Myth about Synethic oil caused oil leak on older cars....?
11-09-2006, 02:17 AM
#1
Three Wheelin'
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Myth about Synethic oil caused oil leak on older cars....?
Greetings,
My 87 951 had an oil leak at the counter balance shafter seals. I brought the cars to the shop, and the mechanic suggested to try switching from my 15W-50 Synethic to the good 'old 20W-50 Mineral oil.
He said that he has seen similar oil leaks on the older cars, like my 87 951 and his Harley Fat Boy, when using Synethic oil... And, the leak stopped when switched back to the Mineral oil.
I don't know, but I am giving it a try to see if this is true. If so, is it because the older engine parts are designed/frabicated with lower tolerance that Synethic oil can "sip" through the seals and gaps?
Anyone can shed some lights on this myth?
With best regards,
- Alex.
My 87 951 had an oil leak at the counter balance shafter seals. I brought the cars to the shop, and the mechanic suggested to try switching from my 15W-50 Synethic to the good 'old 20W-50 Mineral oil.
He said that he has seen similar oil leaks on the older cars, like my 87 951 and his Harley Fat Boy, when using Synethic oil... And, the leak stopped when switched back to the Mineral oil.
I don't know, but I am giving it a try to see if this is true. If so, is it because the older engine parts are designed/frabicated with lower tolerance that Synethic oil can "sip" through the seals and gaps?
Anyone can shed some lights on this myth?
With best regards,
- Alex.
11-09-2006, 02:21 AM
#2
Rennlist Member
Yes, it does happen to people on here. Basically the newer synthetic oils have smaller particles that are able to squeeze themselve through the seals and whatnot that natural oil isn't able to do. At least that's what I read... (I didn't switch to synthetic upon this being mentioned to me).
So yeah, I'd try switching to natural oil to see if that would get rid of the leak. If nothing else you can always switch back to synthetic - its not like running natural oil is bad for the engine or anything. There was only natural oil around when these engines were made (unless yours has been rebuilt).
So yeah, I'd try switching to natural oil to see if that would get rid of the leak. If nothing else you can always switch back to synthetic - its not like running natural oil is bad for the engine or anything. There was only natural oil around when these engines were made (unless yours has been rebuilt).
11-09-2006, 03:21 AM
#3
Burning Brakes
I'm not saying that you car might not leak less with dino oil than synthetic, but these cars can work just fine with synthetic. When I bought my car over a year ago, I switched it to synthetic oil and I don't have any oil leaks, even the one time I used the reportedly extra thin Mobil 1.
11-09-2006, 09:05 AM
#4
Set to Full-Auto
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My daily - 87 944 with great maintenance history - uses full syn Mobile 1 with no leaks.
My Brother's - 84 944 with poor maintenance history - uses full syn Mobile 1 with little to no real leaks.
My Brother's - 84 944 with poor maintenance history - uses full syn Mobile 1 with little to no real leaks.
11-09-2006, 09:06 AM
#5
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From what I have read the bearing clearances in synthetic cars are closer together therefore the smaller molecules of the oil work fine, but cars that were not made for sythetics have larger bearing clearances and synthetic doesn't provide the cushion a regular oil provides.
11-09-2006, 09:29 AM
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You are getting that leak because it is common for that seal to leak. Do a reseal on it and keep running the synthetic everything will be fine.
Sometimes people will switch to synthetic when the car has lots of leaks that have just plugged themselves up from the sediment that organic oil has. After putting in the sythetic the points that were leaking will start to leak again. All this means is it needs seals and then the synthetic will be fine. Do the job yourself and you are looking at a couple of hours of fun. Let a shop do it and you are looking at a couple of bucks.
Sometimes people will switch to synthetic when the car has lots of leaks that have just plugged themselves up from the sediment that organic oil has. After putting in the sythetic the points that were leaking will start to leak again. All this means is it needs seals and then the synthetic will be fine. Do the job yourself and you are looking at a couple of hours of fun. Let a shop do it and you are looking at a couple of bucks.
11-09-2006, 10:06 AM
#7
Race Director
Well if you don't have any oil leaks the car won't leak on sythetic. I run synthetic on my 944 NA race engines that I have rebuilt. They don't leak.
My stock 944 turbo motor I run dino oil since it does have leaks. Synthetic will leak worse in this car. The use of dino oil is really just a stop gap until I fix the oil leaks.
