Radiator flush quick question - drained fluid only warm not hot after 20min

[str8flexed]

Quick question. In the middle of a full radiator flush. After draining 8L, filled the radiator up with distilled water and idled with the engine on for 20-25 minI also went and feathered the accelerator a bit.

When I opened the valve on the bottom to drain, I was curious and touched the water. It was lukewarm at best.

Any ideas? I thought it was supposed to be piping hot. Makes me think something is wrong. Did the thermostat not open? Maybe I should just put the radiator cap on and go for a drive? I kept the engine on while having the fluid in a funnel, not pressurized with a cap.

 

[jgue467]

What was ambient temp? I think 20-25 idle mins should raise temps to normal, 190s allowing thermo to open, its probably lukewarm because that is the coolest part coming out first, the hotter water is entering at top.

Did you turn on the heater to allow that water to move out also?

 

[phattyduck]

Idling on a cool day? There's a good chance the bottom side of the rad is pretty cool. If the upper radiator hose is hot, the thermostat is opening.

Why not just go for a drive? You can run weeks with just water in there (maybe put in some watter wetter or similar if you are going to run for any reasonable time). I've done that on other projects when I'm checking for leaks and other performance issues and I don't want to waste coolant...

-Charlie