Engine Oil Fuel Dilution Problem Is Back

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Steel188 said:
5k oil changes! Blimey, next you’ll be telling us we should use 4* petrol :D

The oil (proper fully synthetic) gets changed at the service interval of 12500 miles, with a weekly check to ensure the level hasn’t changed .............. again!

I can just imagine the conversation with my leasing company, if I said I’ve had the oil analysed, and I disagree with the vehicle manufacturer’s published servicing regime! I’m pretty certain it would involve men in white coats and a padded cell! :lol:

Let’s just accept there are cultural differences between us that make these exchanges interesting, frustrating and wonderful all at the same time. Peace.

Did you get the maintenance manual with your PHEV when you bought it? Because mine clearly says that the OCI should be 5000 miles if driven in more harsh/demanding conditions, and 7500 miles otherwise. Actually, which MY PHEV do you have? I wonder if Mitsubishi originally recommended 12500 miles and then backed off on their estimates because of fuel dilution issues on later years? Note that it doesn't say 5000-7500 ICE miles, it says 5000-7500 total miles.

jaapv said:
Actually, you did...

Well no, that really depends on how long you plan to keep the car, and whether you think something else would break that would make the car not worth fixing prior to any issues showing up in the engine. I'm really not sure how long I'll keep this car, but I'm definitely at least curious about what results I'm going to see. Especially after my friend reported ridiculous amounts of fuel dilution in his Cayenne S E-Hybrid and did his first oil change at 5k miles which probably corresponds to only around 2k ICE miles. And the data I'm seeing generally shows the same. I probably do about 50% of my miles in EV mode and I'm changing my fully synthetic Mobil 1 0W-20 with extended performance Mobil 1 filter at between 2500-3750 ICE miles, because fuel dilution starts to get out of hand beyond that.
 
Yes I did get the manual, the European servicing intervals are annually or 20,000km, whichever occurs first, so for the UK it’s 12,500 miles.

I have just checked the MMCUK website, and it still says the same.

Now I am lucky, to drive the miles I do, there aren’t many weeks where I don’t drive 200-300 miles a day, at least twice, which gets everything thoroughly hot and burns off any water or fuel that’s got somewhere it shouldn’t.

But to answer your question about don’t I want to know about what’s going on at a microscopic level in my engine..........no I don’t, and every European who has replied (so far) has the same feeling about this alien concept..
 
Steel188 said:
Yes I did get the manual, the European servicing intervals are annually or 20,000km, whichever occurs first, so for the UK it’s 12,500 miles.

I have just checked the MMCUK website, and it still says the same.

Now I am lucky, to drive the miles I do, there aren’t many weeks where I don’t drive 200-300 miles a day, at least twice, which gets everything thoroughly hot and burns off any water or fuel that’s got somewhere it shouldn’t.

But to answer your question about don’t I want to know about what’s going on at a microscopic level in my engine..........no I don’t, and every European who has replied (so far) has the same feeling about this alien concept..

With a usage pattern like that, I don't think you will be seeing any fuel dilution issues. As long as you get the oil up to operating temperature (which probably takes 10-15 minutes) and hold it there for at least 30 minutes once a week, you're probably fine.

One interesting note about that second to last sample (the one on March 1, 2019) is that it was taken about 2 weeks after I drove the PHEV to Tahoe. This involved taking the oil up to operating temperature and holding it there for many hours. In fact, there was awful traffic on the way up, very slow, and it took some 7 hours to get up there. I was running the ICE for heat too. And perhaps not so surprisingly, there was very little fuel dilution in that oil.
 
So you are changing oil on guidance of a variable value. Running down the motorway for half an hour to visit your grandmother would serve just as well.
 
jaapv said:
So you are changing oil on guidance of a variable value. Running down the motorway for half an hour to visit your grandmother would serve just as well.

Possibly. For the sample with only a trace of fuel dilution, about a month and a half before going to Tahoe, I drove the PHEV to Southern California, which was another long trip that had the oil at operating temperature for many hours.

