OM605 in bits

[Codger49]

A very impressive write-up with extremely useful photos.

I just wish I had your skill (and bravery).

I look forward to the 'finished and running'stage.

 

[notsofast]

a very impressive write-up with extremely useful photos.

I just wish i had your skill (and bravery).

I look forward to the 'finished and running'stage.

+1

 

[Wackeldackel]

Another update...

Sorted the wiring loom at last, I managed to re use all the connectors without breaking any, once wrapped with loom tape it looked good as new, not factory colours but it will do the job.



Then I reinstalled the fuel pump using the little locking pin and the engine at 14 degrees ATDC, the poor quality picture shows (in the mirror) the inspection plug on the side of the pump, a couple of tweaks to get the timing point bang in the middle of the inspection hole and then the pump mounting bolts were tightened.



Then finally I removed the sump, I ended up using a pickle fork balljoint splitter to get the drag link off after lots of BFH action and a bit of cursing.



Then I undid all these bolts, lots of different lengths and sizes so my template came in very handy.



To get the sump out easily I had to lift the engine until it was touching the bulkhead under the windscreen, even like this it still took a bit of manouvering to get the sump out.



Finally the sump was off and I could clean it up, the paper gasket was welded on all the way around, more of which later...

 

[Wackeldackel]

And this is what was awaiting me in the bottom of the sump...



Lots of swarf, ballbearings, bits of vacuum pump idler arm and a couple of washers from the vacuum pump. I took as much out with the magnet as I could then drained away the remaining oil, then cleaned off the old gasket. This took a good couple of hours scraping, I had the most success by scraping away the hardened top layer of the paper, then sloshing on a lot of diesel with a paintbrush and allowing it to soften the paper gasket a bit. After a wipe over with brake cleaner I was left with this




With the sump off I looked at the bottomend of the engine, turned the crankshaft by hand and everything looked ok, no obvious signs of wear. I also cleaned a lot of swarf out of the metal gauze in the oil pump pickup.



Then it was time to refit the sump, tighten up all the 34 bolts around its perimeter and refit the oil cooler. Then I fitted some new rubber gaiters to the drag link, packed full of nice new grease and refitted that as well as the steering damper.

 

[Wackeldackel]

Next up I poured some diesel in the crankcase, spun the engine on the starter for 30 seconds and drained it out just to get any last bits of swarf out that may have been stuck anywhere. I couldn't be bothered to drop the sump again so I syringed some more diesel out of the simp plug and the rest will come out on the next oil change.

Next up was putting everything back together. I cleaned a lot of oily tarry gunk out of the inlet manifold and breather hoses, cleaned the air filter box and connecting pipe and then wire brushed, primered and painted the scabby battery tray.



Then I bolted a few bits back to the engine, first the water pump, then exhaust manifold, all the bits and bobs running around the auxiliary belt, radiator and shroud and finally all the fuel lines with new clips to hold the rigid pipes and new leakoff pipes between injectors.



Then I plugged in the new wiring loom and sorted the jumble of vacuum lines around the fuel pump.



More pics to come....

 

[Wackeldackel]

Finally once everything was bolted back where it should be I filled up the power steering fluid, filled the crankcase with oil and aded coolant to the expansion tank and in the engine block. I reconnected the diesel feed and return lines and turned the engine by hand 10-12 times just to start things moving and then I turned the key to see if she would start for the first time since February!



After about 30 seconds cranking she fired, caught and ran, a little bit of knocking from the new injectors but I'm sure they will quieten as they bed in and also running a little smokey....which I'm hoping may just be the last bit of diesel in the sump thinning the oil too much so it gets past rings or valve stem seals, hopefully another oil change tomorrow will sort this.

Next job was to get the air out of the cooling system. Surprise surprise my Circoli brand thermostat didn't want to open....



The bottom radiator hose where the thermostat sits was stone cold, so out with the coolant again and into the kitchen with the thermostat....



Surprise surprise the thermostat opened about where it should have done, I heated it a couple of times and let it cool then fitted it back to the waterpump. I started the process again, same result, bottom hose cold, temperature gauge rising, bad thermostat? I fished the old Wahler genuine MB thermostat out of the bin, changed the rubber seal with the new one and fitted the genuine one. Still no luck and still the temp gauge crept up and up. I'm going to try boiling this one in the kitchen to perhaps shock it into opening, after 2 months perhaps it's got a little sticky but I cannot think what else could be causing this overheating. I flushed the radiator, flushed the oil cooler, opened the bleed screws front and back of engine to get any air out and as a last resort I ran the engine with no thermostat. As a result it ran very cold, somewhere below the 80 degree mark on the gauge where in the past it always sat at a rock steady 85.

