Are you overheating? Look here.

[JLangevin]

Ok, so I have decided to write a little helpful post for those who are battling the summertime heat right now... perhaps I will even try and submit this and request a new section to the tech guide (Engine Cooling).

Ok, so you have tried everything? Youve installed....
-New Radiator
-New Thermostat
-New Radiator Cap
-Flushed the system
-Verified fans are operational
-Replaced hoses
-Inspected/Replaced Water pump (nasty job)
-Inspected ducting

... and you are STILL regestering temps in the 220's? Well, after installing all those new fangled parts, you have introduced a ton of air into the system at different points of the cooling system... for instance, when you replace the upper hose, you introduce air to the engine side of the cooling system, and when you replace the lower hose/thermostat, you introduced air to the radiator side of the cooling system...

You see, the system has a capacity... That capacity when sealed, can be filled with either coolant or air... air is BAD! It always rises to the top of liquid.. (Take a water bottle and turn it upside down... notice the bubble? ) - When the air rises to the top, it forces the coolant to the bottom... since the water last leaves the head, its at the top most portion of the cooling system, the fill neck.

Now, water WILL flow through the system, but air will created pockets of steam which are VERY hot. Steam is so hot in fact, it used to be water, until it was forced into a gas by the hot engine. The air not only takes up space in the cooling system, it also hinders coolant flow, therefor creating an overheating issue.

Here is the method I use for purging air from the system. Many will say "Just remove the cap and let the car idle" WTF Well, when you remove the cap, you also relieve all system pressure, and guess what... introduced air back into the system! Since the pump is trying to create pressure, it will have to fill the volume, therefor sucking air right into the system. Instead, go to Autozone and buy the following

-Pressure release radiator cap (temporary) Some hate these, I run mine all the time
-1 Gallon of Coolant
-Water Wetter Additive

Install the radiator cap (WHEN THE SYSTEM IS COOL) This system works best if you have a logger since you can see real time tempratures. Keep in mind, these tempratures are at their hottest when the computer sees them. That are taken from the thermostat housing just as they are being let into the radiator. The coolant entering the vehicle is substantially cooler.

Turn on your logger, and let the car get to operating temprature. I like to hold the car at about 2k RPM to let it cool faster and build a good amount of pressure. You should notice the logger reach around 203 when the thermostat opens, even though its a 180*, dont ask me why, but thats how it is in several cars Ive tested on. I do however, think my sending unit is a little off. The fan should also come on at about 210*

Now, here is where you test to see if you have air in the system... take the car for a spin around the block, get on it a couple of times, build some nice heat, now, go home, turn off the car and open the hood and listen... do you hear (bubble, garble, bubble, garble, BLAH) ?? If so, that AIR!! Lift up on the pressure release tap and let the system vent to the overflow bottle... one of two things will happen, you will either hear that bubbling get louder in the overflow, or you wont.. what you WANT to hear is a nice rush of coolant, smooth and peaceful to the ears, if you hear what sounds like boiling, thats a combo of hot coolant and air. You can even go a step farther and pull up on the cap to the overflow and see if you have coolant coming out of the tube... if you hear bubbling, but only see a slow drip or drool of coolant, guess what.... AIR!

Now, to purge this air, push the pressure release tab back down, and turn the car back on and turn on the heater. Let the car idle again... wait about 2-5min and watch your logger (if you dont have one, just guess) and wait until you see roughly 210 or 213 (or 222 in my case) and pull up on the tab with the car running, the air thats resting on the top will be released to the overflow... now push the tab back down, the system will now draw coolant back from the overflow and replace the air with coolant.. IF you are really low on coolant like I was, you can release the cap, remove it (be careful, make sure system pressure was released, and look inside... you may see coolant flowing, you may not... mine was so low, all I saw was an empty fill neck. I got my coolant bottle and reved the engine from the trottle body, I saw some flow, but it went away... if you hold the butterflys open at about 2k, you can pour the coolant in slowly until you see the neck fill up... then put the cap on and repeat the procedure until you no longer hear the bubbling.. When done, fill your overflow with coolant as per the fill line and call it a day. Watch the temps closely and have a nice day.