For the most recent sample however, about 2-3 weeks before I took it, I drove up to Mount Hamilton, which took at least an hour, and measured a coolant temperature of 98°C when I got to the top. This is the highest temperature I have ever measured in this vehicle. However, there was still a huge amount of fuel dilution. I still haven't exactly pinned down what causes this; I was expecting less fuel dilution because of this drive but it was a lot higher than I expected. So, I am continuing to gather more data to figure out exactly what's going on. Was it because this trip was not long enough? Maybe. The limited amount of data I have been able to gather however should be throwing up red flags for folks who don't take very many long trips and try to keep the PHEV in EV mode as much as possible, with the ICE only starting up occasionally at the ends of trips and/or if more than 60 kW of power is demanded, and then shutting down 3-5 minutes later.
 
6000km? That’s ludicrous! I was put off this car a little with an interval of 12000 miles, my last two cars were at 18000 miles (diesel). At 12000 miles I will need to take it in more than once a year, at 6000 Km I’d be putting in more oil than petrol!
 
mellobob said:
The interval recommendations are interesting. On my 2018 here in Canada the recommended interval is 6000km (note KM, not MILES). What is it in the USA?

In the USA, it's 5000 miles (8046 km) if driving in "demanding" conditions with the engine starting and stopping a lot, and 7500 miles (12071 km) otherwise. I would guess that if you're doing a lot of long drives, you can use a 7500 mile OCI, as my TBN was still at around 2.9 after 6k miles. But if you're using it for short trips and the ICE is being used less frequently, you should use a 5000 mile OCI to prevent fuel dilution from getting out of hand.
 
jaapv said:
Well, it seems Europe is the most undemanding place on earth... I'll stick to the 20.000 km.

Forget about the fuel dilution issue, there's almost no way that the bases in the oil that neutralize the acids generated by combustion will last that long. Unlike the fuel dilution data I have, the TBN data at least follows a consistent trend. TBN of Mobil 1 0W-20 synthetic starts off at around 9.5-10. At 3700 miles, I was down to 5.0 (this was the first batch of oil that came with the car, not necessarily Mobil 1, and may have been exposed to a lot of stuff that slightly used engines don't put out, so take that sample with a grain of salt). At 5000 miles, I measured 4.5, and at 6000 miles, 2.9. The data I have is a little bit noisy, and doesn't fit a straight line, but there's almost no way you're going to have enough TBN after 20000 km. Once your Total Base Number, or TBN, goes below 2.0, your engine starts to corrode from the acidic byproducts of combustion that can no longer be neutralized. You're talking about doubling usage from when I measured a TBN of 2.9 at this point, which I can almost assure you is not a good idea.
 
OK. So Mitsubishi is crazy - and most other car brands as well. 20.000 km is rather the norm over here. And surprise-surprise - problems with excessive engine wear are very rare.
 
jaapv said:
OK. So Mitsubishi is crazy - and most other car brands as well. 20.000 km is rather the norm over here. And surprise-surprise - problems with excessive engine wear are very rare.

Based on the data I have gathered, and the fact that they're recommending much shorter intervals in other countries, I would agree. Yes, they're crazy. Actually, it's crazy to be recommending different OCIs in different areas unless there's really something in the gasoline or other factors that account for it, and even crazier to have such recommendations vary by a factor of 2. In any case, since you're either too cheap and/or insufficiently curious to do your own oil tests, I'm simply passing along the information I'm seeing from my car and that information tells me that pushing things out to 20,000 km is not a very good idea. What you choose to do with it is up to you, but I'll just say that I would never buy a used car that you've owned.

By the way, note that many European makes of car have much bigger oil reservoirs. I mean, you're aware that the VW Touareg takes 7 quarts of oil right? And many BMWs and Porsche SUVs take as much or more oil than that. When you've got more oil, you have more time before the TBN falls to levels requiring replacement.
 
