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1987 560 SL; 2004 E320 4Matic Wagon
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I have read every thread I could find on this but what I am about to ask was never a topic thread only stated by some within a thread asking about head gasket replacement.

Regardless of quality of parts used and quality of work done can this be expected to need replacement every 100,000 miles on the inline 6 engine? Thanks
 

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1989 300SE 240k miles
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2,569 Posts
I have read every thread I could find on this but what I am about to ask was never a topic thread only stated by some within a thread asking about head gasket replacement.

Regardless of quality of parts used and quality of work done can this be expected to need replacement every 100,000 miles on the inline 6 engine? Thanks
Originally, it was a flaw in the gasket design. That theoretically has been taken care of.

However, the length of the engine causes strain on the outer edges of the head. Leaks at the front and rear of engine are in-line 6 issues, not Mercedes specific issues. Many cars, the people simply tighten the head bolts, drive some more, get a leak, tighten the head bolts. And never replace the head gasket. ..there are several people in the forum now trying this on their m103. And so far, it seems to be working (as the guy that messed it up and is replacing his head gasket).
 

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1999 C280 (sport), also 2001 SLK230
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486 Posts
I've been looking for a W126 for a couple of months and I have a few observations which might be helpful. First, if you have neither mechanical skill, nor bodywork nor interior repair skills, you need to seriously think about your total cost of acquisition, which will be much higher than your purchase price. And I'm not referring to normal maintenance items. You probably need to start with a very good, clean, low mileage example that's been well cared for, and you absolutely need to get a prepurchase inspection by someone experienced with older Mercedes, and preferably with W126. This probably rules out the dealer in many cases. I'd much rather have someone like Pierre Hedary look at my potential purchase than some 25 year old dealer tech who's never so much as sat inside a W126, even if he's a really good mechanic. Even then, you are very likely to find yourself replacing head gaskets, timing chains, doing a front-end rebuild (ball joints, tie rods, control arm bushings, stabilizer rod bushing, shocks, etc.) and possibly a transmission, all of which are quite expensive jobs if you're not doing the work yourself. And a good mechanic will likely refuse to do a bare-bones job of any of these items; he'll likely insist on doing all the "while-you're-in-there" stuff, so you don't come back angry in six months because of the failure of a peripheral item, like a water pump with a head gasket job.

Second, even if you are mechanically skilled, something like a front-end rebuild is probably going to cost you about $900 in parts if you buy quality, OEM parts, which is highly recommended. A head gasket replacement is likely to cost several hundred and up, and that's without a full reconditioning of the head(s). Other parts prices can be astonishingly high, like several hundred for a harmonic balancer (if you can even find one), or $400 for a warm-up regulator, though at least some of these can be rebuilt. Still, the point is that restoring and maintaining an old Mercedes is going to be expensive whether you can do it yourself or not. And some parts costs will turn out to be absurdly high. (Just be glad you aren't looking for a Porsche; their parts costs are astronomical.)

Third, while mechanical work is expensive, it's nothing compared to rust restoration, paint, and bodywork. I live in Boston, part of the rust belt, and I'd much rather pay a few hundred extra to have a car remotely inspected in California and fly out there to pick it up than deal with fixing something rusty. Several members here have commented that the Mercedes undercoating is unparalleled in hiding severe rust damage. Caveat Emptor! Even if you can do your own bodywork, it's time consuming. Oh, and interiors are also quite expensive. For example, you can buy new leather for the front and rear seats, but it's about $800 for the fronts and about the same for the rears, and that just gets you the leather, e.g., you or someone else will have to install it and deal with any broken springs, compressed stuffing/foam, etc.

So to get and drive a nicely-sorted W126 can be a very costly matter, and IMHO, it's wise to have some of these numbers in your head when considering the trade-offs.

Oh, and if you buy a car that needs some work, and you do it, don't expect to recoup your expenses either. Yeah, you might get more, but unless you can buy a car really cheap for its condition (which is difficult), you're almost certainly going to lose money over short-term ownership.

So buy a car that you will love and drive for many years, and take that mentality shopping.

I'm personally still wrestling with these tradeoffs. I'm mechanically able to fix a heap, but also blessed to have the luxury of being able to pay top dollar if I choose, though my cheap side makes that difficult, hehe. So I'm still trying to sort out exactly what I'm looking for and what I'm willing to pay. And I did see the CL ad for the ivory 300SE that you're looking at in Raleigh.

