Hi Joe - Part 1
Don't you love the way these dealerships treat you like an idiot. Sounds like you had the same problems as I did. Going in to limp home mode was the first issue I noticed and with a trailer on I only just had enough power to get home. I live in a country area too. Having a background in electronics and previously racing cars in Australia (state level) I tend to self diagnose my own cars, if I have trouble. I presume you had the 'money light' well that's what the dealerships call it anyway, come on, as I did. That light is shaped like an engine. None of the cheap fault code scan tools I had were helpful so I invested in a quite expensive one. The cheap ones will clear a code but I needed more diagnosis.

With the scan tool I found a faulty sensor it's called 'Turbo boost pressure sensor'. Now this little sensor has been called a few different names by many people including those that should know better and I'll bet that what you believe (or were told) was a solenoid, was in fact this pressure sensor. when this sensor goes faulty and even though the turbos are spinning you don't get any boost pressure. Of course the ECU knows this and sets a code and turns on the engine light. Don't ask me how I know, but this boost pressure sensor is a well known problem, however the dealerships won't tell you about it. After my self diagnosis they owned up " yes that sensor fails all the time and has been upgraded many times too. We can get get you one it's over $200. Ok so I got the sensor and fitted it. Car now ran better and that pesky engine light was under control or was it?

See Part 2
For more

 

Part-2 The DPF filter
If you own a CX5 with a Diesel engine, then you may not know, but you also have a DPF filter. Mandated to be fitted to Diesel engined vehicles built from 2009.I had no idea I had one and it appears it is a well known source of problems with later Diesel engines. Fitted to the exhaust system just after the engine, it's job is to stop the nasty emissions from reaching the tail pipe.

The only problem is it gets clogged up during normal driving and has to be put through a cleaning process. You can observe this cleaning process taking place as the i-stop light goes off and the litres/100km increase. Of course the cleaning process is handled by the engine management quite well. Now here's where the problem starts. If you live in a city and do short trips the engine may be doing a DPF clean and before it finishes you turn the engine off. The management starts the clean again when you restart but more short trips with early turn offs and the filter clogs up. Of course the advice (I never got and you probably didn't either) to avoid this situation is to go for a highway drive once a week.

If you live in the country (Like I do ) you generally do longer trips and you shouldn't have any problem. I believe my problem with the Turbo pressure sensor filter caused a problem with my DPF and it clogged up. So after fitting the new Turbo boost sensor I focused on the DPF. My scan tool gave me live data on the pressure across the filter but I had no Idea what it should be, Further reading on mr gurgle showed companies can clean the filter by removing it and manually cleaning it but I found out you can buy some DPF cleaner that you pour into the petrol tank when you fill up so being easy and cheap I went ahead. This could be a good Idea to do regularly if you live in a city with a CX5 Diesel. I noticed an immediate improvement in power and acceleration so I was pleased that this stuff seems to be helping clean the filter.

Ok so now I have the engine seemingly running much better and turbo boost and acceleration back to normal. Must admit I hadn't noticed it was so bad). The DPF cleaning times seem to have got shorter now too, so you would think I have solved all my issues, but there's another biggy around the corner - I'll cover that in part 3 next.
Ross

 

Part 3 Blown Head Gasket

Ok so with my CX5 now running better I turned my attention to the cooling system which during the other problems had exhausted some coolant out of the overflow tank onto the motor. You could smell the coolant when it was parked overnight in the garage. I tried a new radiator cap but no change. I studied the system a bit and concluded that when the engine was up to operating temperature coolant (being under pressure) would vent into the overflow tank and add to the cold level. When engine was stopped and cooled down, that excess coolant would be drawn back into the radiator. What I found was the radiator wasn't drawing coolant back and the overflow tank filled up and overflowed. Temporarily I decided I would return the excess coolant to the radiator manually with a syringe. This was a daily chore while I completed further tests. Of course I did this transfer of coolant when the engine was cold and I was surprised to find there was still some pressure released when I removed the radiator cap. So my diagnosis so far pointed towards a head gasket allowing combustion pressure into the coolant but to prove this I bough a test kit and sure enough this proved indeed I have a blown head gasket.
Now I originally purchased the 2013 CX5 Diesel to tow our caravan and it has performed well. I had no Idea this model had issues but clearly I am not alone. It seems the only issue I don't have is the Diesel contamination of the oil. Car was recalled by local dealer for leaky injector seal tests but I was never told whether they found any (sound familiar). From most of the research I have done the explanation is - Leaking injector seals allow diesel to get into the sump bypassing the pistons and contaminate the oil. This can raise the apparent oil level, not to mention the detrimental effect on the engine. Apparently one fix was to change the dipstick with one that has a higher maximum oil level mark. It's depressing to think that this may be true.
Anyway all of this has led me to purchase a new SP125 CX5 with a 2.5L petrol engine of course and a Turbo. Would be nice to hear from Mazda NZ and if they would consider fitting a new head gasket to my old CX5 which I need to sell to help pay for my new one.

