M112 Vacuum Oil Change

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GadgetBoy

Active Member
Joined
Aug 19, 2011
Messages
145
Location
Belfast, N. Ireland
Car
ML320 and CLK200K Cabrio
Part 1

If this has been done before I apologise for the duplication.

I bought my C240 a few weeks ago and while it has a service history and the oil was changed about 2000 miles ago it was well over a year ago. So. oil change time.

You're going to need, oil, an oil filter, an oil filter wrench and I'm using the vacuum method so we have a vacuum extractor.

oil00000.jpg
oil00000.jpg


Right. Let's get started. Park the car on a level surface and open the bonnet. (Always a good start for maintenance.)

oil01.jpg
oil01.jpg


Gently tug the corners of the engine cover upwards and it'll detach.

oil02.jpg
oil02.jpg


The bits we're interested in are shown here.

oil03.jpg
oil03.jpg


First things first. Remove and wipe the dipstick and lay it down beside the vacuum pump probe. Mark the length of the dipstick on the probe with some tape. More later.

oil00001.jpg
oil00001.jpg


Insert the probe in the dipstick hole. Make sure the tape disappears. You'll hear/feel a good "thunk" when you're at the bottom of the sump.

oil00003.jpg
oil00003.jpg


Remove the oil filler cap.

oil00004.jpg
oil00004.jpg


Pump the vacuum pump about 20 times. Oil will flow!

oil00002.jpg
oil00002.jpg


About every litre (see marks/bands on pump vessel) pump about 20 times again.

oil00005.jpg
oil00005.jpg


You can leave the pump to do its thang and get on with other stuff. Use your strap wrench to loosen the oil filter housing. Place a rag round the top and remove.

oil00006.jpg
oil00006.jpg


Place the oil filter assembly in a basin to drain.

oil00007.jpg
oil00007.jpg


Now is a good time for a cup of tea.

oil00008.jpg
oil00008.jpg
 
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Part 2

Now the M112 has 8.5 litres of oil and the vacuum vessel is 6 litres so we need to stop and empty it. Note I have just under 5 litres.

oil00009.jpg
oil00009.jpg


Lift the probe until you see the tape. This will ensure the end of the probe is out of the oil and it won't siphon all over your garage floor/drive.

oil00011.jpg
oil00011.jpg


Detach the probe from the vacuum vessel, fit the spout and pour the used oil into a suitable container.

oil00012.jpg
oil000012.jpg
oil00012.jpg


Refit the probe, place at the bottom of the sump again and pump again.

While the last bit of oil is extracting we can fit the filter. Pull the old filter off the assembly and wipe down. Remove the 4 O-rings. The picture shows where each one is.

oil00013.jpg
oil00013.jpg


Fit the new filter, apply a small amount of new oil to each O-ring and fit - largest first.

oil00014.jpg
oil00014.jpg


When the pump has evacuated all the oil you'll hear a cinema sucky straw sound and the feed pipe will clear.

We have approximately another 4 litres.

oil00015.jpg
oil00015.jpg


oil00016.jpg
oil00016.jpg


We're done with the vacuum pump now.

The easiest way to fill up again is through the oil filter housing.

oil00017.jpg
oil00017.jpg


Insert your funnel and fill away. Introduce a volume slightly less than you removed, check the dipstick and top up to the Max mark.

oil00018.jpg
oil00018.jpg


Re-fit the oil filter assembly and tighten. If you don't have the correct square-drive tool (I don't) you're more likely to over-tighten it than under-tighten it. If you're straining you're over-tightening it! If you have the correct tool torque it up properly.

Start the engine and make sure the oil pressure warning light goes out. Run the engine for a few minutes then switch off and let it sit for at least 5 minutes. Check the oil level again and top up if necessary.

Finally. Reset your service indicator.

oil00019.jpg
oil00019.jpg


A lot of people don't believe vacuum pumps get all the oil out. This is the oil I extracted.

oilzz.jpg
oilzz.jpg


We have about 4.5 litres on the left and 3.75 litres on the right. That's 8.25 litres and my oil was at the Min on the dipstick. In my book that's pretty much all the oil.

I hopes this helps others and I can thoroughly recommend the vacuum method.
 
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thx great post

just in case but people MUST use the four O rings for oil filter other wise you can damage engine with oil starvation
 
Excellent write-up, and in fact this method is quite generic and can apply to many MB engines. Well done.
 
Excellent post - I'm a fan of vacuum extractors also.:thumb: My only comment would be that by potentially introducing the new oil directly into the main oil gallery it doesn't pass thro the new filter first. This is OK provided you are SCRUPULOUSLY clean in your operations. If you fill via the filler cap to sump route the oil has to pass through the oil pump inlet strainer and the new filter cartridge before entering the main oil gallery which IMHO is the safer routine oil change practice.:dk:
 
Makes no difference. Filling by the filler goes directly to the sump as well. The strainer is so coarse it wouldn't remove much contamination anyways, it's not a strainer per se, it's there to stop you dropping things in.
 
very good saves you lying on the cold wet ground
 
Nice writeup and a good effort :thumb:

But - I have to say that I wouldn't recommend using a chain wrench on the plastic oil filter housing cap, it could easily crack or become damaged, and as you mention - you have no way tightening it correctly (just needs gently nipping up, 25Nm IIRC).

You can buy a suitable tool from various suppliers (76mm), or the proper MB workshop tool isn't even that expensive (£10-20 from memory).

Part number is 103589020900 - probably needs a 'W' in front of it.

The draining/vacuum debate is a long running one, personally I prefer to drain - I find it very quick and easy to do, the undertray only takes 2 minutes to remove, and you can leave it dripping out whilst you do other stuff. Vacuum will suck all the way to the bottom, but 1/2 hour later more oil will have dripped down from the sides to the bottom of the sump. Vac it all out from the bottom, wait 1/2 hour then take out the sump plug and see ;)

Normally gives you a quick opportunity to glance underneath and look for fluid leaks etc (oil, coolant) on the tray or on the engine itself.

Horses for courses and all that I guess :)
 
I agree totally about having the correct tool for the filter housing. Especially if you have little or no experience. A chain wrench, as opposed to a strap wrench, will slip before it does any damage.
 
Sorry to dig up an old thread. But just wanted to say thanks to you, GadgetBoy. Followed your tips with the extraction pump (I bought the same one)- very straight-forward job in the end. Thanks :)
 
Just a quick question. What spec oil 229.1 or 229.3? It must be at least the 229.3 for that engine.
 
I am a massive fan of the oil extractor pumps.. I have been using one for around 10 years on various cars i have owned..
I have a PELA 650 and I wouldnt be without it...

As an aside they are great for draining the LHM fluid from Citroens...
etc, etc..
 

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