Synthetic oil in an old old 190E ????
 

My 1988 190E (2.6L 5 Sp) has over 240,000 miles on it. It is time to change the oil. I bought the car a few months ago and as far as I know, there has always been "real" motor oil put into it (previous owner swears by Valvoline Turbo). My question is: dare I put in something like Mobil 1? Or will that synthetic oil seep past seals or be of little advantage on a motor with this many miles on it? Your comments, please. Thank you.

Synthetic oil is a bit more expensive to purchase, but it does have the advantage of longer protective life (i.e. more miles between oil changes, 15,000 vs. 5000).

The molecules are a bit smaller, therefore it does have the characteristic of being able to seep past aging seals and gaskets that would not normally have leaked with dino oil.

My point is this...if you change your oil at regular intervals (5000 miles or less), then stick with dino oil. Otherwise, there is no harm in using synthetic on an older motor. The potential for new leaks cropping up varies from one vehicle to the next.

Newer dino formulations have been upgraded over the years, and are safe to use at up to 7500 miles in many cases.

I use dino on all of my cars except the ML. It has the FSS intervals set at around 15K, so I started the maintenance program with synthetic oil right from the start.

Oil Leaks with synthetic oils?
 

Older engines which didn't receive close attention to oil change intervals often have a varnishing/crud material on the interior of the gaskets and seals of engines, transmissions and etc. If one then changes to synthetics, the detergent action will clean the varnishing/crud off the seals and two situations can occur; 1. after minor leaking, the swelling additive in the synthetic will reseal a good gasket and you're good. 2. After leaking, the synthetic oil will continue to leak thru damaged seals and gaskets and you have a problem. It's your call on this! Roger (edited 11282001)

Semi synthetic was MB recomended from new in my '87 190E 2.0, and I still use it after 200k miles. Changed every 6k.

I am finally a convert in the E320
 

Went to Mobil 1 this past oil change on my E320 at 111,xxx miles. I do not expect any leaks.

My expectations were set to high - I only drove it for a short distance after the oil change and looked underneath when I got home this evening and noticed a little on the garage floor. Put it on the stands and I tightened the drain plug slightly. Based on what I could tell while under there this looked like the culprit. I will keep ya'll posted.

I would go for a semi-syn oil.

I had tried synt on my 136,000 mi '92 190E 2.6 and found it too be too thin and the oil found its way out of every little gasket leak it could find...stick to dino for these high mileage cars in my opinion. I have Mobil 15w50 in my 500E for about 2000 miles and will be switching back to dino or semi-synt after the 3000 miles are up...I have not seen or noticed any improvement with the synt other than my wallet being lighter after buying the stuff....it does work great on my SCCA racer though which revs at high rpms all day long.

If this car is your daily driver and is not garaged, I would go synthetic for its better flow properties at low temperatures. I have noticed that Mobil 1 has a strong detergent capability, a trait possibly shared with other synthetics. If the P.O. has been less than enthusiastic about the frequency of oil changes, you may want to do a filter (not necessarily an oil) change in about 1,500-2,000 miles after your oil change to get rid of the heavier crud.

You can peak into the oil fill hole with a flashlight and see if there's any obvious sludge. My guess is that it will be clean. The P.O. probably used good oil at first anyway, and I don't even know if they sell anything these days that will sludge up a modern engine.

Around 1990 I had an '80 Ford truck with a 302. The thing had so much sludge built up that the rocker arms had carved out an area where they travel and the rest of the valve cover was packed solid!!!

Paul C's suggestion to change the filter in the middle of the first round is a good one.

Everything is cool now - I snugged the drain plug down a little and there are no leaks and actually the car seems to run just a tad bit cooler.

My experience with Mobil 1 15W50 in high milage MBs is very good -- niether the 300SDL my brother has nor the 87 300D used any before the switch, and niether does now. I've not yet managed to get the oil changed on the 300TE, but expect it to use about the same amount after as it does now -- about a quart in 1000 miles (mostly front cover leak, I think).

Some folks have reported various amounts of new leakage after the changeover, though.

Both cars run a little smoother and start nicely on the synthetic, so I will stay with it.

Peter

Update
 

This past weekend I said what the hey and changed the oil in the CRV over to Mobil 1 5-30W. Neither vehicle is leaking and the best thing I have noticed is that since going with Mobil 1 15-40 in the E320 it NEVER gets to 100dC no matter how bad the traffic.