Synthetic oil causes oil leaks?

[uvachief]

I've been using Royal Purple synthetic oil in my 1986 naturally aspirated 944. Like most 944s, it leaks oil. However, I was told by a mechanic that using synthetic oil is a bad idea as it is likely to increase oil leakage. He told me that synthetics contain detergents which scrub the engine clean, including the seals and can cause the engine to leak more oil than non-synthetic oil. Anyone got an opinion?

Mine did drink and leak out 3 quarts of royal purple in 1600 miles over 3 months which is ridiculous. I am noticing drips where I park it in the driveway but nothing significant. Even my spot at the parking garage at work doesn't have anything other than some silver dollar size stains on the driver's side and passenger side of the engine. No pooling what so ever. What could cause it to burn up that much oil? I am beginning to believe the mechanic.

[89-944NA]

The viscosity and small molecules of synthetic oil will cause it to leak past old seals that petroleum based oils don't leak around. After I got my 951, I changed the oil from the 20w-50 Valvoline VR-1 the PO used to Mobil 1...man I found leaks that I have never seen an engine leak from. Back to the VR-1, and the problem has returned to the original small almost un-noticeable leaks. I'm using about a quart (maybe a little more depending on how I drive it) of VR-1 between changes now.

After upcoming complete overhaul, I will go back to the Mobil 1 (possibly)...

[TibetanT]

The 944 is NOT suppose to leak oil. If you are leaking oil, there is a reason for it and the synthetic oils do effectively cause a higher oil pressure to read on your gauges when running.

I would go through all the records that came with your car and see if a complete engine overhaul was ever done. Usually, when a complete engine overhaul is done, now days, the seals used are of a higher quality and will be a better "player" with the synthetic oils. If your car was overhauled and is leaking oil there is a good possibility that products of low quality/low cost/non-Porsche specification type parts were used. If this is the case, find them and replace them before it damages your internals.

I run Mobil 1 synthetic 15W-50 during the summer months and change over to Mobil 1 synthetic 5W-30 during the Winter months here in the Inland Northwest. My car has never, ever leaked a drop of oil during all the years I have owned my 944, period!

Always use the best components when replacing parts in your Porsche to ensure that they last per Porsche's specifications. If you track your Porsche 944, then you will need to ensure that parts that meet or exceed Porsche's racing specifications are used; this will be an expensive endeavor if you choose to go that route.

Good luck and I hope this helps.

[TibetanT]

Forgot to mention this in my earlier post:

If your 944 is burning 3 quarts of oil in 1600 miles, then you may have a serious problem within your head, such as: valve guides are out of specification, valve seals are too old and leaking, valves are not seating properly, and or all your piston rings need replacement.

I would think about not driving the car until the heads can be checked via a leak-down test, and a compression test. These two (2) tests will probably identify the above mentioned situation. It sounds like the heads need work soon from what you have described above.

Good luck.

[Rasta Monsta]

Originally Posted by uvachief

Like most 944s, it leaks oil.

[flash968]

due to its chlorine component, royal purple has been shown to create consumption issues in higher mileage engines

switch oil

[Jordanarendt]

I use 20w50 (in only run my car in the summer). I read a thread somewhere that had a link to a porsche mechanic of 20+ years that had a very convincing argument for not using synthetic oil. Mostly due to increase wear on parts. Heavier oil protects better, was his experience.

[Jordanarendt]

928 AUSTRALIA - Bruce's Tech Tips - Bruce Buchanan, Independent Porsche Repairer

here is the link

[uvachief]

I meant to mention that prior to 2 weeks ago the engine ran like a top. Very smooth and quiet. Much to my chagrin, I have learned that my oil pressure gauge is stuck and not operating (even though the voltage meter is working so go figure). I check the oil level at most gas fill ups but didn't do so for the last 2 which spans about 4 weeks. I was driving recently and noticed a slight ticking sound coming from the very front of the passenger side of the engine. I pulled over and checked the oil level. I was 3 quarts low from full. Not a good thing. I am assuming I have damaged the valves or the hydraulic lifters. The engine has never been overhauled. I don't know the exact mileage as the odometer stopped working at 139k. I would guess the real mileage is less than 150k. I only put 1600 miles on it since the last oil change and managed to burn up or leak out 3 quarts.

