The Stovebolt Site Forums The Shop Area Engine Shop Synthetic oil leaks?

I just changed from Rotella T3 API CK 15/40 to Valvoline High mileage synthetic, API SP 10/30. After a trip to the dump (20 mi) there are two new leaks: The rear main drip has gone from an annoyance to a 3" puddle overnight on the shop floor. Also a JIC swivel fitting on the oil filter began leaking. Though it had some end-play, it never leaked before.

Anybody have a similar experience with synthetic vs dino oil?

FWIW I also changed from a Wix 51515 filter to a Baldwin BT217. Between the larger filter and the change from 15/40 to 10/30 oil, the oil pressure comes up faster and it's about 5 lb. higher now compared to the Wix when it was new. The pressure gauge connects on the downhill side of the full flow filter.

Changing from a high viscosity oil (15w-40) to a lower viscosity oil (10w-30) can absolutely cause more oil to leak from existing orifices.

When I switched from 10w-30 to 20w -50 oil in my Cadillac, oil leakage was cut in half.

Why did you change the oil type and the viscosity in the first place?

I use straight 30 weight, but some people think DFW is the waiting room for the place where dead bad people go so anything beginning with the number 10 or 15 doesn't work as well for me.

I use Mobil 1 15W50 in my old engines. I add some ZDDP to protect the lifters. I don't notice any more leaks than with petroleum based oils.

Unfortunately, a well known outcome with synthetics.

I had read and heard about leaks from synthetics but though maybe I'm special somehow. Apparently not.

I changed oil grade to API SP to get the additive package that protects camshafts. This according to tests run by Lake Speed the motor oil geek. Using that grade obviates the need for ZDDP additives, he says. Perhaps there is an SP-rated oil that isn't synthetic; otherwise, I think I'll go back to VR-1 20/50 which didn't leak. Between that and Castrol GT 20/50, the previous 235 ran 200,000 miles before burning #6 piston. Oh, and a few years worth of DELO from my tanker days.

Anybody got a 0.040 over 235 piston? I'll post on the parts wanted.

Penn grade 1, 10w30 or10w40. Has the ZDDP and a partial synthetic package. Essentially the old Kendel 1 with an upgraded lubricant package.

Could be your new oil has more cleaners in it and removed the crude blocking the old leaks so now it leaks more. Not really the type of oil that made it leak more, it just cleaned better. You may find you DINO oil will leak just as much now that the engine has been cleaned up.

Change it back and lets know what happens.

I will tell you my take on this, but I have no imperial research or proof to back it up. Our old motors were engineered for use with Dino oil. So the bearing oil cushions, viscosity, flow, lubricity, all engineered around this type oil.

Modern motors are engineered to use synthetics. Some motors, it all you can use. So there is a difference.

It may be that synthetic cleans better. Or it maybe that the flow characteristics with the synthetic are way better then Dino oil and that it seeps to places Dino can’t flow out of. I don’t know. But I do know that our old motors run just fine with Dino oil and that is probably what one ought to stay with to avoid any unforeseen and unwelcome issues.

I'm in the same boat. Only mineral oil non synthetic in the old stuff. And straight weight, though I think multi viscosity is mentioned in the old owners manuals? I'll have to look again.

Valvoline VR-1 20W-50 works well in my truck. Plenty of zinc without needing to add anything.

The 20w-50 does seem to keep the hot idle oil pressure a bit higher than the 15w-40 I ran previously. Pegs my 30 lb gauge with even the bit of throttle. Idle stays in the 15 psi range.

In my case, crud isn't the problem as the engine only has 12,000 miles on a major frame-out overhaul.

One change I made is that I had been using a sealed up filler cap in conjunction with the factory PCV system which theoretically should have produced a vacuum in the crankcase and sucked air in all the places oil leaks out of. I finally ginned up a hose from the valve cover to the air cleaner like it's supposed to be and ran it that way for a couple hundred miles before changing from the Rotella T3 to the 10/30. I didn't notice any additional leakage on that trip but it's hard to say. Like 2-stroke Detroit Diesels these engines tend to leak when you work them hard. It's been 100 degrees most days lately so that might have an affect on leakage; causes me to leak water from all over and gets in my eyes. The last trip in hundred degree heat got me to chase down the AC gremilins that make the A/C quit after an hour or so. Found and fixed.

I start leaking all over beginning in late April or early May and continue until close to Turkey Day. I think it is somehow causing me to lose my hair.

I've noticed if I seal my dipstick (which I did by making a round inner piece that holds a couple of O-rings) I get a slight negative pressure inside the crankcase. It seems to help with leakage. I use a sealed filler cap with a hole in the top and run the line to my air cleaner like you did.

JW 51, glad you addressed the oil pressure, since I’ve I had lots of concerns about the idle pressure.

With the 10/30 syn in hundred degree weather my engine holds about 15 PSI at 700 RPM. 180 oil temp. I will try the o-ring on dipstick trick.

I had to make a new dipstick as mine was a generic one people had guessed at various oil levels with to the point it made no sense at all. So I used some brazing rod, some 1/4" diameter brass rod, an old coin...think it was a French Franc. I cut the piece of 1/4 inch brass rod, drilled a 1/8" hole in it and then before soldering it to the brazing rod I spun it in a drill press and used a small round file to make some grooves for the O-rings.