I recent swapped out my water pump, radiator and hoses, and drove the car around for 45 minutes...

I then blew the alternator, and so the car was parked for a week or so... This past weekend, I popped the radiator cap, and it was stinky and still under pressure (made a mess, but it was just water)...


Mainly curious as to why the radiator would still be under pressure after a week... Not sure what the stinky water is from...

Previous owner must not have used anything but water, because the water was rusty-looking when I drained it...

I am just using drinking water and I will add some Water Wetter once I know everything functions well...

Don't use tap water. Go to the grocery store and buy distilled water to use in the car.

Also, don't bother with Water Wetter. It's affects are temporary and it can weaken some paper based gaskets such as water pump gaskets thus causing leaks.

Don't use tap water. Go to the grocery store and buy distilled water to use in the car.

Also, don't bother with Water Wetter. It's affects are temporary and it can weaken some paper based gaskets such as water pump gaskets thus causing leaks.


I don't use tap water. I honestly was using bottled drinking water... I usually buy distilled water, but I basically "save" all the extra "old' water (1/2 used bottles, etc) from parties and kids... I figured I have this sitting around...

I have used Water Wetter for YEARS, and NEVER had a problem (neither have many friends that also use it).

Where did you hear the "affects" are temporary, or that it eats gaskets? Just curious, I know EVERY product has horror stories and I have heard people say WW is a waste,, but I have never heard those particulars about Water Wetter...

Where did you hear the "affects" are temporary, or that it eats gaskets? Just curious, I know EVERY product has horror stories and I have heard people say WW is a waste,, but I have never heard those particulars about Water Wetter...

Personal experience.

Also, bottled drinking water and distilled water are not the same thing. What an engine needs is distilled water.

I'm curious. Why straight water and WW? You have no lubrication, corrosion protection and a lower boiling point than with Ethylene Glycol coolant. I'm not saying you're wrong, just wondering how you made the decision.

I'm not intending to answer for Tony, but water alone has a greater cooling ability than an anti-freeze/water mix. And since he lives in California, I don't think a freeze up is of great concern. Running water alone is a good choice if you live in a climate that allows you to do it without risk.

I'm not intending to answer for Tony, but water alone has a greater cooling ability than an anti-freeze/water mix. ...

Really?? I've always heard that EG also raised the boiling point too, or are you talking about the ability to transfer heat?
Darn it, now I have to go find out for myself. :)

100% water transfers heat better than a 50/50 mix.

In a properly functioning cooling system the boiling point should never become an issue. Regardless of which is used, the boiling point of the coolant should be sufficiently higher than the temperatures experienced in the engine as long as the pressure is maintained.

100% water transfers heat better than a 50/50 mix.

In a properly functioning cooling system the boiling point should never become an issue. Regardless of which is used, the boiling point of the coolant should be sufficiently higher than the temperatures experienced in the engine as long as the pressure is maintained.

Thats right, pure water is better for heat transfer than having EG, but Pure water does lack the additives that are good for cooling systems. Water Wetter has additives that lubricate the pump seals, protect from corrosion and alter the surface tension to aid the heat transfer...

I don't believe everything I read, but, here's what Redline says...

WaterWetter® is a unique wetting agent for cooling systems which reduces coolant temperatures by as much as 30ºF. This liquid product can be used to provide rust and corrosion protection in plain water for racing engines, which provides much better heat transfer properties than glycol-based antifreeze. Or it can be added to new or used antifreeze to improve the heat transfer of ethylene and propylene glycol systems. Designed for modern aluminum, cast iron, copper, brass and bronze systems.

· Doubles the wetting ability of water
· Improves heat transfer
· Reduces cylinder head temperatures
· May allow more spark advance for increased torque
· Reduces rust, corrosion and electrolysis of all metals
· Provides long term corrosion protection
· Cleans and lubricates water pump seals
· Prevents foaming
· Reduces cavitation corrosion
· Complexes with hard water to reduce scale

I have used it for many years as well as many of my friends, and while I don't have scientific evidence, we all noticed a reduction in water temps and have NOT seen any ill effects (such as Rich's gasket-eating problem).


