Topped off Motul 8100 with Mobil 1 - reduce OCI?

[ledslinger]

Running 5W40 Motul 8100 Ex cess in my 2000 Concorde 2.7 with almost 130K miles. On a road trip and smelled oil at a stop and decided to check the oil which was full a few days ago. A full quart low and notice some oil spray on the frame rail, so it has sprung a leak. Put in a quart of Mobil 1 0W40 which brought it to a half quart low. Don't know if the oil pan or rear main seal is leaking. Neither makes sense to allow oil to get on manifold mounted converters or on frame rails next to engine. I'll have to pressure wash the area, then run to see where it is coming from when I get home.

Should I reduce my oil change interval since I don't know if the additive package or base oils of the top off meshes well with the Motul fill, or don't worry about it. I usually do about a 5-6K interval with 229.5 oils in this engine and all looks clean through the fill cap. I'm at about 2K miles on this fill of Motul.

 

[RedOakRanch]

You're already running a short OCI, no need to shorten it any more.

 

[hpb]

Wait and see where the oil leak is coming from first - but if it turns out to be something minor and doesn't require much engine disassembly to fix, I wouldn't worry about shortening the OCI.

 

[Kuato]

Agree with both above; M1 can easily go 10k in most applications so you should be good to your usual 5-6k...assuming no head gasket issues of course.

 

[BrocLuno]

Naw, just fix the leak and drive on. Change at 7,500

 

[UltrafanUK]

All normal engine oils are supposed to be OK when mixed. The only real reason to reduce the OCI would be if the top up oil had a conventional base when the rest of the oil was a full synthetic, IF you would have used a shorter OCI for a conventional base oil. Even then I would only reduce the OCI if the amount of top up oil was significant.

 

[Olas]

Originally Posted By: ledslinger
A full quart low

Put in a quart of Mobil 1 0W40 which brought it to a half quart low.



I think your dipstick is broken

 

[demarpaint]

I wouldn't worry about the mix. I would be searching high and low for the leak and try and to fix it though.

 

[ledslinger]

Originally Posted By: Olas
Originally Posted By: ledslinger
A full quart low

Put in a quart of Mobil 1 0W40 which brought it to a half quart low.



I think your dipstick is broken


I drove further before I got to my destination and purchased the Mobil 1 so it had leaked more by then.

 

[Olas]

Ok, I understand now!
Sorry

 

[mazdamonky]

My vote goes toward fix the leak, if it doesn't require the oil to be drained, such as by an oil pan drop, then extend your OCI to 7500 plus miles. 10k on the next OCI

 

[ledslinger]

I did a quick look for the origin of the oil leak and tightened the oil pan bolts, and the leak seems to have slowed. I may have dodged the rear main seal as being the problem. I bought an oil pan gasket since my factory manual says you can drop the pan with only disconnecting the stabilizer bar. I hope it is that simple and am curious to see the inside of the engine at 130K miles.

So the mix is about 4 quarts of Motul 5W40 and a 1.5 of Mobil 1 0W40. I'll run that for my normal 5-6K mile interval since that is well within the capabilities of these oils as noted.

 

[BrocLuno]

Heck, I'd drain that nice stuff into a clean pan and set it aside when the pan comes down. I'll bet you motor looks great.

I'd install the new pan gasket and a new filter and pour that oil right back in after passing it through a clean shop towel. That mix prolly has a lot of life left in it...

But it's often more satisfying to change the oil too

 

[Gene K]

Originally Posted By: mazdamonky
My vote goes toward fix the leak, if it doesn't require the oil to be drained, such as by an oil pan drop, then extend your OCI to 7500 plus miles. 10k on the next OCI


I dont think 10,000 miles is a good idea on the 2.7L Chrysler...
They are known oil killers.