5w-40 vs 15w-40?

[Emil]

I would like to change my oil and use Mobil Delvac 1 but it only comes in 5w-40 where the recommended weight is 15w-40. I really want to use synthetic since I've have great luck with it in the past but I'm not too sure if the 5w is going to cause a problem. The truck will be staying in Florida which makes it an even more difficult decision. Suggestions?

[Roger926]

you will have no problem with Delvac 1 5W-40...it provides good cold cranking properties, getting the oil into the top of the engine quickly on startup, while moving to a 40W when reaching operatiing temp just like any other xW-40 wieght multigrade.

being in Florida is not an issue....it will still provide superior engine protection regardless of climate.

Originally posted by Emil
I would like to change my oil and use Mobil Delvac 1 but it only comes in 5w-40 where the recommended weight is 15w-40. I really want to use synthetic since I've have great luck with it in the past but I'm not too sure if the 5w is going to cause a problem. The truck will be staying in Florida which makes it an even more difficult decision. Suggestions?