<bless> The Atlantic is a very wide ditch. :roll: I have no idea how much a quart is, BTW. As for doing oil tests, there are simply no facilities for doing so for lack of demand.
 
jaapv said:
I have no idea how much a quart is, BTW. As for doing oil tests, there are simply no facilities for doing so for lack of demand.

Good grief, they don't teach unit conversion in school over there? Or at least how to ask Google how many liters are in 7 quarts?
 
STS134 said:
jaapv said:
Well, it seems Europe is the most undemanding place on earth... I'll stick to the 20.000 km.

Forget about the fuel dilution issue, there's almost no way that the bases in the oil that neutralize the acids generated by combustion will last that long. Unlike the fuel dilution data I have, the TBN data at least follows a consistent trend. TBN of Mobil 1 0W-20 synthetic starts off at around 9.5-10. At 3700 miles, I was down to 5.0 (this was the first batch of oil that came with the car, not necessarily Mobil 1, and may have been exposed to a lot of stuff that slightly used engines don't put out, so take that sample with a grain of salt). At 5000 miles, I measured 4.5, and at 6000 miles, 2.9. The data I have is a little bit noisy, and doesn't fit a straight line, but there's almost no way you're going to have enough TBN after 20000 km. Once your Total Base Number, or TBN, goes below 2.0, your engine starts to corrode from the acidic byproducts of combustion that can no longer be neutralized. You're talking about doubling usage from when I measured a TBN of 2.9 at this point, which I can almost assure you is not a good idea.

I think I know why there's such an OCI difference between Europe and other places... it's called Mitsubishi Service Plan, or MSP. This doesn't exist in USA. An example can be found here: https://www.mitsubishi-motors.co.uk/owners/service-plan

(According to Mitsubishi UK, 90% of owners decide to go with this plan. You'll notice they recommend 12,500 miles/1 year intervals for regular ICE vehicles too) Similar in nature to USA BMW's "free" maintenance plan, which many have noticed elongated service intervals even though the fluids remained the same. Not sure about Mitsubishi ICE vehicles, but if I go 12,500 miles in my BMW X1 which uses fully synthetic Castrol oil, it'll look like thick nasty sludge (aka not good for the engine).

Here is an excerpt from Mike Miller, BMW master tech (same principle):
The factory oil change interval is controlled electronically, but is presently about every 15,000 miles. If you are running BMW's oil, oil analysis has indicated that oil and filter change intervals of 5,000-7,500 miles are prudent for long-term ownership... Old fashioned petroleum oil usually calls for 3,000-5,000 mile drain intervals, again verified by oil analysis.
 
Woodman411 said:
I think I know why there's such an OCI difference between Europe and other places... it's called Mitsubishi Service Plan, or MSP. This doesn't exist in USA. An example can be found here: https://www.mitsubishi-motors.co.uk/owners/service-plan

LOL! Yeah this is why I don't like service plans. They have all the motivation in the world to do the minimum amount of maintenance required to make it past the warranty period without something breaking. Beyond that, they really don't give a damn, because it's your proble, not theirs.

Woodman411 said:
(According to Mitsubishi UK, 90% of owners decide to go with this plan. You'll notice they recommend 12,500 miles/1 year intervals for regular ICE vehicles too) Similar in nature to USA BMW's "free" maintenance plan, which many have noticed elongated service intervals even though the fluids remained the same. Not sure about Mitsubishi ICE vehicles, but if I go 12,500 miles in my BMW X1 which uses fully synthetic Castrol oil, it'll look like thick nasty sludge (aka not good for the engine).

Here is an excerpt from Mike Miller, BMW master tech (same principle):
The factory oil change interval is controlled electronically, but is presently about every 15,000 miles. If you are running BMW's oil, oil analysis has indicated that oil and filter change intervals of 5,000-7,500 miles are prudent for long-term ownership... Old fashioned petroleum oil usually calls for 3,000-5,000 mile drain intervals, again verified by oil analysis.

It really says something when you present empirical evidence that the oil needs to be changed at X miles, and someone buries his or her head in the sand and just refuses to believe it, simply because the instruction manual says something, when there is empirical evidence AND a statement from a lab that analyzed an oil sample from this exact model of car saying otherwise. Hence my statement that I wouldn't buy any car previously owned by jaapv.

