Major servicing (OM636) - what to check, what to replace?

[GTom]

I am thinking on doing a major service on my Mercedes OM636 before the season as it hasn't been serviced for a longer time.

The engine works and sounds fine otherwise, just want to make sure that there is no hidden problem leaving me engineless in the worst possible moment. Any suggestions, what needs to be addressed beyond the usual oil & filter replacement?

Thinking about a compression test and injector cleaning. The injector pump itself is also very rusty from the outside, I am worried about its integrity - maybe time to get a replacement :ambivalence:?

 

[VicS]

Some manuals etc here which might be useful.

http://www.motoren.cloudns.cx/menus/mercedes.php

Don't fix what's not broken though.

 

[Sea-Fever]

I am thinking on doing a major service on my Mercedes OM636 before the season as it hasn't been serviced for a longer time.

The engine works and sounds fine otherwise, just want to make sure that there is no hidden problem leaving me engineless in the worst possible moment. Any suggestions, what needs to be addressed beyond the usual oil & filter replacement?

Thinking about a compression test and injector cleaning. The injector pump itself is also very rusty from the outside, I am worried about its integrity - maybe time to get a replacement :ambivalence:?

Water pump bearings on mine were knackered...a new pump is not mega pricey and good to keep as a spare - if the pump bearings fail the pulley does not run true causing early failure of the alternator belt and then you'll have no charge and no freshwater cooling at all....not w good scenario. I caught mine in time but the belt was already very worn.

 

[Sea-Fever]

I also took the opportunity to fit an off engine spin on fuel filter (Mann) from westfield 4x4 and was considering an off-engine oil filter as well but haven't got to that yet.

You will know already, I'm sure, to regularly replace the impeller and keep a spare, together with checking your raw water intake strainer.

 

[GTom]

Perfect, many thanks for both of you! A little shopping then @Westfield's and I have something to start with.

 

[PaulRainbow]

Thinking about a compression test and injector cleaning. The injector pump itself is also very rusty from the outside, I am worried about its integrity - maybe time to get a replacement :ambivalence:?

None of these are service items. If you have problems that need fixing, these might be areas to look, but as it runs OK, don't waste your time and money. If the pump looks scruffy, clean it and paint it with some Hammerite, rusty exterior doesn't necessarily point to internal problems.

 

[catmandoo]

contact Manfred Prinz at sales@west-4x4.demon.co.uk. H e marinises thes engines from refrigeration trucs etc and also keeps a set of spares

As a start however you could check your oil pressure and normal working temperature . . I bought a reconditioned one in about 2008 and its still operating a t 8 bar and 80 deg C. .
Check your fresh water cooling fluid a, drain and flush system and replace . At the sam e time you could look at the contdition of the circulating pump and decde if you need a new one (rusty). Theres a little vent a the top of the pump housing which needs to be clear . could be blocked with debris . . Injector pump spares are getting short . there are two makes the Bosch or the TDZ . TDZ is very rare so if you have one and its knackered a small conversion is necessary to fit the Bosch . on the other hand you may have to find a specialist to refurbish the Pump .. By the way do you regularly check the oil leven on the injetor pump cam shaft , also have a look at the lift pump on the side of the block . it works with a small spring compressed by a cam . Several million compressions may cause fatigue or failure . Try to get a spare pump or even a couple of spare springs . if you have the standard internal oil filter , cleaning it is messsy then Manfred sells a conversion kit for a spin on complete with hoses . . Check the torque on the head gasket bolts manual has the settings
But first of all contact Manfred he has a check list and can supply most spares

 

[simonfraser]

fit a camera in the engine bay then you can see what needs to be replaced / fixed b4 it sprays your engine with salt water / oil.

 

[GTom]

contact Manfred Prinz at sales@west-4x4.demon.co.uk. H e marinises thes engines from refrigeration trucs etc and also keeps a set of spares

As a start however you could check your oil pressure and normal working temperature . . I bought a reconditioned one in about 2008 and its still operating a t 8 bar and 80 deg C. .
Check your fresh water cooling fluid a, drain and flush system and replace . At the sam e time you could look at the contdition of the circulating pump and decde if you need a new one (rusty). Theres a little vent a the top of the pump housing which needs to be clear . could be blocked with debris . . Injector pump spares are getting short . there are two makes the Bosch or the TDZ . TDZ is very rare so if you have one and its knackered a small conversion is necessary to fit the Bosch . on the other hand you may have to find a specialist to refurbish the Pump .. By the way do you regularly check the oil leven on the injetor pump cam shaft , also have a look at the lift pump on the side of the block . it works with a small spring compressed by a cam . Several million compressions may cause fatigue or failure . Try to get a spare pump or even a couple of spare springs . if you have the standard internal oil filter , cleaning it is messsy then Manfred sells a conversion kit for a spin on complete with hoses . . Check the torque on the head gasket bolts manual has the settings
But first of all contact Manfred he has a check list and can supply most spares

I have a TDZ unit, maybe I'll grab a good second hand unit if I see one for backup...
Speaking of injectors, wasn't aware of their need for lubricant.

 

[GTom]

Regarding lubricating the TDZ injector: am I right, that this one, circled red should be the dipstick?

(not my injector unfortunately, mine is covered by rust - hope I won't break anything by getting the dipstick out...)

 

[Trevor D]

Regarding lubricating the TDZ injector: am I right, that this one, circled red should be the dipstick?
View attachment 77671
(not my injector unfortunately, mine is covered by rust - hope I won't break anything by getting the dipstick out...)

I'm a little late to the party here, but does anyone know if you add the oil through the dipstick hole, and how much?

 

[Bilgediver]

I am thinking on doing a major service on my Mercedes OM636 before the season as it hasn't been serviced for a longer time.

The engine works and sounds fine otherwise, just want to make sure that there is no hidden problem leaving me engineless in the worst possible moment. Any suggestions, what needs to be addressed beyond the usual oil & filter replacement?

Thinking about a compression test and injector cleaning. The injector pump itself is also very rusty from the outside, I am worried about its integrity - maybe time to get a replacement :ambivalence:?

Bear in mind that as others have said a compression test is not a service item but something that does show up impending problems however the compression pressure in a diesel engine is a lot higher than a petrol engine so you need more substantial equipment than you see in Halfords along with an adapter to fit your engine injector or glow plug pocket.

 

[PaulRainbow]

I'm a little late to the party here, but does anyone know if you add the oil through the dipstick hole, and how much?

You fill it from the filler cap, big red thing on top of the pump, until it's at the correct level on the dipstick.

 

[PaulRainbow]

Some manuals etc here which might be useful.

http://www.motoren.cloudns.cx/menus/mercedes.php

Don't fix what's not broken though.

I know the thread is a couple of years, but the point of a service is to fix things before they go wrong.

 

[Trevor D]

You fill it from the filler cap, big red thing on top of the pump, until it's at the correct level on the dipstick.

Awesome, thanks! Any idea what the general consumption is like, and how often to check it? Mine is a bit of a pain to get at....