I usually use Delvac MX 15w-40 in my 2005 sportster but was in the local parts store and they didn't have any.
I bought Castrol Activ 4T 15w-50 instead, as recommended by Castrol.
What i found interesting is that the 15-40 Delvac has an HTHS of 4.3 and the Activ 4T 15-50 is 4.1.
This is even though the 40 and 100 deg viscosities of the Activ 4T 15-50 are quite a bit thicker than the Delvac MX 15-40.
Am I correct in saying the 15-40 Delvac holds up better in an operating engine and is therefore actually thicker in operation?
Cheers
I bought Castrol Activ 4T 15w-50 instead, as recommended by Castrol.
What i found interesting is that the 15-40 Delvac has an HTHS of 4.3 and the Activ 4T 15-50 is 4.1.
This is even though the 40 and 100 deg viscosities of the Activ 4T 15-50 are quite a bit thicker than the Delvac MX 15-40.
Am I correct in saying the 15-40 Delvac holds up better in an operating engine and is therefore actually thicker in operation?
Cheers
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