Will water make my car overheat?

[jesse_gabriel]

I had an overheating problem with my 1.8t so I decided to change the thermostat because the water pump was changed about 10-20K miles ago. I was using water to test when I finished because I didn't want to waste coolant if there was a leak or something, it overheates after its warmed up if I exceed 3K rpms. Could this just be the water?

[gilber33]

Water is actually better for engine cooling. Buts it's corrosive and freezes in the winter.

[vwblackb5]

Water actually has a very high specific heat capacity, meaning it takes high amounts of energy to raise the temperature, which makes it a great insulator i.e poor conductor of heat. Would recommend DI or distilled water for the sole reason of preventing minerals from contaminating your cooling circuit components.

Science


TL;DR Water will not make your car over-heat any more than a 50/50 mix of G12. Vote is for stuck thermostat again or bad h20 pump.

[Charles.waite]

Water is actually better for engine cooling. Buts it's corrosive and freezes in the winter.

Thats not true. When water boils it causes serious overheating issues. Half of what coolant does is raise the boiling point super high so that that can't happen.

Also, running straight distilled is fine. I ran it for 4 months in my car because I needed to replace my oil cooler but didn't have time and didn't want to waste perfectly good g12. had no issues. If you're overheating with water its not the the water thats the problem.

[Furly]

What brand thermostat did you install?

[CyberPMG]

How bad is it overheating? Is it causing the alarms to go off? If so, you may have done some damage to the head (I was lucky and only damaged the head gasket). If you're catching and stopping before the warnings come on, then the engine is likely safe.

Have you checked other areas that may be blocking coolant flow? Does the radiator feel warm on both ends when touched or is it hot on one side and cold on the other (sign of a clogged radiator)? If the coolant temp is staying good under 3k RPM and will never climb higher than normal, then it might be the water pump failing.