W126 V8 vrs. Straight Six
 

I'm getting ready to replace my current 1983 380 SEL with a later, better maintained car. I love the W126's, so I'm looking at two very nice 1989 models.

I love my 380, but it was a foolish purchase, in that it was cheap. You know the rest. I keep pouring money in, but I still have long way to go to get it up to the level of either of the two cars I'm looking at. It finally dawned on me that it would cost me less to sell the 380 at a big loss and buy a better car, than to finish bringing the 380 up to snuff.

One is a 420 SEL, and the other a 300 SEL. Both have full records, excellent paint, beautiful interiors, fully functional accessories and about the same miles (185,000). They are also priced almost the same.
I drove them and they both drove very nice, with the 300 SEL being slightly slower. However, my real question is the expected longevity of the six vs. the V8, and the comparative maintenance costs of keeping one or the other in top shape.

Any advise on the comparative virtues of the two engines would be highly appreciated.

Both are at the point where a top end engine refresh is on the horizon, if not already done.

It's $$$ for the M103, $$$$$ for the M116.

Jim

Top engine refresh is a good point. As I said both cars have full records, but I didn't look close enough to see if one or both had the work done.

I'm not sure I'd choose one or the other based solely on that that one item, but it would definately be important. I'm a pretty handy DIYer. Is one engine type easier to DIY than the other?

I passed on a couple of M103s due to reading about premature headgasket failure and that is something that kept me hesitant especially for a clean one. Make sure that that has been done if you are going to pay a pretty penny for a 300SE/SEL. I was happily persuaded to purchase my last W126 to date being an M117 560SEC and I haven't looked back. My US 380SE was a foolish purchase but I got her from a Benz tech who did the majority of the service himself. Body will need attention but for what I am going to do with her, She's not going to be as some of the prime examples here moreso personal pride.... Then again I'm a big fan of the Ratrod scene....

If the M103 has the mileage you indicate, then almost certain it has had a head gasket replaced. They usually went around 50K-60K miles from new.

M103 won't give you V8 performance, but your maintenance/repair cost would be lower with the M103.

M103 a great strong engine for a DIYer !!!

Is it really fair to call headgasket failure on a 20 year old car with 150k to 200k miles "premature" head gasket failure? 103 head gasket issues are less common than 104 and less expensive to repair. Timing chain issues alone point to going with the 103 motor, unless you feel it underpowered.

Do 89 models have the updated interior?

-J

They do - first year. It's a good year, new interior, still no air pump.

The V-8 still has the potential to require helicoiling of the aluminum block if the heads are removed. Not a problem with the iron block M103/104.

This adds considerably to the cost.

I like both engines, the M103 is a sweetie if you just want a cruiser.
The M116 and M117 V-8s are much nicer when you want some power....

I've owned lots of examples of M103/M104 and the M116/M117, and if I couldn't talk myself into the eight, then I'd want a diesel in my W126.... :)

BTW, if you are considering a 420, do yourself a favor and look at 560SELs. They have more equipment, more power, and tended to be taken care of better by at least their 1st and maybe 2nd owners....

The 89 and up cars are the best of the breed, as well.

Jim

When did they get the air pump?

My 90 560SEL has one... and I think my 86 560SEL parts car does too.

Perhaps this only applies to the six cylinder? My 89 300TE didn't have one.
I know our 95 does, just had to replace it.:(

Jim

Sixes got the air pump in 1990 model year, on both the E and S. S class got the new interior in 1989, E class in 1990.

<quote>
BTW, if you are considering a 420, do yourself a favor and look at 560SELs. They have more equipment, more power, and tended to be taken care of better by at least their 1st and maybe 2nd owners....
</quote>

I've been looking for the right W126 since last fall. I can find tons of them, but finding really nice ones in northern Illinois isn't so easy. Of the dozen or so I've looked at these are the only two that were nice enough. Unfortunately all the 560's, SD's & SDL's I've seen have been dogs. WOOF!

Right now I'm leaning toward the 300 SEL. I like the color better, and the tires are brand new Michelins. I plan to give them both a really good test drive tomorrow to see if one really is better. I'll also give the records a good going over.

I really appreciate the advise. It's a big help. I don't want to make another "Cheap" Mercedes mistake.

boy, I looked at an 83 380 SEL and didn't buy it for I forget why and then read later that MB went to a single roller timing chain from a dual roller chain that tended to stretch and then jump sprockets causing major engine damage. Is that the same engine? this was a hardtop 2-door that looked like the convertable but was longer in wheelbase, actually a very cool looking car.

oh yeah, just remembered, I bought an 83 633CSi instead...that was it.....