When i drive the car for a bit the water in the reservoir starts to boil. I just replaced the raditor and the termostat. The oil looks good. Everytime I open my hood when it is cool there no water in the reservoir or very little. There also no leaks anywhere. What could be the problem?

Headgasket.

+1

Search the forums if you're new to cars or the platform in general. The repair isn't difficult, just tedious.

The car is not over heating. The gauge is showing normal temp and the oil look good also. I dont think its the head gasket coud it be any other causes.

It could be the radiator or t stat sticking, but you already replaced those, so I would have to go with headgasket as well. Coolant overflow tanks are not designed to boil...

Only other cause I could think of is you used STRAIGHT WATER in your cooling system.

So if i replace with coolant could that fix the issue? If so what color coolant do i use?

....

Are you saying you do have just plain water out of a hose in your cooling system?

Yes i do but i never thought water will harm.

I can almost guarantee thats your problem. Water boils at 212*. My Eclipses fan comes on at 210. Plus its under pressure. Go buy a gallon of Peak or some other good brand coolant from autozone or walmart or whatever. Try to stay away from 50/50 premade. Anyways, I always have another gallon jug on hand, so I pour half of the coolant into an empty jug, and fill both with water, giving me 2 gallons of 50/50 antifreeze mix. Try that and see if you still have problems.

water shouldnt really be the issue IMO... change your rad cap and pressure test the system. then if they both come out okay still having an issue burp the system, mines doing this too brand new motor. im thinking i still have air in it. burped it once and it got a little better.

How do you burp the system?

Originally posted by panthers4
Yes i do but i never thought water will harm.

Anytime water is used, you better use DISTILLED water. Normal tap water has minerals and deposits that will build up in your cooling system.

You shouldn't have a problem using just water. Modern cars use radiators that pressurize the "coolant" to 10-20 psi. When you pressurize water you actually raise the boiling point to something like 250 degrees, alot of pure race cars run pure water or Water Wetter mixtures.

I have to both agree and disagree with what Code4 said... Yes tap water does have impurities in it that will collect in the cooling system, but it would take years and numerous coolant changes and fills for the impurities to build up to a point that a lightly modded engine would overheat.

The first thing I would check is the radiator cap to make sure it holding pressure, if you have a pressure leak from the cap then the fluid will push out of the cap into the coolant reservoir as it heats and trys to pressurize. Resulting in boiling coolant.

Here's my little check list;

Leak in the cooling system;
Look for the easy obvious; signs of leakeage. Puddles on the ground. Lots of coolant on the tranny/backside of engine (pesky heater hoses)

Cooling fans;
Sit at idle to see if the fan comes on (duh). If they don't, you may have to rev it up a couple o' few of times to get heat going. Of course, watch the gauge as you do it.

Thermostat;
Pull thermostat and check it by boiling it in water and seeing if it opens fully (though most just replace it. Cheap and easy flip flop).

Radiator cap;
Have the radiator cap pressure tested (though, like the thermostat, most just replace it),

Radiator;
Look for obvious signs of rust and green/white flake build up on the exterior (usually located on the lower half). See if fins are just flaking off. Look for "wet spots". Pull radiator and have it pressure tested.

Blockage in the cooling system;
Flush the cooling system seperately (radiator then engine side) to check for blockage.

Water pump;
Check for signs of "weepage" under the water pump. Listen for grinding or squeaking (usually a chirping sound) coming from water pump. Look in the radiator cap opening and see if the coolant is actually moving (obviously, do this when engine is cold).

Headgasket;
Comp check and leak down. Look for oil contanimation or oil levels filling themselves up, lol. Look for air bubbles in the coolant as well as hardening of the coolant lines(pressurizing from the headgasket allowing combustion chamber pressure in the cooling system). Look for white smoke out of the exhaust after warm up. Check for hydrocarbons in the coolant (though this all could be good, but you could still have a bad headgasket. That's the tricky part).

.....and the etc. is for whatever I forgot/missed

Originally posted by Fasttopass
You shouldn't have a problem using just water. Modern cars use radiators that pressurize the "coolant" to 10-20 psi. When you pressurize water you actually raise the boiling point to something like 250 degrees, alot of pure race cars run pure water or Water Wetter mixtures. I have to both agree and disagree with what Code4 said... Yes tap water does have impurities in it that will collect in the cooling system, but it would take years and numerous coolant changes and fills for the impurities to build up to a point that a lightly modded engine would overheat.

