Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 15, 2025 ...

Oil drain plug will not torque down! 1998 U320 Cummins M11

September 22, 2014, 05:24:14 pm

I just got done draining my oil and while installing my drain plug I noticed it would not snub up tight. I'm using a standard size 1/2 inch ratchet so I'm not putting any toque on it. The threads don't appear to be stripped but once I get the drain plug all the way in it will not tighten up!! Any suggestion?

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #1 – September 22, 2014, 05:33:07 pm

Look at the threads again, especially the ones in the sump. Sounds like threads are stripped  somewhere. Plug could have been over tightened previously and they stripped when you tried to tighten the plug. I don't know how thick the area of the threads is, but you may have to put a helicoil insert in the repair the sump.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #2 – September 22, 2014, 05:39:54 pm

Steve,
I just removed the drain plug again and sure enough the threads came out with the plug! Will I have to remove the oil pan to install a helicoil? If so where would I take it to get that done?

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #3 – September 22, 2014, 05:41:20 pm

you can get the part from Cummins. It is not expensive.  I did remove my pan to put it on.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #4 – September 22, 2014, 06:07:25 pm

Greg,

That has happened to several members here and on other forums. It has a lot to do with dissimilar metals, that is the oil pan is aluminum and the plug is steel. One of our members ( I think Wyatt) has a tap and another plug of some type that was left over from his repair and was wanting to sell them. He may chime in & tell you the rest of the story, but I think he did his on the engine and didn't pull the pan.

Pamela & Mike

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #5 – September 22, 2014, 06:49:26 pm

All Cummins M11 oil pans are a problem waiting to happen as it is very easy over tighten the steel drain plug into the aluminum pan. Most techs will not use a torque wrench, and over tighten drain plugs. One solution is to permanently install one of the popular quick oil drainers BEFORE the threads strip out. Cummins has a part for this common problem.

We have seen the aluminum threads come out with drain plugs. SAME potential problem with Allison transmission drain plugs as their plug is steel and pan aluminum. Even an Allison Stewart Stevens tech did not use a torque wrench when putting back the drain plug.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #6 – September 22, 2014, 07:38:49 pm

Certainly makes me thankful ours came with a quick-drain fitting already installed. I don't know whether or not a previous owner had a problem with the plug, but thankfully we won't. (As a bonus, it also makes draining the oil easier and somewhat less messy!)

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #7 – September 22, 2014, 08:18:52 pm

Service records on our m11 show a helicoil being installed

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #8 – September 22, 2014, 10:59:23 pm

Greg,

You might be beyond the threads, maybe try using a copper washer.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #9 – September 22, 2014, 11:22:32 pm

We had a small leak at our drain plug and at regular oil service, FOT fixed.  They removed the pan and a machine shop fixed the threaded area.  I think they installed a steel piece with threads.  Cost 90.00 if I remember correctly.  No more leak!

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #10 – September 23, 2014, 07:37:28 pm

I added another washer per Jim Frerichs post and was able to get a much better bite on the drain plug. But there is no way that I can torque it per the Cummins manual to 65ft lbs. I'm also having a hard time finding a helicoil that matches the 1-18 uns drain plug.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #11 – September 23, 2014, 09:48:16 pm

You might want to call the nearest Cummins Service Center.  The cost of a Helicoil kit in the 1" range is over $300.  They would likely charge less.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #12 – September 23, 2014, 11:07:12 pm

Call these folks, TIMESERT.COM  they have a thread insert kit, specifically to repair the threads in oil pans that have been pulled
 out and that is what happened. 65ft lbs is a lot less than most folks think when their pulling on a wrench, then, they usually give it just a little extra because it doesn't feel tight enough. Happens all of the time. Use a NEW sealing washer available at NAPA. All of the work can be done without pulling the pan by greasing the end of the drill bit/tap, the shavings will cling to the grease. Most importantly, take your time. Another solution is a company called Fastenall. They carry a wide assortment of thread inserts in stainless.

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #13 – September 23, 2014, 11:35:33 pm

 
It is 1" x 18.. pc

Time-Sert does not have anything btw..  pc
 

Quote Selected

Re: Oil drain plug will not torque down! 1998 U320 Cummins M11

Reply #14 – September 24, 2014, 04:29:58 pm

After talking with Wyatt today I'm going to tap the pan out to 27mm and install a Fumoto drain valve. I will post photo's of the process. Thank you all for helping me on this dilemma.

Quote Selected