5w30 cold pump ability

[OVERKILL]

Originally Posted By: KrisZ
Originally Posted By: il_signore97
Originally Posted By: OVERKILL

Yup, the guy with the SuperDuty in the room next to us, who I can only assume had 15w40 in it, still didn't have his truck running by the time we left. CAA was there and had a big portable "start cart" hooked up to it as well as a generator running the block heater

LOL... (Trying not to laugh at the expense of others, but your story is funny!!! I sure wouldn't want to be in that situation!)


There is nothing funny about it and in diesels, the oil choice has zero relevance on start vs non start condition. At those temps if the truck hasn't been plugged in or had a Webasto unit running, it simply will not start, as the diesel fuel cannot properly vaporize and generate enuogh heat through compression. You could have MMO in the crank case and it would not help one bit.

As it was mentioned many times before, running ANY oil that meets manufacturer specifications will not be a deterimental factor in a non start condition, the battery condition will.
My cars experienced the same winter sitting outside and had no trouble starting in the morning with conventional. If I lived in a place where -35C was a routine occurrence, a good coolant and oil heater would be my first choice, not a unicorn oil.


While that is certainly true, my buddy Jon's 6.0L PSD started fine in the -20's unaided with Mobil Delvac 1 5w40 in the pan. Yeah, it romped a bit (and he always had Stanadyne in the fuel) but there was a significant difference between the romp his truck did and the trucks at work that had 15w40 in them.

Most of the time of course he'd plug the thing in but you always end up in a situation at some point where you can't and it is bloody cold. How fast they roll over is certainly relevant to them starting or not (heat of compression), as of course is fuel gelling and other fun stuff (like if your glow plugs are healthy).

 

[KrisZ]

Originally Posted By: OVERKILL


While that is certainly true, my buddy Jon's 6.0L PSD started fine in the -20's unaided with Mobil Delvac 1 5w40 in the pan. Yeah, it romped a bit (and he always had Stanadyne in the fuel) but there was a significant difference between the romp his truck did and the trucks at work that had 15w40 in them.

Most of the time of course he'd plug the thing in but you always end up in a situation at some point where you can't and it is bloody cold. How fast they roll over is certainly relevant to them starting or not (heat of compression), as of course is fuel gelling and other fun stuff (like if your glow plugs are healthy).


Speed does affect the starting, I agree, but I started quite a bit of diesel machinery and the cranking speed starts to increase about the third starting attempt. That's how quickly the oil is beginning to thin. So if the glow plugs are not to snuff, all the thinner oil will do is get you started on fewer attempts, but you will still start, provided the temp is not too low. But below 30C the oil alone will not help you. And before someone picks up on less starter wear, get the glow plugs and batteries taken care of first and start plugging in the car, as even with the best oils, you will have to keep cranking quite a few times each day with faulty glow plugs.

Just to remind everyone, I'm not disputing here the fact that a good quality synthetic with good CCV characteristics has no benefit, not at all. All I'm disputing, is the belief that anything else, especially conventional will leave you stranded in the extreme low temp weather.

In the example you gave about the Super Duty, we don't know the state the batteries were in, the glow plugs or what kind of oil was in the crank case. But people quickly jumped in on the "blame the thick oil" bandwagon. Just saying...

 

[OVERKILL]

Originally Posted By: KrisZ


Speed does affect the starting, I agree, but I started quite a bit of diesel machinery and the cranking speed starts to increase about the third starting attempt. That's how quickly the oil is beginning to thin. So if the glow plugs are not to snuff, all the thinner oil will do is get you started on fewer attempts, but you will still start, provided the temp is not too low. But below 30C the oil alone will not help you. And before someone picks up on less starter wear, get the glow plugs and batteries taken care of first and start plugging in the car, as even with the best oils, you will have to keep cranking quite a few times each day with faulty glow plugs.


I think we are on the same page. That said, I don't think "romp" is particularly good for the engine (not sure how detrimental it is either though, on the flip side) and it seems to be generally accepted that a 10w30 or 5w-40 reduces cold start romp and I've seen it with my own eyes. I think that's generally something we can agree on to be desirable

Originally Posted By: KrisZ
Just to remind everyone, I'm not disputing here the fact that a good quality synthetic with good CCV characteristics has no benefit, not at all. All I'm disputing, is the belief that anything else, especially conventional will leave you stranded in the extreme low temp weather.


Well, we could always pull out those hypothetical situations where the starter or batteries are marginal and the added load of the thick oil is the make or break for it starting or not, LOL!

But generally I agree with you. I think the biggest benefit is having proper oil flow with the better cold flow characteristic oil. An oil that is below its CCS or below its MRV, there is the risk that it may not pump. After all, you are operating outside of its designed range of temperatures.

Originally Posted By: KrisZ
In the example you gave about the Super Duty, we don't know the state the batteries were in, the glow plugs or what kind of oil was in the crank case. But people quickly jumped in on the "blame the thick oil" bandwagon. Just saying...


True. But I'd wager he probably DID have 15w40 in it. It is the most common weight. In that case, he was in fact operating below the designed operating range for the oil.