I mean, oil analysis is kind of expensive, but if you're just going to not do analysis to try to save money, you should err on the side of changing oil too often. That won't actually hurt your engine. This really isn't a game to see how long you can go without destroying the ICE especially if you're just shooting in the dark and not even getting the oil analysis numbers. I'm still trying to nail down the best OCI, and most evidence seems to be pointing toward 7500 miles w/ Mobil 1 0W-20 full synthetic + Mobil 1 Extended Performance oil filter. Beyond that, I highly doubt that the TBN is going to stay where it needs to be to prevent the engine from corroding. But note that I've been steadily increasing the interval at which I take the sample: from 3700 to 5000 to 6000. Sure, I may have been changing it a little too frequently in the beginning, but it's far better to do that than not change it frequently enough.
 
I think it's 3 countries that still use the imperial system of measurements, so maybe you should cut some slack for every other country in the world that doesn't. And even your pints, quarts and gallons are different sizes to what UK measurements were, so you need to be more specific and say "US quarts".

And you're again assuming that, just because you can measure something in your oil, it's meaningful for everyone else. Yearly / 12,500 mile / 20,000 km services are common in Europe except for exotica like Ferraris and McLarens, and I'd hardly liken the PHEV to those. And yet despite the obvious problems that you suggest that this must be causing us, cars seem to drive on here just like cars in the states. Have you ever considered that it might only become an issue for more than 99% of people long after the car has been dismantled for some other failure?
 
Seems to me that STS134 is sharing some useful and helpful information here and is being ridiculed for it.

Now that mine is out of warranty I will be performing my own oil changes so that I know that at least they have been properly done. I don't trust a garage to do it thoroughly all the time. I will take the advice of the owner's manual, my own driving style and journey type as well as useful information like that which STS134 has kindly shared.
 
ThudnBlundr said:
...
Yearly / 12,500 mile / 20,000 km services are common in Europe except for exotica like Ferraris and McLarens, and I'd hardly liken the PHEV to those. And yet despite the obvious problems that you suggest that this must be causing us, cars seem to drive on here just like cars in the states. Have you ever considered that it might only become an issue for more than 99% of people long after the car has been dismantled for some other failure?

Just because a practice is common, even from the manufacturer, doesn't mean it's good for the vehicle long-term. Witness the plethora of turbo-charged engines in the past 5 years, motivated by smaller displacement and increased emission regulations. For those who have lived long enough, turbocharging was popular in the 80's, only to fall out of favor in the 90's when eventually it was the first costly part to break down. Deja-vu? Don't know, but logic shows that anything spinning at 20,000+ rpms will wear out, and it's still costly to repair today. Short-sighted by the manufacturers? Maybe. It's telling that Toyota, one of the most conservative well-known for reliability, willingly chooses to avoid turbo-charging in favor of reliability, bucking the industry trend.

Same trends can occur in maintenance. I don't know much about Mitsubishi history, but I know BMW. They had a reputation for being costly to maintain, so to counter that, they started their low-maintenance or free maintenance program, knowing that most BMW owners lease their vehicles for 3 years and switch vehicles after that. So for the first 3 years, there is almost no maintenance done to the vehicles. Even the tranny fluid, which they previously recommended to change every 50,000 miles, somehow became "lifetime fluid", even though the fluid part number didn't change. The after-effects were disastrous - reports started to trickle in of auto-trannies blowing up as early as 80,000 miles. BMW eventually back-tracked and quietly removed the "lifetime" label, but this took over 10 years to play out.

You have to live long enough and observe the trends, and most importantly, effects of those trends. Smaller displacement engines, which are the trend now due to ever tightening emissions, puts more demand on engine oil, not less. People are driving their vehicles harder and more aggressively. Traffic congestion is worse than before, and stop-and-go driving puts even more stress on engine oil. Due to these factors, it is highly doubtful engine oil technology has advanced enough where we went from every 3,000 miles, to 5,000, to 7,500, to now 12,000 or even 15,000 miles before engine oil change. But every car is different, even among the same model due to tolerances. Everyone has a different routine and commute. So the only way to validate whether a yearly 12,500 mile oil change is appropriate, is to do an oil analysis.
 
