ML320 No Start and Oil Cap Deposits
 

A couple of times over the last three weeks or so my wife's 1998 ML320 has failed to start in the morning after sitting overnight in sub-40 degree weather. When you turn the key, all the instrument lights come on, as does the fan, but there is no start. Not even a click. Trying five or six times yields the same results. Now for the strange part. I switched on the headlights to verify that the battery is not the problem and voila! The engine cranks properly with the headlights on. In each of the cases where the engine would not start, switching on the headlights first then trying to start the vehicle cures the no start condition. Any ideas?

While changing the oil this afternoon I noticed milky-tan colored deposits on the bottom of the oil cap and on the upper part of the filler neck. I checked the drained oil and the coolant and both appear to be good with no cross-contamination. I have heard of this before on some other vehicles where moisture-laden air enters the cylinder head and condenses on the underside of the cap where it mixes with oil. From what I can remember, this happens with vehicles that are driven on short journeys where the engine does not always reach its proper operating temperature and burn off the water moisture. Anyone else have these deposits?

re: Turning on Lights before Start
 

This is an old trick to "warm" the battery up before attempting a start. The battery has some resistance so drawing current through it to the headlamps creates heat and warms it up - makes it more efficient and able to provide more current. I'd say your battery is getting ready to go. As for the deposit under the oil filler lid, sounds like some moisture got in your crankcase and has been boiled off by hot operating temperatures. Check it frequently to see it it comes back after the oil change.

I used to have the milky oil deposits mainly caused from short trips in the winter months. The deposits have seemed to gone away when I switched to Mobil 1 0W-40 weight oil during the winter. I used to run Mobil 1 15W-50 in the winter before 0W-40 was available locally.

By running the engine up to temperature for a while (30 minutes) will burn off the moisture.

Thanks okc329 and rjnonnie. The build date on the ML is 2/98 so the battery is almost five years old and probably near the end of its usable life. The weather here has just recently turned colder and no doubt the battery is struggling with the lower temperatures. I have been using Mobil 1 15W50 for the last six months since purchasing the vehicle. It may be better to switch to 0W40 for the winter months. Thanks again for the help.

Alex Lynch
1998 ML320 72,000 miles
1992 735i 249,000 miles
1986 635CSi 161,000 miles

Check the water level on the battery. Top it up, and if your problems continue, try a recharge. If that fails, buy a new battery.

A build-up of engine oil sludge on early FSS-equipped vehicles was the subject of the infamous class-action lawsuit against Mercedes-Benz, which they have now agreed to settle.

In particular, the reliance on conventional oils recommended by Mercedes and very long oil change intervals indicated by the FSS system was leading to engine damage. Mercedes quietly changed to synthetic oils as recommended lubricants and, in harsh climates, now recommends more frequent oil changes than indicated by the FSS system.

You may want to check out http://www.jacobsenlaw-pa.com for details...you won't get any info from your Mercedes dealer.:rolleyes:

The oil cap deposits are sending you a message.

Modern oils contain an additive that immulsifies any moisture into the oil preventing it from depositing this moisture throughout the crankcase. When the oil has immulsified all the moisture it can contain, extra moisture is deposited around inside the engine. What you are seeing on the cap is a small portion of the moisture being deposited all over the inside of the crankcase.

It is time to drain the oil while the engine is at full operating temperature. It also is telling you that you need to change it more frequently.

Best of luck,

Considering the cost of a new engine vs. a few quarts of oil, I would change the oil every 3,000 miles, or twice a year, whichever comes first.

You should also make a point to take the ML on an occasional long run to burn off condensation.

Since its purchase five months ago my signficant other has added 20,000 miles to the odometer. The vehicle averages about 1000 miles per week usually with one long journey of around 700 miles and ten or so short journeys of 30 miles. I have read about the problems with dinosaur oil an ML engines and have been using Mobile 1 15W50 since acquiring the vehicle. To date, I have changed the oil and filter three times with 7k miles between changes. The deposits have only occurred recently with the onset of colder weather. I did hear from one other ML owner who experienced the same problem but after switching to synthetic Mobil 1 0W40, the problem has not re-occurred. Perhaps it is advisable to use 0W40 for the winter months?

The change in recommendation to Mobil1 synthetic oil was anything but quiet. Letters were sent directly to the owners of the affected vehicles.
I believe the reason for the milky sludge on the bottom of the oil cap in cold weather is due to the fact that the cap and the neck the cap attaches to is plastic. It doesn't get as hot as the metal parts of the engine and any moisture in the engine tends to condense on these 2 parts. It isn't present in the hot months. It's almost like a first sign of winter when it appears and first sign of spring when it disappears. Fully heating the engine seems to help a little, but it seems like it's always there to a certain extent in cold weather.

Gilly

If you keep the car registered with Mercedes you should have gotten a letter extending you warrantee to 150,000 miles with the FSS system. I recieved one for my 1999 E300.
If you need a new battery call road side assistance to do it. They carry the batteries ( a diesel and a gas battery. Merceds now only has 2 kinds of batteries)and wont charge you labor for the instalation. If you bring it to the dealer they charge you labor. teh Mercedes battery is the way to go I used Sears batteries for years due to the Mercees cost. They finally got smart and lowered the price. The deisel battery is about $120. The Sears was $119.
Dave

Well Gilly, I should have said they were very quiet about the FSS problems in Canada. No letters, no warranty extensions, no oil change coupons. My dealer knows about it and they DID change their service recommendations but even MB Canada won't admit the problem.

I never thought I'd be envious of the legal sharks you have on your side of the 49th :(

My 98 E320 battery lasted under 5 years, it also gave out when the weather started to turn cold. The car spent it's first two years in San Diago. I believe that the warm climate shortens the life of a battery.

A new battery and a fresh oil/filter change to 0W40 and you should be ready for the winter months.

BTW Mobil 1 0W40 is rated for year round use - not just winter months.

Since you purchased your ML320 six months ago, check the maintenance log to verify that the coolant has been changed every 3 years and the brake fluid every 2 years (from the date of manufacture).

Hi Alex,
I have nothing to offer, except...sell it and buy a '94-5 E320 wagon! Then you can help me fix my leaky engine.
Cheers,
Tom