I have a 2006 (mazda5) Turbo Diesel. It has been halfway between full and X for about a month. Have contacted two local Mazda Garages, both asked if DPF light had come on, answer No. Both said do not worry oil level will fluctuate, if light does come on thats when you come in and see us. Keep checking level.
http://tinypic.com/3ia1sbad
This picture is my DPF/Cat unit I have been advised the pipes are connected to pressure sensors, 1 at front and other at rear of unit. The pipes go forward to engine compartment and connect to the sensors which are mounted on bulkhead. It also has 4 electrical sensors, 1 before unit, 1 on front unit, 1 on rear of unit and 1 after unit.

Questions.

1. How does the DPF regeneration process work and what actually triggers it? I know it uses excess fuel to burn off the carbon. Presumably it has some sort of sensor but does it work on pressure, differential pressure, measure some sort of gas or what?
Answer:- Have been advised that regeneration starts when DPF indicates unacceptable level of particulates. Injects fuel into engine on exhaust cycle to burn off particulates

Hope this helps towards your understanding/appreciation of the engine

 

Hi Sally,
Thanks for the info. It all helps.

After my post I did some further "searching" and it appears a DPF may have both "active" and "passive" regeneration. "Active" is when the ECU deliberately adds more fuel etc to enable soot burn off whereas "passive" relies purely on temperature/gas flow to burn off the soot. I'm not sure whether the Mazda 5 uses "passive" as well as "active". As the DPF is not too far away from the engine I suspect it may use "passive" but would be happy to be corrected.

If it does use "passive" it would suggest the idea of periodically driving for 15mins at over 2000RPM would enable regeneration without so much fuel getting into the oil, thus maintaining the oil nearer normal levels.

 

This may, or may not apply to you but I thought I'd share my experience with the oil level...

I had our Mazda 5 (diesel) serviced a couple of months ago and they [presumably!] changed the oil, etc. After about six weeks I thought I better check the oil level and to my amazement the level was about 5mm from the "x". I was about to call the garage who serviced it but I thought I better take another reading first. When I took the next reading it was more difficult to see a clear "edge" to the level so I took another reading. This time the level was a bit lower. After taking two or three more readings I noticed that as I pushed the dipstick down into the sump it has a tendency to twist. So I decided to try pushing it down while holding it tight to prevent it from twisting. This time I got a nice clear reading at exactly the "normal" level. I tried this again (without allowing it to twist) and I got another "normal" reading (a good way away from the "x").

I can only assume that if the dipstick is allowed to twist as it is pushed down through the tube towards the sump the side of the stick can run against oil that's built up on the inside surface of the bottom of the tube (although without removing the sump to take a look I am just guessing!).

I don't know if the manual mentions preventing the dipstick from twisting while checking the oil level, but using this method saved me an embarrassing drive to the garage to complain.

Hope this helps you out and you don't actually have a rising oil level problem.

 

All I can say is be careful.

From my experience when our oil was nearly at the x mark over 6 liters of "oil" drained out of the sump without removing the filter.

The refill oil capacity was around 4 litres from memory so 2 litres of extra "oil" had entered the sump.

 

Found this article at the weekend. It is about 2007 Mazda Mazda3 2.0D - 2.0 liter Turbo Diesel for Europe. I am assuming it is nearly the same engine across the range?
Is this another piece of the jigsaw?

Euro Stage4 Emissions
To achieve Euro Stage4 compliance, Mazda3’s 2.0 MZR-CD employs the latest in Mazda diesel engine technology and a diesel particulate filter system. Its multi-stage fuel injection is programmed to keep particulate matter (PM) left over after combustion to a minimum. The engine has an electronically-controlled intake shutter valve and exhaust-gas recirculation (EGR) valve to reduce the production of NOx.

These engine technologies are combined with Mazda’s catalyzed diesel particulate filter system that reduces PM emissions to almost zero and ensures Euro Stage4 compliance and lower operating costs. The system is fitted with a silicon carbide ceramic filter with a honeycomb structure that captures PM in the exhaust, while letting gases pass through.

Over time, the captured PM accumulates at the porous dividing walls of the filter. In order to prevent the filter from becoming blocked with PM, self regeneration takes place at certain intervals. When this occurs is determined by the Mazda3’s powertrain control module (PCM), which monitors the amount of PM in the filter.

