Greetings everyone!! First time poster here. Recently bought a 1990 300E with 97,000 km and want to do an oilchange. I would like to use Synthetic. Would there be any issues that might arise as a result of the change in type of oil???

 

Yes and don't. keep it on conventional oil.Of the required weight.Yeras of varnish build up on the gaskets have coated them and changing to synthetic with it's smaller chain molecules and cleaning properties will work off the coating an potential leaks will develop.
Just change it at the factory intervals and enjoy it,you will gain nothing by putting in synthetic and will be throwing out pricey syn to often since you can not go to extended oil change intervals on that engine.
ohlord

 

I would advise completly against synthetic oil...it's junk...just dumped syntheticfrom my 300TE (put in by the previous owner)...synthetic oil is total bullcrap.....no doubt

 

I have never used synthetic in my CLK, because I know that synthetic is very aggresive on rubber seals, hoses, and gaskets; It tends to dissolve them or make them brittle. Some makes say to use synthetic and state the seals are compatable, but it just seem that way to me. My CLK has over 200k now, and has only had $600. in engine repair the entire time. I have always used 30W.

 

I think you're gonna find that synthetic oil in the mileage you stated, will do its best to seek life outside your engine. I.e., through your seals as it works now to soften them, or past your rings and out your combustion camber etc. After a total rebuild with seals compatible with synthetics and after breaking in/setting your rings, it's the ONLY way to go.

You might have really good luck with a heavier weight for now like Cliff & I use: Castrol GTX20-50W, especially of you're burning some oil.

Kevin

 

Can't agree with Cliff. Synthetics aren't *****
I do agree with Ohlord.

Synthetics are undoubtedly superior to conventional mineral oils BUT ONLY in installations that have been designed to take advantage of synthetic's superior properties which are extreme operating conditions (sustained high speed) and extended life up to 15k mile.
For these properties you pay dearly.
A sump full here in the UK is circa £100 (175USD) whether filled at an MB dealer or DIY retail.

On a personal note I cannot believe how clean my M112 engine is at 140k which has always been run on Mobil 1 Syn. The oil cap is like new, with the steel clips still bright silver rather than a horrible brown colour. Interestingly the oil is brown rather than black as observed on the dipstick.

However, my recommendation FWIW is stick with the original manufacturers oil type and viscosity. Change at the recommended intervals using an appropriate filter element.
Stuart

 

hi everyone
i have the same question as wingboy.
I bought my MB E320 1995 ( my first MB) last year and started using synthetic oil. but i don't know do i really need to use synthetic because i just heard it from my friend that it is a good oil and i can use it up to 5k miles.

 

sorry, but I stand by my position. If the owners manual does not call for synthetic oil I absolutely would not put that stuff in. Just as people put Bosch Platinum plugs in when the manual does not specify them yet Pepboys will sell them to you...bad move...

 

Cliff,
It's OK to use syn on a rebuild with new seals, as long as you use dino to set the rings first. I did some research on synthetics in the front & rear differentials on the 4matic. MB doesn't "support" the use of synthetics in their differentials, in cars of our vintage. However, if the seals hold, there's no reason not to use syn in there as long as you use the limited slip additive in the rear for the clutches. It's not logical that they would 'retro' support a non-factory product for their older cars.

But an MB engine designed to run on copper core plugs, should stay with copper core plugs. I would stay with MB hydraulic fluid for the 4matic along with MB power steering fluid for the steering pump-simply because I haven't gotten a clear picture there what brands convert. However, I'm trying Amsoil syn ATF in the tranny shortly. When you get out of the internal combustion part of an auto, there's not that much of an issue with seals and synthetics.

Kevin

 

Some good discussion here. When I bought my '98 E320 with 118K on the clock, I immediately put it in the shop for a full purging. All fluids were replaced with Amsoil Full Synthetic fluids. WhenI bought the car the dipstick handle was broken off. I got the dipstick out with a set of needle nose pliers only to see that it was 1/2 full but black as hell. The underside of my cap was black too. After the shop did the first change, I purchased a Liquivac and oil filter wrench. By doing it myself, I save money every time. I stuck with the Amsoil 5W40 at intervals of between 4K and 7K each change until about 155K. I then ran out of my stash of Amsoil and switched to Quaker State 5W-30 Syn oil. My current oil is Valvoline 5W-30 Syn. I have detected no leaks and no excessive burning at all. My filters went from black to a nice golden brown color after about the 4th oil change. I do not ever have any smoke coming out of the tailpipe.. ever.

I've been told that my '98 was actually designed to run on conventional oil but syn is 100% okay to use I wish. I have stuck with the syn since I bought the car. It runs awsome and only burns about 1/8th of a quart on the dipstick after about the 5K mark from the last change. Some folks have told me that I should stick with 5W-40 but I have seen no difference running the syn 5W-30. Whatever you decide to use, change your filter each time and don't go by the dangerous FSS system which will help you to build up sludge as fast as the previous 3 owners of my car.

These are wonderful cars that are unmatched on the highway. Best of luck to you.