RELIABILITY AND RUNNING COSTS

[CarlosGee]

Back in mid September 2017 I purchased a 65 plate Mazda CX5 SPORT NAV AWD Auto 2,2 diesel which I loved.. It had 10k on the clock.. now its mid February 2018 and it has nearly 18k on the clock so a decent bit of mileage done,, Today I have had to get the AA out to it due to the low oil pressure light coming on.. On googling this it appears that this is the Mazdas regeneration of the dpf having been dumping unused diesel from the regen into the sump increasing the oil levels and subsequently contaminating the oil...,, THe AA have this issue about the CX5 as a very common fault on their laptops ,, They dropped the oil to acceptable levels and cancelled the warning light but the car now has to go into the dealers to get checked out and I understand have an oil and filter change.. so basicall]y a mini service after 8k when the servicing interval should actually be 12.5k... Now fallen out of love with the motor.. I am looking at other brands..Can spend around 23-24k... Looking at Hyundai Sante Fe; Kia Sorento or Volvo XC60... all will easily be able to tow my van at 1450KG MTPLM but have any of you guys had experience of these tow cars particulary interested in the reliability aspect of them and any issues you have had or heard about. .. I got rid of my Toyota Avensis to get the Mazda purely for the better towing capability but the reliability of that Avensis was perfect..I am after the same sort of experience.. Not interested in ride; cornering, acceleration etc etc just want a reliable motor... I would have got a RAV4 in the blink of an eye but Toyota didn`t do the Rav 4 in the automatic spec that I wanted . anybody any experience on the above 3 contenders? I am also open to other ideas ,,, Cheers Carl

 

[otherclive]

Not unusual. I had a 2010 Volvo 2.4 D5 XC70 and they did the same. Mine wasn’t affected by rising oil levels but quite a lot were but a general recall from Volvo saw the oil level reduced by about 0.5 litre and the electronic dipstick software revised to show the lowered oil level as at Max. Then if the DPF regeneration led to an increase in sump level the warning light came on when you had 0.5 litres of fuel in your oil diluting it. The car didn’t have a conventional dipstick but a very small one set deep in front of the engine which was for technicians to use when changing the oil. Sold it in 2014.

 

[Hutch]

I am on my second Santa Fe , first one a 08 plate this one a 64 plate, now 3 1/2 years old , 45 k miles. Auto , Runs lovely towed about 20, 000 miles get about 28 mpg towing a Coachman 560. 1600kg, no problems maybe I am lucky but the sat Nav is rubbish. A good tow car.

 

[ProfJohnL]

Hello Carlos,

A forum is not the best place to see relative reliability information, becasue at best only a few contributors if any will have experienced all your preferred models, and secondly people generally only post on a forum when something has gone wrong, not when every things alright.

You might be better looking up the JD powers reliability surveys.

 

[Martin24]

Parkers and Honest John reviews may be worth a look.

 

[otherclive]

The German TUV publish some good reliability data too.

 

[xtrailman]

I get oil rise on my CX-5, in fact I've had it on both CX-5s .
I only do a max of 7K miles so it never gets near the max mark on the dipstick, marked by an X.
Latest 65 plate appears better than my 2013 car though, and according to owners of the revised 2017 car (with increased low end torque and modified pistons and rings) reports are of no oil rise. I'm not totally convinced of this myself.

My advise if buying a CX-5 is get the oil changed at 7K miles.

I'll probably buy another as I love the car, rumour has it that both power and torque is to be increased to 190ps and something like 335 pound feet torque.
And I have to say the torque convertor auto is excellent.

Forgot to mention the 2017 can now tow 2100kg.

 

[Raywood]

We are on our third Mazda and have never had that problem or any other for that matter of any concern and we have had them over ten years. Just before we sold the first one the warning light did flash but the garage found this was a faulty connection although it was due a service then anyway.
All diesels are subject to the DPF problem and if there is one a warning light should come on before it becomes a serious problem and it flashes if it has gone too far. Basically all diesels need a regular good run at a decent speed and many are far worse for this problem than Mazda. Provided you do give it a regular run at over 40 mph then there should be no problem but whatever you buy you do need to make sure they get it.
Having said that if you did any distance with the problem, get rid, as it can cause the valves to fail.

