Oil for leaking rear main seal

[ChrisJH]

My 2001 Frontier SE V6 seems to be leaking slightly from the rear main seal. Ive done an AutoRX treatement on it, and switched to German Castrol (so its 0w-30, probably a little too thin).

Question is, now what should I switch to? Should I bother with synth? I was looking at the Mobil high mileage stuff.....should I just use their dino high mileage stuff, or spend the $$$ and get the Mobil1 versions?

The truck will be outside all of the time, including winter so cold starts will be there. Id like to get decent mileage out of the oil, so I can avoid changing it in the dead of winter.

Thanks in advance.

-Chris

 

[ChrisJH]

And while we're at it (sorry, cant edit original post).....

Is it possible the leak will go away with more mileage on the German Castrol? It hasnt been in very long, maybe 1500 miles or so.

Thanks.

-Chris

 

[gedcruise]

I have had Mercedes that liked to leak at the rear main seal. I found that with some revs and the higher oil pressure, the leak was nil. I am saying that, because the diesel might have dripped noticeably at idle in the driveway, but actual consumption, as well as the under car oil streak evidence, weren't there.
Now, an oil known to be good for helping leaking elastomeric seals is Maxlife. You might try it.

 

[Merkava_4]

You've got a huge array of options here. For starters, Amsoil's site says you can go all the way up to 10W-40 above 0*F.

There's a huge assortment of high mileage oils with seal conditioners that you could try in both conventional and synthetic.

The seal conditioners might swell the rear main seal up enough to slow the leak and maybe even stop it all together.

 

[SargeGTO]

Replace the seal.

 

[ThirdeYe]

If you don't have any money to replace the seal, try running some Valvoline MaxLife. We did that in my sister's car that was leaking and it stopped the leak within a few hundred miles. Granted, it was a slow leak. It probably depends on the severity of the leak. It was just a few drips a day, so it wasn't a large leak.

 

[Merkava_4]

Quote:

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Replace the seal.

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That's the ideal thing to do, but some engines have to be pulled out for the replacement of the seal. You have to weigh the {cost+time} of that against a few drops of oil on the garage floor.

 

[Curious Kid]

I went to my dealer to pick-up a few of the o-rings that would be needed when I drop the pan (old ones have started to leak causing drain-back leading to the Hydraulic lifter clatter after sitting just a day in 50 deg. f weather). I also picked up a freer flowing filter than I had previously tried because of it's silicon ADBV, and thought if I can't get to things this I could try the $10 bar's rear main seal treatment (which is also suppose to help o-rings and other gaskets).

I got home and drove the car up on the ramps. I looked over things and saw that I could move over the power steering lines, but as for the many pan bolts were tucked behind the engine/transmission platform framing. I opted to hold-off till next year when I just might get around to pulling the engine and tranny as one and give the seals, belts, and a few internals a change. Went ahead and changed the engine filter, and topped off with the seal "repair" additive (3/4 a qt).

I have used Castrol's HM 5w-30 for an OCI (help slow things), and now have MaxLife blend with some M1 top-up + additive of course. Oil pressure has seemed to build faster (light's off sooner), but as for the clatter I'll have to wait for the temp to drop back down. Haven't been watching for the drip or two that I get when parked from the rear seal.

Good luck.

 

[ChrisJH]

Id love to replace the seal, but its definitely a major job. Either I pay a ton of labor, or I try to DIY it and it takes a lot longer than it should (its a 4x4, so I need to pull the xfer case, etc).

Its a rather small leak.....wherever I park the truck, I dont even see any oil on the ground. If I go under the truck you can see a moist spot that corresponds to where the rear main would be leaking (apparently a common issue with the 3.3L Nissan V6 from that year). I topped the oil off after changing it, and a month later Im looking at being down about 3 oz or so. Honestly the engine might be using that much, but I dont see any smoking so I tend to think its the rear main instead.

I'll give Max Life a try, its cheap enough (at least compared to replacing the seal). The truck was normally run on 5w-30, for the 40K miles before I put in GC, so Im thinking that maybe going to a heavier oil just might do the trick (at least for a while, hopefully).

-Chris

 

[rocketj55]

I had a leaking rear main seal on my 1995 Mercury Grand Marquis. I was using 5 qts 5w-30 oil (usually Castrol GTX) and I was losing about 1 qt between oil changes (usually 3-4 months). I used CSL Engine Restorer 8 cyl. and the oil consumption stopped. Eventually, other problems cropped up that repair was too costly, so I stopped using CSL Engine Restorer and the oil consumption resumed.

 

[Greaser]

Some oils leak more than others.Chemical make-up thats all.Mobil 1 made my rear main seep on my Jeep that never did.Started using Delvac 1 and it dried right up.Now I use Esso XD-3 and it has been bone dry for a few years now.

 

[Herdfan]

Valvoline Maxlife. Trust me, I had the same issue on a Jeep with the notoriously leaky rear main.
If that fails, replace the seal. Actually, you should replace the seal anyway, but Maxlife will help minimize the weeping.

 

[Curious Kid]

For the expense in labor, I here you ChrisJH. From what I've been hearing, a rear main seal on my FWD w/auto transmission would cost me about $800-$1000. Gulp! According to Edmunds car review, my car's worth no more than $3000 private sale, but of course it's worth more than that to me.

It's my first FWD vehicle (I've only owned two vehicles so far), so there's some inexperience that makes me hesitant on doing it myself, thinking available time and how far it is to source OE parts should I forget something or something else pops up.

I do agree that I'd rather replace the seal, all the seals actually for at one point in time before switching from synthetic, just about all my seals began to weep (I bought the vehicle used with 65k on the clock some 6 yrs ago). That's another reason I'd like to do the work myself, so as to give things a total once over and freshen all that's needing...which would cost me more than the rear main seal replacement estimate!

Take care and good luck.

 

[artificialist]

If you can find Maxlife Full Synthetic, I would recommend that.

I had an old Honda that lost a small amount of oil, changed to regular Maxlife, and the leak ended.

I'm only suggesting full syn MaxLife because you can keep using synthetic, but add the benefit of an oil with extra seal conditioners.