6 cylinder om642 engine issue

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Liam7755

Member
Joined
Sep 3, 2023
Messages
37
Location
Cambridgeshire
Car
Jeep patriot 2.1 om651
Hi group,

I’m at a crossroads with my car .. it’s actually a Chrysler 300 and it’s running the 6 pot diesel engine from Mercedes. It runs the om642 .. this one is a 2008 with the duplex chain setup and for the most part it’s a nice all round motor actually! The 300c are just ‘one of them motors’ to me and I really like them.

I have only one concern and that’s if I should do my oil cooler seals or not?

There is no oil leak on the floor, it doesn’t use any either! But it does seem to leave little spots of coolant! I’ve had the water pump done and the pipe work checked and it’s all fine .. so I’ve been told that it actually could well be the egr cooler unit (in the v as they say) so it would be pretty much the same job for the cooler seals anyway!

My question is .. is this something I can do at home in a warm garage over a few days with ease? My knowledge goes back about 8 or 9 years fiddling with engines/ancillaries

Are there any special GARAGE only tools required for this job?

What are risks of doing it myself? other than snapping bolt heads/dropping gaskets etc (which is a risk anywhere it gets done to be honest)
 
If it’s leaking from the oil cooler it’ll be exactly the same symptoms except coolant instead of oil. Yes, there’s coolant in the oil cooler too! The valley of the vee has a drain that exits the block on the right hand side of the engine, just behind the starter motor (if it’s on that side, some are on the other side). There is a small, about 5mm, diameter hole there. If coolant is coming out of there it’s coming from the valley. Bear in mind there is an EGR cooler in the valley, and the two halves of the intake manifold have a coolant pipe that links them, sealed with a couple of O rings. Leaks from either of these will drop coolant into the valley. Take a look at your EGR valve too. These also have a coolant passage within, sealed with ball bearings pushed into place. I’ve seen obscure leaks here before too
 
If it’s leaking from the oil cooler it’ll be exactly the same symptoms except coolant instead of oil. Yes, there’s coolant in the oil cooler too! The valley of the vee has a drain that exits the block on the right hand side of the engine, just behind the starter motor (if it’s on that side, some are on the other side). There is a small, about 5mm, diameter hole there. If coolant is coming out of there it’s coming from the valley. Bear in mind there is an EGR cooler in the valley, and the two halves of the intake manifold have a coolant pipe that links them, sealed with a couple of O rings. Leaks from either of these will drop coolant into the valley. Take a look at your EGR valve too. These also have a coolant passage within, sealed with ball bearings pushed into place. I’ve seen obscure leaks here before too
Ok so to answer some of what you’re saying .. just so we’re on the same page .. the coolant weep is like a steady slow drip. Not huge, but enough to notice. It’s also right in the middle of the floor below the sump/subframe if that helps? More towards the middle/back of the engine. Does sound like oil cooler seals
 
You need to get right under there to have a look. If it’s coming out of the weep hole it’s from the valley, 100%
If it’s not coming out of the weep hole it’s elsewhere
 
You need to get right under there to have a look. If it’s coming out of the weep hole it’s from the valley, 100%
If it’s not coming out of the weep hole it’s elsewhere
Problem is it’s so blinking intermittent .. in the sense I can tick over for 20 minutes or more and it don’t drip .. then I can go for a drive and it drips 3 or 4 times when I park up briefly to go in to a shop.
 
You need to get right under there to have a look. If it’s coming out of the weep hole it’s from the valley, 100%
If it’s not coming out of the weep hole it’s elsewhere
Wondering where did you get your nickname from ;D how many percent you put on "elsewhere".... Om642 has two weep holes, first at the front... coming out near/above starter motor. Second at the back, heading into bell housing and on the floor. But 100% is bit over confident, what if coolant was coming from thermostat dripping all way down reaching,like you said weep hole. Would you strip everything all way to the cooler?
 

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Hi group,

I’m at a crossroads with my car .. it’s actually a Chrysler 300 and it’s running the 6 pot diesel engine from Mercedes. It runs the om642 .. this one is a 2008 with the duplex chain setup and for the most part it’s a nice all round motor actually! The 300c are just ‘one of them motors’ to me and I really like them.

I have only one concern and that’s if I should do my oil cooler seals or not?

There is no oil leak on the floor, it doesn’t use any either! But it does seem to leave little spots of coolant! I’ve had the water pump done and the pipe work checked and it’s all fine .. so I’ve been told that it actually could well be the egr cooler unit (in the v as they say) so it would be pretty much the same job for the cooler seals anyway!

My question is .. is this something I can do at home in a warm garage over a few days with ease? My knowledge goes back about 8 or 9 years fiddling with engines/ancillaries

Are there any special GARAGE only tools required for this job?