Anyway, I'd counsel patience. Eventually the right car will come up at the right price. @isthenew suggested to me that the prices of these cars, which frankly are gas guzzlers, might take a hit as rising gasoline prices begin to hit the national consciousness. It's a good point and might make waiting a virtue.

Best of luck whatever you do,

Kim G
Boston, MA
Where I look for a W126 every day, and sometimes twice.

P.S. Six cylinder models are less desirable than the V8s. Just keep that in mind, even if you prefer a six. I kind of want a six, but it took me a while to realize that everyone else wants the V8s.
 

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1991 560sec. 1991 560sel 1969 280SL
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1,646 Posts
I've been looking for a W126 for a couple of months and I have a few observations which might be helpful. First, if you have neither mechanical skill, nor bodywork nor interior repair skills, you need to seriously think about your total cost of acquisition, which will be much higher than your purchase price. And I'm not referring to normal maintenance items. You probably need to start with a very good, clean, low mileage example that's been well cared for, and you absolutely need to get a prepurchase inspection by someone experienced with older Mercedes, and preferably with W126. This probably rules out the dealer in many cases. I'd much rather have someone like Pierre Hedary look at my potential purchase than some 25 year old dealer tech who's never so much as sat inside a W126, even if he's a really good mechanic. Even then, you are very likely to find yourself replacing head gaskets, timing chains, doing a front-end rebuild (ball joints, tie rods, control arm bushings, stabilizer rod bushing, shocks, etc.) and possibly a transmission, all of which are quite expensive jobs if you're not doing the work yourself. And a good mechanic will likely refuse to do a bare-bones job of any of these items; he'll likely insist on doing all the "while-you're-in-there" stuff, so you don't come back angry in six months because of the failure of a peripheral item, like a water pump with a head gasket job.

Second, even if you are mechanically skilled, something like a front-end rebuild is probably going to cost you about $900 in parts if you buy quality, OEM parts, which is highly recommended. A head gasket replacement is likely to cost several hundred and up, and that's without a full reconditioning of the head(s). Other parts prices can be astonishingly high, like several hundred for a harmonic balancer (if you can even find one), or $400 for a warm-up regulator, though at least some of these can be rebuilt. Still, the point is that restoring and maintaining an old Mercedes is going to be expensive whether you can do it yourself or not. And some parts costs will turn out to be absurdly high. (Just be glad you aren't looking for a Porsche; their parts costs are astronomical.)

Third, while mechanical work is expensive, it's nothing compared to rust restoration, paint, and bodywork. I live in Boston, part of the rust belt, and I'd much rather pay a few hundred extra to have a car remotely inspected in California and fly out there to pick it up than deal with fixing something rusty. Several members here have commented that the Mercedes undercoating is unparalleled in hiding severe rust damage. Caveat Emptor! Even if you can do your own bodywork, it's time consuming. Oh, and interiors are also quite expensive. For example, you can buy new leather for the front and rear seats, but it's about $800 for the fronts and about the same for the rears, and that just gets you the leather, e.g., you or someone else will have to install it and deal with any broken springs, compressed stuffing/foam, etc.

So to get and drive a nicely-sorted W126 can be a very costly matter, and IMHO, it's wise to have some of these numbers in your head when considering the trade-offs.

Oh, and if you buy a car that needs some work, and you do it, don't expect to recoup your expenses either. Yeah, you might get more, but unless you can buy a car really cheap for its condition (which is difficult), you're almost certainly going to lose money over short-term ownership.

So buy a car that you will love and drive for many years, and take that mentality shopping.

I'm personally still wrestling with these tradeoffs. I'm mechanically able to fix a heap, but also blessed to have the luxury of being able to pay top dollar if I choose, though my cheap side makes that difficult, hehe. So I'm still trying to sort out exactly what I'm looking for and what I'm willing to pay. And I did see the CL ad for the ivory 300SE that you're looking at in Raleigh.

Anyway, I'd counsel patience. Eventually the right car will come up at the right price. @isthenew suggested to me that the prices of these cars, which frankly are gas guzzlers, might take a hit as rising gasoline prices begin to hit the national consciousness. It's a good point and might make waiting a virtue.

Best of luck whatever you do,

Kim G
Boston, MA
Where I look for a W126 every day, and sometimes twice.

