Oil dilution

Hammer68

Member
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CX-5
In 2016 we purchased my wife a 2016.5 AWD CX-5. She loved it and I thought it was a pretty nice car. I was driving a 2010 BMW X5 also a beautiful riding car but hard on fuel and very expensive to repair. I decided in 2017 that I too would buy a Mazda CX-5 GS AWD. And first it was great no issues until January 2018 came. Oil pan was double full of fuel I had to have the car towed to the dealership which was very good to change the oil at no charge. So to date this has happened every month with my last oil change done in April. The Dealership and Mazda Canada says it's my fault because I don't drive the car much. But I don't remember seeing in my purchase contract where it said I had to drive the car a certain way or distance for it to meet the terms of the sale or fuel mileage as stated. Nor could I find anything in the owners manual. The car is warm by the time I get to work and to date we have had no issues with my wife who incidentally drives less than I do for work. Each time the oil was double full. I can see a little fuel in the oil but not double!! Any thoughts.
 
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Yes, its an awkward one. It might settle down now the weather is warmer and the attached bulletin is all geared towards low temp operation. However, if the problem persists, it might be worth digging in and asking for further investigation in case it is getting in some other way. Ill just have a little read up and report back.
 

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In 2016 we purchased my wife a 2016.5 AWD CX-5. She loved it and I thought it was a pretty nice car. I was driving a 2010 BMW X5 also a beautiful riding car but hard on fuel and very expensive to repair. I decided in 2017 that I too would buy a Mazda CX-5 GS AWD. And first it was great no issues until January 2018 came. Oil pan was double full of fuel I had to have the car towed to the dealership which was very good to change the oil at no charge. So to date this has happened every month with my last oil change done in April. The Dealership and Mazda Canada says it's my fault because I don't drive the car much. But I don't remember seeing in my purchase contract where it said I had to drive the car a certain way or distance for it to meet the terms of the sale or fuel mileage as stated. Nor could I find anything in the owners manual. The car is warm by the time I get to work and to date we have had no issues with my wife who incidentally drives less than I do for work. Each time the oil was double full. I can see a little fuel in the oil but not double!! Any thoughts.
Sekmor has been botheted by oil level fluctuation / oil dilution on his 2014.5 CX-5 since new. But his dealer eventually fixed the issue by ECM software update. Some oil dilution issues could be able to get corrected by the updated ECM software. Honda is doing the similar updates in China to limit too much fuel been injected into cylinders during cold start and other situations for its oil dilution issue on 1.5T.

Here's a little update, since our CX5 was having the dilution problem for the first couple years. Very noticeable in winter, warm weather driving was not a problem.
About a year ago, I was on the last attempt at a fix and left the car with the dealer. FWIW, it had been in there several times for the same problem. Anyways, this time they did a bunch of ECM/ECU updates, and surprise surprise, the problem seems to be fixed. Just completed an oil change at 8000 kms, November > May, so running the entire winter. I checked it a couple times during that period and the level did not fluctuate. Took out 5L and dumped a 5L jug back in.
A couple other noticeable things......the exhaust tips were always covered with soot. Since that repair, they are clean as a whistle, the inside of the pipe is shiney spotless. Car runs great, excellent fuel mileage, good throttle response, runs better than ever since we bought it new.
 
Thanks for the info

Yes, its an awkward one. It might settle down now the weather is warmer and the attached bulletin is all geared towards low temp operation. However, if the problem persists, it might be worth digging in and asking for further investigation in case it is getting in some other way. Ill just have a little read up and report back.

I will be asking for a full refund as they have done nothing to help me except oil changes. They offered a remote starter and then changed their minds. No where in the sales contract does it say how far and how often should you drive it. Had they explained this to me at the time of sale I would not have bought it. My wife car has to issues with fuel dilution Same car same engine.

I really appreciate your reply and the supplied document.
 
Thanks for the update

Sekmor has been botheted by oil level fluctuation / oil dilution on his 2014.5 CX-5 since new. But his dealer eventually fixed the issue by ECM software update. Some oil dilution issues could be able to get corrected by the updated ECM software. Honda is doing the similar updates in China to limit too much fuel been injected into cylinders during cold start and other situations for its oil dilution issue on 1.5T.

Mine is now half full once again. Last oil change April 30th.

Thanks
 
Being in Canada, how long to you set the car in idle upon first start up in the morning? I would suggest to let it warm up at least 2-3 minutes in your case......if you have the option I would even enable sport mode for the first 5 minutes when you finally drive off to keep the rpms high and warm up the engine.

You may want to verify with another dealership if you require an ECU update?
 
Being in Canada, how long to you set the car in idle upon first start up in the morning? I would suggest to let it warm up at least 2-3 minutes in your case......if you have the option I would even enable sport mode for the first 5 minutes when you finally drive off to keep the rpms high and warm up the engine.

You may want to verify with another dealership if you require an ECU update?


Thanks I knew nothing about this ECU update. In 5 months no one has mentioned it either with Mazda Canada or the dealership. I do warm the car up in the morning for a least 5 minutes and it is warm by the time I get to work.
 