Next job now is to have a look at the water pump, make sure I haven't missed cutting out any holes when I made new gaskets for it, plus an oil change to hopefully stop the smoking. In hindsight I wish I had done the valve stem seals while the head was off but according to the engineering company who did the helicoil for the glowplug the valves were seated fine and not leaking. The only other thing that may be causing the smoking is possibly fuel pump timing not quite right....I will do the oil change, test drive and seevwhat happens. In the worst case I suppose a bit of tuning the pump by ear might be necessary. If anyone reading this has done that and is it advisable or not please say...the likes of Dieselmeken and DieselpumpUK on youtube make it look childs play to tweak these pumps but I'm not so confident!

So at least the car is running now, if a little hot and smokey. Once these niggles are ironed out I will post a few more pics. To everyone who said thanks or well done, thank you I do appreciate it. I'm not a trained mechanic, but thanks to info available on this site and others as well as the videos on youtube I've managed (fingers crossed) to get my car running again when it would have been so simple to call the scrap man and write it off.

 

[Bellow]

but I cannot think what else could be causing this overheating.

Are you certain the 'stat is being fitted correct way round ie, with the temp sensing part facing the engine?
I knew a (very talented!) engineer who once made this mistake on a Pinto.

 

[Wackeldackel]

Are you certain the 'stat is being fitted correct way round ie, with the temp sensing part facing the engine?
I knew a (very talented!) engineer who once made this mistake on a Pinto.

Yup, there's a mounting notch in the thermostat housing which means the thermostat will only go in one way up. In the picture above, the spring side of the thermostat (the side at the bottom of the pan) is inserted into the engine/ back of the waterpump and the top of the thermostat where the rubber sealing ring is mounted is in the thermostat housing which connects to the bottom radiator hose....it's a bit of a puzzling one

 

[a111r]

Circoli are the cheap brand sold by ECP. I've seen a high failure rate with them.

When my S124 E300D oerheated it was due to the expansion tank cap not sealing properly.

 

[Wackeldackel]

Circoli are the cheap brand sold by ECP. I've seen a high failure rate with them.

When my S124 E300D oerheated it was due to the expansion tank cap not sealing properly.

Trouble was I was running the engine with the expansion tank cap off and opening and closing the bleeder screws on the cylinder head to get the air out....and still the temperature gauge kept rising! If the expansion tank cap was on it would have simply pressurised and boiled....the bottom radiator hose from the thermostat was stone cold while the top hose was hot as was the coolant coming out of the bleeder screws....I'm thinking about pulling the waterpump as well although when I had it on the bench it seemed fine to me.

 

[Bellow]

and the top of the thermostat where the rubber sealing ring is mounted is in the thermostat housing which connects to the bottom radiator hose....it's a bit of a puzzling one

Confused!
Normally, a 'stat will feed to the top hose (the increasing density of the water as it cools on traversing the radiator being significant enough to be part of the circulation 'mechanism').

 

[Wackeldackel]

Confused!
Normally, a 'stat will feed to the top hose (the increasing density of the water as it cools on traversing the radiator being significant enough to be part of the circulation 'mechanism').

Yup yup yup....on my petrol engined 300E the thermostat is on the top radiator hose....However on this diesel engine and all the other OM60X engines the thermostat is on the bottom hose, between the radiator and the water pump, bit of a peculiar place for it

 

[Bellow]

Yup yup yup....on my petrol engined 300E the thermostat is on the top radiator hose....However on this diesel engine and all the other OM60X engines the thermostat is on the bottom hose, between the radiator and the water pump, bit of a peculiar place for it

OK, I think I follow.
The coolant then flows in the opposite direction compared to a normal (top hose) system in that on opening the coolant flows form the rad to the engine as opposed to from the engine to the rad. And the temp sensing part is as per top hose system on the engine side.
Should work then - but installed the motor runs hot, and removed it runs cold - definitely pointing to the 'stat being at the heart of this.

The bottom radiator hose where the thermostat sits was stone cold,

Was there any heat in the top hose?

 

[Wackeldackel]

Yes, the top hose was hot, I ran my hand across the radiator which was also warm. The coolant coming out of the bleed screws was hot. The only place that was still cold was the bottom hose where the thermostat sits. When I drained the coolant each time to swap the thermostats the coolant in the expansion tank would drain first from the tap on the bottom of the radiator (cold) then the coolant from the top of the cylinder head and radiator came out (hot) which tells me that the thermostat couldn't be opening or there was a blockage there near it or the water pump. I'll have a look this afternoon but it will involve taking the exhaust manifold off to get the water pump out!

 

[Wackeldackel]

I opened the bleed screws whilst filling the system with coolant so as much air as possible came out the bleed screws, and once the engine was running I loosened them both to get a few more bubbles out. Normally when the thermostat opens I'd expect the coolant level in the expansion tank to drop a little as all the coolant starts circulating the engine but it didn't move at all. I'll have another look and see what happens....

 

[Bellow]

.

Next job now is to have a look at the water pump, make sure I haven't missed cutting out any holes when I made new gaskets for it,

Something related to the above is all I can think of.
Reasonable to say the 'stat isn't seeing the signal to open so there must be some mechanism (which has been lost) to circulate hot water from high in the engine to the (presumably) lower (situated) 'stat.
Have you the old water pump gasket at hand to examine for holes that could facilitate the above? (I never bin anything until the job is absolutely and completely finished - and too often not even then!)