Wrong, wrong and more wrong. Did I mention that you were WRONG?

Race cars run straight water because the engines are being drained rebuilt and refilled with such short run times that it doesn't matter. Coolant has corrosion inhibitors and extra additives that help it to stick to the metal parts of the engine for better heat transfer. Also, depending on the PH balance and mineral content of your local water corrosion can start happening at an alarming rate. Aluminum (our cylinder head) is EXTREMELY susceptible to this corrosion, and rust can happen just as fast in the cast iron block causing scaling that breaks off and clogs the cooling system causing overheating, leaks and other problems (ever seen a cylinder wall crack because of rust? I have.) Another problem is that even though the system is pressurized to raise the boiling point, the engineers designed the engine to operate within the raised boiling point of properly mixed coolant, NOT WATER. Properly mixed coolant has a pressurized boiling of over 250, water only gains 1-2 degrees of boiling temp per PSI of pressurization. You'd have to pressurize the system to 50 psi to get that high of a boiling point, and by then yor hoses would explode.

I would never run a street car on straight water unless it was a quick trip and I had no other option. Even then I'd pull the T-stat before I did.

Mark I feel as though you have typed that exact same list before:)

Originally posted by itsaslow95
Mark I feel as though you have typed that exact same list before:)

Heh heh, yeah, I've copied and pasted that on four different sites now :shrug (tuners, neons.org, here and hondatech). Couple years ago I got sick of seeing basically the same thread on "why is my car overheating?" (over at tuners). Thought a little list would cut down on some of the repeats. I was wrong. I have since copied that about 4-5 more times over there, lol.

Well, so much for that funny search button.....

Originally posted by RoninEclipse2G

Originally posted by Fasttopass You shouldn't have a problem using just water. Modern cars use radiators that pressurize the "coolant" to 10-20 psi. When you pressurize water you actually raise the boiling point to something like 250 degrees, alot of pure race cars run pure water or Water Wetter mixtures. I have to both agree and disagree with what Code4 said... Yes tap water does have impurities in it that will collect in the cooling system, but it would take years and numerous coolant changes and fills for the impurities to build up to a point that a lightly modded engine would overheat.

Wrong, wrong and more wrong. Did I mention that you were WRONG? Race cars run straight water because the engines are being drained rebuilt and refilled with such short run times that it doesn't matter. Coolant has corrosion inhibitors and extra additives that help it to stick to the metal parts of the engine for better heat transfer. Also, depending on the PH balance and mineral content of your local water corrosion can start happening at an alarming rate. Aluminum (our cylinder head) is EXTREMELY susceptible to this corrosion, and rust can happen just as fast in the cast iron block causing scaling that breaks off and clogs the cooling system causing overheating, leaks and other problems (ever seen a cylinder wall crack because of rust? I have.) Another problem is that even though the system is pressurized to raise the boiling point, the engineers designed the engine to operate within the raised boiling point of properly mixed coolant, NOT WATER. Properly mixed coolant has a pressurized boiling of over 250, water only gains 1-2 degrees of boiling temp per PSI of pressurization. You'd have to pressurize the system to 50 psi to get that high of a boiling point, and by then yor hoses would explode. I would never run a street car on straight water unless it was a quick trip and I had no other option. Even then I'd pull the T-stat before I did.

I did not mean he should run his car on TAP water form now on, but that it wouldn't cause the resevior to boil.

"depending on the PH balance and mineral content of your local water", I'm not saying you should run TAP WATER. If you run only water then you should only run DEIONIZED WATER AKA PURE WATER, WATER FREE OF IMPURITIES, but that has nothing to do with his problem.

I can agree with what you say about TAP water rusting and oxidizing the iron/aluminum of the motor, but not in any type of "alarming rate", possibly if you have the worst water in the world. Yes I have seen a cylinder wall crack because of rust, the motor had been sitting outside in the elements for years.

Also When I say "race cars" i'm not talking about NHRA dragsters or funny cars that get rebuilt after every race. WATER has been proven to cool more efficiently than water/antifeeze mixs, MEANING cars running only water usually run at a lower temperature durring extreme driving. Cars using ONLY water run 10-15 degrees cooler. UNFORTUNATELY I'm not 100% sure of the exact boiling point of pressurized water, or the equation you use to calculate the raise in waters boiling point. So yes water run in a 15psi system (I think the 420a has a 15psi system) might not have a 250 degree boiling point, but might infact have a 235 degree boiling point (15 x 1.5(differance between 1 and 2)=22.5 + 212 (point water boils at atmospheric pressure)=234.5).

