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Castrol Magnatec 5W-30 and 10W-40 no good at all for K20A6?

dandreye

dandreye

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Accord 2L MT (CL7)
Hi All,

Apologies for yet another oil related question but at least it's a fairly specific inquiry ) Following recent theft of my old Honda Accord 6 (F20B6) I'm now left with several Castrol Magnatec 5W-30 and 10W-40 cans. Are they any good for my new Honda Accord 7 (K20A6), which needs Honda's 5W-20 as per Owner's Manual? If not... I'd like to understand what exactly would be wearing out in the engine faster with each of them than it would have with the right oil - just for curiosity really although it'll help motivate myself to buy 0W-20 )

As for synthetic vs mineral, the Owner's Manual says "You may use a synthetic motor oil if it meets the same requirements given for a conventional motor oil: it displays the API Certification Seal, and it is the proper weight", which I suppose implies mineral as the 1st choice (I think some of those Magnatec ones in question are mineral while the others might be part synthetic).

Many thanks in anticipation!
 
You'll be fine with 5w30, I've been using that for years in our FRV k20
 
Hi All,

Based on F6HAD's advice above in this almost 5-year old thread I've used up almost all my Castrol Magnatec 5W-30 A5 by now, and have had no obvious issues except modest oil burn. Just back from Tesco where there's a deal on it these days - with the following question to be sure: is A5 any superior than A3/A4, C3, C2 etc, particularly for my petrol engine K20A6, which has done ~104k miles by now? I saw Honda mentioned among several other makes on most if not all of them but why not get the best one. My understanding is that A5 has lower viscosity than all other variants, hence closer to the officially recommended 0W-20, but I could be wrong.

Also what exactly can I expect to suffer in my engine if I use Castrol Magnatec 10W-40 instead of 5W-30 during the warm time of year? Will it still make it through all those thin oil channels? I still have a pair of old 4L cans with it left from my old car and there's really no other application for them that I could think of.

Many thanks in advance!
 
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@SayamaAccord:
Thanks for your reply. I saw that Exol oil referred (positively) from a number of threads here, so it must also be good. Just trying to work out the answers re Castrol meanwhile.

Update: Been reading about excessive camshaft wear issue on K20/K24 engines with oils above "-30", which explains why Honda revised their initial recommendation downwards (to 0W-20). Looks like 10W-40 is a definite no then?
 
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