As Rich mentioned, "Distilled" water is the best choice. this is because it has a lower mineral content. Minerals (especially from tap water) can eventually build up and clog a radiator. "Hard" water is even worse...

I live in California, and where I live, we might see a few nights per year with temps below 30 degrees ( maybe 15-20 nights below freezing), but my garage is usually much warmer, so I don't have a need for the "anti-Freeze" capabilities of EG... Its also a much stickier mess when it leaks or is drained...

The boiling point of pure water is 212 degrees at atmospheric pressure (open radiator with NO cap)... With a cap, the boiling point is raised (I think its somewhere around 246 degrees with a 16 lb cap, but really I forget, PV=nRT??)... In my last Chevelle, i actually ran a 20-lb rad cap, to increase the boiling point further (didn't need it though, but cheap insurance)...


Still wondering why my water was stinky and still under pressure... I have felt a little residual pressure in other vehicles, but this was pretty significant (IMO) and after a week of sitting. But I don't recall such foul smelling water...

I'm thinking the smell is probably algae/bacterial growth. Locomotives (most) use straight water with additives to prevent this, along with other additives for lubrication and such. Without an anti algae additives the water gets really nasty smelling. The idea of straight water in that application isn't better heat transfer, though. It's due to the tendancy for coolant to find it's way into the crankcase. EG would eat up the bearings.

The pressure is probably from the system "breathing. As a hot engine cools the coolant contracts and air is drawn in. On a cool night the system cools even more and more air is drawn in. When the underhood temp goes up with the ambient temp, pressure builds because of the pressure cap. This can happen even if you have a coolant recovery system, but is more common on older vehicles without a recovery bottle.


I knew WW modified the surface tension of the water. I didn't know it had other components for lubrication.

Using distilled water also helps avoid electrolytic metal transfer (or whatever it's called). Ever have an aluminum intake or thermostat housing that looked corroded? There are small electrolytic forces at work that remove aluminum and move it to iron when the two are close to one another. Water with minerals in it aids this process, "pure" water does not. Absolutely pure water (there really is no such thing outside the laboratory) is not a conductor.

Anti-freeze and other coolant additives typically include chemicals that help eliminate or at least counterbalance this effect in the water portion. Even an old 50/50 mix can be as damaging as highly mineralized water.

Is it possible that the water pump pressurized the system above ambient in some portion of the system? If this happened before the warmup expansion it could draw additional coolant into the system. Then you would have pressure when you removed a cold cap.

Of course that would require some kind of flow restriction for the pressure increase. How is the thermostat bypass?

I'm thinking the smell is probably algae/bacterial growth. Locomotives (most) use straight water with additives to prevent this, along with other additives for lubrication and such. Without an anti algae additives the water gets really nasty smelling. The idea of straight water in that application isn't better heat transfer, though. It's due to the tendancy for coolant to find it's way into the crankcase. EG would eat up the bearings.

The pressure is probably from the system "breathing. As a hot engine cools the coolant contracts and air is drawn in. On a cool night the system cools even more and more air is drawn in. When the underhood temp goes up with the ambient temp, pressure builds because of the pressure cap. This can happen even if you have a coolant recovery system, but is more common on older vehicles without a recovery bottle.


I knew WW modified the surface tension of the water. I didn't know it had other components for lubrication.

Sounds viable to me. Anyone ever see the picture of a railroad tank car that had collapsed into itself? The supposed theory was, they steamcleaned the inside of the tank late in the hot afternoon, then closed the tank up for the night. Once the temps cooled off, the thing cooled down, and it imploded. I'll see if I can find some pics...

The pressure is probably from the system "breathing. As a hot engine cools the coolant contracts and air is drawn in. On a cool night the system cools even more and more air is drawn in. When the underhood temp goes up with the ambient temp, pressure builds because of the pressure cap. This can happen even if you have a coolant recovery system, but is more common on older vehicles without a recovery bottle.



But this pressure was with a COLD engine, sitting for a few days... So any air that was drawn in should still be at atmospheric pressure...

I am now thinking the bacteria growth might be responsible for both the pressure and the smell...

I think I figured the rest of my cooling system issues, so I'll probably be draining the current water soon, and refilling with distilled and WW...