Recently Serviced Observation

[Wass]

Since our car has been serviced by Lexus its entire life, I have wondered whether the oil being used is always 0-20 or the much cheaper 5-30 grade. We had an old prius which I used to use 0-20 grade oil from an original toyota container. The CT goes to be tended professionally and I noticed that having both oil changes in the same week, keeping both the cars in the same garage at the same temperature, the oil dripped off the Prius dipstick much faster than the CT dipstick.

The reason I decided to check the two together was because I originally bought the car 2nd hand, newly serviced from Lexus Tunbridge Wells and drove the car for the next 10000 miles averaging 65 mpg. We then had the car serviced locally but i started to drive the Prius because my wife and I decided to swap since the prius was higher mileage and i was just ramping up the CT mileage. Since getting the car serviced locally, neither of us have ever got close to the average i initially managed in the first 10000 miles.

I once queried the dealer about this problem and they "analysed" the oil an pronounced it "within Lexus specification".

Now I am going to change the oil and filter myself and will use the 0-20 toyota oil and see whether our lost 10% fuel economy returns.

I have done the maths and I have calculated that over 10000 miles, using the thicker oil costs £45 more even allowing for the fact that the thinner oil costs more than the thicker oil.

I will report my findings.

[ColinBarber]

Does your service receipt state what oil was used? Not that it proves anything but it is much more serious if they are stating that 0W-20 is being used but it isn't.

[Wass]

Surprisingly ( not), it doesn't say what type or grade of oil was used. This sort of thing wouldn't be something dreamt up by the mechanics though would it? The invoicers would be "in on the act".

The thing is: I believe that both 0-20 and 5-30 are recommended for the car...its just that it uses less fuel if the engine runs with 0-20 in it.

[ColinBarber]

There are several grades that are permitted in terms of keeping within the manufacturer warranty however 0W-20 is the preferred grade. It is used in the factory and really should be used unless it is unavailable when you can use one of the alternatives - no dealers should be using anything else on Toyota/Lexus hybrids.

[poippy baby]

Hi Wass, what were the findings from your original post?

[Wass]

Hi Wass, what were the findings from your original post?

I have just changed the oil. The oil which came out of the car is about 2 weeks old and has done 100 miles. It smelt burnt and was much thicker than the correct toyota 0-20 which I replaced it with. I also noted that a cover appeared to be missing from the underside of the car but it wasn't the cover which would need to be removed for oil and filter changing. Its too early to tell exactly how this has affected fuel consumption. However, early indications are good.

[Wass]

I have just finished a round trip to my fathers house of 200 miles.On previous occasions, with the previous oil which had been provided and filled by the professionals at Lexus, the car did 61 mpg with the air conditioner off. Today it did 69 mpg with the air conditioner on. Although the on board computer is wildly optimistic and the figures are 10% optimistic, the comparative figures show a considerable improvement which would support my original theory that the Lexus dealers are not fitting the recommended oil as a matter of routine because it is cheaper to them to fil with alternative grades and we, the suckers wont notice, and even if we do they say that they have checked the oil and found it within Lexus recommended guidelines ( which the treacle they have been filling with, is).

It seems to be a loophole/catch22 type thing. Cant do anything about it other than specify that the Lexus appointed servicer fills with 0/20 and details this on the invoice.

My initial calculations of the savings to be made were a little inaccurate by today's figures. The savings made by filling with the right 0/20 grade oil over whatever was in our car, are greater than 10%.

Can one blame a business for trying to find a legitimate way to save themselves money? I would say no. Can I be blamed for feeling a bit put out and feeling a bit ripped off? Again I would say no. Does this make me feel more confident about autotraders boasting "full service history" or would I feel more confident to see "owner maintained". Hmm makes me wonder... " full service bodgery" seems more relevant.

[ColinBarber]

You may want to speak to Lexus GB and see what they have to say on this subject. They are the ones that seem to have dictated the current servicing costs and I assume costs have been calculated based on using certain fluids.

Using 0w-20 compared to 5w-30 should produce some benefit but 10% seems way over. As you say the fuel computer is a bit all over the place so that could account for 3% and possibly another 3% just in traffic and variations in driving from one day to another.

