Can running straight water in radiator/block cause overheat?
 

I'm just getting China drivable, and need to flush the motor a tad, so I just filled up with water in the block and radiator. I also burped top hose as much as possible. No overflow bottle on '80 240D btw.
Driving the car with the AC on, it was hovering around the 85-90 degree area for the first 5 minutes or so. {ambient mid-hi 80's} Then it creeps up the the 100 degree mark, and passed it just a tad.
Super clean, almost new looking radiator from looking through cap opening. New thermostat.
Is just running water enough to account for this higher temp? I've heard of folks running a few hundred miles to do a citric acid flush, so it would seem water should be OK, but yall tell me.....
Thanks

Not sure of the temps but I would think it could be a faulty thermostat.. So I would check that. Another note, I would not run straight water on a sleeved block for any extended amount of time. This could cause the cylinder sleeves to rust and breaking the seal, then leaking coolant into the crankcase.

If you're using a 120 cap, the boiling point is 223F.

That doesn't mean that you can run right to this point as the bubbles begin well before this temperature and the localized cooling drops precipitously when the bubbles begin to form.

However, if the engine remains below 100C., you shouldn't have a problem for the short duration of the project.

I would begin to back off the power and become quite cautious if the gauge climbs up above the 100C. mark.

The sleeves are of a dry type so there's no danger of any seals breaking.

That's good to know! Thanks

Jimmy,
you better get that xerex coolant asap. Lake lavon and surrounding lakes around mesquite are high in sulfurs and the deposits are not that nice. you can run the car for a while on distilled water, but there is still the problem of the bubbling which loweres the effectivity of the coolant.

Hope to see the now famed China soon.

Will do, and that is good info. Raining right now, though......