Update on 315 exploding engines.

Hugh.M

Member
I suggest from experience to rebuild/modify these engines BEFORE they hand grenade.
You can lead a horse to water!!
Pull it out while it is good and possible to fix, see Eric, myself NSW or one of the other mechanics who has figured it out.
The oil pressure kits are excellent.
 
Thanks for the info Hugh. Where are you located in NSW? I haven't started rebuilding mine yet but as I already stated my engine had a cracked piston (possibly 2). I do want it to last so I want to look into this further. Have you rebuilt one of these and if so was it successful.
Tim
 
Hi Mal.
I'm in Wollongong. Would you mind if I send my phone number to you on your email. Just need to have a chat about what you have found or what you recommend to prevent future destruction of my engine.
Tim
 

Slithytove

Bastet
Hi everyone.... I just would like to know if the EXPLODING ENGINE issue is only an issue for the 315 engines for AUSTRALIAN MARKET ??

Just curious as to why if this is the case.

Regards
Rhonda - YES I have a 315. I am currently trying to decide what to do with it. :bash: :yell: :censored: :cry: :eek: as I'm sure you all are.
 

Elja

New member
Heyy, I am reading the post, not sure you got the solution but I found somewhere that the crankshaft is not balanced good or not straight. Not sure, have read about it a year before when I wanted to buy sprinter 315 and ended up with 311 because my friend said to me that the 150hp engine has much issues. Don't know if it is caused by so much power (pressure on the shaft) or factory mistake.
 
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HotWired

Member
Hi owner,
missing and blowing smoke .....hardly fits the 'exploding engine' syndrome and isn't 325k way passed where its claimed the crook ones usually let go. Isn't this more likely a fuel system or head issue ?
 

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
Depends how long the bottom end has been left to melt. The ambos go at 200k because they are driven hard and heavy 100% of the time. This one wasnt an ambo, hence it lasted longer.
 
Finally started to rebuild my 315 cdi engine which has been sitting around for a while. I have posted here a few times before however the sprinter (and engine) was parked about 400km away from me. I used the Christmas break to pull the engine out and bring it back to the coast for a rebuild. As I was going through the parts I realised that I had misplaced the oil baffle plate. I looked up the part through benzcat specifically for the om646. 986 it was here I saw this footnote

- Text footnote
Footnote Description
[100]
THE OIL BAFFLE MUST NOT BE MOUNTED, PLEASE REMOVE THE OIL BAFFLE INSTALLED EX-FACTORY AND SCRAP IT
Is anyone aware of any TSBs related to the removal of the oil baffle on the 315cdi. Makes me wonder if its related to the failure of these engines.
 

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
Thats intetesting. I will talk to Eric and see if he can find out from his inside man at MB.

On the surface of it though, its not going to change the physical distortion of the main caps. It might help cool a red hot spun bearing a bit better, and keep the engine running a few hundred km longer before it explodes.
 
I agree that it may not make too much difference once the bearing is compromised but it is quite strong language they have used in the footnote. If it didn't cause any issues then why even bother mentioning it at all. From my understanding only the 315cdi has this plate. On a separate issue I have also noticed that the main cap bolts are very short when compared with other diesel engines I have worked on before and didn't feel overly tight. It might not be any wonder the caps distort.
 
I am in the process of checking the crank on the 315 finally. I thought in the interests of this thread I would share what I find as I go. This motor did not have a crank or oil pressure issue but had a cracked piston and blown head gasket in between cylinders 2 and 3. From memory it has done around 160000km and is an ex ambulance or patient transport (not sure). After reading most of the posts I decided to pull the engine from the van and check the crank just to be on the safe side. My initial inspection of the crank shows light marks on the shells and bearings of no. 2 main and no. 4. This is likely contamination of the oil at some point. The main journal measurements are all around 57.96 (give or take. 01) and the big ends are within spec. The runout on the crank was (. 04mm) This motor was marked with two dots on the block surface, sump side which indicates yellow main bearings and the crank is also marked with 5 G's which indicates yellow bearings. The next step is to fit the main caps and see if any distortion has taken place. If not I will have the crank polished and refit with new bearings and continue the build.
 

HotWired

Member
I'm disappointed this baffle issue didn't trigger a recall .......
- Text footnote
Footnote Description
[100]
THE OIL BAFFLE MUST NOT BE MOUNTED, PLEASE REMOVE THE OIL BAFFLE INSTALLED EX-FACTORY AND SCRAP IT
Is anyone aware of any TSBs related to the removal of the oil baffle on the 315cdi. Makes me wonder if its related to the failure of these engines.


Interesting to see what Eric's contact at MB has to say.
Colin
 
I'm sure that on the MB information somewhere it may give an indication as to why its so important to scrap this part. There also appears to be an updated oil pump pick up tube replacement for this engine according to both the parts list and the WIS. It does say why though. I am currently attempting to check the main caps for distorsion in my engine but I may need a Dial bore gauge as the telescopic measuring tool I have are not as accurate as I would like (probably operator error). I am also going to check the oil pump further. I checked out the bores last night for all 4 cylinders. It was interesting to see that cylinder 1 was an A code and cylinders 2, 3 and 4 were X coded. That means Cyl 1 specs are 88.000mm to 88.006 and the rest of them are 88.006 to 88.015. Since my measuring equipment only goes to. 01mm they all just came up as 88.00 or 88.01 across three points of the thrust face. When I get some more photos I will post as I go. Another point of concern I did find was as I mentioned a while ago is the main cap bolts. They are m11 bolts and have a max length of around 63mm. The bolt is threaded along its entire length. I can see this as a weak point as the other night I was trial fitting the caps and found movement as the bolt diameter is smaller than the holes in the caps. This would make the bolt rely on the claiming force to hold the cap steady, any movement off its radial axis like thrust movements could move the caps out of alignment. I think it would be better to see the top of the bolt unthreaded and a snug fit into the cap to reduce off centre movement. I will show a photo of this shortly. Looking at the Om651, the cap bolts are M12 but are also 106mm long which could eliminate cap distortion.
 

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