Can I go fully synthetic?

[Catlover]

I just had my Prius serviced today by Mr Toyota. I usually specify when booking in over the phone and when I actually drop the vehicle off that 0w-20 is used. Today I forgot, BUT when I went back to collect (and pay😪) I asked what oil was put in and it was actually stated on the Invoice/Service sheet , 0w-20. So not all Toyota dealers are going for the option of biggest profit margin (if indeed many or none are doing that). Though 5w-30 is acceptable, in the case of the Prius (and Auris Hybrid), 0w-20 is mentioned first so that in my mind is the preferred choice and thus what I want. I dont know what the service handbook says re 2009 petrol Auris says.

As for changing from semi to full synthetic I dont know if there would be a negative reaction, I suspect not.

What is important, and all the more so you doing short runs and not a lot of annual miles is to change the oil and filter regularly in accord with manufacturers recommendations or even sooner. Every 2 years is way to long. Compared to potential engine problems the cost of 5 litre of oil and a filter is cheap. The way to longevity is to change the oil and filters, no secret to that.

 

[FROSTYBALLS]

The views of some oil companies who should have the right information:

https://www.mobil1.co.uk/learning-centre/synthetics-lab/myths-about-synthetics.aspx

https://www.valvoline.com/about-us/faq/synthetic-oil-myths

https://www.pennzoil.com/en_us/education/know-your-oil/why-synthetic-oil.html#iframe=L3NvcHVzL3Blbm56b2lsLzIwMTZuZXdzbGV0dGVyLz9sb2NhbGU9ZW5fdXM

https://mobiloil.com/en/faq/ask-our-auto-experts/questions-for-auto-experts/what-will-happen-switching-from-synthetic-motor-oil-to-conventional-oil

https://www.cenex.com/about/cenex-information/cenexperts-blog-page/oil-and-lubricants/five-engine-oil-myths

https://www.shell.co.uk/motorist/motoring-tips-and-advice/why-synthetic-oil-for-my-car.html

According to the above using a synthetic oil will NOT affect the oil seals, and moving from semi to fully synthetic will not be bad for the engine

[ziauris]

Toyota dealer said they used 5w-30 semi-synthetic in my auris too, but i changed to 5w-30 fully synthetic. My car does not use a drop of oil, still at the fully mark after 6 months of driving. Check your car for leaks on the top and bottom of the engine around the sump and oil filter -make sure it is on (hand) tight, tight's good! Don't get any work done at Huddersfield Toyota, I wouldn't trust them with my wheelbarrow.

The auris seems crap, doesn't seem to have any warning lights, it's written on honestjohn that someone driving an auris had very low oil levels and no lights came in on the dash so it doesn't have any warning lights for low oil. This is very bad as even cars cheaper than the auris have warnings for non-working side lights/indicators and low fluid levels, but if the Toyota does not have these warnings, I can't understand why other than penny pinching.

[mrfixer]

I have spent half a lifetime in the motor industry and I can tell you that engine failures due to lubrication breakdown are almost unheard of nowadays. Obviously you need to maintain the oil level and change at least annually to avoid sludge (which is a problem on some engines).

In Thailand I run a 1999 Camry 2.2.  It has spent hours crawling in Bangkok traffic with the outside temp at 40+ deg and then blasting along highways at 70-80mph.  The car now has 400 000 km on the original engine and still doesn't use any significant amount of oil.  Its had a change every 6 months using the cheapest 5W-30 oil and a no-name filter from B-Quik (a local fast-fit chain).  Just change the oil regularly and don't worry too much.

[paul9]

Was going to order oil flush online from ECP and put in their sale code, but it didn't cover the oil flush. To save hassle, I just decided to grab the flush off the shelf and pay cash without an order in the depot. Online, flush was £5.29. Depot price was £2.49. I got an oil filter from them, but for the oil I just bought Ford spec fully synth 0W30 from Asda (red container Tetrosyl oil). Just as cheap as the ECP "sale" price. One of these days, they could be in legal trouble for their "sale" practices. At the very least, if they sorted out their pricing schemes, I would buy more from them, instead of sourcing from eBay and other places as much. Diesel Avensis for that fully synthetic I bought, BTW.

Some VVT engines are supposedly very sensitive to oil thickness, as the thinner oil they specify is need to run properly through small diameter oil channels and holes in the valve timing adjustment mechanism. Watch out for that, if you are trying to use thicker oils.

[mrfixer]

10 minutes ago, paul9 said:

 

Some VVT engines are supposedly very sensitive to oil thickness, as the thinner oil they specify is need to run properly through small diameter oil channels and holes in the valve timing adjustment mechanism. Watch out for that, if you are trying to use thicker oils.

The kinematic viscosity of a 0w20 at 100deg.C. is about 9cSt.  A 5W30 is about 10cSt.  Its sweet FA difference to be honest.  Anything up to a 40 would be ok. 

KV is non-linear with temp and increases massively at low temps. Around 0deg.C. can be 800+ cSt. so its important to run a 0W or a 5W for winter cold starts - ensures the oil gets round quickly. Important on Toyotas because they tend to run with a high fast idle - i.e. revs can jump to 2000rpm on a cold start.

[paul9]

I didn't think there would be a lot in it, but as with frequent oil and filter changes, as they say, it is cheap insurance.

[furtula]

5W30 is used in most cars, your shop probably orders it by the barrel, and recommends it as best possible oil, as they will benefit financially from it the most.

I think you should be just fine, car was engineered to have 0W20 as default.

I did hear of stories of people trying to switch from mineral to semi or fully synthetic and that the cars started leaking a lot, but this is not your case, and that was like 15-20 years ago.

 

If the oil was really bad, it would be beneficial for him that you install it, right? More work..