Toyota look to achieve a 10% improvement which each hybrid generation, if 10% was made up just by the oil they wouldn't have had to do anything else between the Gen 2 and Gen 3 Prius :)

[Wass]

You may want to speak to Lexus GB and see what they have to say on this subject. They are the ones that seem to have dictated the current servicing costs and I assume costs have been calculated based on using certain fluids.

Using 0w-20 compared to 5w-30 should produce some benefit but 10% seems way over. As you say the fuel computer is a bit all over the place so that could account for 3% and possibly another 3% just in traffic and variations in driving from one day to another.

Toyota look to achieve a 10% improvement which each hybrid generation, if 10% was made up just by the oil they wouldn't have had to do anything else between the Gen 2 and Gen 3 Prius :)

I really don't see what might be achieved by talking with Lexus since as far as I can see, this is all perfectly legitimate.My fuelly figure will be more indicative of the real picture when I have finished this tank of fuel. However, early indications are at least 10%, like it or not. Who is to say that the treacle used was 5/30 anyway?It might have been 10/40, 20/50 etc. Point taken about the different generations of Prius which has spurred me to wonder whether an oil grade cheaper than 5/30 was used routinely.

All this has caused me to lose all confidence in "professional" Lexus trained personnel.

[ColinBarber]

If you don't think the correct oil is being used then unless you inform somebody nothing will be done about it. Toyota almost mandate that 0w-20 is used in Toyota hybrids, there is no reason to think that that also shouldn't be stating the same to their Lexus dealers.

[ColinBarber]

The CT owners manual states the following:

If SAE 0W-20 oil is not available, SAE 5W-30 oil may be used. However, it should be replaced with SAE 0W-20 at the next oil change.

Therefore dealers certainly should be using 0W-20, or at least every other service otherwise you aren't conforming to the warranty requirements of the vehicle.

[ColinBarber]

I contacted Toyota GB about oil and received the following:

Thank you for your email regarding the oil type for your vehicle.

I can confirm that the type of oil used by Lexus centres is stipulated by Toyota GB, you will be able to find out the exact code from you Lexus centre.

I would therefore say that Toyota GB would be interested if you feel the correct oil isn't being used. Ultimately the dealer could lose their franchise if they continuously don't conform to policy.

[Wass]

We have now completed one full tank after the oil change which I carried with Toyota oil from a sealed can. The improvement, as initially indicated was just over 10%. 59mpg best before oil change, 66mpg now. This has been calculated top up to top up rather than from the on board computer ( on board computer is inaccurate but never the less, consistently inaccurate). The on board computer agreed with these figures in magnitude of percentage savings if not in actual mpg readings. The on board computer actually said about 62 prior to my oil change and said 69.5 today.

Arguing that Toyota need have only changed the oil in order to achieve a 10% saving from the previous generation of engines doesn't quite make sense since putting 0/20 oil into a generation2 prius doesn't gain 10% better figures, it achieves about 2% better figures since I tried it. Toyota have actually redesigned the engine and its control protocols and algorithms from the old1.5 to the 1.8. It feels like they have also redesigned the cam profile too in order to achieve higher savings. One thing is very clear in my mind though, the 1.8 engine in the Lexus is definitely suited and designed with 0/20 oil in mind. I have yet to encounter the newer 1.5 engine which is fitted in the yaris but I suspect that it isn't the same as the old 1.5 fitted to the gen 2 prius.

Overall, I have to say that I am quite pleased with the results in that I had thought that something was broken when the car wouldn't perform anywhere near as well from 15,000 miles to 50,000 miles as it did from 5000 miles to 15000 miles. This coincided with my wifes increased usage of the car and I had initially assumed that she was heavier footed than I. ( just to explain the out of phase servicing, the car was bought 2nd hand from Lexus with 5000 miles covered and the initial 10000 mile service completed.

It seems there is nothing wrong with our car or my wifes driving and the fault lay elsewhere. A fault which I can easily rectify by specifically requesting that the service is not started unless the correct grade of oil is available and is detailed on the service paperwork as having been supplied once the service is complete.

[Wass]

Here we are, a year down the line, and I have just completed a tank full to tank full fuel usage  check since the service in July. I dont use the car much in the summer hence the time gap. Sure enough, the fuel consumption has  risen by about 10% again and so I shall change the oil myself to ensure the car runs on 0/20.I shall monitor the fuel consumption having changed the oil.

 It will take a week for the oil to arrive but hopefully, I will get this work done towards the end of my holiday.

[Verbout]

Very interesting read