When filter capacity is reached, the PCM initiates burn-off of the accumulated PM in the filter by injecting small amounts of fuel during the exhaust cycle, raising the exhaust gas temperatures for a short period. Further measures to increase the exhaust gas temperature are closing the EGR valve and intake shutter valve.

Mazda3 uses a catalysed diesel particulate filter with channels in the filter coated with platinum, which lowers the light-off temperature of the collected PM and allows filter regeneration at a lower exhaust gas temperature of between 350ºC to 500°C. This means that the new Mazda3 MRZ-CD 2.0 litre turbo diesel does not need a special fuel additive and is maintenance-free. It also allows the diesel particulate filter system to regenerate under normal driving conditions that mixes urban and extra-urban driving.

Also found these on youtube:-
http://www.youtube.com/watch?v=xiTEZGwA-wE
http://www.youtube.com/watch?v=gSE-R...eature=related
Needs a translation please

 

Regarding my rising oil level greater than design.

Car is now booked in on March 5th for an oil change at my local Mazda dealer. When I explained the position the receptionist said this should not happen so they will also check it out. I'll let you know what happens.

From all the recent helpful feedback my summary of the situation is as follows:-
1. Car has been driven for too long at too low RPM. Even though the car does not feel laboured in 6th gear when doing 50mph in future I will only use 6th when doing 65-70mph.
2. At least once per week I will drive for 10-15mins at 2000rpm to help burn off carbon build up automatically
In winter when ambient temperature is near zero I will do it 2500rpm to be sure of getting the exhaust hot.
3. Another forum confirms the figures of 4.1ltrs for "F "and 6.3ltrs for "X" on the dipstick. This equates to a fuel dilution of more than 30% - not a nice thought! I would have thought 10% was a more acceptable maximum.
4. The "you tube" videos and sallys DPF photo clearly indicate soot build up is measured by differential pressure across the DPF part of the filter. It looks like the DPF filter actually consists of 2 parts - a catalytic section where the burn off is initiated and the "sintered" filter itself where soot accumulates and is then burnt off. Presumably the 4 sensors referred to are all measuring temperature.
5. I too have had to check the dipstick more than once due to it not being very easy to determine the correct reading. One way that helps is to rub a bit of chalk on the dipstick first. Also I find the level clearer when the engine is cold.

 

When I explained the position the receptionist said this should not happen so they will also check it out. I'll let you know what happens.

I am a little cautious about the above comment from the receptionist after having read the information contained in my:-
Mazda 5 Servicing Guide (Ref MCAG2355 09/05) Page 3.
While driving your vehicle it is quite normal for the engine oil to be mixed with very small quantities of diesel fuel. This may lead to the engine oil level reaching the "X" mark on the dipstick. If this happens the engine oil must be renewed and the vehicle computer must be reset.

Food for thought:
(1) Why change oil when only half way.
(2) Why reset computer when only changing oil.
(3) Can the oil tolerate dilution and still maintain its lubricating properties.

Observation:-
Wonder if they will only syphon oil out (dip stick tube) to reduce oil level.
Curious
What are the costs involved

And finally
Best of luck hope all goes well.

 

Car had its oil changed yesterday. Total cost (not including filter) was £71.77.

Unfortunately the usual receptionist was not there - only a young person filling in. Normally I would also speak to the mechanic but he was out road testing a car when I picked my car up.

So I can only assume no unusual cause of the high oil level was found.

As a sidenote when I was paying my bill another chap was paying his. His was a Mazda 6 diesel and he had brought it in due to a dpf light coming on. His bill included paying for 3.5ltrs oil.

It seems to me the comments by wrxseeker on post#8 are ever more relevant. Mazda are hardly going to advertise their diesel cars as only being mostly suitable for motorway driving but it seems this is the reality.

 

Hi Rhodri
Car had its oil changed yesterday. Total cost (not including filter) was £71.77.
Did they reset computer as per manual after oil change ?
Regards

Sally

 

I am not 100% sure if they reset the computer. The mechanic who did the oil change has worked with Mazdas for a long time and I am confident he will have done it.

Why it actually needs doing is beyond me. I have read the previous posts about possible engine damage etc and still fail to understand any link between the condition of the oil and the fuel injector timing. Also not everyones oil is going to be diluted by the same amount for the same mileage. The only thing I can think of is that some oil will be carried over into the dpf and maybe the way the ecm controls the regeneration process varies depending on the projected oil condition.