Mobil SuperSyn 10w-30 Synthetic Oil

[BADCASE]

I’m about to change my 406 engine oil and contemplate dumping 12 quarts of 10w-30 Mobil SuperSyn synthetic in for the following reasons: To ease winter startup, to resolve conventional oil breakdown problems because my truck get low usage ie. 100 miles over the last three years. Mobil’s info does not address in their technical data any problems with synthetic oil in increased gasket leakage. Anyone out there had good or bad experiences with this brand and type of engine oil?

[Merz-Ben]

I have not had any experience with the Mobil Supersyn, but I can tell you that IMO it is a bad idea to change over an engine that has been running on Dyno oil for a few decades to synthetic oil. I run a MB and Volvo repair shop, and almost every time a customer insists that I change over their older car or truck to synthetic in the engine, it turns into a pull the engine and replace every gasket in the thing kind of excercise within a month or so. I'm talking massive leaks that leave pools of oil where the vehicle was parked. Keep in mind that most of these vehicles were over 10 years old and 200K miles or more, but it turns out real bad a majority of the time from my experience. Now in the gear cases, I have had very few issues with leakage when changing to synthetic and things run much cooler... I believe that it has a lot to do with the heat produced in engines vs. gear cases that causes the engine leaks.

Don't get me wrong, I have no doubt that the synthetic is better for the engine and will last longer, ect, but you should plan on replacing almost all of the seals and gaskets in the engine if you do switch. It is possible that you may be one of the lucky ones that have an engine that recieved religious oil changes and has no sludge or gunk built up around any of the seals and gaskets... but those are few and far between on a 30 year old Case mog.


Cheers,
Ben

Edit: I'm not saying don't switch to synthetic, but beware of the possibility of leaks.

[b101uk]

I have to say my experience is a little different to Ben’s above, but this maybe due to the change in dynamic between driving in the USA/Can vs. UK & EU, i.e in the UK your never more than 75miles from the sea so ultimately trips are shorter i.e between major cities like London & Birmingham or Glasgow

In my view what kills engines when you switch from average quality mineral oil witch has been used long-term to a high quality synthetic oil (an additive fortified mineral oil) is the engine will expire for one simple resion, a blocked oil filter!

IMO:
If you buy a used vehicle witch even if its has service history your never quite shore what oil has been used, an “average quality mineral oil” wile fine for preventing ware but dose not have the sludge cleaning capability of a high quality synthetic oil even when fresh, what happens is all this sludge ends up in the filter and starts to restrict flow until it eventually blocks it, however normally the engine has expired or been damaged due to prolonged low oil pressure at high rpm befor total blockage and or the point ware the bypass valve opens allowing oil to miss the filter.

To get around this buy your self 3 oil filters with your new high quality synthetic oil, change the 1st filter with your oil as per a service, replace that filter automatically at between ~150mils and ~200mils from service, then change to the 3rd filter ~300mils to ~350mils after the second filter (apx >450mils <550mils after service)

At the end of the day you only have to ask your self “if I have sludge in my engine and I put something in there that will clean it ware is it going to end up?” also sludge is much heaver than the oil it displaces in the filter so there can be quite noticeable weight difference especially in spin-on cartridge filters of the same make (used), though its less noticeable but still there in filter elements like Unimog’s use if you weigh them.

[esde]

I have to agree with Ben. Many years ago I drove a 420sl on a 9000 mile trip around the US. It had never leaked a drop, we filled it with Mobil synthetic before the trip, and left a trail of synthetic the entire 9K. I started leaking the first day of hard driving in the mountains, lucky we noticed the drops when we stopped for fuel.

[graphic66]

Had the same experience in my 230SL, leaked like crazy. For those of you with the m127, m130, m180 gassers, check for the top rubber "garden hose gasket" that goes on before your filter. Most times it is missing and your filter is being bypassed. Check out this thread from the Pagoda SL Forums Pagoda SL Forums - Oil Filter Washers and Seals This site has a wealth of crossover info on your gas Mog motors

[BADCASE]

Thanks for your responses! I will use high-grade conventional oil instead of synthetic because most of you with synthetic have had experience gasket leakage, that alone dissuades be from using synthetic. My engine is 27 years old and the truck has only 8,800 miles on it so the sludge issue is not the problem but the age of the gaskets is.

BADCASE