Diesel Fuel Injection Systems Feedback

I used to own a peugeot 406 HDI 2000/1 model which used to foul its oil in visual terms from about 500km, but my current Wrangler CRD 2.8 takes about 8000km to reach the same state and I have been thinking it was due to the piezo injectors being more accurate in terms quantity and flexibility. Is that the reason or is sulphur content a factor and or what else?. Particulate filtered vehicles require a different oil viscosity compared to non filtered....why is it so?.
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Reply By: jeepthing - Sunday, Mar 09, 2008 at 08:10

Sunday, Mar 09, 2008 at 08:10
From discussions I have had with both a Mobil and Castrol oil technician it is not the viscosity rather the oil must be C3 compliant or equivalent. According to both these guys the C3 cleans the particulate filter which is located in the exhaust system same as a cat converter for petrol engines. It's all to do with exhaust emissions. The way it was explained to me was the C3 component triggers the engine management system to shoot raw diesel into the particulate filter to clean it. If this didn't happen the filter would clog over a period of time and cause damage to the engine.
I have the V6 CRD (Mercf engine) and I have also spoken to a Merc technician who told me the same thing. I use Mobil 1 ESP 5w 30 which is C3 compliant. Also told by the Merc tech that this is the only oil Merc uses for it diesel engines.
AnswerID: 291724

Follow Up By: Member - Davidp P (VIC) - Sunday, Mar 09, 2008 at 09:56

Sunday, Mar 09, 2008 at 09:56
I bet there are a number of oldies like me who cant get their head around a 5W30 oil in a diesel when you consider the bearing pressures involved not to mention the heat. I understand the use of synthetic, but the weight (5W30) astounds me, I thought that was to get to advertise a lower fuel consumption figure(?).......silverback
FollowupID: 557064

Follow Up By: jeepthing - Sunday, Mar 09, 2008 at 16:07

Sunday, Mar 09, 2008 at 16:07
The specs for the 5w 30 fully synthetic means it will handle extreme heat and pressures. I also think that the extremely fine tolerances that they achieve these days of engine design requires a fine oil otherwise everything will not be fully lubricated. Prior to the CRD I had a 4.7 V8 Laredo which had the same oil spec and I always insisted on full synthetic.
I remember I forgot to tell the service manager at one of the oil changes and they put in Castrol Magnatec 5w30 and the engine sounded noisier at idle, I took it back and asked what oil they had used when told it was Magnatec I dumped it and replaced it with a full synthetic and the noise went so what this said to me was the full synthetic was obviously lubricating far superior to the magnatec even though the viscosity was the same.
My son has an ss commodore and he changed to a full synthetic same deal quietened the engine.
FollowupID: 557118

Follow Up By: Member - Davidp P (VIC) - Sunday, Mar 09, 2008 at 17:44

Sunday, Mar 09, 2008 at 17:44
As far as I know that Magnatec 5W30 they put in your Jeep is what the Jeep dealers refer to as Magnatec Professional a HYPER expensive Castrol synthetic which can only be obtained thru the trade. I think its a way of keeping the price from being discounted by retail outlets, a form of price fixing, thats why I use Penrite synthetic for diesels 5w40 in my Wrangler.....silverback
FollowupID: 557124

Follow Up By: jeepthing - Sunday, Mar 09, 2008 at 19:13

Sunday, Mar 09, 2008 at 19:13
Whatever it was it certainly didn't lubricate as good as the Castrol SLX 0w 40 they normally put in it...so after that I did my own oil changes using The Edge 0w 40 which according to the Castrol tech I spoke to was better than the SLX.
I had a look on the Penrite site and noticed that the oil you are using is not C3 compliant so I'll stick with the Mobil 1 ESP 5w 30. Jeep Australia did issue a service bulletin towards the end of last year instructing their dealers to use the Mobil 1 because it's C3 compliant. I buy it through a Mobil depot in 20l drums still cheaper than the dealers charge and they buy it in 200l drums
FollowupID: 557146

Reply By: Member - Mike DID - Sunday, Mar 09, 2008 at 09:29

Sunday, Mar 09, 2008 at 09:29
Diesels with Particulate Filters collect the soot on a filter medium which burns off the carbon through a catalyst action.

But if there is a lot of soot produced then the catalyst needs extra heating - this is done by overfueling the engine.

Some sump oil that's left on the cylinder walls will burn off and the residue gets onto the Particulate Filter. If the sump oil contains any metals that kill off the Filter catalyst, then the Filter won't work after a while.

That's why special oils are needed - they must be free of any ingredients whose combustion products would contaminate the Particulate Filter.
AnswerID: 291734

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