My stock 944 turbo motor I run dino oil since it does have leaks. Synthetic will leak worse in this car. The use of dino oil is really just a stop gap until I fix the oil leaks.
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11-09-2006, 10:21 AM
#8
I run 0w40 Mobil 1 in both my 951 and 924S with no leaks and no oil consumption.
My BMW 740IL with 165,000 miles is a different story. With synthetic oil it goes through 1 quart per week. With Havoline "High Mileage" mineral oil it goes through one quart a month. I put roughly 2,000 miles on the car per month and run 5w30. There are no leaks, the oil is being consumed in the combustion process.
My BMW 740IL with 165,000 miles is a different story. With synthetic oil it goes through 1 quart per week. With Havoline "High Mileage" mineral oil it goes through one quart a month. I put roughly 2,000 miles on the car per month and run 5w30. There are no leaks, the oil is being consumed in the combustion process.
11-09-2006, 01:33 PM
#9
Rennlist Member
MYTH
____________________________________
1986 944 NA - Guards Red - 91k miles - minty
1983 944 NA - Platinum metallic - 5500 mi beginning a new life
1985.1 944 NA - Guards Red - donor car
1984 911 Carrera Coupe - Guards Red (gone, but not forgotten)
"If you're not living on the edge, you're not living"
____________________________________
1986 944 NA - Guards Red - 91k miles - minty
1983 944 NA - Platinum metallic - 5500 mi beginning a new life
1985.1 944 NA - Guards Red - donor car
1984 911 Carrera Coupe - Guards Red (gone, but not forgotten)
"If you're not living on the edge, you're not living"
11-10-2006, 11:39 PM
#10
I suspect it is a visocosity effect and not the chemistry of the oil. For any given set of operating conditions, lower oil viscosity will tend to leak easier than higher viscosity.
11-11-2006, 09:11 AM
#11
Rennlist Member
When I purchased my 951 it ran on dino oil and had no leaks. I switched to synthetic and instantly it started to leak at the front seals and the back of the balance shafts. I would say that there is deffinetely something to the myth. I switched back and the leaks where much better but still there. I have since fixed it, but I am still running old dino oil.
11-11-2006, 09:41 AM
#12
Administrator - "Tyson"
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Originally Posted by robert944h
From what I have read the bearing clearances in synthetic cars are closer together therefore the smaller molecules of the oil work fine, but cars that were not made for sythetics have larger bearing clearances and synthetic doesn't provide the cushion a regular oil provides.
11-11-2006, 12:09 PM
#14
Rennlist Member
Let me ask a different question. Why do you want to run synthetic?
What benefits are you not enjoying with dino oil that you hope to now enjoy with synthetic? If you put synthetic into a car that was successfully running leak free on dino, and suddenly had 1 or 2 expensive leaks crop up (e.g., from the RMS, front seals, or cam tower base gasket), would you be OK with it? For some, the answer is yes -- they like working on their cars and will view it as the perfect opportunity to clean everything and implement improvements. Others will be less amused, particularly if they were under the impression that switching back will eliminate any leaks that crop up. It may, but don't bet on it.
If you don't track your car and it's working well as is, I wouldn't bother.
What benefits are you not enjoying with dino oil that you hope to now enjoy with synthetic? If you put synthetic into a car that was successfully running leak free on dino, and suddenly had 1 or 2 expensive leaks crop up (e.g., from the RMS, front seals, or cam tower base gasket), would you be OK with it? For some, the answer is yes -- they like working on their cars and will view it as the perfect opportunity to clean everything and implement improvements. Others will be less amused, particularly if they were under the impression that switching back will eliminate any leaks that crop up. It may, but don't bet on it.
If you don't track your car and it's working well as is, I wouldn't bother.
11-11-2006, 03:03 PM
#15
Nordschleife Master
Originally Posted by seattle951
I run 0w40 Mobil 1 in both my 951 and 924S with no leaks and no oil consumption.
My BMW 740IL with 165,000 miles is a different story. With synthetic oil it goes through 1 quart per week. With Havoline "High Mileage" mineral oil it goes through one quart a month. I put roughly 2,000 miles on the car per month and run 5w30. There are no leaks, the oil is being consumed in the combustion process.
My BMW 740IL with 165,000 miles is a different story. With synthetic oil it goes through 1 quart per week. With Havoline "High Mileage" mineral oil it goes through one quart a month. I put roughly 2,000 miles on the car per month and run 5w30. There are no leaks, the oil is being consumed in the combustion process.