240: Oil Leak - Crankcase Pressure Problem

[Mathesar]

Hi All - I have at terrible oil leak that appeared right after I did several routine maintenance fixes while doing an auto to M46 swap. Here’s want was done just **before** the problem appeared.

1. I replaced the rear main seal using the Aftermarket - Rear Crank Housing + Seal Kit from IPD that has the seal pre-installed in a new housing that you swap in. It was very easy to do, and I torqued it to spec. - so I can't imagine that I f____ed that up, but who knows.
2. I replaced the whole PCV system including the box, flametrap housing, and all the hoses, except the oil return hose. I did it without removing the intake manifold, so it was a geometrical nightmare getting it out, and back in, but I was pretty sure I did it all correctly, including not disturbing the oil return hose during removal, and carefully easing the new box back into it.
3. I replaced the oil with Total semi-synthetic 10W30 (not sure what was in there before), and a Mahle filter that IPD matched to the car, but it wasn’t as “tall” as the filter that was on there.

Its a 1990 245 DL with a stock 2.3 liter redblock 4 cylinder with 215,000 miles on it. Prior to this, it ran well and used less than half a quart every 3000-4000 miles. It didn’t smoke and only leaked a drop or two a day if it stayed in the same place. It always had a whistle/whine, and still does. The previous owner attributed this to leaking to leaky vacuum hoses, which I think can affect crankcase pressure, but this doesn’t seem to be a change from before to after my new oil leak.

After I did all this work on it, it was just a faster leak at first (small puddle), from just in front of the bell housing, passenger side, but it performed just fine, so I continued to drive it for a a while, thinking that I could just add oil as needed until I formulated a plan to attack the problem. In all, I drove it about 650 miles, and I am just praying I didn’t do any serious engine damage. On my last 300 miles the temp gauge kept creeping up slightly above its normal spot, it was just spraying oil, needing half a quart every 50 miles, and smoking a little from the oil fill port.

I haven’t done a latex glove test, or built a manometer, but, it seems like these symptoms are a textbook case of massively elevated crankcase pressure. I am going on the theory that I did something wrong installing the PCV system, and/or that the PCV oil return hose is broken or dislodged. Here are my questions for the forum:

1. Do you agree that excess crankcase pressure caused by something I did to the PCV system is the most obvious cause of my oil leak, or should I be looking somewhere else first?
2. To pull out the PCV system and really make sure its right, should I just take off the intake manifold to get better access? If so, will I need any parts other than a new manifold gasket?
3. To inspect/replace the PCV oil return hose, it looks like I might end up having to drop the oil pan (which is why I didn’t do it in the first place). I don’t have a cherry picker. Can someone give me a link to a thread or posting, or a video on removing oil pan from a 240 without removing the engine?
4. If my brand-new rear main seal was not the root cause of all this, what are the chances that it is still good now after 650 miles of having oil forced past it? I really really don’t want to go back there again so soon if I don’t have to.

[dl242gt]

Well if the oil return hose is clogged. The pcv system gets very oily and crankcase pressure isn't relieved so well.

I always recommend the manifold being taken off. That way you can see the oil return hose and clear it out if it's blocked. Do the glove or oil cap test and see how it's doing.

If there was a groove where you installed the rear main seal. Oil will leak past that. The lip of the seal can make a groove in the crank. When you install the seal. Volvo gives you extra room so a new seal can be installed on a fresh surface on the crenk if needed. You can either set the seal deeper or more shallow wherever the fresh area is.

The excess crankcase pressure from having the oil return clogged made me do this mod to the system. Works great for quite a while now. https://forums.tbforums.com/showthread.php?t=338673

[Mathesar]

Thanks for that Dave. Help me understand the advantage of this mod. over just replacing the clogged oil return hose. ($12). Is it way easier to do, or is the resulting set up superior in some way?

- Will

[Cwazywazy]

Originally Posted by Mathesar

Thanks for that Dave. Help me understand the advantage of this mod. over just replacing the clogged oil return hose. ($12). Is it way easier to do, or is the resulting set up superior in some way?

- Will

IIRC you can't replace the return hose without removing the oil pan.

[J_pelchy]

Originally Posted by Cwazywazy

IIRC you can't replace the return hose without removing the oil pan.

I mean, to do it properly, probably not. Also with an old brittle return hose it's unlikely it'll come out in one piece. There's a piece of metal that bolts in with the oil pump that holds the hose in the correct spot so it doesn't go into the crank but if you didn't want to pull the pan there is always a way around it.

[dl242gt]

Yes I did the mod because it accomplished the task much easier than pulling the hose up and out of that vise grip bracket inside the engine. I didn't think the oil drain hose would come up and out in one piece and didn't want to leave a chunk in that bracket. The hose in my engine was completely clogged and I couldn't even push a piece of hanger wire through. So I did a diy pcv version that has worked well for quite awhile.

BTW Stealthfti used to suggest cutting the oil return hose so it's only a short piece of hose for easier draning back into the engine.

[Cwazywazy]

Originally Posted by dl242gt

BTW Stealthfti used to suggest cutting the oil return hose so it's only a short piece of hose for easier draning back into the engine.

Isn't the point of the hose that it goes under the oil level?