Actually, straight weight oil doesn't cause sludge build-up.
It's using non-detergent oil that can contribute to sludge build-up, and I don't think much of anything anymore, requires non-detergent oil.
Using multi-viscosity vs. straight viscosity is a matter of personal preference for older engines. Some like one while some like the other.
There are other factors that can cause sludge build-up besides non-detergent oil (e.g.- engine getting overheated, neglect, lack of maintenance, etc.).
And some engines are more prone to sludge than others. Remember the Toyota engine fiasco from a few years back? And, of course, multi-vis was used in them.
Over the years, I've owned a lot of tractors. Used straight 30wt (detergent of course), and 15w40 and have had absolutely no problems with either one.
I have made sure though, that I use a good quality name brand oil.
It's using non-detergent oil that can contribute to sludge build-up, and I don't think much of anything anymore, requires non-detergent oil.
Using multi-viscosity vs. straight viscosity is a matter of personal preference for older engines. Some like one while some like the other.
There are other factors that can cause sludge build-up besides non-detergent oil (e.g.- engine getting overheated, neglect, lack of maintenance, etc.).
And some engines are more prone to sludge than others. Remember the Toyota engine fiasco from a few years back? And, of course, multi-vis was used in them.
Over the years, I've owned a lot of tractors. Used straight 30wt (detergent of course), and 15w40 and have had absolutely no problems with either one.
I have made sure though, that I use a good quality name brand oil.
