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S80 Oil Trap and Port Cleaning Tips

S80 Oil Trap and Port Cleaning

MVS (now) Contributor John (johnljoseph) took a day to clean and Stage 0 his S80’s B5254T2 engine. Things went well until he got to cleaning the oil drain down from the trap. He tried a coat hanger. Didn’t work. So he used a snake attached to a drill and that worked.

Now, if you’re reasonably familiar with Volvo “whiteblock“5-cylinder and 6-cylinder (inline 6 not V6)engines, you know this is a weak spot in their design. If you don’t believe me, see these various related Volvo PCV tagged posts. I don’t want to get too off-topic, but don’t worry — it’s never been what I would call a severe design problem. But still, it wasn’t genius design either.

Clean a S80 Oil Trap

Well, what began as an effort to check out the health of the Flame Trap / Oil Trap / PCV / EGR system (I know it isn’t really any of those) on my 2005 S80 2.5T (engine B5254T2) has turned into an odyssey. I took the manifold off, I worked my way through the vacuum lines (who knows if I have them hooked back up correctly) and the plugs and all. Finally, after cursing Volvo design engineers a few times, I got the Oil Trap box removed.

It was completely full but thankfully hadn’t blocked the upper engine hole yet. Inside the box was sludge that I cleaned out by immersing the box in gasoline repeatedly and letting it drain out and then throttle body cleaner. Much of the material was grainy and hard like coffee grounds.

The exit from the box, the lower oil drain hole, was completely clogged. I attached my compressor to a rubber nipple and couldn’t get any pressure through the clog. It was solid. I had read all the articles about the convoluted design of the oil drain but I didn’t want to drop the oil pan. I wanted to unclog the oil drain and then change the oil.

Initially I was able to get an unbent wire coat hanger down the hole (Which opens in the lower back of the hole if you are looking for the exit to the oil sump). I could get it in about six inches before the hanger couldn’t be pushed any farther. I thought I was toast and would have to drop the pan. I looked all over for something that I could snake down the hole but couldn’t find anything better than the hanger.

My wife came in and suggested that my son had something that might help, a trumpet cleaner snake. It looked perfect, although it is a bit flimsier than a snake should be. It is a three foot long snake with a flimsy brush on either end. I cut off one and ad attached it to my drill. I managed to get it kinked a few times and had to cut it shorter but after a few false starts managed to have a fairly manageable snake.

I got it fed down into the hold and it made it to an impasse which gave way after 5 minutes of drilling. The snake made it farther, I assume to the bottom of the oil pan, and then stopped. I tried for 10 minutes to get it to snake farther to no avail and then suddenly it popped through the blockage (or around the corner).

I slowly withdrew the snake allowing it to “brush” the chamber well on the way back up and then checked to see if my compressor could get air down into the hole. Surprisingly it did. There was no resistance at all and I could hear it gurgling.

I wanted to post this for any others in a similar situation that might be looking for a way to unblock their oil trap, oil exit hole to the sump. I am sure there are other things that would work better than the trumpet cleaner that I used. Something stiffer would have been better but I don’t know if something stiffer could have gotten around that final bend in the pipe / channel.

2005 S80 2.5t EGR / PCV / Oil trap clog solution

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