Chippy01

MPG issue after service and tyre change.

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Bit of a long post, but please bear with me here …..

My 2011 Gen 3 T-Spirit went in for it's 60,000 mile service on the 14th November to my local Toyota service centre.

While it was in there, I was phoned to say that the I need 3 new tyres as the ones on the car were showing sidewall damage and rubber rot. 
Now I am normally 'on the ball' with regards to tyres. I knew my tyres will need replacing before  my next NCT (MOT) which is due in January, but I hadn't checked them recently. I informed the service manager that I will do my own check on the tyres when I get the car back.
Apart from that issue, the service went as expected. New Oil and filters all round, Hybrid Health Check passed, and everything else tested checked out perfect.

When I got the car back, that following weekend I took the wheels off the car to check the tyres. The three tyres highlighted in the service receipt did indeed have some sidewall damage, and rot could easily be seen. The fourth tyre  was OK, albeit about 3/4 worn. Weighing up my options, I decided to change all 4 (but keep the 'good' tyre as an emergency fitment, if needed)

First off, I went online to check out the old tyres (they were on the car when I got it 30,000 miles ago) re rolling resistance and wet grip.
Three of the tyres were Michelin Premacy HP, with a r/r rating of E and a w/g rating of A. The fourth was a Dunlop SP Sport 3000, with a r/r rating of F and a w/g rating of B, according to the info I could find online.
On the 22nd I had my new rubber sorted and fitted. Got a deal on some Cooper Zeon CS8's, with a r/r rating of C and a W/G rating of A. Has to be better than what was on it, anyway. Oh, and I run my tyres at 36psi.

Since the service and new tyres were fitted, I have really struggled to get my MPG over 54mpg. I am travelling the same roads, at the same speed, at the same time.
I know winter temps and weather conditions impact on fuel consumption, but not this degree. Normal summertime mpg figures is around mid to high 60's (per tankful), with winter normally running high 50's to low 60's. But the 3 weeks since the service and the tyre change hasn't been particularly cold, in fact it's been quite mild for the time of year, albeit a bit wet at times.

I read a previous thread on here about having the wrong Oil in a Gen3 could impact the mpg also. Checking back on the service receipt, under Oil used it read 'FUEL ECON E/G 5W

So, with the above info, what is hitting my mpg? Possible wrongly labelled tyres? Wrong Oil in the engine? Something else?

I want to go back into Mr T tomorrow morning and have a chat with the service manger, and any 'ammo' I can take with me would help.

T.I.A.

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5W on the receipt suggests they have used a cheaper 5W/30 Oil rather than the recommended 0W/20.  5W/30 is still listed as acceptable in the manual, so they can get away with it, but it will make a noticeable difference to economy.

That said, the new tyres may also be having an impact. You can ignore the EU ratings as they are a crock of s**t.  The OEM Michelin Primacys are actually a very economical tyre. 

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Also, check the Oil level.  Dealers are famed for overfilling (they seem to want to put the claimed capacity in, without taking into account not every drop gets drained!).

5mm or more overfill has been said to hit mpg, and I've heard of a number of owners insisting the dealer removes excess Oil after a service.

Most Toyota Hybrid engines don;t consume any Oil until around 100,000 miles or above (some not even then), and then progressively start to need a little topping up between services.   By the time one of my Gen 1 Prius was sold with 163k on the clock, I put 1 litre in about 7,000 miles after a service (when the level was getting close to MIN) and that tided it over  to the next service.

Also, it's possible the new tyres need more pressure than the previous ones, so I'd suggest watching the tread wear for any signs of over/under inflation (sadly, this takes some time to show up).

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If you have 5w30 Oil instead of 0w20,  then you will see a hit of a few mpg. It took a long time for dealers to get the message. However, a relative had their Auris HSD serviced a few months ago at our (under new ownership) dealer, and had 5w30 Oil used. She would have taken it back for replacement if she hadn't px'd it for a Prius shortly afterwards. I avoid the problem by taking my own Oil, which incidentally saves about £30 each time.

As PeteB says, dealers always overfill the Oil, as they take the Toyota figure as gospel. My dealer (also PeteB's) learned after I got them to take out the excess for the third time. The Gen3 and Gen4 only resulted in qround 5mm overfill, but the Gen2 was ridiculously over

Tyres may have a even greater effect on mpg. As Jay says, the EU ratings are a pile of poo, mostly because (AFAIK) manufacturers do their own testing. My experience is of replacing a set of Michelin Primacys with Hankook Ventus Prime 2, which had a significantly better economy rating. In practice  the Hankooks had 2-3 mpg worse fuel consumption, had much shorter life, as the tread pattern had vanished by 3 1/2 mm whereas the Michelins were still good at 2mm. All in all the cheaper tyres were much more expensive per mile than the Michelins. 

