TD42T - cleaning water passages on engine stand

[nissannewby]

I found a Cummins doc that states it can be used safely at twice that (5:1) but limit it to 3 hours in the system.
The fact that I'm doing it with cold water gives me a little more leeway.

Yeah it can be but 10:1 will usually suffice and gives you some left over of need be.

Yeah cold water may hamper it a little and running the richer ratio may help.

When we use to do it we would fill the systems then go and sit on the dyno at constant load until we saw 110 degrees in oil temp. Then dump and fill with coolant.