P.S. Six cylinder models are less desirable than the V8s. Just keep that in mind, even if you prefer a six. I kind of want a six, but it took me a while to realize that everyone else wants the V8s.
 

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1985 MB 500sel (Euro)
Joined
746 Posts
Check Engine's post #24 above should be required reading for anybody considering a W126. It also should not turn you off to these cars. I got mine from the first owner at 100K miles, in great condition, have driven it another 200K miles (applied for my 300K badge last week) and have gone through almost everything Check Engine describes on the maintaining, parts and rust/paint side. Yes, it has cost a bundle especially since I am lucky enough to have a good mechanic who is (a) honest and (b) insists on doing it right. side. And, I would do it all again.
 

Outstanding Contributor
1989 560SEC, 1989 560SEL, 1995 E420
Joined
5,203 Posts
Just a small data point here, we've had our SEC 11 years on March 19th, 2021. We've put just over 100,000 miles on it. I do all the work and have pretty good parts sources. The car has cost us an average of $1382/year in maintenance and $2370/year in fuel.

Our SEL has been with us very close to seven years and has cost $750/year in maintenance and $1415/year in fuel. We've put on 41,000 miles.

Like Stewpot, I would totally do it all over again and have absolutely no intention of stopping.
 

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1985 MB 500sel (Euro)
Joined
746 Posts
And a good mechanic will likely refuse to do a bare-bones job of any of these items; he'll likely insist on doing all the "while-you're-in-there" stuff, so you don't come back angry in six months because of the failure of a peripheral item, like a water pump with a head gasket job.
Bingo. Now I know why he is "Lucky" Mike, he can do his own work. I am lucky also, but those costs do add up over the years, especially since I have a lot more labor costs and a mechanic who is of the "while-you're-in-there" school. My very rough figures come out to more than double Mike's, for the SEC at $3200 per year. But, add in the SEL and it comes to $2000 for him. I could have had a couple of new Camrys, (with no disrespect to Camrys), but I prefer my 500SEL. Especially when you consider that the monthly cost is still much less than a new car every ten years. And, when I do have to rent a car, I am so grateful to turn it back in when my car is ready. That's as close as I can get to apples to apples.

Miles driven comes out approximately the same. Lucky Mike is doing perhaps 15,000 per year with both cars. Since retirement I am doing around 10-12,000 annually, but did more when working and driving to Florida from DC to see aging parents. I stopped checking gasoline costs when I realized that for most years the 25-30 cents a gallon I paid in 1957 translated to about the same in steady 1957 dollars. Even today 25 cents is worth $2.34 and average cost in Florida today is $2.80. I do pay more for non-ethanol, but its worth it. Just ask someone who lives in the UK or the EU what they have to face. :eek:
.(Edit: Mmmm, we seem to have gotten off topic.)
 
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1989 300SE 240k miles
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Even today 25 cents is worth $2.34 and average cost in Florida today is $2.80. I do pay more for non-ethanol, but its worth it.
$2.80 a gallon! We鈥檙e paying more than that for regular grade on the real coast of Florida. I paid like $3.50 for premium this week. And that鈥檚 not ethanol-free..

I budget myself $200 per month for parts for the MB. When I have open months, I buy parts in advance for future repairs (ie the head gasket I bought 6 months ago). Or I buy 鈥渓et鈥檚 see if this works鈥 parts. Like my sunroof rails from the UK.

I figure it鈥檚 less than a car payment. And it keeps me out of trouble.
 

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05 W905 Sprinter-02:SL500 Silver Arrow-00 W220 S500-90 W126 300SEL-1986 W201s 16V NAM & EURO.
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$2.80 a gallon! We鈥檙e paying more than that for regular grade on the real coast of Florida. I paid like $3.50 for premium this week. And that鈥檚 not ethanol-free..

I budget myself $200 per month for parts for the MB. When I have open months, I buy parts in advance for future repairs (ie the head gasket I bought 6 months ago). Or I buy 鈥渓et鈥檚 see if this works鈥 parts. Like my sunroof rails from the UK.

I figure it鈥檚 less than a car payment. And it keeps me out of trouble.
So $3.50 in your FL now ? I am will be there and stay for two months with my T1N Airstream diesel so expecting fuel cost around over $4.00 per gal soon !!!
What is HELL of this Admin been doing , just a simple thing like control the fuel prices like previous Admin in the pass 4 years things were went well now is big SUCK.
 