Most likely you got a leaky injector. Some oil dilution is normal with these engines, but a significant amount is a sign of injector troubles.

You need to take the car out onto the highway for at least 30+ minutes at least once a week. It's important.
 
Being in Canada, how long to you set the car in idle upon first start up in the morning? I would suggest to let it warm up at least 2-3 minutes in your case..

What does Canada have anything to do with warming up the engine.?? We do have temps up here above freezing.

Actually starting the engine and letting it idle for several minutes does not help the issue. I've "trained" the wife to start the car, listen for the engine tone, (the initial extra fuel burn 10 seconds) and then drive away nicely until the temp light goes off.

As of now, our oil issue seems to be ok, car runs fine. We have about 68,000 kms and still going strong, so the dilution must not have hurt anything. But when it was a problem, I could record the oil level rising per day, it was so obvious. Then we would go on a long road trip (like 3000 kms), it was 100% perfect. The dealer did fuel pumps, injectors, all kinds of things without results. When they did the computer work, all the work order says is ECM updates, no other info. But I'm a car guy, and notice things that only car guys can. Engine did have a different exhaust tone, accelerates different, so there was definitely something updated in the ECM. Have not been back to dealer since but if I have to for any warranty work, it will be noted on the work order not to touch that part. You know how they like to say, oh we did you a favor and added all the newest updates.

As for the comments like, it's normal, must drive it more, go on road trips, IMO is all BS. If you can't buy a new car and use it to go to the corner store once a week, that's pretty crappy technology.
 
What does Canada have anything to do with warming up the engine.?? We do have temps up here above freezing.

Actually starting the engine and letting it idle for several minutes does not help the issue. I've "trained" the wife to start the car, listen for the engine tone, (the initial extra fuel burn 10 seconds) and then drive away nicely until the temp light goes off.

As of now, our oil issue seems to be ok, car runs fine. We have about 68,000 kms and still going strong, so the dilution must not have hurt anything. But when it was a problem, I could record the oil level rising per day, it was so obvious. Then we would go on a long road trip (like 3000 kms), it was 100% perfect. The dealer did fuel pumps, injectors, all kinds of things without results. When they did the computer work, all the work order says is ECM updates, no other info. But I'm a car guy, and notice things that only car guys can. Engine did have a different exhaust tone, accelerates different, so there was definitely something updated in the ECM. Have not been back to dealer since but if I have to for any warranty work, it will be noted on the work order not to touch that part. You know how they like to say, oh we did you a favor and added all the newest updates.

As for the comments like, it's normal, must drive it more, go on road trips, IMO is all BS. If you can't buy a new car and use it to go to the corner store once a week, that's pretty crappy technology.

Idling the engine for several minutes would just make the problem worse if anything... Idling is never good for your engine, especially when the engine is cold.

It's not called crappy technology, It's called a failure to do your research and note the inherit issues of owning a direct injection vehicle. Understanding how direct injection works and why fuel dilution happens as a result will go a long way. But your only options are to use a better quality oil and take the car for more highway trips, or simply buy an older port-injected motor and not complain.
 
* As for the comments like, it's normal, must drive it more, go on road trips, IMO is all BS. If you can't buy a new car and use it to go to the corner store once a week, that's pretty crappy technology.
Idling the engine for several minutes would just make the problem worse if anything... Idling is never good for your engine, especially when the engine is cold.

It's not called crappy technology, It's called a failure to do your research and note the inherit issues of owning a direct injection vehicle. Understanding how direct injection works and why fuel dilution happens as a result will go a long way. But your only options are to use a better quality oil and take the car for more highway trips, or simply buy an older port-injected motor and not complain.
I have to agree with Sekmor. Our 2016 CX-5 only sees 20 miles city driving each day, and haven't been driven on the highway as long as I can remember within a year. It doesn't have oil dilution issue as far as I can tell.

Almost every 4-cylinder gasoline engine in the US now has direct injection. Research or not, it doesn't matter. :)
 
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What does Canada have anything to do with warming up the engine.??

As for the comments like, it's normal, must drive it more, go on road trips, IMO is all BS. If you can't buy a new car and use it to go to the corner store once a week, that's pretty crappy technology.

Couldn't agree more.
When a dealer or car company starts telling you you're not driving properly, or often enough, or far enough, or fast enough, or that you live in a part of the world that's too cold in the winter, then there's something seriously wrong with current engine technology.
In this day and age, we should be able to drive our new cars anyway we damn well please, including taking a 2 mile trip to the corner store in the middle of winter.....without having to warm it up for an hour or taking it on the highway for a 75mph run.
Total rubbish.
 
Do not Buy any Mazda products!! The company does not stand behind their product nor do they wish to help the consumer with an issue that they know they have. I tried the CAMVAP approach only to be told the issue was mine for not driving enough. The dealership and the manufacturer will do nothing for me. We have purchased our last Mazda. Their loss. I purchased all my vehicles from Guelph City Mazda. They even have a Service Manager who doesn't even know anything about cars. What a poor way to treat people that have spent 100K with them over the last 9 years.
 
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