I replaced the upper and lower manifold gaskets on a 1996 SE 3.8. I did it in a hurry and in reviewing what I did I know that I made a mstake on the upper gasket. I failed to insert the clear plastic tube tube that runs up to the PCV valve into the upper manifold (black plastic Plenum) . How and why I missed this I don't know but when I looked at the old parts 2 days later I realized what I had done

Should I disassemble and correct? Do I get a new upper gasket or can I reuse the old one? It'* been in for 4 days and less than 300 miles. Let me know what you think.


Spit

I would add the tube. We can guess that it is there so that the crankcase vapors are more evenly distributed among the cylinders and not just dumped on one end (which is what you have now). You can certainly re-use that upper gasket. I have pulled them and re-used them after a year with no leaks.

Bill,

Thanks for the quick reply. This site is great!! I have read some of your posts as well as some of the other contibutors and I am in awe of how much technical knowledge you all have. I bought this 96 kind of quickly and didn't do my research like I should have, and didn't know to look for the coolant leak/LIM problem. so it was kind of an OH MY GOD! when I found it. I was in a hurry to buy and fix, in order to get the car to my in-laws who needed a good reliable car quickly

I never would have attempted it without the great detailed info on this site...I just never saw anywhere how the tube fitsinto the upper maifold at the PCV eacuse it'* so obvious... When I looked at the old parts in my garage it was like DUH! of course that'* how it goes.... Now what did you screw up Einstein?

Well the nice thing about having to do something over is that it'* a lquicker the second time around being a ittle more familar with the situation.

You're welcome. This is the most amazing car forum I have found online. The information is excellent; the site is maintained with civility, and the response time to mechanical questions is unbelievably quick. Glad to have you with us.

On one that I did, I didn't have it in quite right, and the tube fell over so that it wasn't in the PCV cavity. While it'* running, pull off the oil breather cap, and you'll hear an interesting humming or drumming noise. That was the only symptom - the car ran fine.

If you are good a fenagling things around, when you pull the throttle body, you may be able to slide the tube in where it needs to be, and the snap it into the holders on the gasket. That'* what I managed to do with a long stiff wire to slide in the tube, some socket extensions for leverage, and a good flashlight. All in all, it may just be easier to pull the upper.

Dang it, now you got me worried... I don't remember any tube in mine...LOL I still got the old one so I'll have to look tonight.

Alright, now ya all got me worried...

That "j"-shaped tube doesn't really ATTACH to anything at the ends, right?

The curved end just kind of "hangs down" at the PCV end of the UIM, and the straight end simply points at the TB, right?

The "J" end slides up into the PCV cavity. It'* not firmly attached...just slips into a hole. It'* held in place by a slot at the PCV side, and then slides into 2 clips on the UIM gasket. The other end points at the TB, as you said.

Alright Archon,

So you're saying the j-tube should fit up into the PCV like this:


This is something of which I was not aware, nor did the FSM (or anything I found previously on this site) say a word about it.

Both UIM'* I've had off (my '98 LeSabre and my Mother-in-Law'* '98 Old 88 ) had the tube just "hanging loose" like this:


So that'* how I reinstalled them. (I did wonder WTF the pipe was for, just hanging there :? )

Granted, both UIM'* I had off had already been replaced...I was doing LIM gaskets. I wonder if the mechanics reinstalled improperly, or if they just wiggled their ways out of the slots?

I'll have my UIM off soon enough for testing my ported LIM...but Is this important enough to go back in and fix on my MIL'* car?

Yes, Andrew, you showed the tube correctly installed here. There is really only one place the curved end can fit into, and that is into the top or outlet side of the chamber housing the PCV valve. It is not a tight fit, and it probably would not do much harm other than to load up cylinders 1 and 2 with most of the crankcase fumes and vapors if it were not connected. (Thanks, Andrew, for the image.)