we've owned an E320 for nearly 4 years now--64K mileage--and it has been mostly a good experience.

Our biggest problem has been the A/C kept loosing refrigerant and it took 4 trips to fix it. Other problems have been oil level sender, fuel tank sending unit and fuel pump.
All in all, we've had more problems than we expected but the car has been a joy to drive --until last week.

My wife mentioned that the high oil level light had come on again ( the sensor had failed in 02) and I checked it. The dipstick was just over full, while the electronic method said everything was fine.Keep in mind we had not changed oil in 9000 miles and were coming up on B service in less than 1000 miles.

I told her to keep on eye on it and i made an appointment for the service. The next day while going down our street, the car's check engine light came on and the car promptly lost power--barely getting it back in the driveway.

We had it towed to the dealer and after 2 days they pronounced it fixed--a vicitim of using 93 octane gas in cold weather!--and the wife went to pick it up. Well, the tow driver apparently put a nice scrape in the rear quarter backing it in and when the serv. mgr. started it up to take to the body shop, the check engine light came on--so much for the fix.

Two days later it is now truly fixed--both catalitic converters were replaced under warranty and now everything is fine--they say.
When pressed for an explanation, the Serv. Mgr. says that in temps below 40F, 93 octane fuel does not vaporize properly because of the octane enhancing agents, effectively allowing fuel to pass unburned through to the crankcase and emission system.
Going forward, the Serv. mgr. recommended using 87 octane in temps under 40F. As far as i know, there are no TB out on this.

This comes as news to me--I've never heard of high octane gas being unburned at lower temps. we drive mostly on interstates and haven't noticed much of a decline in MPG. Likewise, the oil quality had not fgotten the point where the sensor indicated a change was needed NOW. I would this to be a common problem in my part of the country if his explanation is true (midwest)

I'd appreciate any info on similar experiences or ideas of what is really going on--thanks in advance.

I have never heard of anything like this before or heard of anyone using 87 Octane because of the low temps.

The service manager is recommmending something contrary to what the book says to do. Sounds fishy to me.

__________________
Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

There was a bulletin back in 1992 on the "Reid pressure value" of preminum fuel causing cold weather starting problems ONLY. YOU never should use 87 octane fuel in that engine. USE at least 90-91 octane fuel.

Sounds like an EXCUSE for the "real" problem!! What ever that was!?

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