If you pour cold water into a hot engine, how much more damage can you expect other than possible cracking the block?

I believe it depends on hot it is. If it is at operating temp, not too much will happen.

If it has overheated, puked, and is not running, you'd be real lucky not to see it crack.

either wait for the engine to cool, or wait long enough that you can run it with the cap off and slowly add the new water to the mix. This will cool the motor slowly and prevent the block from cracking.

Other than cracking the block?? I think that would be the only worry... the water goes straight into the block from the hole in the top of the radiator by the time it gets anywhere else its warmed up enough to not do any damage to anything else

Not necessarily. I have seen an engine block crack when this happened. Years ago, aka 1969, back when full service stations were in business, Customer came in to refuel.

I add pump nozzle to tank for fillup. Lift hood to check vitals. Oil level okay but I hear oil frying, upper rad hose warm, not hot to touch. Remove cap to check coolant level. There is none.

I asked customer if engine temp light came on, he replied it had not. I asked the duty part-time mechanic about the water bucket. He said he had it and would take care of it since he had nothing to do at the time.

He poured in the water, and out came geyser. After it stopped spewing, he added more water. Continued until level was fill. Closed up the radiator and shut the hood. I had already filled the tank, clean the windows, checked the tire pressure, and collected the money, $2.25 for eight gallons. Customer drove off happy as a clam.

Next day, I came to work after school and here is the same car on the side lot. I asked and I was told it had a cracked block, milk in the oil pan. Part-time mechanic didn't work there any more.

Hell, I actually cracked the block in my old Nova by simply splashing through a big mud puddle. I guess those old blocks were prone to cracking during temperature shock.

I spray cold water into my engine everyday. I rigged up a water injection setup on my dodge truck. The system sprays a fine mist of water varying the amount depending on the TPS.

Why do you want to pour water into your engine? If you wanted to clean up the combustion chamber, just get a water sprayer and spray some water in while it's running. I know some people just dump water in, but I think mist is more quickly converted to steam which is what cleans the chambers.

I have never heard of pouring water into the combustion chamber, I thought that was what carb cleaner, injector cleaner, stp and the likes were for. Seems to me like water in the combustion part of the engine would be a bad idea. Anyway, I am certain he means putting water into the radiator, not down the carb throat.[/color]

Pouring water into the carb to clean the combustion chamber is an old shadetree trick. It works very well if it isn't poured too fast to either kill the engine or hydro lock it.

It does as paulm describes, if poured in small amounts, the carb atomized the water and when ingested in the combustion chamber, it becomes steam and helps to remove carbon.

Back in the '70's, this was the method of reducing detonation. The water reduces combustion temperature, thus, more ignition advance could be dialed in, more power.

Haingh, weird.... I imagine you'd have to be pretty careful when doing it eh? I think I'll just stick to the additives myself.

heck, water injection was big way back then...lol. I had on electronic setup, 2 stage vacuam trigger, adjustable, on a 406 back in 82 or so. Darn thing ran on a 50/50 mix of leaded reg & 93 unleaded, with 12:1 compression!