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Thanks for the replies so far.

If EU labels on tyres are not worth the sticker they're printed on, why have them? Surely they are there as a guide for us poor Joe Soaps to decide which tyre might be the best for a particular installation?.

When checking out my old tyres, I discovered many types of Michelin Premacys, all of which had a r/r rating of B. EXCEPT the Premacys HP, which my car was wearing at the time. So when you say you had good Premacys, I would have to ask "Which version?"

I shall up my tyre pressure over the weekend to 40psi, and see what that does to my consumption. I shall also be having a little chat with MrT this morning, to see if they will admit to which Oil was used. I did check the level, and it is bang on the top pip, no overfilling.

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In theory, the EU labels should work as you suggest. In practice they simply don't. Two tyres with the same eco rating can deliver wildly different real-world fuel consumption as I have discovered to my cost on more than one occasion. 

I believe the Primacy HPs on my Gen3 and those on my Auris HSD were actually C-rated. When looking to replace them, I remember seeing Primacy HPs which were E-rated, yet otherwise apparently identical. Whatever I had, they were brilliant tyres as they'd passed 60,000 miles before they needed replacing and in 17" form on my Gen3 delivered better economy than the B-rated 15" tyres/wheels I replaced them with.

40psi would be a good test - I found that to be the optimal pressure for economy on 17s. The Oil is definitely going to be dragging the engine though, if it's 5W/30.

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I went to MrT this morning, as I said I would.

No mechanics on duty, but the service manager confirmed that 5w30 was used at my service. Looking back over her records, she could see that 5w30 has been used for every service my car has had there.

I was also told that 0w20 is only used on models from 2016 onwards. Well, says I, my handbook recommends 0w20, and to use 5w30 if 0w20 is unavailable, but to change it out as soon as possible.

I also said that the car does not feel right. That it appears to be struggling. I've had the car for 30,000 miles and I know well how it performs, and it's not performing as usual. And that I left it for 3 weeks before coming in, just in case I was imagining things.

Perhaps it is the tyres? Are new tyres harder on fuel than worn ones? Hard enough to knock 10mpg off of my usual consumption rate? I wouldn't have thought so.

Anyway, I was asked to bring the car in on Monday morning and they would check it out.

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0W-20 is Toyota's preferred Oil for hybrids. It has also been the preferred Oil for Optimal Drive petrol engines since late 2008.

See the following to check which Oil to use - 

One can use Toyota's online tool contained within the following blog article to check the correct Oil for one's car - https://blog.toyota.co.uk/find-the-right-oil-for-your-toyota?utm_source=ToyotaOwnersClub&utm_medium=ForumLinks

This shows that for a 2011 Prius, the correct oil is 0W-20.

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Its a common trick for garages to re-fill with the cheaper Oil. As everyone says: 0w20 is the right Oil but would you believe it? most garages dont stock it! I once challenged the garage which refilled my car with the recommended alternative and was told they had refilled the vehicle with the recommended Oil although when pressed, they declined to tell me what grade that Oil was. I started to buy my own Oil and use the stuff they fitted during the service as a flushing Oil. I would drain it off after 200 miles and reinstate my fuel consumption by refilling with 0w20. I suppose I could've saved myself some time by giving my Oil to the garage to refill for themselves ,however , having been seen off by their shoddy tricks once, I thought it better to personally see  to it that the right Oil went in. 

Oh the things we do to get those official stamps in the book eh?FSH means so much to most people and yet means nothing at all to me

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This Oil issue has been discussed on this forum many times in the past. It is a load of rubbish that OW20 is used only on models after 2016. My 2011 and 2014 Prius models were serviced and the dealer always used OW20. Dealers should know OW 20 should be used on all hybrid models. I would insist the Oil in your car is drained and the correct OW20 Oil is used. Who is this out of touch dealer?

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Oil is the reason and the tyres as a accomplishment to the Oil. 0w20 should be only the Oil in hybrid, also if you want to change the viscosity for some reason just use 0w30 or 0w40 A5 specific grades, do not change the smaller number “winter” as this is what actually make 0w20 best in Hybrid engine where cold and frequent start and stops are happening. In my personal experience Toyota own 5w30 Oil  was one of the worst oils that been used in another car in the past few years, back than I did some research and found that that particular Oil was a semi synthetic Oil made Chevron-Texaco. Probably ok for a cars that are not driven a lot and under loads on motorways, most likely and in a city environment. Just sharing my experience and personal preferences. Currently using Petronas Synthuim 7000 0w20 in Auris Hybrid 2010, change every 10k miles and so far happy. 

Regards 

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I've had the same problem with my Gen 4, after it's 1st service I noticed a drop in mpg,  went back and asked what Oil was used and they insisted it was OW20 , however it was 10mm over the top mark of the dipstick  ( which is actually mentioned in the handbook that the top mark is excessive) which the service manager said was normal. Customers will think they have not got good value if it's not filled right up!   really?