What are risks of doing it myself? other than snapping bolt heads/dropping gaskets etc (which is a risk anywhere it gets done to be honest)
 
It's same risk, as if you took it to the garage.job itself is straight forward just time consuming. I've done it myself not long ago and took me about 20hours. Including brakes , looking after kids etc. Get yourself torx set and few extensions. Take pictures and make sure you put bolts you have removed back where they were as some are different sizes. It's good exercise for your brain. And in the end you richer by approx £1000 and all the experience.good luck.
 
It's same risk, as if you took it to the garage.job itself is straight forward just time consuming. I've done it myself not long ago and took me about 20hours. Including brakes , looking after kids etc. Get yourself torx set and few extensions. Take pictures and make sure you put bolts you have removed back where they were as some are different sizes. It's good exercise for your brain. And in the end you richer by approx £1000 and all the experience.good luck.
Thanks for the comments bud. I think it might be something in the v as there isn’t any where at all that is leaking visually otherwise, but it certainly has a leak. I thought initially it was the water pump as the pump was loud anyhow. Replaced that and checked all the coolant pipe work during that process and everything is fine! It’s in a weird place .. just below the steering rack .. I initially thought it was coming from a bolt on the oil cooler line for the gearbox but that doesn’t carry coolant I’ve been told.
 
Wondering where did you get your nickname from ;D how many percent you put on "elsewhere".... Om642 has two weep holes, first at the front... coming out near/above starter motor. Second at the back, heading into bell housing and on the floor. But 100% is bit over confident, what if coolant was coming from thermostat dripping all way down reaching,like you said weep hole. Would you strip everything all way to the cooler?
I think you misinterpreted what I meant. A leak from the weep hole is coming from the valley. The thermostat will drop coolant into the valley, so it’s on that list. Heater hose for example isn’t going to come out of the weep hole. There’s coolant in the turbo pedestal too, another possibility and weep hole there too.
The rear weep hole is the one near the starter motor. The way the engine is slightly inclined in the car any fluid always shows at the rear one first in my experience. Leak needs to be pretty bad to be showing at both.
 
Hi group,

I’m at a crossroads with my car .. it’s actually a Chrysler 300 and it’s running the 6 pot diesel engine from Mercedes. It runs the om642 .. this one is a 2008 with the duplex chain setup and for the most part it’s a nice all round motor actually! The 300c are just ‘one of them motors’ to me and I really like them.

I have only one concern and that’s if I should do my oil cooler seals or not?

There is no oil leak on the floor, it doesn’t use any either! But it does seem to leave little spots of coolant! I’ve had the water pump done and the pipe work checked and it’s all fine .. so I’ve been told that it actually could well be the egr cooler unit (in the v as they say) so it would be pretty much the same job for the cooler seals anyway!

My question is .. is this something I can do at home in a warm garage over a few days with ease? My knowledge goes back about 8 or 9 years fiddling with engines/ancillaries

Are there any special GARAGE only tools required for this job?

What are risks of doing it myself? other than snapping bolt heads/dropping gaskets etc (which is a risk anywhere it gets done to be honest)
You can definitely do the oil cooler seals in your warm garage and while you're at it get the egr and intake manifolds cleaned. I also replaced the swirl flap connecting rods on the intake manifolds as the originals were very badly worn. I would suggest getting on YouTube. Get your gaskets off MB and torque all bolts to the correct values. Looks daunting but if you're good with tools you shouldn't have any problems and you won't regret it. No special tools required besides a decent female torque socket set and low and medium range torque wrenches.
Good luck
 
Hey guys further update .. the leak of coolant seems to have went away for 5 days! Not a single drop! Then it came back again. I cannot for the life of me see where from but I can say it is FRONT of the engine around the AC compressor unit area on the front subframe???
 
Hey guys further update .. the leak of coolant seems to have went away for 5 days! Not a single drop! Then it came back again. I cannot for the life of me see where from but I can say it is FRONT of the engine around the AC compressor unit area on the front subframe???
There is lots of places where water could leak from. Either way you need to strip air filters,common rail, manifold end the rest. But before you start, definitely get one of those...


Endoscope Camera Wireless Endoscope 1200P HD Inspection Camera Premium IP67 Waterproof WiFi Borescope with Flexible Rigid Snake Cable for Android IOS iPhone Samsung Smartphone PC (Black, 5M) https://amzn.eu/d/aAlkbht

Of I didn't have one, my local "cowboys" would take gearbox off only to find out that oil wasn't leaking from crankshaft seal. £1000 badly invested.

On another note, I wonder if one of holes got blocked with debris and leak isn't that bad. Chance why it disappeared and then appeared at the front.
 

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There is lots of places where water could leak from. Either way you need to strip air filters,common rail, manifold end the rest. But before you start, definitely get one of those...


Endoscope Camera Wireless Endoscope 1200P HD Inspection Camera Premium IP67 Waterproof WiFi Borescope with Flexible Rigid Snake Cable for Android IOS iPhone Samsung Smartphone PC (Black, 5M) https://amzn.eu/d/aAlkbht

Of I didn't have one, my local "cowboys" would take gearbox off only to find out that oil wasn't leaking from crankshaft seal. £1000 badly invested.