ThudnBlundr said:
I think it's 3 countries that still use the imperial system of measurements, so maybe you should cut some slack for every other country in the world that doesn't. And even your pints, quarts and gallons are different sizes to what UK measurements were, so you need to be more specific and say "US quarts".

And you're again assuming that, just because you can measure something in your oil, it's meaningful for everyone else. Yearly / 12,500 mile / 20,000 km services are common in Europe except for exotica like Ferraris and McLarens, and I'd hardly liken the PHEV to those. And yet despite the obvious problems that you suggest that this must be causing us, cars seem to drive on here just like cars in the states. Have you ever considered that it might only become an issue for more than 99% of people long after the car has been dismantled for some other failure?

Woodman411 said:
Just because a practice is common, even from the manufacturer, doesn't mean it's good for the vehicle long-term. Witness the plethora of turbo-charged engines in the past 5 years, motivated by smaller displacement and increased emission regulations. For those who have lived long enough, turbocharging was popular in the 80's, only to fall out of favor in the 90's when eventually it was the first costly part to break down. Deja-vu? Don't know, but logic shows that anything spinning at 20,000+ rpms will wear out, and it's still costly to repair today. Short-sighted by the manufacturers? Maybe. It's telling that Toyota, one of the most conservative well-known for reliability, willingly chooses to avoid turbo-charging in favor of reliability, bucking the industry trend.

Same trends can occur in maintenance. I don't know much about Mitsubishi history, but I know BMW. They had a reputation for being costly to maintain, so to counter that, they started their low-maintenance or free maintenance program, knowing that most BMW owners lease their vehicles for 3 years and switch vehicles after that. So for the first 3 years, there is almost no maintenance done to the vehicles. Even the tranny fluid, which they previously recommended to change every 50,000 miles, somehow became "lifetime fluid", even though the fluid part number didn't change. The after-effects were disastrous - reports started to trickle in of auto-trannies blowing up as early as 80,000 miles. BMW eventually back-tracked and quietly removed the "lifetime" label, but this took over 10 years to play out.

You have to live long enough and observe the trends, and most importantly, effects of those trends. Smaller displacement engines, which are the trend now due to ever tightening emissions, puts more demand on engine oil, not less. People are driving their vehicles harder and more aggressively. Traffic congestion is worse than before, and stop-and-go driving puts even more stress on engine oil. Due to these factors, it is highly doubtful engine oil technology has advanced enough where we went from every 3,000 miles, to 5,000, to 7,500, to now 12,000 or even 15,000 miles before engine oil change. But every car is different, even among the same model due to tolerances. Everyone has a different routine and commute. So the only way to validate whether a yearly 12,500 mile oil change is appropriate, is to do an oil analysis.

Absolutely correct. The thing with this car is that the engine only puts out around 60-70 kW, which on that power gauge is about where the "V" in the word "PHEV" is. Which means that it revs up to max power nearly every time I get in the car and go somewhere on the freeway. In a high performance European SUV, you won't use those upper rev ranges very often, because the ICE is sufficiently oversized. This is done because it's better to operate a smaller engine closer to its optimal point on the consumption map when you are cruising down the freeway than a larger engine at an inefficient spot because the power demands are too low BUT, it also means that when you do want extra power, you are stressing the engine close to its mechanical limits, and unlike in cars with a larger ICE, this happens routinely*. Also, if the car is abused so badly that something else fails before the engine does, then it doesn't really matter how often you changed the oil. And on a lot of vehicles, the owners don't maintain them very well. Just go to any used car lot and pull the oil filler caps off of all of the engines there and look inside. It's absolutely horrendous what you tend to see.

