I did this change as part of an investigation into contaminated oil and smeg on the back of the oil filler cap.
At the time it didn't look like a head gasket failure as there was no steam from exhaust, the plugs were all the same colour. The systems were pressure tested and it didn't appear to be the issue. Later though after giving the engine the beans and getting it good and hot (and changing said cooler). It was clear the head was the issue.
See also:
http://www.slkworld.com/slk-r171-class-diy/109674-oil-filter-housing-replacement.html
for some pictures though it's not the vehicle I did it on it does show the unit, though there is some confusion as two guys talk about different jobs.
It's a bit of a job to do on the SLK 200 as you have to go in from above and below, well at least I did.
Above:
You need to take the air filter unit (two Torx bolts at the back) off after removing the feed pipe from the front of the engine. To get at the filter unit bolts you need to remove the air mass sensor (three Torx screws, one underneath is difficult to find/access). I think the air mass sensor is also connected by a 2" rubber pipe held on by a hose clip. Once the airfilter bolts are out it comes off by drawing it to the rear of the vehicle, it's on some rubber mounts at the front. At this point to can see the oil filter unit but I couldn't get at all the bolts so I went in underneath as well.
Underneath (disconnect the battery) :
Remove the under tray, then the starter motor (disconnect the battery). The starter is on two very long Torx bolts and you'll need a sexy ratchet for the top one.
The thick starter cable is a bit of a pain, you can undo it while it's in situ but likely it won't come off until you can move the starter.
I left the thinner cable connected and tucked the starter out the way up front.
Next you need to loose the oil breather box that is on the side of the engine (two torx bolts in different places), once you can move the box it just goes over to the side a bit off the large spigot.
Now you can access the housing and it's 4 bolts. I drained the coolant and the oil, best to take the filter out so the housing drains completely. Still dropped some stuff so stick rags in the hole where the starter was.
Once it's off the cooler is held on the filter unit with 4 bolts. The seals I got for MB dealer were £13. They are arranged so that any leak is to the outside world and not between the ports so don't hope like I did that that might be the issue.
There's a 1" coolant hose hose on the unit and it's best to leave that on and disconnect the other end from the back of the engine. It's more accessible.
For the hose clips be best to get the fancy plier bowden cable gadget.
'VS1663 Remote Action Hose Clip Tool' by Sealey
As regular pliers just won't get in. It was £13.
The cooler is a robust alloy unit and although MB UK have sold 40 in the last year I suspect it is to prove it's not the cooler on the way to the head gasket change rather than the cooler itself. I got the cooler from Amazon for £62 delivered.
Hella 8MO 376 756-731 Oil Cooler
I found a handy site that gave equivalent numbers of lots of parts here:
Car Part HELLA 8MO 376 756-731 (8MO376756731), Oil Cooler, engine oil
Replacement is the reverse though after fitting back the oil breather box (or whatever it is) you need to connect the thick wire on the starter before you bolt it up. The cable is run from behind and you need to manoeuvre it into place. You can tighten it after the starter is bolted up but if you bolt it in place the cable won't reach to go on after.
I seem to recall the rest was straight forward.
If anyone in UK want the cooler (65k miles) and a good set of seals any time give me a shout.
Apologies if I've missed anything or got it the wrong way round but is was a few weeks ago now.
Regards, Chris
P.S. just been talking to a repair guy about the head gasket and the reason they go is they corrode....what a crock. MB engines and head gaskets corroding, German engineering at it's best, not impressed...
At the time it didn't look like a head gasket failure as there was no steam from exhaust, the plugs were all the same colour. The systems were pressure tested and it didn't appear to be the issue. Later though after giving the engine the beans and getting it good and hot (and changing said cooler). It was clear the head was the issue.
See also:
http://www.slkworld.com/slk-r171-class-diy/109674-oil-filter-housing-replacement.html
for some pictures though it's not the vehicle I did it on it does show the unit, though there is some confusion as two guys talk about different jobs.
It's a bit of a job to do on the SLK 200 as you have to go in from above and below, well at least I did.
Above:
You need to take the air filter unit (two Torx bolts at the back) off after removing the feed pipe from the front of the engine. To get at the filter unit bolts you need to remove the air mass sensor (three Torx screws, one underneath is difficult to find/access). I think the air mass sensor is also connected by a 2" rubber pipe held on by a hose clip. Once the airfilter bolts are out it comes off by drawing it to the rear of the vehicle, it's on some rubber mounts at the front. At this point to can see the oil filter unit but I couldn't get at all the bolts so I went in underneath as well.
Underneath (disconnect the battery) :
Remove the under tray, then the starter motor (disconnect the battery). The starter is on two very long Torx bolts and you'll need a sexy ratchet for the top one.
The thick starter cable is a bit of a pain, you can undo it while it's in situ but likely it won't come off until you can move the starter.
I left the thinner cable connected and tucked the starter out the way up front.
Next you need to loose the oil breather box that is on the side of the engine (two torx bolts in different places), once you can move the box it just goes over to the side a bit off the large spigot.
Now you can access the housing and it's 4 bolts. I drained the coolant and the oil, best to take the filter out so the housing drains completely. Still dropped some stuff so stick rags in the hole where the starter was.
Once it's off the cooler is held on the filter unit with 4 bolts. The seals I got for MB dealer were £13. They are arranged so that any leak is to the outside world and not between the ports so don't hope like I did that that might be the issue.
There's a 1" coolant hose hose on the unit and it's best to leave that on and disconnect the other end from the back of the engine. It's more accessible.
For the hose clips be best to get the fancy plier bowden cable gadget.
'VS1663 Remote Action Hose Clip Tool' by Sealey
As regular pliers just won't get in. It was £13.
The cooler is a robust alloy unit and although MB UK have sold 40 in the last year I suspect it is to prove it's not the cooler on the way to the head gasket change rather than the cooler itself. I got the cooler from Amazon for £62 delivered.
Hella 8MO 376 756-731 Oil Cooler
I found a handy site that gave equivalent numbers of lots of parts here:
Car Part HELLA 8MO 376 756-731 (8MO376756731), Oil Cooler, engine oil
Replacement is the reverse though after fitting back the oil breather box (or whatever it is) you need to connect the thick wire on the starter before you bolt it up. The cable is run from behind and you need to manoeuvre it into place. You can tighten it after the starter is bolted up but if you bolt it in place the cable won't reach to go on after.
I seem to recall the rest was straight forward.
If anyone in UK want the cooler (65k miles) and a good set of seals any time give me a shout.
Apologies if I've missed anything or got it the wrong way round but is was a few weeks ago now.
Regards, Chris
P.S. just been talking to a repair guy about the head gasket and the reason they go is they corrode....what a crock. MB engines and head gaskets corroding, German engineering at it's best, not impressed...