Originally posted by Fasttopass
If you run only water then you should only run DEIONIZED WATER AKA PURE WATER, WATER FREE OF IMPURITIES

That is distilled water.

Originally posted by CODE4

Originally posted by Fasttopass If you run only water then you should only run DEIONIZED WATER AKA PURE WATER, WATER FREE OF IMPURITIES

That is distilled water.

LOL. Thanks Dave, you beat me to it.

LOL, Its the same differance. Deionized is what they call it in chemistry.

Hahaha has it really come down to arguing about distilled water?

This is 2gnt. Not some other forum (were not going to use names)

Originally posted by itsaslow95
Hahaha has it really come down to arguing about distilled water? This is 2gnt. Not some other forum (were not going to use names)

I think it all boils down to a misunderstanding of what the other persons view is on the situation by both parties. Plus I don't think I worded things in a manner that accurately got my point across in the beginning.

However I can say that I would take the G Nazi's advice over most other people on this forum because they do have a good understanding of these cars.

Originally posted by Fasttopass
I think it all boils down to

I think it all boils down to a level of understanding that cools tempers and evaporates worry. Wether cooler heads prevail, depends upon the stream of conciousness that is being allowed to pour out of ones' thought processes.

If we temper our anxiety and tap into that flow, we can see our resevior of knowledge fill and radiate throughout the system. Allowing us the temperate level that we so desperately seek in the impure journey of the high pressure world. Thus we won't generate heated arguements and release corosive attitudes that deposit gallons of impure thoughts toward our fellow man.

Now if we attack these hot-headed attitudes stat, then we can circulate a pure understanding of the system's malfunction and allow our compassion to leak through. Until, at some point, it breaks though the ignorance and is capable of flowing into a more reserved world. Then the animosity will evaporate and we can cap off the pressure that wants to polarize (not ionize) the the complete system as we see it today.

Originally posted by bullettdsm

Originally posted by Fasttopass I think it all boils down to

I think it all boils down to a level of understanding that cools tempers and evaporates worry. Wether cooler heads prevail, depends upon the stream of conciousness that is being allowed to pour out of ones' thought processes. If we temper our anxiety and tap into that flow, we can see our resevior of knowledge fill and radiate throughout the system. Allowing us the temperate level that we so desperately seek in the impure journey of the high pressure world. Thus we won't generate heated arguements and release corosive attitudes that deposit gallons of impure thoughts toward our fellow man. Now if we attack these hot-headed attitudes stat, then we can circulate a pure understanding of the system's malfunction and allow our compassion to leak through. Until, at some point, it breaks though the ignorance and is capable of flowing into a more reserved world. Then the animosity will evaporate and we can cap off the pressure that wants to polarize (not ionize) the the complete system as we see it today.

Oh boy..... Haha. That was deep.

Once again, Mark fires back with some epic win.

Originally posted by Fallen4ng31
Once again, Mark fires back with some epic win.

Just the rantings of a schizophrenic psychopath :shrug

WoW
If that was alittle shorter I would use it as a signature.

But aside from the little misunderstanding and the EPIC words said on this thread. Did you every figure out what was causing your resevoir to boil?

To burp the system:

With the car cold. Remove the rad cap. Turn heat on full blast.

Start the engine and let run for minute.

Wait until you see the coolant start to circulate good, this means the thermostat is open.

With the throttlebody increase the rpm to about 3000-3500. You'll see the coolant go down usually. Sometimes it goes up a tad. Try not to make a mess. Hold it like this for 5-10 seconds and abruptly let off.

Repeat this about 5 times then with it still running put the cap back on.

See if it gets hot still. If it does but takes awhile this is probably your issue and there is more air in the system. Repeat process.


Theory: the cooling system is under pressure, 8-17psi depending on make. Any liquid under pressure has a higher boiling point than it does at atmospheric pressure. If there is air in the cooling system it will not pressurize all the way and when the liquid gets hot it expands. This overcomes the spring in the cap and opens the overflow putting the coolant into the resivour. In the tank there is no pressure therefore the liquid boils. Antifreeze or water it's the same principle. However I will side with code4 additives in tap water(and hose water) are corrosive to the waterpump,radiator, cylinder jackets, heatercore , and thermostat. Distiller water works fine though depending on where you live.

Hope it helps

Had the same problem with mine and it was the Head Gasket.

Build it and boost it.