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1998 SLK 230
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3 Posts
When looking for a 300se, if a bad head gasket is suspected, what does it run to have it done and should anything else be done at the same time. Looking at a 175k mile car, one owner, never had it done. Car seems well cared for appearance wise.Thx.
Be certain you differentiate between a valve cover gasket and a head gasket. Headgasket leaks ALWAYS manifest poor running conditions. Hardened valve cover gaskets leak oil which often drips on to the exhaust manifold. VCGs and are inexpensive simple to replace.. do it yourself. Save money... most shops do not "really" want to work on cars exceeding 10 years.. the "we get it right the second time" shops willingly do so. Spend the money on materials and tools. At the end you'll have the tools and the satisfaction of a job well done. YouTube will show you how.
 

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1999 C280 (sport), also 2001 SLK230
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486 Posts
Headgasket leaks ALWAYS manifest poor running conditions.
Overall a good comment about learning to do your own work, but there are several Mercedes inline sixes that are notorious for head gasket leaks, the M103 and M104 are two that come to mind. It's due to some combination of dissimilar metals (aluminum head & cast iron block) along with Mercedes having some trouble with the initial gasket design, though I'm not sure subsequent gaskets really fixed the problem. And it has nothing to do with maintenance or how you drive.

Cheers,

Kim G
Boston, MA
 

Registered
05 W905 Sprinter-02:SL500 Silver Arrow-00 W220 S500-90 W126 300SEL-1986 W201s 16V NAM & EURO.
Joined
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Overall a good comment about learning to do your own work, but there are several Mercedes inline sixes that are notorious for head gasket leaks, the M103 and M104 are two that come to mind. It's due to some combination of dissimilar metals (aluminum head & cast iron block) along with Mercedes having some trouble with the initial gasket design, though I'm not sure subsequent gaskets really fixed the problem. And it has nothing to do with maintenance or how you drive.

Cheers,

Kim G
Boston, MA
Again this tell it all : The German mind has a talent for making no mistakes but the very greatest
Have fun with that , I am just a lucky guy so far .
 

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1979 SLC
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41 Posts
Discussion Starter · #35 ·
So I've noticed a trend lately when I inquire about cars that are available. Some have some seemingly minor issues, reasonable mileage. They are going so quickly that I can't even imagine with that sort of response from potential buyers that the seller would even bother accomodating a PPI. Any thots?
 

Registered
1989 300SE 240k miles
Joined
2,569 Posts
Mmmmm... thots....

The used market is super-hot right now. There aren鈥檛 many new cars available, so people are buying used.
 

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1991 300SE, 2015 ML350
Joined
79 Posts
I'm the guy who got tired of replacing leaky head gaskets every 100k, and decided to try a thoughtful headbolt re-torque process.
Never saw it done on this or other forums, so I guess I kinda invented it.
It's been a couple years now, and it's working fine. Absolutely dry and spotless, the only way I'll accept it.

That being said, if you want to actually have a nice, fully functional 30-year-old Mercedes as a daily driver,
being able to fix everything yourself is an absolute requirement. Otherwise a new Maybach might be a better financial choice. Hmmm, that sounds like fun!

Cheers,
DG
 

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1999 C280 (sport), also 2001 SLK230
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486 Posts
It just depends on the seller, I suppose. As someone else who's trying to buy a Benz far from me, I've had pretty bad luck so far. One car in San Jos茅, CA turned out to need quite a bit of mechanical work, though to his credit, the seller let my friend take it to a mechanic. I've emailed several others posted on CL, cars which have not sold quickly, and the sellers haven't even emailed me back. And then there was the car north of Dallas, where the guy called me back almost immediately, seemed amenable to bringing the car to a local mechanic, but who just stopped responding to me the next day.

So this is quite a frustrating process, honestly.

So I see you're from Raleigh. I don't know how far afield you are looking, but if you can go see the car yourself quickly, you can certainly figure out quite a bit on your own, certainly the basics -- headlights, brake lights, horn, windows, sunroof, etc. Test every last thing you can test, and also watch the owner while you do this. A dishonest person will start to get nervous. Don't let on that you aren't a total expert, and see how the owner reacts.

