This is not mercedes related, but it is close enough people here may have some input.

The vehicle is a vw golf with an AAZ swapped in, with rather questionable wiring, quite a bit of rust, unknown mileage, etc, that my sister (who has pretty much no car knowledge) purchased at the advice of some friends for quite a bit of money. It has never started easily, and the glow plugs dont appear to work. She has driven it for about a year like this, and she starts it by cranking until it starts to fire, then holding it at high RPM until it will stay running at idle, then drive away. Lately it has gotten harder to start, and since it doesn't have a functional parking brake she also noticed that it rolls much more easily in gear than it did before. It is currently her only car which she uses to get to work, but the same people who advised her to purchase it want to sell the AAZ and put a TDI in it soon and don't think fixing the glow plugs is worth the trouble, so they told her to just use starting fluid to start it. I have my own opinions on the whole thing, but I haven't had anything to do with it at all.

Who are "these people"? They sound like idiots. Putting new glow plugs in is cheap (if that is the only problem). Starting with no glow plugs long term will kill the starter and battery.

Edit: Starting fluid should never be used in an idi diesel engine!

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Sweet Jesus!!! For the love of GOD DO NOT USE STARTING FLUID!

Test the glow plugs and/or replace them if they are bad, much easier on you (and the engine)! IF you run into or still have problems, let us know and as a collective group we will be able to help.

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

If they have been routinely running it at full rpms right when started, I suspect the engine is toast at this point. Rings are probably shot and compression is probably right on the edge of where it will still run. Engine needs rebuild or replacement most likely.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

No idea if the only problem is bad glow plugs, it was like that when she got it, and now it seems to have been losing compression (harder to get started, rolls in gear on a slope easier, more blowby, etc). I just ordered some glow plugs, so we will see. I don't normally ever work on it or I would have tried to fix it before, it will be interesting to see what happens.

Yes, thats what I think probably happened. She has been doing that for quite a while and doesn't know enough about how engines work to know what will happen. Not much I can do about it though, she doesn't really listen to me, and the person who has done most of the work on it for her is the one who suggested starting fluid rather than new glow plugs...

When people act like that I usually just let them go do what they wanna do. Let her use starting fluid, then the engine will be dead and out of its misery.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

The bad thing is, if it dies completely then it turns into my problem, so thats not so good either. I will change the glow plugs and see what happens, but I have a feeling the engine is probably just about dead. I guess a compression test would be the next step after that. Swaping in a different engine wont be too cheap, since the engine thats in it is a Canadian one, and a newer diesel needs a different transmission, and its awd...

Canada isn't that far away-we have procured tractor engines from across the border relatively easily. It can take a little time to go through customs, but isn't a big deal. Probably easiest to send it with a freight company that goes back & forth frequently as they will know the proper procedure for bringing an oily engine over.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

if starting fluid is used, don't bother to do a compression test. the motor is shot.

when the starting fluid hits the glow plug, it will fire regardless of where the piston is. if the piston is going upwards and it forced downwards by the ether combustion....x 4 that. imagine the damage.

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Ben
1987 190d 2.5Turbo

Rusty Mk3 + bad engine = trash.

Pull any good bits off, and send the rest to the scrap yard.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Your Sister won`t listen to you.

She has some Idiot people work on it and giving bad advice.

You mention you don`t work on it, but if it dies, then it is your problem. Why?

How old is your Sister? Teenager? or just a typical Sis/Bro relationship, that sometimes isn`t all that good. Are you the younger or older brother?

Starting Fluid is a very bad idea, broken Pistons, Ring land and Rings. seen it. Have a Piston to prove it.

Throw in some GP`s and see if it helps this tired old abused engine.

Do these VW`s Diesels need a Valve adjustment? could the Timing be off for the hard start?

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Do a compression test while the glow plugs are out. Won't take much time and it will tell you whether any future work on the engine is worth the effort.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

There is no valve adjustment, the AAZ (and all vw diesels after 1986) use hydraulic lifters.

Remember that the AAZ motors have problems with the crank pulley too. The bolt loosens up, and it lets the pulley wobble which damages the crankshaft. Once the end of the crank is damaged the whole thing has to be replaced.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Since you already purchased some glow plugs they are worth a try. If none have been working maybe the engine still has reasonable compression. Otherwise I seriously doubt it would even start with no glow plugs.

Test each old glow plug to see what shape they are in. Sounds like the person your sister is following for information is either really stupid or some form of crook.

Any of us that have owned these older volkswagon engines fully realize that you do not operate them on a daily basis without working glow plugs. If these are the same people that overcharged her for the car initially she needs a wake up call.