 

[Wackeldackel]

I don't think it's quite that complicated....the thermostat just sits there and thermostats!! When its hot it opens when it's cold it closes, the only thing related to temperature apart from that is the coolant temperature sensor on the cylinder head for the gauge on the dashboard, the thermovacuum valve next to it that tells the autobox to change softer at low engine temperatures and the viscous clutch.

Fingers crossed I can get the old thermostat unstuck and double check the water pump and oil cooler for blockages. The picture on page 2 of this thread shows the water pump and associated gubbins and there are quite a few little coolant passages to check....fingers crossed it's something simple!

 

[Wackeldackel]

Todays update...first job was to check the old genuine MB Wahker brand thermostat in a pan of water on the cooker. It opened just fine at about the right temperature, rather than try with the Circoli cheap and cheerful one I decided to put this one back in for now until I get another OEM one.

Then it was time to get the waterpump off. First things first, off with the airpipe, EGR valve and crossover pipe



Then to get to the auxiliary belt, off came the radiator shroud along with the viscous fan clutch and the fan itself.



And yes I did stand the fan and clutch vertically after taking the pic...to be honest it's probably overdue for replacement or I might have a go at a nifty DIY refilling repair of the viscous clutch that I have read about online....

Then I undid the tensioner and released the auxiliary belt, and took the pulley off the front of the water pump, which left me this;



Looking at it from the side of the engine, you can see here the thermostat housing which attaches to the bottom radiator hose.



Next I removed the thermostat housing and prised the two pipes out that connect the water pump to the oil / water heat exchanger in the sump, they are the two pipes at the bottom in the centre of this picture, the heat exchanger itself is the silver box on the side of the sump just above the container of blue coolant.



I wanted to avoid taking off the exhaust manifold as it's a bit fiddly to bolt back on, so I tried splitting the waterpump into two halves to let me wiggle it out. This wasn't a success, this picture shows the water pump itself towards the front of the engine and its mounting bracket where the thermostat goes, behind it trapped by the exhaust manifold.



So without removing the exhaust manifold the only other way to get it out was from the bottom, which meant taking off the alternator and its mounting bracket, which left me with this....



Then finally I could wiggle the two parts of the waterpump out for a better look. This is it completely disassembled...



I gave it a bit more of a clean up, checked all the coolant passages were clear and checked the gaskets I made weren't covering any holes. Everything was fine, the pump itself spun nice and freely and there was no play in the bearing either.

This shows what was mentioned yesterday, the thermostat can only be fitted one way around with the temperature sensing part towards the engine, as the shape of the thermostat housing and the mounting notch in it won't allow the thermostat to be installed back to front.



Once I was satisfied that everything was in order with the water pump and thermostat I put it all back together, everything apart from the viscous fan and shroud and then opened the bleeder screws and filled the system with coolant. I ran the engine up to temperature, kept squeezing the hoses and opening the bleeder screws and lo and gehold the temperature held steady, a little hotter than usual due to no fan behind the radiator but I ran the engine for half an hour with no overheating like yesterday! Success!!

 

[Wackeldackel]

Next up after that was to try and tweak the fuel pump a little to quieten the engine down a touch. This involved removing crossover pipe, plastic cover over the injectors, throttle linkage, inlet manifold and the radiator shroud. Once all that lot was removed I could get to the bolts that hold the fuel pump in position. I got the engine up to temperature then turned it off. Then I slightly slackened the bolts slightly then restarted the engine. With the engine running and revving up to about 1500-2000rpm I turned the adjuster screw on the pump slightly anticlockwise half a turn at a time then clockwise half a turn at a time. I did notice a change in how the engine sounded and I stopped where there seemed to be the least clatter. Then stopped the engine, tightened the bokts and put it all together. This little video shows how it sounded, still not perfect I think but not bad.

 

[Wackeldackel]

Lastly I went for a little test drive ariund the block a couple of times. The car ran well, again a bit clattery and knocky at times and definitely smoky too. I think the fuel pump needs further adjustment to quieten things down a little and help with the smoking, but as soon as I got the car back home I changed the oil and filter, as well as putting a magnet into the sump drain hole and oil filter box to get any last bits of swarf.

Hopefully this oil change will have taken out some more of the diesel left in the sump that was probably not helping the smoking. Last few jobs for next week are install a proper OEM thermostat and once again replace the two O rings on the fuel shutoff valve as they have started to weep for some reason, despite being less than 6 months old! I'll also have another go at tuning the pump a bit to see if I can get rid of some more clatter.

At least now the car is running reasonably, as a final note I collected all the bits of swarf, vacuum pump and ballbearings etc and this is the combined total of what I fushed out of my engine....



A salutary warning to anyone who has an OM60X engine.....don't ignore your vacuum pump!!!