 

[otherclive]

We are on our third Mazda and have never had that problem or any other for that matter of any concern and we have had them over ten years. Just before we sold the first one the warning light did flash but the garage found this was a faulty connection although it was due a service then anyway.
All diesels are subject to the DPF problem and if there is one a warning light should come on before it becomes a serious problem and it flashes if it has gone too far. Basically all diesels need a regular good run at a decent speed and many are far worse for this problem than Mazda. Provided you do give it a regular run at over 40 mph then there should be no problem but whatever you buy you do need to make sure they get it.
Having said that if you did any distance with the problem, get rid, as it can cause the valves to fail.

It's not quite true that all diesels suffer DPF problems. There are older diesel on the road that don't have DPFs. It all depends when the manufacturer changed the model. Also the problems of DPF aren't standard across all makes. It will vary as some marques have the DPF much closer to the exhaust manifold so it heats up quickly and regenerates more speedily. The last Defender was a case in point as LR knew that farmers often use them on very short journeys and I'm cold conditions. The last thing they require is a continual DPF alarm. I believe that Nissan/Renault also put the manifold in the head on later models.
Also the type of regeneration system can the likelihood of DPF related problems. Injecting excess fuel into the exhaust stroke seems to give rise to rising sump levels. Whereas injection fuel downstream into the exhaust seems better.
Driving conditions play a major part in whether you encounter a DPF related problem. Town traffic, short journeys etc all exacerbate the problem. My 2010 Volvo D5 and current Superb neither have suffered DPF problems as they tend not to be used for short journeys. I frequently use premium diesel as its detergent level is higher than for regular diesel and it also has a much lower ash content. And at the end of the day it's the ash that finally writes off the DPF.
The ageing 11year old non DPF Nissan is the workhorse and at its last MOT its emissions were incredibly low. It too gets dosed with premium diesel every so often and two tankful before its MoT.
Both the Volvo and Superb recommended running at 1800+ revs in the event of a DPF warning. That puts my speed well above 40 mph, so I'd have to put them in manual sport mode to keep revs at 1800+ and drive around on local A and B roads with the engine spinning above 1800 rpm and not getting myself liable for ticket. "Just regenerating my DPF officer" isn't likely to be accepted in mitigation.

 

[xtrailman]

Going on a run or using premium fuel will do little or nothing with a Mazda.
The DPF is cleaned on a timed system, it doesn't wait for you to go on a run, it operates regardless, so interrupting a regen is purely by chance. And that's when unburnt diesel finds it way into the sump.

 

[otherclive]

Going on a run or using premium fuel will do little or nothing with a Mazda.
The DPF is cleaned on a timed system, it doesn't wait for you to go on a run, it operates regardless, so interrupting a regen is purely by chance. And that's when unburnt diesel finds it way into the sump.

I use premium fuel for its higher detergent content which keeps today’s complex piezo injectors cleaner, and with a much lower ash content it will extend the DPF life as even the best regenerating DPF still creates residual ash which will eventually clog up the DPF as it cannot be burnt. I don’t subscribe to some views that premium fuels increase power, or give 25 miles extra per tank. Totally irrelevant to me when a full tank could give up to 600 mile range.

 

[Hutch]

I am with you, anotheclive, the premium fuel keeps the fuel injectors cleaner and therfore the fuel burn is better, .

 

[otherclive]

Going on a run or using premium fuel will do little or nothing with a Mazda.
The DPF is cleaned on a timed system, it doesn't wait for you to go on a run, it operates regardless, so interrupting a regen is purely by chance. And that's when unburnt diesel finds it way into the sump.

I’m puzzled by your comment that the Mazda DPF regeneration is a timed process. That is most unusual if not unique as I would have thought it to be determined by differential pressures across the DPF which trigger regeneration. In fact the 7 page Launchtech write up of Mazda DPF does say it’s pressure activated. To have a timed system makes no sense for fuel economy as it is not distance related and soot is only generated when the car is driven and is affected by driving conditions and distance. IE how much fuel has been used and how much soot it creates. So how is the timing interval determined. Too frequently and you waste fuel and risk raising sump level. Too infrequently and you risk clogging the DPF.