Ross

 

So recently purchased a Japanese import CX5 2.2 diesel 2015 model 105km. Within days had the overheating issue hit us with loss of power and whole host of dash lights went on, loads of japanese writing! Which then disappeared. The dealer (generic second-hand Japanese imports company not a Mazda dealer) took it back and had the head gasket replaced and a new filler cap. The mechanic (familiar with Mazda diesels) told the dealer the whole injector system was clogged with soot and the 1st injector needed replacing. All was done. Then drove off lot again and engine started juddering and sounded terrible. Bottom line, I found this thread and asked for my money back! Thankfully the dealer agreed. I can have my money back, the cheque is cut. Thing is I really love the vehicle. had a Mazda 3 1.6 diesel in the UK in 2000s and loved it. I would like to get a suitable CX5 it fits so many of my needs. Just don't want a lemon! Questions are -
1. What would it take to get the first vehicle to a good state of reliability? Or does it require the whole engine replacement (impossible to achieve here in St Lucia) to get the reliability we would all crave?
2. Should I get a petrol engine version? The dealer brings in loads of Japanese exports so he can do it but doesnt usually do the petrol as they incur higher duties which makes them more expensive. If so which engine version? 2.0 or 2.5l? Thing is all the reviews I have seen from the UK recommend the diesel! St Lucia has a lot of short drives and stop-start in traffic, so I suspect petrol is better suited to our conditions as these conditions are likely to heighten the diesel soot build up problems?
3. Is there anything to be wary of with the petrol version? Or are they kosher?
4. What year would you need to go for to get a solid and reliable diesel? Dealer has a 2016 (second half of the year) 2.2 diesel coming into the country in the next 2 weeks. Would a 2016 be OK or still have all the same issues? How to tell if it did have them and they have been dealt with?
Thanks all for your thoughts.
Cheers.

 

Caribjames my advice is to buy a petrol CX5. I like the CX5 but there have been a lot of problems with the Diesel engine.

Regards
Ross

 

Buy a 2.5 petrol. 99.99% bulletproof.

 

Thanks for the advice I take that as a solid thumbs up for the petrol option!

 

Hi, just thought I’d add to this post.
in July 2021, my daughter purchased a 2014 CX5 2.2 deisel from a Mazda dealer in Perth, WA.
She has just had the dreaded engine overheat and failure. Also the fuel in oil dilution. Took it back to the dealer, they have done an diagnostic check on it and I’m happy to report that after 4 days, they have agreed to replace the motor. The only charge to us is the $950 diagnostic fee. Which I don’t understand why I’m being charged that, but it’s better than $12k plus! They are also supplying a hire car for the duration of the replacement. Gotta say I’m pretty amazed with the outcome. I was prepared with a lot of info from this forum to argue it with them, but credit to them for being upfront and honest about it,
Thanks,

 

Would you be able to help with more details maybe the fault codes. I have my Aussie Mazda CX5 2103 Grand Touring Diesel here in NZ and this is happening to me right now but no one wants to accept responsibility for this. My car has done 128k. I would really like to push the issue but everyone is playing dumb about this fault with the exhaust sensor

 

I'm back here reading this thread with terror - Absolutely love my 2015 (Jap import) 2.2 Diesel CX5 and touch wood its flawless so far but its a little under 60K.

Its doing a mix of short city driving with the odd tow the caravan hundreds of kilometres and tour and its the torque for the caravan that I just can't see a petrol engine duplicating.
Its so effortless accelerating off the mark with ~950KG of caravan on the back.

Its also such a dream without the van on the open road but I could like with the petrol then.

We're doing mazda dealer oil changes like clock work and they hook it up to the computer each time so hopefully we'll get nice early warning of any issues.

The DPF cleaning cycle I'm picking will be running well when we tow or get on the open road. Hopefully we do that frequently enough. My wife takes it on the motorway weekly but really only a little over 10 mins at over 80Kph each time so I don't think that'll be enough?

How frequently should the DPF cycle be run - Maybe I need to schedule a weekend trip out to a nice pub/cafe a regular intervals that I know will be long enough to trigger it - Is there a way with the right software / cable (Looking at a USB cable and FORscan) that will indicate when the last DPF cleaning cycle was run?? I really want to try and do what I can to hopefully keep her running well as it is such a nice car to drive and so unbelievable steady and each with the van on the back.

Before this I towed with a 4L straight six ford falcon and a 3.5L V6 Mazda and they don't compare. The ford was pretty good but still wallowed a bit at takeoff with the low revs.