I told him that when the car arrived from Japan it was 10mm below the top mark and asked them to lower the level but they wouldn't lower it 10mm,  the car never recovered the mpg I got that 1st year.

Now it's had it's second service it's over the top mark again and my mpg has definitely dropped even more and I'm cheesed off with it as I can't face another argument with their moronic service manager

 

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Brand new tyres may affect fuel economy until they're bedded in a bit. Also, I think it has got significantly colder in the past few weeks, so I'm sure that's not helping either. Personally I'd stick to tyres that claim to be low rolling resistance - I use Goodyear EfficientGrip Performance and they've been fine, though aren't the longest lasting tyres in the world.

5W30 appears to be the norm for Toyota dealers in Ireland, they will claim it's the "recommended". But to be honest I've used both in mine and noticed no appreciable difference.

I have heard that overfilling the Oil can lead to fouling of the inlet manifold - I do not know how much of a concern this is though, or how much overfilling is required to cause this.

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21 hours ago, Chris Dance said:

This Oil issue has been discussed on this forum many times in the past. It is a load of rubbish that OW20 is used only on models after 2016. My 2011 and 2014 Prius models were serviced and the dealer always used OW20. Dealers should know OW 20 should be used on all hybrid models. I would insist the Oil in your car is drained and the correct OW20 Oil is used. Who is this out of touch dealer?

Our dealer has always used 0W20 in my cars, the Gen 3, Prius+ and current Gen 4, I think they even put it in SWMBO's Gen 2 now.

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Herself took the car into Mr T this morning. According to the paperwork, they changed the Oil out for 0w20, and did a full diagnostics on the rest of the drive.

The next few days for running in and out to work will see if it makes any difference. Watch this space.

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After another regular trip today that registered 15mpg less than usual I've decided to drain my Oil out and refill by purchasing some 0w-20, this is the only way I can be sure that it has the correct Oil. Then see if I get a considerable improvement to mpg so I can challenge the dealer, taking their word is meaningless, I'm in to 2 years of a 3 year service contract so don't get a receipt showing what fluids were used, at 2 years old the car has done 11,500 miles

What Oil can I get other than Toyota's which is seemingly £70 for 5ltr  direct from them. I need to be wary of online sellers as so much is faked these days so would hope to buy locally

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With regards the Oil, on eBay Burrows car parts (a chain of Toyota dealers in Yorkshire), are offering 5ltrs of 0w/20 of the genuine Oil, delivered, for £40.

EuroCarParts have a flash sale on Oil until midnight (so 'click and collect' for Wed. or Thurs.?), but their range of 0w/20 is limited. Their own brand, Triple QX, is still £37 with that discount; at that price I'd rather have the Toyota one from Burrows.

Or, PiperCross in Northampton are selling Petronas brand very keenly on eBay (£23?), but then you are unable to easily track its origin, which you mentioned you'd prefer to be able to.

Given that the Burrows price is the price that a dealer *can* sell at with postage included, perhaps you could negotiate a discount at your local Toyota dealer off the back of that as a benchmark?

If I understand it correctly, the engine Oil with use tends towards a monograde (i.e. it gets thinner as the viscosity index stabiliser package wears).  So your 0w/20 might be more of a 0w/15 by the time it gets changed out.  As the new Oil is 'thicker', it may impact your mpg slightly until it gets some use.  So it could be that even if the correct Oil is used that the mpg will dip compared to the old Oil, at least initially. 

If you did drain your own Oil, why not keep a sample of it to see if you can measure the thickness of it compared to your new Oil, or even to any 5w/30 that you may have knocking around?  If you have the barrel of a syringe, you can measure the time it takes for a measured quantity to drain through the orifice.  If this is too quick, make the hole smaller, so the timings are more easily measured.  

From my (limited) experience, you should be able to see if it is basically a 0w/20 or a 5w/30.  Make sure the samples are the same temperature, of course.  The above may well be a symptom of having 'too much time'.

A Toyota garage local to me overfilled the engine Oil by over a pint, I know this because I drew it out the dipstick hole with a 50ml equine syringe and some tube.  So you have my sympathies.  I'd have thought that much more than that and the crank webs may start splashing in it, if they haven't already!

0w/17.5 already exists, and is in use in some Fiats by the way.

HTH.

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15 hours ago, Gerg said:

With regards the Oil, on eBay Burrows car parts (a chain of Toyota dealers in Yorkshire), are offering 5ltrs of 0w/20 of the genuine Oil, delivered, for £40.

HTH.

Thank you Gerg,

I have now ordered  some from Burrows,  I'll have to see if I can get under the car one way or another or alternatively use a dipstick pump, some claim they work very well providing the Oil is hot

 

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I have a Pela 6000 pump that I have often used, just not on this Toyota.

