Is it better for the machine to use washing powder or liquid?

Please can only washing machine engineers/repairers/designers answer. Thanks.Is it better for the machine to use washing powder or liquid?
Last time I had to have my washing machine repaired, the repairman told me that the base of these liquid detergents is pig fat, so it can build up over time and clog things. Don't know if he knew his stuff or not, but I always use powder. If you're worried about it diluting first, add the powder, let the washer fill and then add your clothes.Is it better for the machine to use washing powder or liquid?
For the quality of the wash then the liquid is certainly the best. The machine starts to wash straight away as the washing liquid is all ready diluted. You will not get pockets of undiluted powder as you do with other forms of detergent. The machine will then stay cleaner and not clogged up with lumps of powder. Still a good idea to put a water softening agent in to cut down on the lime scale around the drum and heating element.
I don't know about the machine, but I think liquid is better for clothes. You don't get the soap deposits as you can do with powders/tablets.
Yeah, you might find a repairman here but I seriously doubt any designers or engineers are here.
You can make a solution of the washing powder and then put it