On another note, I wonder if one of holes got blocked with debris and leak isn't that bad. Chance why it disappeared and then appeared at the front.
Thanks for the info! I feel like it could be from the front weep hole .. POSSIBLY but the coolant itself is also piercingly red! Not mixed with contaminants or oil or anything so I would have guessed it’s just coming from a direct pin hole or lose joint somewhere perhaps? I’ve taken apart coolant reservoir and wiggled it all whilst engines running etc and I cannot make the leak happen. It’s so strange and it actually looks like the thread on one of my oil cooler pipes to the gearbox is weeping and wet with coolant!! But it cannot be from that because I’m told that it does not carry coolant in them pipes, just oil?
 
Automatic transmission fluid is red...
 
It is by the looks of it. I don’t want to jump straight on that though as it looks/feels more watery .. certainly isn’t oily
Starting from the bottom....oil cooler than, egr cooler, turbo cooling, and if I'm right there is some water or can be in the manifold. Each one will end up dripping down to V and then either through bell housing or hole further forward. Just like on picture. What year is your car?
 
Starting from the bottom....oil cooler than, egr cooler, turbo cooling, and if I'm right there is some water or can be in the manifold. Each one will end up dripping down to V and then either through bell housing or hole further forward. Just like on picture. What year is your car?
Yeah that crossed my mind as I cant see it, so in the V could be plausible BUT the leak is so so small!! Its a single drip per every 5 or 6ft of ground covered! In my garden after a long drive I can see a drip every few steps to where I drive in to the driveway so I KNOW its fresh as its wet .. but when I quickly jack it up, there is ZERO visible leak anywhere!! It seems to stop when idle. And maybe im being thick as a plank of wood here .. but I CANNOT locate a drain hole near the bell housing/block. Where the block meets the gearbox also seems too far back from where the drip is seen. My car is a 2008 .. the 220ish bhp variant ..
 
Yeah that crossed my mind as I cant see it, so in the V could be plausible BUT the leak is so so small!! Its a single drip per every 5 or 6ft of ground covered! In my garden after a long drive I can see a drip every few steps to where I drive in to the driveway so I KNOW its fresh as its wet .. but when I quickly jack it up, there is ZERO visible leak anywhere!! It seems to stop when idle. And maybe im being thick as a plank of wood here .. but I CANNOT locate a drain hole near the bell housing/block. Where the block meets the gearbox also seems too far back from where the drip is seen. My car is a 2008 .. the 220ish bhp variant ..
I'm on the mission here :)....I used to use Facebook group for conversations like that, but decided to come off social media :D and always did my best to help and often people helped me.....so, as I'm not quite sure about set of your engine, this is only my advice based on "nothing" and my car which is different to yours but not necessarily. Both holes on mine are on the left hand side of the engine, so maybe if/when you jack your car up, you doing it in the direction so prosumebly coolant moves away from those holes, chance why you can't see anything. Also, only because "I'm on mission".... I would try this:

UV Dye & UV Torch Kit Leak Detection Fluid For Car Cooling Antifreeze System RLD2 https://amzn.eu/d/c2bdRzu

Bit of magic 🪄.... Add it to your coolant run engine for a bit and ideally use torch at night, while is dark. Cost nothing, definitely less comparing to full on job, as mentioned above. Even if it requires coolant drain.

Hope this helps :)
 
I'm on the mission here :)....I used to use Facebook group for conversations like that, but decided to come off social media :D and always did my best to help and often people helped me.....so, as I'm not quite sure about set of your engine, this is only my advice based on "nothing" and my car which is different to yours but not necessarily. Both holes on mine are on the left hand side of the engine, so maybe if/when you jack your car up, you doing it in the direction so prosumebly coolant moves away from those holes, chance why you can't see anything. Also, only because "I'm on mission".... I would try this:

UV Dye & UV Torch Kit Leak Detection Fluid For Car Cooling Antifreeze System RLD2 https://amzn.eu/d/c2bdRzu

Bit of magic 🪄.... Add it to your coolant run engine for a bit and ideally use torch at night, while is dark. Cost nothing, definitely less comparing to full on job, as mentioned above. Even if it requires coolant drain.

Hope this helps :)
Thanks again for your time to reply. Forgive me as I’ve never used it before but how will that UV stuff help me narrow it down? Coolant is bright orange/red as it is and is easily visible type thing. I may well just order some new coolant and flush the system once again for the sake of £35. But I still find it a very strange leak! I went out this evening for 35 minutes and as I drove in my driveway there was no leak this time! One thing I’ve noticed is that when my car is stone cold my coolant level is on maximum line. When it’s up to temperature it rises of course and when I opened the cap earlier I noticed that it was high enough to be seeping into the drain off pipe on the reservoir! Is that right?
 

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