Need some some help/experienced opinions.....love this forum...first time posting.
Wife parked car at home, 420SEL. No problem as far as she noticed....next day car won't start....will turn over..no start. She tries starting the car in a span of 5-6 minutes...stops.
She calls me....I tell her to call a mobile mechanic...to diagnose the problem. He's fixed a vibration/tierod problem before/ done a tuneup/ looked over the car etc. about a month ago. I've been looking for another mechanic in addition to the one who's done some minor work on the benz because he is pretty busy most of the time.

He checks the engine at the house....wife calls me with diagnosis... no compression at passenger side of head....timing chain problem....most likely valve damage.He will fix t-chain,damaged valves replaced..$4,500..WOW.Has car towed to his place..calls next day..waterpump needs changing..$400 add...$4,900.
2 days later, calls again..more bad news...found a broken piece of the guide railing left side/passenger side.
Bottom line....add $2,000 more for total of $6,900..BIG WOW!!!!
Does anybody feel sorry for me yet I ask him where are you at as far as teardown....he says valve covers/manifold etc.
I also ask him how much to I owe him at this point...he says well at this time for his labor $2,000.
That is the excact amount he wanted upfront before he left the house...surprise,surprise.
I tell him tow the car back to the house.
Explaining the problem as best as I could above....can this much damage occur to the heads/valves turning the engine over for 5-6 minutes maximum to try to start??????
Remember, wife drove the car home with no problem according to her, parked it and could'nt start it next day.
Mechanic????? showed me the broken piece guide rail but come on now.
The car wasn't running/driving and all this damage????? $6,900....

Any toughts and opinions are greatly apprecciated.THANK YOU!

Well of course the rail broke! The m116 engines that have not had timing chains or guide rails ever replaced are notorious for doing this.

He's taking you for a ride. $4500 for ONE HEAD? Ridiculous. What's the extra $2000 for? BS. Rails aren't more than $50 in parts and no more extra labor if he's taking it apart to do the heads anyway. The bottom rails don't need to be touched until about 500k miles usually. The tops are the ones that get beat. Therefore, you don't need to pull the engine or take the front timing cover off or anything.

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For those prices you could get in to a very good reman long block from MB or Metric. I don't doubt the diagnosis though, yeah those things start making REAL expensive noises in a hurry. I'm not seeing the mileage on the car listed anywhere......
Gilly

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Thanks Tomguy for your response.Cars mileage....151,830

Thanks for reply Gilly. Cars mileage....151,830

WOW 150K on it, way too soon for something like this to happen ("damn straight" I can hear you say). And wife says no expensive noises? You should at least get the entertainment value of hear things crunch. BIG problem now is this guy saying $2K for removing the intake and valve covers. Don't know how to get around that, not much on that end of things. I think tomguy may be wrong, and he can correct me, but rails mean pulling the timing covers off, big work. I still think the mechanic is way high, but yeah a considerable more amount of work, but expected, usually a busted chain wipes those out pretty quick. But wife should have heard a pretty loud commotion out front. How'd the guy arrive at the fact it needs a waterpump, this damage should have no bearing on the water pump at all, just thought he'd look around for MORE work to do? Have you have to add coolant or in any other way can you verify the pump was going? It's good to want to do SOME extra work, in the case where you'd have the pump removed anyways (such as removing the timing covers) and it seems rough or noisey for example, and an honorable man would just throw it in on the deal (the labor) if it is removed/installed in the course of the work at hand (I know the pump on these V8's are pricey btw, so maybe the $400 IS just for the part). BUT the thing that bothers me about this guy is that if he just has the valve covers and intake manifold off, how does he know at this point the water pump should be replaced? Guy sounds really flaky to me.

Gilly

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Comments:

1. The water pump is easily accessible and done when the rest of the work is being done, darned considerably less than the book 6 hours.

2. The UPPER guides don't need timing cover removal. HOWEVER, if a piece or pieces fell in the engine, I'm pretty sure some serious work is required to drop the oil pan to get it, unless you are lucky and can account for everything. There have been SOME who have left them there - personnally, I wouldn't do this.

3. Even a genuine MB part is less than the price you mention for the water pump, list. Less expensive replacements (some have iffy opinions about them) are available.

4. 150K is "not too soon"; I think # of years are also involved.