This took me about 15-20min total, but I got all the air out of my system and saw my idle temps steady at 206 to 210 at times (90* outside) this is a drop from 217, 219, 222 and climbing. I hope this has helped you, as I know that tracking down cooling problems are one of the most frustrating things next to electrical issues. If this artcile has helped you, you know what to do, REPUTATION! But seriously, keep the car cool, and the boost high! Happy DSMing!

 

[TurkF26]

Very good post on how to purge the air out of the system. I do however have to say that there are plenty of other things that can cause overheating//high temp problems. I work for 1-800 Radiator so i deal with these problems day in and out.

There is a significant difference between overheating and running hot. Overheating is referred to when the antifreeze (not really called coolant because antifreeze doesn't provide cooling to your car but rather raises the boiling point of the water) boils due to a problem with the cooling system of the car. If you car is just running hot, chances are its either related to air in the system or poor maintenance. on the system itself. If your car has actually boiled over and overheated, than that is where you have to start your investigation on what is causing the problem. If your car overheats, DO NOT just start replacing every cooling component in your system. This will cost you a lot more money and time that it really is worth. Most of the time, it is something really obvious like a busted hose, cracked radiator,etc... Fortunately for us DSMer's, we don't have to worry about this next problem that does come up a lot.

A lot of car manufacturer's use a water pump with a plastic impeller blade. If the cooling system is not maintained like it should, over time the components in the water will break down this impeller causing the water pump not to function at 100%. If its a newer car, than the easiest thing to do to prevent this, is use the car manufacturer's recommended antifreeze (dex-cool, Toyota's red antifreeze, etc...) All these antifreeze's have detergents and such inside them to prevent the breakdown of vital cooling parts.

If you car runs warmer than normal or overheats when your A/C is on, a lot of the time the problem is related to the condenser. When a condenser starts to fail, it will put out a lot more heat than normal. What this does is preheats the air too much before it enters the radiator. The air is already so hot, that when it passes through the radiator, it cannot cool the aluminum fins anymore thus causing cooling problems.

One MAJOR thing to do to prolong the life of your cooling system/radiator, is do not use regular tap water/hose water. Instead go to the store and grab some distilled water or buy the premixed antifreezes. Using tap water will corrode much of your cooling system prematurely causing lots of problems. Also, for a temp. fix on cooling problems, try changing your mixture of antifreeze to water. So if you are running a 60/40 mix, try going to a 70/30 mix. By increasing your antifreeze to water mix, you raise the boiling point of the water in turn helping your cooling system.
I didn't mean to hijack/steal your thread but since you were talking about cooling problems, i figured i would share some of my knowledge.

 

[JLangevin]

Well, technically, overheating only reffers to higher than optimal tempratures, but there is a difference between running hot, and damaging parts. If you continue to run an engine progressivly above its reccomended heat range, other damage will incure... for instance, if you look down at your logger and you see 220* then 230* and continues to climb, you most likely wont damage your engine as long as you cut it off and let it cool quickly, its typically when someone is on the highway and looks at their temp gauge once every 50 miles when damage starts.

But, your imput is definitly appreciated.

 

[TurkF26]

Well in my little radiator world we refer to overheating as not able to drive the car/ spiked temp. gauge. It is normal to see temps around 210-225 in 100 degree+ weather because of the temperature of the air. Also like i stated above, a good amount of cooling problems are related to the ac condenser failing. If you car has been in a front end accident and the condenser and radiator have been replaced, there area lot of condensers out there that are very inefficient. A lot of people like to spend the least amount of money when replacing a radiator/condenser. If you replace your condenser with a "tube and fin" designed condenser, chances are in 100+ degree weather, you will have colling problems and air conditioning temps that are above normal. The way you can tell what condenser you have is if you can look at the top of your condenser, and can see/feel fins sticking up off the top, chances are you have an aftermarket tube+fin designed condenser. OEM condensers are usually "parallel flows" or "serpentine" designers. These are way more efficient and better working than tube+fin condensers.

One other big problem that comes up quite often is a faulty radiator cap. If a radiator cap is bad/faulty, it will keep a below normal pressure in your cooling system. For every lb of pressure added to the cooling system, you raise the boiling point 5-8 degrees. Now this does not mean to run a 25+ lb cap on your stock car because you will either burst a hose or a tank on your original radiator. Recommended pressure for most import cars is a 16lb cap.

All in all cooling problems/issues can be very tricky to diagnose like JLangevin stated but can be pretty simple to fix/diagnose if you know what you are looking for