I've been using mineral oil but am thinking about changing to the synthetics. My mechanic says mineral oil is fine for my car and get no benefit from synthetics. He claims syn oils are for newer MBs. Anyone has different views?

 

Sorry about posting again for the same issue. I did not realize Tin Man responded on 04/13/2004. Tin Man, thanks for your input.

 

My mechanic says the same thing ... but I am an old engineer and chemistry makes a difference to me. I bought a '96 E320 new and have always used synthetic oils and lubricants. Because I've always kept to fairly low replacement intervals, i.e., 3-7k miles, I don't think I've ever really stressed the oil to the point where synthetic lubricants perform better that crude stock base oils (dino juice). Yesterday, I had my mechanic perform various shores on the car and we looked inside the valve cover to see how things where doing at 52,000 miles. I could not discern whether the valve cover and mechanicals were any cleaner using synthetics vs crude stock oils. Bottom line, in my humble opinion, is that if you stick to low replacement intervals around 3-5k miles, it doesn't matter what you use so long as you stick to appropriate viscosities. You've also got to admit that no matter what oil you use, the filtration is the same. Still, I'll keep to synthetics -- voodoo I guess. cp

 

Do not use synthetic oil as it is much thinner than regular mineral oil. I made the mistake and the car developed oil leak which was not there before. It is better to replace mineral oil regularly as it has shorter life than synthetic brand.

 

I just read the thread about synthetic oil causing a leak. I bought an 89 300 SE and immediatly changed the oil to synthetic. It too developed a leak in the head gasket. I just thought it was just wear and tear. I'm curious, Did you go back to organic oil and did the leak stop??

 

That's an urban myth. Synthetic oil does not cause oil leaks. If you had a leak with synthetic then you had the same leak with dino. Usually what happens is when someone changes to synthetic they have this misinformation in the back of their mind and become paranoid. They start looking really close for oil leaks because some nut on the Web said it would leak. Lo and behold, they find a leak. Not a knew one. They just notice the one that was there all along. They just never worried enough about leaks before the switch to track any down.

 

having a leak by using a synthetic oil will be a big issue.

i use synthetic oil for years now, no matter if the car is new or old...and got no complaint about the leak related with it.