box and flame trap might be part of the problem.
I am going to remove the breather box and clean it to the best of my abilities if I can get it off in one whole piece.

DO you think the muffler blow-out was due to old muffler or due to a plugged breather box or some combination of the two?

Ten years ago I answered the cam plug question THIS WAY.

I believe the cup-shaped plug goes in with flat bottom first, at least that's how my 2004 response reads to me now (note the use of "in") where I said:
"using a small wood block in the plug to pry against".

Search here (top, right) on rear cam plug for more reading on the subject.


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Bets in order of likelihood:

1) Rear Cam seal (plug)
2) Split aftermarket breather box (or OEM cleaned with brake cleaner) dumping oil, but that's pretty fast for that kind of leak
3) Rear main ... if it's basically fallen out. I think this is really unlikely.

It's probably the cam plug. You should still check the breather system because if that's plugged, it can cause positive crankcase pressure and make the cam plug fail.

Check the rear cam plug, feel behind the head.
Dan

Based on your posted information, I would bet that the engine rear main seal has failed, which is usually due to a clogged flame trap system.

$25 for the replacement seal part, many, many, hours of labor to replace. (You have to pull the transmission to get to it). If this is the case, don't feel bad, this has happened to a lot of people, who have not maintained the flame trap system.

And...before you replace the rear main seal, you need to trouble shoot the flame trap system, so that you don't blow out the new seal.

Art Benstein has a write up on his Web site: http://cleanflametrap.com/RMS.html
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If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 350,038 miles, will she make it to 400K ?? >>You haven't really worked on a car until you draw blood<< :-}

it is not the rear main seal if the back of the block is wet with oil. That would be a leak under the car and on the lower part of the bell housing, but wouldn't make itself known on the back of the block.

Is the back of the cylinder head wet with oil? If it's onky on the rearcof the engine, I wouldcalmost guarantee the cam plug seal. Feel back there to make sure it's still there