15W40 in an engine that calls for 5W30

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Absolutely. Might nick an MPG or two from you at the very worst. I wouldn't intentionally run it but if I had 15W-40 laying around I would (done the same with 0W-40).
 
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Your V-6 probably holds close to 5 qts of oil. Maybe do 2 oil changes with gallon of the 15W-40 each oil change and thinned out with a quart of 5W-30 mixed in additionally?
 
Wont hurt a thing. In fact a HDEO has different detergent so it may clean up something another oil left behind
 
It shoudn't do any harm.
It also won't do any good.
Since you have the oil laying around, run it over the hot summer months.
I doubt you'll notice any difference in fuel consumption.
The JD+ is intended as a long drain oil, so you could probably run a fill of it from early spring through early fall.
What is its API rating?
Current spec diesel oils are intended for use with ULSD, and regular gasoline contains more sulfer than ULSD, so it may not be possible to run the oil as long as I would have thought.
 
Originally Posted By: xxch4osxx
I'd run half 15w40 and the other half what you regularly use.

I'd go a step further than that and pick-up some Toyota 0W-20 to mix 50/50. That will give you the equivalent of a 5W-30 with a decent 170 VI.
 
Run it! Until the someone shows you proof of a negative outcome of thicker oil, go for it. I bet we'll compare notes in ten years and nobody will still have proof of a negative outcome.
HDEO is real good oil usually, well as far as I've seen personally.
 
Try it. If you don't like how the car runs change it out. It could show you that it runs great and you decide to use it full time OR the engine may get sluggish and you don't like it. Either way its valuable info.
In Florida type weather it isn't going to do any harm
 
It won't do any real harm, BUT it will give your battery and starter motor a harder time cold starting. Below about minus 5C it can cause a slight increase in cold start related wear factors.
If you do decide to use it, the difference between a 40 and the 30 recommended does not matter much, but don't play the chemist by mixing it with another oil type.
 
Originally Posted By: skyship
It won't do any real harm, BUT it will give your battery and starter motor a harder time cold starting. Below about minus 5C it can cause a slight increase in cold start related wear factors.
If you do decide to use it, the difference between a 40 and the 30 recommended does not matter much, but don't play the chemist by mixing it with another oil type.


He is in Florida. Florida is on the southern part of the country where its very hot. And this isn't. A diesel. All the points you just copied from you last response and posted here dont really apply.
And if Caterham says mix then its fine to mix. I take his word over skyship's any and every day of the decade OP.
Sunkship likes to think he is an expert,most of us think he is delusional.
Just my humble opinion.
 
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