W202 C250TD failing to start...

[crookedvulture]

Cheers Toolman, I'l order the pipes and O-Rings from MB tomorrow. As for the non return valve, is this something I can pick up from the stealership too?

 

[crookedvulture]

I have been reading that it might be the case if I keep the tank above 1/2 way, the car should start on level ground. Does anybody have any experience of this? Have got the back wheels sitting on wooden blocks just now

 

[toolman1954]

I bought a specific Merc part for the non return valve, but the diesel place I used said he kept non return valves at a much cheaper price. Until I got mine fixed I just used to park nose downwards on a hill. Fuel Shut off valve was MA000 476 37 32 @ £26-30.

 

[crookedvulture]

Amazing, thank you again! Have found a Diesel place nearby so will give them a call tomorrow and see what they say.

 

[Michael Naidoo]

Mercedes C250TD estate

My diesel C250 TD Estate, 1991 starts beautifully when COLD, but the starter fires and whistles when hot - won't start, drains the battery, will push start, or start if I wait about an hour for it to cool down - ideas? Faulty hot battery? Faulty starter armature? Injectors? - please help

 

[spoton]

odd

youve got a a strange fault there, if it was starter/battery related youd expect cold starting to be worse especially this weather however the noise you describe is difficult to diagnose without hearing it

do you mean jump start as in leads from another car, if that works youve more than likely a starter/battery/charging fault

if it was air in the fuel lines hot or cold wont affect how it starts

 

[neilrr]

What year is it?

 

[frostbite]

Glad you found the problem. I was going to suggest checking the starter motor cranking speed, even if it seems ok. I had very similar problems on a Ford diesel, went through all the usual glow-plug, injector, fuel pump and filter stuff. Then after a friend mentioned it I changed the starter - £80 and about half an hour. Perfect starting!

 

[Michael Naidoo]

No - not jump start - push start with the clutch (Kick start) down an incline (called run start in the US) - weather not a problem - it's 35C in South Africa

Could it be injectors? Will they not work well when hot?

Could it be diesel pump calibration?

 

[neilrr]

My diesel C250 TD Estate, 1991

What year is it?

Reason I ask is 'cos MB didn't make the C250 TD in 1991. It might be helpful if we knew what car & year we were discussing.

 

[spoton]

compression

No - not jump start - push start with the clutch (Kick start) down an incline (called run start in the US) - weather not a problem - it's 35C in South Africa

Could it be injectors? Will they not work well when hot?

Could it be diesel pump calibration?

traditionally a well worn engine becomes hard to start when warm due to compression loss bump starting it turns engine over faster than starter so it will start, could be your problem how many miles on the car? has it had proper engine oil services

 

[Michael Naidoo]

Sorry - the logbook (registration paper) says 1991 - I will try to unearth the service book. The car came down from Zimbabwe, so there might be some confusion - it is a W124, Mercedes 250 TD (so T = estate, and D = diesel) - no turbo

 

[Michael Naidoo]

traditionally a well worn engine becomes hard to start when warm due to compression loss bump starting it turns engine over faster than starter so it will start, could be your problem how many miles on the car? has it had proper engine oil services

Thank you

I will look at the starter first as the cheaper option - one auto-elek has suggested that the starter armature may be less efficient when hot, and this may result in a lower than required cranking speed, mileage = 330 000 km (200 000miles), but motor not smoking, and not taking oil - will a compression test help? And if compression fails, then I suppose I am in for rings, etc, what about diesel pump calibration?

thank you for the really good advice - otherwise, the car is in great shape - and I love the Dicky seats at the back, everything else works (well) - which is what you'd expect from an older Merc

regards, and thanks for all the really helpful replies

Michael

 

[grindles]

hi
i have the same model but older; it doesn't like starting in the morning and my garage man says that he reckons the compression is on its way out. he said try turning on the ignition and warming the glow plugs several times before trying to start, so i did and it made no difference. it does start but behaves like the old diesels in the 1960s (you have to wind it up for a few seconds with plenty of accelerator). if it is a compression problem, are there not likely to be other symptoms?
it has done 600K km so not a bad innings
appreciate any suggestions!

 

[a111r]

Test / check the easy things first.

Glow plugs and the relay, if runs OK after the engine's warmed up a bit.
Leak off hoses between the injectors letting in air?
Fuel filter bolt, seal or O rings doing the same?
Lift pump sucking OK?

If these areas are all OK, then get a compression or leak down test done.

If it's still on the original injectors, they won't be helping. Cheap to recondition, though.

 

[grindles]

thank you

thanks for your suggestions a111! i'll give them a try

 

[spoton]

compression

Thank you

I will look at the starter first as the cheaper option - one auto-elek has suggested that the starter armature may be less efficient when hot, and this may result in a lower than required cranking speed, mileage = 330 000 km (200 000miles), but motor not smoking, and not taking oil - will a compression test help? And if compression fails, then I suppose I am in for rings, etc, what about diesel pump calibration?

thank you for the really good advice - otherwise, the car is in great shape - and I love the Dicky seats at the back, everything else works (well) - which is what you'd expect from an older Merc

regards, and thanks for all the really helpful replies

Michael

compression test would quickly eliminate engine health as a factor, if done yourself youll just need adaptor for the glowplug holes to fit tester theyre pretty cheap to buy now, a good engine should be in the region of 400psi then allow some for age etc however if it doesnt use oil or smoke and starts well when cold youd tend to think injectors and compressions are all ok but youve got to start somewhere !!