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What this video covers

Mixing different oil weights in a marine diesel engine — specifically adding 30W when only 15W-40 is available — is the question Nigel Calder addresses in this short Q&A with host Jan Attenstedt.▶ 0:24 Calder's position is direct: running an engine low on oil is worse than topping it up with a mismatched weight or brand.▶ 0:43 He draws on personal cruising experience where obtaining the exact specified oil was impossible, though he acknowledges he has no controlled scientific data to back the claim.▶ 0:00 The practical guidance is to use whatever oil is available to keep the engine running, then switch back to the correct specification as soon as it can be sourced.▶ 1:23 Calder and Attenstedt invite listeners with harder technical evidence to contribute to the comments section of their marine diesel engine maintenance course.▶ 1:09 The core takeaway: oil compatibility matters, but an engine running on slightly wrong oil outlasts one running dry.

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