[968 GUY]

So Royal Purple causes tuberculosis?????

[flash968]

lol - clever

[misnblu]

Originally Posted by flash968

due to its chlorine component, royal purple has been shown to create consumption issues in higher mileage engines

switch oil

I would disagree with this as I'm using RP for my Chevrolet that has 196,000+ miles on it and it's been beaten down at the track and daily driving it for most of it's life.
It uses (maybe) one quart of oil for every 5K miles and that's the max it may use.

The same holds true for my now daily driver Toyota which has lots of miles on it and no exceptional leaks to be found and again, one quart per 5K miles.

I did notice improved performance from the RP along with better gas mileage in the Toyota going from 36mpg when I first bought to the car to a now consistent 42mpg with a high of 44mpg with the car being driven hard every day. It's a fun car to drive so I tend to act like Speed Racer.

The 944 though I won't use nothing but Rotella or the Valvoline VR1 oil as that's what you're supposed to use for these cars. Some things are not meant to be changed because of technology but my other cars have faired quite well with the RP in their bellies.

Btw, the 944 is tight as a drum with no leaks at all.

[flash968]

sorry - independent double blind controlled tests have proven it (i had nothing to do with them, and the company that did them had no interest in any oil - they merely conducted the tests of all of the major oils, same weight, and never knew which one was which until after the test) - i was actually rather stunned myself to see and hear the results, both in data, and failed engines

i'm not sure the results were ever published, and i think the company that did the testing had to sign a non-disclosure agreement, but i'll see what i can get out of them

yes, rp made more power on the dyno than a number of the oils, but that wasn't the whole story - the chlorine component resulted in a breakdown of the oil that resulted in very high contamination, higher oil temps, and a decrease in sealing capacity and a tendency to burn

if you aren't experiencing problems, count yourself lucky - it scares the bejeezuz out of me - i tried one change of it on one car, and immediately i started burning twice as much oil - out it came and it will never see one of my cars again

use at your own risk

[ecostellodo]

the way i understand it all is this,

synthetics have similar sized oil molecule and the synthetic molecule size is smaller than with conventional oils. Therefore, oil leaks will show up.

the bottom line is if you have always used synthetics, stick with synthetics.
if you have always used dino oil, stick with dino oil.
don't switch

eric

[flash968]

not exactly, but it can happen - in reality, it's more about the polymers and how they act differently in synthetics

but not all synthetics are created equal, and they all act differently

i am continually amazed at oil technology - i come from the era of straight weight oils, where heavy was good, heavier was better, and really heavy was just right - it took me a long time to warm up to multi-viscosity oil - synthetic was a huge leap for me

things that make you go "hmmm" - since oil is what is used to make plastic or "synthetic" parts, what the heck is synthetic oil made of? real stuff?

there is a ton of information out there though, and it makes for some pretty interesting reading

[89-944NA]

No, Royal Purple DOES NOT CAUSE TUBERCULOSIS, it causes Purple Poo....a little potty humor here guys

[89-944NA]

Hey Flash968, remember those funny looking glass bottles with the funnel tops? You know, the ones that service stations (yeah you younger guys, they USED to be called service stations) used to sell that 10,000 wt reclaimed oil in? Stuff was so thick and loaded with wax that it was a BLACK/GREEN COLOR!!!!! Kinda looked like

[333pg333]

Here you go. The best oil thread for our cars and it's on this site.

Ultimate Motor Oil Thread or Why we hate CJ4/SM oils

[M758]

If you have oil leaks then synthetic is more likely to find them. Engines is tiny oil leaks on dino oil can turn into big ones on synthetic. All this means is that you have an oil leak. You have two choices. Fix the leaks so you can run synthetic or run the dino oil.

The 944 can run syntheic and not leak or burn oil. However an old motor with old seals oil leaks are common.

[smokin_944]

6 years ago when my WP and belts service was done, I had the engine resealed and switched from regular dino oil to Mobil 1 15/50. The engine has never leaked. However, I might be 1/2 to 3/4 of a liter down after 3000 miles depending on the driving I am doing...