Changing oil type: dino to synthetic

[Ron in SC]

I have a 1992 300 TE wagon with 132K miles on it. I don't know what type of oil was used previously. Suprisingly this car has virtually not oil leaks or even seepage. I say suprisingly becasue I have another 1992 300 E sedan with 126K miles on it and it does have some oil seeping. I changed to synthetic oil Mobil 1 15W-50 in the sedan at 60K miles.

I'm just wondering if under the circumstance it would be best for me to just use dino in the wagon.

Below is some information I got from checking this topic.

From what I've read, the synthetic oil can remove deposits left by the natural oil. The concern is these deposits may be blocking leaks. So by switching, you end up leaking oil. Some people mistakenly blame the oil for causing the leaks.


Switching to synthetic on a high mileage car? You may or may not have problems with leaks. Gasket and seal material has gotten better lately and the detergent properties of good synthetics are not as harsh as they used to be. It all depends on how much the sludge in your engine is acting as a seal for the oil.

Not a viscosity issue WRT leaks. Synthetic oil has more detergent properties. It will remove the sludge that is plugging the leaks.

[Ali Al-Chalabi]

I have done it on a 20 year engine with 200k miles that has never been opened, rebuilt or resealed in any way. Never caused a problem. I also started using it in my C280 at 60k miles. Now has 145k miles and still doesn't leak a drop.

[jlomon]

I have a '94 C280 with about 90K miles on it, and there is a minor leak on the head gasket that I'm monitoring. I'm keeping with the dino oil as opposed to switching to synth for the very reason you mentioned. If my motor was visibly dry I would make the switch.

[lkchris]

There are NOTHING but "old wives tales" etc. speaking against using synthetic oil. None of it is real.

Just do it.

[Ali Al-Chalabi]

Originally Posted by lkchris

There are NOTHING but "old wives tales" etc. speaking against using synthetic oil. None of it is real.

Just do it.

I agree.

[jlomon]

Originally Posted by lkchris

There are NOTHING but "old wives tales" etc. speaking against using synthetic oil. None of it is real.

Just do it.

I'm sorry you feel that way. Having done about 10,000 oil changes in my lifetime, and having seen this very thing happen first hand, I have a different opinion. Not a chance I'm prepared to take on my car, but by all means if you're comfortable do it on yours.

[Roncallo]

Originally Posted by jlomon

I'm sorry you feel that way. Having done about 10,000 oil changes in my lifetime, and having seen this very thing happen first hand, I have a different opinion. Not a chance I'm prepared to take on my car, but by all means if you're comfortable do it on yours.

Well having done about 10,001 oil changes in my life time including 4 years of municipal car fleat service, I have never seen this happen. But I did enjoy running my 93 Taurus 220,000 miles at 8500 mile change intervals. It's still going. I'v just witched over the 560SL at about 105,000 miles to Mobil 1 after replacing the head gasket, which was leaking oil. Maybe it was the regular oil that caused the leak.

John Roncallo

[clean1scene]

Originally Posted by lkchris

There are NOTHING but "old wives tales" etc. speaking against using synthetic oil. None of it is real.

Just do it.

I disagree with you somewhat. Years ago I had a 1948 Chevy pickup. The guy that had it before me only used non-detergent oil. The first time I changed oil I used a modern oil and the engine started leaking like a sieve. Before I changed oil the engine didn't have a single leak. So I would think that if the synthetic has stronger detergents that leaks could develop on older engines.

[DslBnz]

I just switched over to fully synthetic oil in my diesel I have nearly 287K miles on the original engine, and its entire life has been run on the regular stuff. After about 1K miles, the oil finally turned black, and I plan to change it at 4K miles. No leaks anywhere. I love it.