Thread: How much oil

Originally Posted by LRTech23

I've never heard of a viscosity test being carried out on a vehicle.

I wouldn't mind knowing why you think it would effect the engine oil in any way. I am not a master on the subject of DPF's but I can see no reason why a filter in the exhaust system that is not lubricated in any way would have an effect on the engine oil itself.

Please note that I am not being sarcastic, I am just interested. As I said I'm not a master on the subject and maybe you know something I don't.

The Mazda CX5 diesel has been having issues with oil dilution and cars actually having oil overfills because of fuel dilution. How and why I don't understand either. This issue isn't limited to the Mazda.

Ok so I've been talking to the technical trainers for JLR Australia, they're saying the oil should only be effected if you have to do a forced regeneration, which is done by dealers, during a forced regen the oil temps get higher than they are designed to and begin to break the oil down. The oil must be changed after a forced regeneration, Which should only be done by a dealer or trained tech.

Other than this a DPF should not effect the oil, it may burn a little as the temperatures still get hot when it is doing a normal regeneration. And technically the manufacturer should use a higher grade oil to assist with the strain put on the engine. However they don't. Mainly because it adds cost, and because they deem that the same oil should be "ok".

LR share this mentality.

Also fuel dilution should not be an issue. If it was, LR would have made a recall on the vehicle. Any diesel in the oil can rot seals, blow turbos and even cause "runaway". I LR had any indication the oil had fuel in it there would be a very large recall I suspect.

LR like any manufactuer would be unlikely to do a recall for dilution as it is not a safety issue and by the time it causes any engine failure it will be way out of warrranty.
In fact LR are not the quickest at recalls; it took ages for them to do the brake servo issue recall.

It will be interesting to see the logevity of DPF equiped diesel engines over tyhe long haul.

Originally Posted by CaverD3

LR like any manufactuer would be unlikely to do a recall for dilution as it is not a safety issue and by the time it causes any engine failure it will be way out of warrranty.

It will be interesting to see the logevity of DPF equiped diesel engines over tyhe long haul.

Runaway is a safety issue. But yes I agree.

Originally Posted by LRTech23

I've never heard of a viscosity test being carried out on a vehicle.

I wouldn't mind knowing why you think it would effect the engine oil in any way. I am not a master on the subject of DPF's but I can see no reason why a filter in the exhaust system that is not lubricated in any way would have an effect on the engine oil itself.

Please note that I am not being sarcastic, I am just interested. As I said I'm not a master on the subject and maybe you know something I don't.

I, like yourself and many others couldn't figure out how an exhaust system component can affect engine oil. Then I did a quick google search (which I posted my take on earlier in this thread). Oil dilution on DPF fitted cars is a known issue (Mazda, Subaru and others)....well maybe issue isn't right, as the manufacturers have compensated for it with monitoring systems. I couldn't find anything on LR though, so not sure if their systems are completely different, if that is possible.

So here's the how again.....

An engine with a DPF (even under normal regen) regularily (how regular depends on variables I imagine) injects extra fuel into the cylinders. I'm not sure if the idea is to create more heat initially in the engine which gets transfered to the DPF or whether the intent is to actually get the fuel into the DPF (for a burn). I couldn't quite work out which in my quick read.

Anyway, it appears that some of this extra fuel can also get forced passed the pistons/rings and into the parts of the engine that are lubricated with oil. So that's what causes the dilution.

So unless LR engines are different there may be an issue. From what I read other manufacturers don't treat it as unusual or that it will only affect some DPF fitted vehicles. They have developed monitoring systems, so they must be treating it (dilution) as a given characteristic of a DPF fitted car.

I know that some piston equipped aircraft have fuel injection into their engine oil for extreme cold climate starting but this is factored into the engineering and it's only for start. How it affects the oil in the long term, I don't know. These 'cold start' events may have to be recorded in the aircraft log...thus affecting future maintenance activities.

So getting back to one of my earlier points...if D4s are using oil and they aren't fitted with a DPF, surely diluting the oil could be very bad for the engine.

As to your regen comments, I'm aware of two types.

Normal, which just happens every now and again to keep the DPF clean. No lights and is almost indiscernable to the driver.

There is another type (which I've actually seen on my D4) which initiates a warning light and a fault is recorded in the ECU. This is the one that the manual covers, that tells you to drive at a set speed for a period of time. It occurred when I'd been close to idle for ages, so I'm assuming it's to compensate for heavier build up.

I don't know what this forced regen is (that you mentioned), is that another level for even higher build-up of stuff in the DPF?

So, in conclussion...LOL....oil dilution is a fact of life in some DPF fitted vehicles....no ifs, buts, maybes. What I'd like to know is, are LRs different and if so, how so? And if they are not (as in they do get dilution) what gets done to manage that?

With only a very small percentage of LRs with a DPF I suppose it may not be well known about these possible issues (if there are any for LR) but it doesn't give owners much confidence if the folks working on their cars know nothing about the scenario, LR or other deisel engine.

I'm not a diesel mechanic and it only took me a few minutes on Google to get a drift of what the issues are, maybe a diesel mechanic could shed some light on the whole thing. Or are DPF fitted vehicles very rare and not particularly well known about?

Cheers,

Kev.

Yeah if you look up at my previous post where I talked to JLR technical Australia, you'll see they arn't aware of any dilution in our products. However that doesn't mean there isn't.

As you said we don't have many DPF vehicles in Australia, the only JLR one I have actually seen is the X-Type diesel with the ford Duratec engine.

The forced regen as I mentioned before requires the oil to be changed immediately after a forced regen because it breaks down the oil molecules from the heat generated, not because of oil dilution from fuel slipping past the rings or anything like that.

It's my understanding that engine wear WOULD be effected if there was more than 45% dilution. However if you get your car serviced regularly, and you drive the car correctly this should not be an issue.

The forced regen I mentioned is when the DPF warning light is red, and you need to get it cleared out by a technician, as you correctly guessed it is for large blockage, to the point that it needs to be forced out. Temperatures are extremely high in the exhaust during this process, a friend of mine who has done a couple of DPF forced regens on Alfa Romeos said on some models you need to have running water on the rear bumper so that it does not melt.

Originally Posted by Celtoid

An engine with a DPF (even under normal regen) regularily (how regular depends on variables I imagine) injects extra fuel into the cylinders. I'm not sure if the idea is to create more heat initially in the engine which gets transfered to the DPF or whether the intent is to actually get the fuel into the DPF (for a burn).

The late injection of fuel is to cause the catalytic converter to get to its maximum permissible temperature to produce the necessary heat to burn the downstream DPF contents. For the 3.0 this only occurs when the ecm detects from the DPF pre and post pressure sensors that a cleanout is required.