Hi everybody,

I am thinking of assembling a box of “cheap” spare parts in the car, that will help me to get going again in a case of a breakdown. This would be for a W126, a 1987 420 SEL.
Although the car is well maintained, I just learned that the fuel pump relay is from 1989 and other non-maintenance parts are probably just as old.

So what do you think can fail and leave me stranded, that is not too expensive to keep in the car? I have

1. spare fuses in the fuse box.
2. a wire to jump the fuel pump relay
3. a wire to jump the temp. sensor so the fan will run on high
4. headlight bulbs kept when replaced with Sylvania Silverstar

OVP, fuel pump relay, belts?

Your suggestions are appreciated.

Reinhard Kreutzer

Voltage regulator that fits in the alternator.

Metal sleeve for the upper radiator neck.

Sixto
91 300SE
87 300SDL
83 300SD

Thanks sixto,

can you actually replace the voltage regulator with board tools stranded on the side of the road? And what would be the symptoms that this piece is the one thats causing the trouble? Dead battery? Rough running?

Thanks for your help

Reinhard Kreutzer

Philips screwdriver and some way to get to the back of the alternator. I don't think you can get to it from above in a 420SEL.

In my case the dash lights lit up at random then stayed on then the car died and wouldn't start.

The only time in the 20K miles I've had the SE that it left me stranded.

Sixto
91 300SE
87 300SDL
83 300SD

Thanks again Sixto,

I'll take a look at the alternator the next time I am under the car/open the hood. A look at the piece on FastLane shows that it is a $44.25 piece and that would certainly fit what I try to do. Would an AAA road service mechanic be able to install it if you had the piece or would they call the tow truck? How did you get out of the bind, towing?

Reinhard Kreutzer

I don't know if the AAA will install it. I doubt anyone unfamiliar would want to mess with it and risk being blamed for something else going wrong.

My tow guy tried to jump it to no avail. It wouldn't stay running. I had it towed home. It wasn't the battery because I still have the same battery more than a year later.

If I had known what was wrong and had the part with me, I would have jacked the front right corner, set the wheel on the spare and had at it.

This is pretty pointless preparation if you preemt failure by replacing a $30 part every five years

Sixto
91 300SE
87 300SDL
83 300SD

Thanks Sixto,

preemptive maintenance for this item came to my mind too...

Regards

Reinhard Kreutzer

If you're paranoid about these things you could keep a DC voltmeter plugged into the cigarette lighter. (Saw one at Wal-Mart for around $12.)
It would give you a little warning if your voltage dropped drastically.
The two times my voltage regulators failed I either wasn't looking at the meter because it was night time (SD on a long trip) or I didn't have one plugged into my wagon.
The ABS light comes on when you get below 10 volts, but by then it's almost too late...

__________________
Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic