Changing engine oil spec after 22,000 miles

Joined
Aug 7, 2009
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UK
Hello, As title says, i would like to switch to a different grade of oil. I run a Toyota Diesel 2.2d4d over in the UK. Manual says i should run it on 5w/30 but dealer has performed 2 services 10 & 20k using 10w/40 shell oil. Firstly if they are using the wrong grade, what potentially could happen? BTW: this is very common here in the UK, nearly all dealers are using 10w/40 i think as some European Toyota engines suffer from heavy oil consumption so dealers started using thicker oil, that and lower cost. Now i'm thinking of changing the oil at 22k miles for 5w/30. Firstly, would this be ok? Would the engine be run in and used to 10w/40 by this mileage. And is it also ok to swap oil so soon after a service? Main reasons for swapping are: well, the manual say 5/30, also i'm worried about low temperature wear coming up to the winter. We get down to 5-10 degrees C but occasional drop to 0 and even had -8 for a week here last year. Also i think i might get better fuel consumption on 5w/30 and possibly smoother running. My only worry is how will the engine react to a thinner oil after all this time and will i get higher oil consumption. Thank you
 
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Joined
Jan 29, 2009
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NJ
So long as the 5w30 meets the specs(and I haven't ever seen a 5w30 diesel oil) then I think it would be ok. 10w40 might be a tad much for your engine especially in a cold climate, maybe try 5w40 which would be a hair better during colder months and giving you the protection that a diesel oil would. That owner's manual may be a generic manual if that truck comes in a gas powered motor as an option. I've seen 10w30 diesel but I myself never saw 5w30. Hopefully one of the big guru's can chime in on this, but 5w40 seems like a safe all year round bet giving you what you want.
 
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Joined
Jan 10, 2008
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Milwaukee, WI
You could change to a 30 weight at any time. The engine isn't used to anything. That being said, I probably wouldn't. You might bet better fuel mileage, but not good enough to make up for the money you spend on the new oil. The 40 weight won't hurt anything. Winter starting might be the only thing that would get me to do anything about it, but I don't think you'll have a problem there either.
 
Joined
Sep 6, 2007
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TX, USA
Diesel engine tends to operate at a higher temperature. That is why they put 10W-40. But the most important is not just the viscosity but the rating. The oil has to be rated for diesel engine. So 5W-30 is fine as long as it is rated for diesel. In the US, they are either CI-4 or CJ-4 (the 'C' is for diesel as supposed to 'S' in the rating like SJ/SM).
 
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Jan 5, 2008
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Central Iowa
viscosity is important depending on the oil ports/channels in the engine. If the OEM recommends a 5w30 it might be due to flow considerations of the oil throughout the engine. I have nothing but diesels in my semi, jeep, ag tractor, etc. They do not, on average run hotter than most gasoline engines. They all run at the thermostat setting and my oil temps hardly ever get above 200F. True, they use heat and compression for fuel combustion instead of a spark, but they don't necessarily run hotter. That the oil meets OEM classification requirements is more important than whether the grade is a 30 or a 40. There are a number of 15L diesels in large trucks that use a 30 weight oil with no problems. I doubt that you are going to press your Toyota as hard as a semi with a gross of 40 tons. The 5w or 10w is just the winter flow rating. Being in the UK, you would probably be better off with a 5w rating. So.... the OEM recommendation of 5w30 is probably right on target. Quite a few oil brands have a diesel rated 5w30 in their product line. Just not found that often on the shelf. Being in Europe, it should be more readily available than in the U.S.
 
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May 7, 2005
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Texas
Almost every fully synthetic motort oil that is not a HDEO will have an API diesel rating of CF. This is an old but not obsolete rating and might be suitable for OP's Toyota. oldskoo1: what does your owner's manual call for?
 
Joined
Aug 28, 2008
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New Hampshire
 Originally Posted By: gonesurfing
VW is specing 5W-30 on our 2009 TDI Jetta. It must meet their own specifications though and is not readily available in the US market, except at the dealer.
Just yesterday I saw Mobil 1 ESP 5w-30,which is approved by VW (spec 505.00/507.00) for their latest US diesels as well as for Mercedes and BMW late model diesels.It was $7/litre at Pep Boys,which is much cleaper than I've seen it elsewhere.
 
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