Here's a data point to consider. My previous car had the Toyota 1ZZ-FE engine, which was absolutely notorious for engine oil sludge problems. Toyota's advice, issued after the car was built after many others out there experienced problems, was to always use synthetic and reduce OCI to 5k miles regardless of whether in "demanding" conditions or not (they recommended 7500 miles for non demanding conditions initially). Which a lot of people simply ignored. Some were reporting that oil consumption was at 2-3 quarts per 5k miles after just 60k miles of engine life: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2488105/Re:_This_fixed_oil_consumption I pretty much always used synthetic though, always changed at 5k miles anyway, and had negligible oil consumption (< 0.25 US qt/5k miles) up to around 180-200k miles. And by the way, I drove that car HARD. I even lost not one but two sets of brake rotors coming down mountain roads in it. One time, around 140k miles, I took it in to the dealer complaining about excessive oil loss, and the tech first tried to blow me off and told me that at 140k miles, losing 0.5 qt/5k miles is completely normal or even below what's normal. I told him it's absolutely NOT normal for this car and to find the problem, and eventually, he did, after dismantling a large part of the engine. The timing chain tensioner was leaking oil. After this was fixed, for around US$2000 in labor, oil consumption went back to its usual level (negligible).

Anyway, in the last few tens of thousands of miles before that car was totaled by an idiot behind me not paying attention at 239k miles, consumption was increasing exponentially, something like from 0.25 to 0.5 to 1.0 to 1.75 qt every 5k miles in the last few oil changes I did. I would guess this was due to the piston rings starting to wear down. Doing proper oil changes won't eliminate engine problems, but it can sufficiently delay them so that you don't have to spend money on an overhaul as soon. Actually, I wanted to overhaul my engine at the time it was totaled, but what stopped me from doing so was that Toyota apparently allows for oil burn at the rate of 1 US qt/800 miles, meaning that I was still way under the allowed specification, and I was afraid that if I took it in, they could even make the problem much worse and just completely disavow responsibility because it left the shop "within spec". I would have waited until it was at around 1 US qt/1500-2500 mi before taking it in for an overhaul, and I think it would have gotten there in maybe another 30-50k miles of use. Everyone who worked on that car in its final 1-2 years of life said that he thought it could easily make it to 300k miles. Had I run dino oil out to 12k miles in that car, I probably would have had to overhaul the engine well before 200k miles.

*I do have some data that suggests that this ICE undersizing is detrimental to engine life. I once drove my car with the 1ZZ-FE engine I mentioned in subsequent paragraphs to the Southern California area from the SF Bay Area, and made very frequent use of WOT (wide-open throttle, aka maximum power) as I was trying to set a time record. My target speed was 95 mph (153 km/h) and I aimed to just keep it there the entire time, but occasionally I'd get stuck behind a truck and I'd have to slow down. After getting past these trucks and other vehicles, I would then floor it to get the speed back up to 95 mph ASAP. This engine was weak enough that you could absolutely put the accelerator to the floor and it was only enough to overcome air resistance around 110-115 mph, and no further acceleration occurred. And, the 75 mph to 95 mph time took around 7-8 seconds even with the accelerator floored because so much of the engine's power went toward overcoming air resistance that there wasn't much left to accelerate with. This trip also included a stretch of over 60 continuous seconds flooring it up the Grapevine on I-5, desperately trying to maintain 90 mph when the car didn't want to go any faster than 85 mph with 2 people and luggage in the trunk up the 6% grade. What happened was that when I got back home, after a distance of around 750-800 miles, a full quart of oil had disappeared from my oil reservoir. Now of course had I done this same trip in a V-6 car, or a high performance car like a Porsche, with a top speed of 130-200 mph if not for the electronic limiter, I probably wouldn't have had to stress the engine to close to its limit so many times. Bottom line, when you have a downsized ICE in a hybrid car, the engine and its oil is put under a much higher average stress level than the engine in a pure ICE drive car, and needs to be changed more frequently. And PHEVs have another unique issue and that is likely related to operating temperature: fuel dilution.
 
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