 

[xtrailman]

Pre 2017 cars would regen around every 150miles, apparently owners of the 2017 cars with engine mods report regen around 300miles.

I'm unsure how the differential pressure is used to regen in addition. There is a video on utube which mentions Mazda unusual method of regen, which I will post if I can find it.

Re premium fuel I agree the extra additives should help clean injectors, but its only of real use for high mileage cars, I would see no benefit because I sell at around 4.5 years with only around 30K miles on the clock, so the car is only just run in.

 

[otherclive]

Pre 2017 cars would regen around every 150miles, apparently owners of the 2017 cars with engine mods report regen around 300miles.

I'm unsure how the differential pressure is used to regen in addition. There is a video on utube which mentions Mazda unusual method of regen, which I will post if I can find it.

Re premium fuel I agree the extra additives should help clean injectors, but its only of real use for high mileage cars, I would see no benefit because I sell at around 4.5 years with only around 30K miles on the clock, so the car is only just run in.

Thanks for the reply. I would be interested in the video if you can locate it.

 

[xtrailman]

I've had a quick look but am unable to find it as yet, it deals with other cars not just Mazda so could be of interest.

 

[Raywood]

Going on a run or using premium fuel will do little or nothing with a Mazda.
The DPF is cleaned on a timed system, it doesn't wait for you to go on a run, it operates regardless, so interrupting a regen is purely by chance. And that's when unburnt diesel finds it way into the sump.

That is not what the handbook says. That suggests that if the light comes on the car is driven at over 40 mph for at least 20 miles to clear the problem. It is if the light flashes that there is a problem and at that point you should stop.
There is no doubt though that there is a known problem with Mazda's older models and serious problems can arise at over 60,000 miles so those are probably best avoided. The magazines report on the used Mazda 6 did highlight this issue and possibly may still be found on the web site.

 

[xtrailman]

Going on a run or using premium fuel will do little or nothing with a Mazda.
The DPF is cleaned on a timed system, it doesn't wait for you to go on a run, it operates regardless, so interrupting a regen is purely by chance. And that's when unburnt diesel finds it way into the sump.

That is not what the handbook says. That suggests that if the light comes on the car is driven at over 40 mph for at least 20 miles to clear the problem. It is if the light flashes that there is a problem and at that point you should stop.
There is no doubt though that there is a known problem with Mazda's older models and serious problems can arise at over 60,000 miles so those are probably best avoided. The magazines report on the used Mazda 6 did highlight this issue and possibly may still be found on the web site.

You have to be careful not to confuse pre skyactive engines with the older ones, skyactive has been around now from around 2012.

I have never had a DPF dash light up on my dash, and I'm on my 3rd car with a DPF.
Its the oil dilution that I don't like, I prefer oil levels to either stay put or drop slightly during use, not rise up, when the dilution becomes too much oil pressure is reduced and brings up a warning on the dash, which is not good.

Not that I've has this problem either, due to my low mileage between changes.

As for driving over 40mph that's really nonsense with the older engines were the DPF isn't close to the engine all that you need do is keep engine revs high enough.
So useing second gear at 2K revs would do the same thing.

 

[otherclive]

Going on a run or using premium fuel will do little or nothing with a Mazda.
The DPF is cleaned on a timed system, it doesn't wait for you to go on a run, it operates regardless, so interrupting a regen is purely by chance. And that's when unburnt diesel finds it way into the sump.

That is not what the handbook says. That suggests that if the light comes on the car is driven at over 40 mph for at least 20 miles to clear the problem. It is if the light flashes that there is a problem and at that point you should stop.
There is no doubt though that there is a known problem with Mazda's older models and serious problems can arise at over 60,000 miles so those are probably best avoided. The magazines report on the used Mazda 6 did highlight this issue and possibly may still be found on the web site.

You have to be careful not to confuse pre skyactive engines with the older ones, skyactive has been around now from around 2012.