Pela offer an aftersales parts service for any future problems.

A benefit of the Pela is that the last section of the suction pipe is a narrow, self-straightening pvc coated metal 'spring', like a heavy duty bicycle brake outer cable. this works quite well.  But there is was only one size (bore) supplied with mine, but I've not found a car it didn't fit.

Earlier Silverline models seemed to suffer from poor vacuum valves, but this is probably easily fixed as DIY.  This one seems a bit of a bargain:-

https://www.amazon.co.uk/Silverline-104616-Fluid-Extractor-Pump/dp/B003G2YV1I/ref=pd_sbs_60_2?_encoding=UTF8&pd_rd_i=B003G2YV1I&pd_rd_r=f3dc8435-fdf5-11e8-8be0-53ba1bdabb1c&pd_rd_w=gZbpG&pd_rd_wg=jyEGX&pf_rd_p=18edf98b-139a-41ee-bb40-d725dd59d1d3&pf_rd_r=S2DW4VWM9VX0BSM1VPAX&psc=1&refRID=S2DW4VWM9VX0BSM1VPAX

You don't get all the old Oil out obviously, this depends on the sump shape etc. or what angle the car is sitting at. The Oil just needs to be warm, if it's hot I usually let it cool down a while.  You don't need to bother yourself with a new sump plug and its all pretty effortless!

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The Silverline one has reasonable reviews but the insertion tube has nothing to keep it stiff, nevertheless I'm considering one of these as the Pela ones are £100+,   one reviewer got a thin aluminium tube from B&Q and fitted the flexible pipe to that which seemingly worked a treat

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Since having the Oil changed, the slight hesitation and 'struggling' that was felt has disappeared. MPG is still lower than I would like, but running against the high winds and rain we have been having these past days might contribute towards that.

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The Silverline pump arrived yesterday, I went out this morning to find that neither of the tubes will fit down the dipstick hole , that means I have to find an even smaller tube which will take even longer to suck out the Oil.   I might end up just going to a local small garage and get then to do it

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On 12/11/2018 at 5:42 PM, Gerg said:

...If you did drain your own Oil, why not keep a sample of it to see if you can measure the thickness of it compared to your new Oil...

Reminds me of a post I read some years ago (wish I could remember which forum, probably not this one) from a couple with a Gen 2 Prius who every 10,000 miles had a sample of their Oil sent to a specialist laboratory for a detailed analysis.  IIRC, it cost some US$30 a time, and they posted a couple of the very comprehensive (but meaningless to me!) reports.

These reports showed (according to those that understood - or claimed to - such things) that even after 100,000 miles without an Oil change (or top up!) the lubricating qualities of the Oil was still more than sufficient, and from memory they went to about 120k before their first Oil change.  They observed no problem with the car, nor any earlier propensity to consume a little Oil than any other models (a Gen 1 Prius I kept for 163,000 miles used none up to about 100k, and by 160k dropped to near MIN after about 7,000 miles from an Oil change, then adding 1 litre kept it well above MIN until the next service).

Wouldn't want to try that myself, but interesting all the same.  I would expect a normal petrol or diesel engine would work it's Oil harder and hotter than a Toyota Hybrid and they may not get away with such extremes.

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16 hours ago, Chippy01 said:

Since having the Oil changed, the slight hesitation and 'struggling' that was felt has disappeared. MPG is still lower than I would like, but running against the high winds and rain we have been having these past days might contribute towards that.

For the 9 years I had my second Prius (a Gen 1), I did a monthly weekend trip to Norfolk from Luton, a round trip of about 250 miles plus local driving while there.

One thing I did find there was no rhyme or reason to the fuel consumption that I could discern.  The load, speeds and driving style were fairly constant (with lots of Cruise Control usage) and as the journeys were late Friday evening and Sunday afternoon traffic was not often much different.  But the mpg on each 125-mile one way trip mostly varied between 50 and 65 mph but was often not what I'd expect given the weather conditions.

Whilst many journeys gave mpg that seemed consistent with the conditions, occasionally a wet and windy journey would be particularity good, other times a still, warm day wouldn't.

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I've taken great interest in the mpg on my Prius which is fitted with 15" wheels, for me that was the whole point of buying it. We do more or less the same local trips each week so I know more or less what each trip mpg will be allowing for the weather. 

Once a month I go to a coin fair at the Motor Museum near the NEC, Its 25 miles from where I live and there is a long stretch of the M42 that is level and slight sloping down. The first year of owning the car I got 75- 82mpg going and around 70 coming back. After the 1st service I struggled to get 70 going. Its 2nd service was late November, last Sunday I went as usual and it just turned to 60mpg as I pulled in to park so something definitely not right there.

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