And if you drive the car, you should certainly be able to tell if the transmission works properly, shifts smoothly, downshifts when pressed, etc., and whether there are weird noises. Also check the transmission fluid level, and the oil on the engine, power steering fluid level, and if applicable, SLS fluid level and color. And there are some engine tests you can do yourself too. Smell the exhaust. Bring a friend and then have him sit in the driver's seat while the engine is idling. Then ask him to briefly floor it. There should be no black or white smoke. While wearing a glove, plug the exhaust pipes with your hands and listen for leaks. If the exhaust system is tight, the pressure should build very quickly (<2 seconds) and the engine should begin to stall. Look into the oil filler cap and see if it's clean or a nightmare of sludge, or worse, there's evidence of water. And look inside the radiator reservoir, and see if the coolant still has the proper color (blue for Mercedes coolant; yellow for the Zerex stuff). Coolant should feel slightly slimy in your hand. If it's too dilute, it'll feel like water, which indicates lack of service. Look also at the brake fluid. If it's dark and dirty, you know the car hasn't been maintained according to Mercedes' schedule. I always look for this in photos of the engine compartment, and it's amazing how few have clean brake fluid.

When you test drive the car, find some gravelly surface and then slam the brake to see if the antilock brakes still work. Even better, if you can find a spot where one side is good pavement and the other is gravelly or dirt, this test works even better. The car should stop in a straight line and you should feel the pulsations in the pedal. Try a few avoidance maneuvers while driving. Any strange noises? Does the car respond?

If you want to go deeper, you can let the engine idle and then remove one spark plug wire at a time. Does the engine react equally to each plug? Or are there some where it doesn't make a difference? They should all react equally. (Now, be careful when you do this, and it's best to wear gloves so you don't get a shock.)

Also, ask the owner to make sure the car is dead cold when you arrive. Does it start easily? After your test drive, when the car is fully up to temperature, shut it down and try to restart. If there are starting problems, then you've found something out.

You can even jack up the car with the spare tire jack and wiggle the front wheels. Wiggle with your hands at 9:00 and 3:00, then do the same at Noon and 6:00 o'clock. This will tell you how worn the front end is. There should be no perceptible play, though maybe a millimeter or two could be acceptable. Any more and you'll likely need tie rod ends, ball joints, control arm bushings, etc. The cost of rebuilding a W126 front end runs about $900 in parts, and if you have someone else do the work, the total job probably runs close to $2,000.

And bring some clothes that will let you look under the car. You don't need to get fully under it to see if it's a mess of dirty oil leaks or mostly dry.

If you can do all these things, and the car performs, there's not much more that a mechanic will find. Of course the mechanic will be better positioned to tell you how bad is bad, but if you do the above you should find most expensive problems.

Finally, keep in mind that this car was very popular for more than 10 years. There are a ton of them out there and if you are patient, the right one will come.

I hope this helps.

Cheers,

Kim G
Boston, MA
Where I'd just like them to call me back.
 

Registered
1999 C280 (sport), also 2001 SLK230
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Mmmmm... thots....

The used market is super-hot right now. There aren鈥檛 many new cars available, so people are buying used.
And this is set to get worse. The car industry has already been reeling due to semiconductor shortages. This week there was a fire in a semiconductor factory in Japan that is dedicated to the automotive industry, and that capacity is going to take a while to replace. So there will continue to be pressure on the used car market.

That said, I think the market for 30+ year-old Mercedes is still a very niche market. I can't see someone who is told to wait 9 months for a Ford Explorer deciding to chuck it all in and buy a W126.

Cheers,

Kim G
Boston, MA
Where my neighbors with 3 small kids who already have 2 large-ish SUVs have decided they need an even larger one. I just roll my eyes.
 

Registered
1979 SLC
Joined
41 Posts
Discussion Starter · #40 ·
I feel your pain Kim! As an exercise, I've taken a few that were pretty high priced and ran an autocheck on them. The results would astound you....collisions, etc. So, some of the cars that look nice, even at some 'dealers;' have poor reports and low scores.
So, yes,one guy who put his car up a day ago I requested a few additional pics. He was supposed to send them the next morning....only to post the car was sold. I think we can blame Pierre H. for this. Lol! He's giving everyone the classic Mercedes bug!
I wonder if there's a price you can buy a neglected 126 at that's cheap enough to take a chance on. Someone suggested contacting a local shop that services these cars for any leads. Does that make sense? I also wonder if prices are higher cause of covid..people sitting around looking for something to do? It also seems that 6 months ago, there were more cars available. Thots?
 
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