changing plugs on a 1995 320e wagon
grober
MB Master
This will give you idea-its about renewing the engine wiring harness but gives an idea what you will see. Look at the pictures starting at the end. 2nd from last picture. You have to remove the rectangular inlet airduct which runs across the top of the engine then remove the long cover over the sparking coils which supply 2 plugs each -one direct connection/ one by a short lead.The cover is held on by several machine screws with allen or torx socket heads. Be extremely careful when handling the plugs leads and associated electrical wiring since the insulation can go brittle with age. PeachPartsWiki: W124 Engine Wiring Harness Replacement Don't cross thread or over torque the plugs in the alloy head.
thanks. Do all the alen bolts need to be removed from the cover? I mean all those that are attached to the block. Which ones towars the block need to be removed? Do all of those alen bolts need to be removed..the ones in your picture?
Jim
Jim
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andy_k
MB Enthusiast
you need to remove the air intake which runs over the top of the engine - a couple of jubilee clips allow you to take out the centre section which is also secured at the back by two 10mm nuts.
Once that's removed, the insert in the cylinder head which is held in by allen bolts needs removing - below that you'll find the coil packs and underneath those are the spark plugs.
Be careful as the loom may well be past it's best - if it's knackered, you're looking at a £500 bill to replace the loom
Once that's removed, the insert in the cylinder head which is held in by allen bolts needs removing - below that you'll find the coil packs and underneath those are the spark plugs.
Be careful as the loom may well be past it's best - if it's knackered, you're looking at a £500 bill to replace the loom
grober
MB Master
Its not the large cam cover itself but the flat "coverplate" you remove- there are several pictures that show you with it removed.--looks to be about 6 machine screws
grober
MB Master
Do you know what a jubilee clip is? 
Its the bright metal band that goes round the duct keep the large bore rubber connecting pipes on . Just slacken the clip screw to slacken the band and wiggle the cross pipe free after undoing the 2 nuts on the 2 mounting studs on the cover plate. Not sure I can explain it better.
Its the bright metal band that goes round the duct keep the large bore rubber connecting pipes on . Just slacken the clip screw to slacken the band and wiggle the cross pipe free after undoing the 2 nuts on the 2 mounting studs on the cover plate. Not sure I can explain it better.Im from the states and we call those by numerous names such as pipe clamps, screw clamps, channel clamps depending on the part of the country your from.
But I suppose that tubing that is on top of the plugs has to be removed? I thought originally the black tubes helsd the plugs but I guess that is the intake.
I'm not used to working on this late a model merc. I'm used to the deisel. these gas mercs are complicated machines. the diesel is straigth forward.
Jim
But I suppose that tubing that is on top of the plugs has to be removed? I thought originally the black tubes helsd the plugs but I guess that is the intake.
I'm not used to working on this late a model merc. I'm used to the deisel. these gas mercs are complicated machines. the diesel is straigth forward.
Jim
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andy_k
MB Enthusiast
I'm not sure what you mean by 'tubing'.
In the recess on the top of the engine (looking at it from the front of the car) you should see a black rubber casing which contains the loom that feeds the coil packs
The coil packs (three of them) need to be lifted upwards to allow you access to the plugs.
If you are really struggling, post a photo of your engine and we'll write notes on it for you
In the recess on the top of the engine (looking at it from the front of the car) you should see a black rubber casing which contains the loom that feeds the coil packs
The coil packs (three of them) need to be lifted upwards to allow you access to the plugs.
If you are really struggling, post a photo of your engine and we'll write notes on it for you
grobers engine is the same as mine. If you look at his 5th picture from the bottom on his pic like you wil see a vaccum hose connection. If you remove the chase cover under it is a tube that has openings running down to each plug. the vaccum at the left is on the end of that tube.
Jim
Jim
I cannot stress this enough - I killed my ECU and coilpacks just by removing the plugs - and I looked at the harness and thought it didnt look too bad!
Where the wires to the coil packs come through the big rubber block they will almost certainly short if the insulation is on its way out.
I repaired every wire under the bonnet by reinsulating but it didnt stop me having to replace the ecu and coilpacks. I am now about to renew the engine harness anyway!
Mark
grober
MB Master
NOW I understand [I think] sorry didn't realise you were from across the pond.
I think you are mistaking the fuel injection rail and injectors at the side of the cylinder head for the plug leads. This has nothing to do with the HT ignition and plugs. You get at them from the top of the engine.
I think you are mistaking the fuel injection rail and injectors at the side of the cylinder head for the plug leads. This has nothing to do with the HT ignition and plugs. You get at them from the top of the engine.
grober
MB Master
Does this help the square things are the coils there are 3 the plugs are marked with red circles under the components you see.
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andy_k
MB Enthusiast
yep - there are three coil packs - you've marked two of them. Lift them up and you will find the spark plugs. The remaining three plugs are under the caps where you have marked.
As I said earlier, be careful with the loom
As I said earlier, be careful with the loom
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