5. Typically this DOES happen at startup; the consensus is that the tensioner (which you also MUST replace but not very expensive) gets old, leaks, and doesn't keep the chain tight upon startup until oil pressure returns, the chain slaps the guides, they break, and so forth. BTW check your valve cover to see if it cracked - used, not too bad but $$$ new.

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All comments well-taken. Good catch on the valve cover, yes the chain can ride up the cam sprocket and damage the valve cover from the inside-out, happens alot. I still think it can be done WAY cheaper (which Strife seems to be saying as well), engine should be abble to be salvaged without this type of expense. I maintain the prices he is quoting is enough for a GOOD reman engine. I may be out of touch on current reman prices though.
Gilly

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okay so one of the chain rails broke .chain jumped time and valves met pistons and voila! bent valves. common prob with this engine especially at this mileage.unusual though passenger side with damage.it is always the left or drivers side.because intake and both heads have to come off for repair and then aluminium block has to be helicoiled[steel head bolts in alu threads] your best way out of this is to find a salvage yard engine to replace yours.engine $ 1200 labor$ 1000 parts $700[so you can replace chain tensioner and rails before it goes in your car] call me if i can help further 214-9567007 david poole european performance dallas tx.

Re #2: He said he found the piece, and therefore wouldn't require removal of the pan to find said piece.

#5: I heard it happens on shutdown, when the engine may turn backwards due to pressure of combustion on the very end. I often notice my fan make a slight "backwards" move on my m117. When it turns backwards, the loose chain "Jumps a tooth" on the sprocket. The next time you go to start it, it doesn't fire, and the starter is what causes the valves to smack the pistons and bend them.

If he wants to charge you $6500, I am pretty sure you can get a reman 420 engine AND have it installed for that price.

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

For $6,500 you could get a re built M116.

I am surprised that it lasted 150k on the original chain. On the M116's the chains should be done every 100k to avoid this.

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I have a 420 short block that I pulled from a crunched 1991-SEL.... It also has the heads but the cam were like new and I sold them to a guy in PA... So no cams, no cam towers, no rocker arms... Still has valves and springs etc in the heads... no timing chain sprockets....
Does your state have any recourse to arbitration over your existing debt... Any one with any sense would disallow much of the 2000 labor.... Jim

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James A. Harris

86420,
Man, do I ever hope that I never actually have to feel your pain. Ouch!

I won't even begin to comment on the mechanical aspects, as both Strife, Gilly, and Tomguy know more than I dare to dream about that.

I would try to find out what that reman engine would actually cost with install, and also try to get estimates on the actual job you have at hand. It seems brutally unfair to call you two days later with a "BTW, please to fork over another two grand" request. You might even go on eBay or elsewhere and find 86 420s in good shape that are selling for that price. You can put all the 86 420s in your watch list and know what the final bid price was. Then you can use the Fn and Prnt Scrn keys (located on the bottom of the keyboard, struck at the same time), open up Microsoft Photo Editor, and paste the results to a file you save. I would be willing to bet that you can get that car - in good running condition - with that mileage or lower for under $7000 on eBay if you're patient.

Here's one for starters: http://cgi.ebay.com/ebaymotors/Mercedes-Benz-400-Series-420-SEL-Mercedes-Benz-1987-420SEL-CLEAN-VERY-NICE-Low-Reserve_W0QQcmdZViewItemQQcategoryZ6331QQihZ020QQitemZ300013662745QQrdZ1QQsspagenameZWDVW
It's an 87 420SEL w/ 164k, but it just had a lot of engine work done, including a timing chain replacement. It's got a $1500 start price w/ an unkown reserve, and no bids. Put it on your watch list and see what happens: the auction is over in less that 24 hours.

I would then go to him - w/o being a jerk - and ask him to reconsider his price considering what your research reveals. He might lower his labor charges substantially if you can demonstrate that he is unreasonably high, particlarly if you stand firm on what you believe is right and are willing to stand up for yourself in whatever forum is necessary (i.e. arbitration or court). I wouldn't be rude to him at any point, as I certainly wouldn't want a guy who'd be doing that level of work on MY car to be angry at me! But I'd sure want to stand up for myself.

The only other advice I can give you is to blame your wife for this, keep holding it over her head for years to come, and demand lotsa lovin' as compensation. After all, the person who turns on the thing when it self-destructs is clearly completely to blame for the ensuing destruction, right? (I'm Just kidding about the last paragraph; I thought I'd at least try to give you SOMETHING to smile about).

I sure hope this works out for you.

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