I have never had a DPF dash light up on my dash, and I'm on my 3rd car with a DPF.
Its the oil dilution that I don't like, I prefer oil levels to either stay put or drop slightly during use, not rise up, when the dilution becomes too much oil pressure is reduced and brings up a warning on the dash, which is not good.

Not that I've has this problem either, due to my low mileage between changes.

As for driving over 40mph that's really nonsense with the older engines were the DPF isn't close to the engine all that you need do is keep engine revs high enough.
So useing second gear at 2K revs would do the same thing.

I too have never had a DPF warning light come on but agree your comments about 40 mph. In my current car which is auto that would equate to around 1100 rpm in 5 th. The roads where I live make it very difficult to do 40 mph for very long before you reach a junction or village, so I would have to do as you suggest pop it into manual and just keep changing gear to keep it above 1800 rpm.

 

[DaveA1]

I have never had a DPF warning light show, in fact I have never noticed a regen. Instructions are that if a steady light appears you run the engine at over 2000revs to clear in about 10mins.
Right or wrong, I preempt this, my daughter lives the other side of Lincoln, which, when we visit, it entails a run along the A46 Fosse Way. I lock motor in Fifth and run at 70mph hopefully this clears the DPF. either going or returning home. So far so good.
Regen's about every 350m. according to the legend!

 

[otherclive]

I have never had a DPF warning light show, in fact I have never noticed a regen. Instructions are that if a steady light appears you run the engine at over 2000revs to clear in about 10mins.
Right or wrong, I preempt this, my daughter lives the other side of Lincoln, which, when we visit, it entails a run along the A46 Fosse Way. I lock motor in Fifth and run at 70mph hopefully this clears the DPF. either going or returning home. So far so good.
Regen's about every 350m. according to the legend!

Ive now had two cars with DPF and also never had a warning light come. So it means that the car does what it is designed to do which is to regenerate when it's differential pressure sensors tell it that the exhaust filter pressure has increased. Your actions seem more designed to blow the captured carbon out of the exhaust, akin to an Italian tune up. But it won't blow them out as the DPF is designed to retain them until the next regeneration cycle occurs. Even at 70mph in top the car should be more than able to regenerate successfully. I could go as far as saying that your approach is likely to lead to more frequent regeneration given the increased fuel burn in running in s higher gear than required.

 

[Craigyoung]

We had no light come on on ours mind either, it just went into limp mode just as I was about to pull away from a roundabout, I then proceeded to take it to a country lane near mine , high revs 1st and 2nd which seemed to sort it out just as I was about to run out of Road !!

Late edit , this happened before we had the caravan then after purchasing the caravan it never happened again for the 4 years that we we kept the car and I think that was due to the High revs that was needed and used when towing.

 

[DaveA1]

I have never had a DPF warning light show, in fact I have never noticed a regen. Instructions are that if a steady light appears you run the engine at over 2000revs to clear in about 10mins.
Right or wrong, I preempt this, my daughter lives the other side of Lincoln, which, when we visit, it entails a run along the A46 Fosse Way. I lock motor in Fifth and run at 70mph hopefully this clears the DPF. either going or returning home. So far so good.
Regen's about every 350m. according to the legend!

Ive now had two cars with DPF and also never had a warning light come. So it means that the car does what it is designed to do which is to regenerate when it's differential pressure sensors tell it that the exhaust filter pressure has increased. Your actions seem more designed to blow the captured carbon out of the exhaust, akin to an Italian tune up. But it won't blow them out as the DPF is designed to retain them until the next regeneration cycle occurs. Even at 70mph in top the car should be more than able to regenerate successfully. I could go as far as saying that your approach is likely to lead to more frequent regeneration given the increased fuel burn in running in s higher gear than required.

Hi OC
Thanks Points taken, I'll leave the forced regen if and when the light comes on.
Thinking about your points, they would apply to the fact that I tow a tin tent for up to 2000 miles a year, my regens would be more frequent,. being an adaptive gear box (Auto) sensing the van and the extra revs before changing up, Although I would not go as far as describe it as an Italian tune up.