I've got a chance to get a w201 2.5d for cheap.

Someone put gasoline in the tank.

What needs to be replaced or fixed?

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Ben
1987 190d 2.5Turbo

The problem with modern diesels is that the high pressure pumps depend on diesel as a lubricant - the pump on a new car would be ruined if the car had been run and petrol reached the pump.

Otherwise drain the fuel system and see how you get on.

I don't think a W201 would suffer as much as newer design.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

If it wasn't driven far then it's a matter of purging the fuel system by flushing it out (I blieve). If he drove it hard then there is going to be damage somewhere - pistons, head... NOTE: you should wait for others to answer more completely before pulling the trigger on it...

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1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

good advice. I have an itchy trigger finger.

my ATM card is already cocked and ready to fire.

this forum has saved my A$$ so many times already by keeping me from buying lemons.

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Ben
1987 190d 2.5Turbo

Safest bet is to assume the engine is toast. Then if it is not you are ahead of the game. I cannot put odds on this in any way as the extent of running on gas could be lied about.

If the person is desperate to get rid of it you might work out something where you try to establish what is wrong actually before money changes hands.

For example disconnecting before the lift pump and putting a jug of diesel fuel there. Dump out the fuel filter and refill it with clean diesel. Try cranking it up.

The issue is this should be done with the owner not present. Otherwise if it were to run okay either the price or availability of the car might change.

I would loosen all the injector lines at the injectors and crank the engine quite a bit to get the diesel into the base of the injection pump and hopefully up the injection lines dilluting the gas present. Then tighten up the lines before attempting the start as well. Remember gas is quite flameable so disable the glow circuit so the dribbling gas from the injector lines cannot ignite. It probably would not but safety first is always better. Soaking up the feed lines spillage is also helpful during the attempted purge. Depending on the strength of his battery this might take awhile. I would almost suspect some recharging or battery swapping to fit that purge in.

How about putting E99 in... I did that by mistake on my 89 F350 (Dedicated alternative fuel pump, with 4 different blends of Bio diesel and one pump for the e99... I grabbed the wrong pump)... thing ran for about 2 minutes... Drained the tank, ran a gallon of ATF mixed with diesel on the next fill up and she's fine now.

I have in my checkered 20 year career as a diesel owner made this error at the pump. Once I discovered it while still had it at the pump and it would not start. A quick tow job to the dealer later and all of the fuel was pumped out of the tank and the primary filter filled with diesel. No subsequent issues. The second time was several years later and I actually drove 2 miles home. I siphoned out the tank and filled the filter, started and I immediately filled the tank with diesel. No harm done.

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87 300D 265Kmi
Factory rebuilt crate 603.96x engine at 200K

I too have dealt with this senario and been fortunate a few times. It is just not a sure thing you will. Thats why the assumption has to be made that the engine might be toast. At the same time it could be fine.

There is not much of a way to estimate the odds as a lot of information is not known in this case.

Damage to the engine depends on the diesel to gas ratio in the tank and on the time driven with the mixture.
If he filled up an empty tank with gas then the engine will not run.
Just replace the fuel and drive away.
If he just topped of the tank then it could stay running, and under the right conditions could melt the pistons, and on a 602 maybe the head.

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76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

Ive seen this done but the car in question was a VW diesel which has a distributor pump with one plunger and 4 delivery ports unlike our pumps.

The engine stopped dead as gas is so runny it could not generate hydraulic pressure by the vane pump to actually fill the pump for the engine to run. I helped the owner drain the tank, blew out the lines, replaced filter, sucked fuel through the return banjo on the injection pump and it ran fine after that.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Gasoline resists compression ignition with it's comparatively high octane rating whereas diesel does not with an octane rating anywhere from the teens to the 30s. So your motor just shuts off once the octane of the fuel gets too high. Barring any damage due to lubrication issues, it should be fine.

A gas burner with diesel mixed in the fuel can suffer engine damage, accelerated wear and overheating due to the knock induced by the reduction in octane.

My daughter filled my two forty with gas and then drove about a hundred miles before the engine started melting down. Ruined a fresh motor.

OTOH I have put gas in my diesel cummings a few times and drove a few miles home without any appartent damage except to my pride.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

It probably depends on the gas / diesel ratio and how long it ran.

I'd say if the gas ratio was really high the chance of damage would be less, the engine would just stall right away. I think MB allows up to 20% gas for winter operation?

-Jason

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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.

My daughter did this on exactly the same engine when my 92 300D was under her care. Car simply died, had it towed, drained fuel system, changed fuel filters, absolutely no ill effects some 40,000 miles later.

I still remember her tearful voice mail when she was so upset the car died..."And Dad, this is NOT the best engine ever made!!" (thinking, at the time, that the problem was with the car).

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I put gas in a Kia diesel van about 15 years ago and it started sounding bad about 2 minutes later. I pulled over and checked the receipt and left the van there. I drained the tank that night as best I could, filled it with a another gallon of diesel and drained again. Put two gallons of diesel in and cracked all injector lines and over a three hour period tried to purge the gas that way. Slowly tightened the lines and she drove just fine for the next 6 months. Never did tell my boss, but the van ran without issues so I left sleeping dogs lie.