I see these questions a lot and didn’t see a FAQ on a quick search so I thought I'd make one to help some people out before they ask questions.

I'm not intending this to be the end all thread to this problem more of a good reference of where to look first when this problem comes up.

First off the cooling system is nothing more then a Thermostat, Radiator, Radiator Fan, Water Pump, Connecting hoses or plumbing, and finally a Heater Core.

There pretty simple so if you have a problem its going to come from one of those area's and 99% of the time its a easy fix requiring a few tools and a little bit of time.

If your driving along and the car is overheating turn on your heater set it to max with the fan on max. This acts like a second radiator and can save you a lot of money if you absolutely must keep driving. Otherwise stop and pull over before you damage your head gasket or warp your head.

So let’s get into the common problems:
Thermostat: What this item does is open when the coolant gets to a certain temperature, you can buy these based on your climate. This can give you one of two problems;
<U>A) Stuck Open</U> - When this happens the car is going to take a long time to warm up and never really get all that warm. It's not a huge problem unless it’s the winter and you want heat to keep yourself warm. This is not a dangerous problem and it is OK to drive around with this condition until it gets fixed. Solution is Replace the Thermostat.
<U>B) Stuck Closed</U> - When this happens the car is going to warm up normally aka the normal time it takes to warm up but once it gets to that temp its going to keep going. What’s happening here is the thermostat isn’t allowing coolant to flow thro the radiator and cool and exchange itself with the warm coolant in the block, so the now Hot fluid is trapped in the block with no where to go and nothing to do but get hotter. This is a dangerous problem because it will more then likely damage the head gasket and more unlikely but still very possible warp the head or other components. If the gauge gets to high Stop the vehicle and let the motor cool down if you must drive it somewhere to get fixed. Solution replace the Thermostat.

Radiator: What this guy does is actually cool the coolant off, how it does that is sending it thro lots of little passages thro the radiator giving it more surface area. Now by doing this it allows it to cool down faster with the "Cooler" outside air. A few problems with this can be;
<U>A) Plugged Radiator</U> - What’s happening here is contaminates got into your cooling system aka oil, rust, ect. Unfortunately this isn’t so much of an easy fix. To tackle this problem you have to drain the system and rinse it out I recommend taking it out completely and spraying it with a garden hose until it runs clean. Depending on what’s in there you might have to use some cleaners but can be saved almost every time. This is a dangerous problem because it will more then likely damage the head gasket and more unlikely but still very possible warp the head or other components. If the gauge gets to high Stop the vehicle and let the motor cool down if you must drive it somewhere to get fixed.
<U>B) Blocked Radiator</U> - The radiator needs to have air blowing past it in order to work so its IMPORTANT to not block it off with intercoolers or have large amounts of debris in front of it. Also all those little fins shouldn’t be bent over if they are take a small screwdriver and straighten them out or they make a "comb" for just that purpose, be careful not to damage the radiator though. This is a dangerous problem because it will more then likely damage the head gasket and more unlikely but still very possible warp the head or other components. If the gauge gets to high Stop the vehicle and let the motor cool down if you must drive it somewhere to get fixed.

Radiator Fan: This gizmo does nothing more then blow air across the radiator when your at an idle. The most common problems with this is;
<U>A) Electrical</U> - Simple as it sounds somewhere along the way the fan just isn’t getting power to turn itself on, and needs to be corrected. This can be a minor problem as long as your not sitting in traffic to long to get the problem fixed.
<U>B) Physical</U> - The fan itself is junk and needs to be replaced. This can be a minor problem as long as your not sitting in traffic to long to get the problem fixed.

Water Pump: Think of this as your own heart it pumps the coolant around no pump no coolant and your engine dies quite quickly. With this there is only one thing that can go wrong. It wears out. Solution replace it if need be and replace it at the scheduled intervals to avoid this colossal problem. Running the motor without this is like putting a gun to your head its just that stupid and dangerous. Tow it don’t take the chance of seizing the motor.

Hoses and Plumbing: These are like the plumbing in your house basically they get the coolant from one component to anther very simple except they take more abuse then your home system and require more maintaince. The most common problems are;
<U>A) Blockage</U> - This happens more so with metal lines or small rubber ones becoming clogged with contaminants from the cooling system aka sludge from oil or more commonly rust. Sometimes you can take these off and clean them and the system out, sometimes you cant and they need to be replaced. If they've been blocked for a while there more then likely junk if there rubber due to fatigue.
<U>B) Fatigue</U> - This happens over time because of the extreme temp differences the hoses go thro, there’s nothing you can do to prevent this other then replace them when they go bad. A sign of fatigue is there week to the touch aka you can collapse them with your hand easily and are very pliable. Also signs of cracks are anther good indicator and they need to be replaced. With metal lines they simple rust out and/or become brittle over time and need to be replaced.

Heater Core: This little guy works just like the radiator but instead of losing the heat to the outside air it transfers it to the passenger compartment to give you heat in the winter. You got to love this guy! It functions in the same way as the radiator and has the same problems because its nothing more then a scaled down version of the exact same thing.
<U>A) Plugged Radiator</U> - What’s happening here is contaminants got into your cooling system aka oil, rust, ect. Unfortunately this isn’t so much of an easy fix. To tackle this problem you have to drain the system and rinse it out I recommend taking off the lines from the engine compartment side and spraying it with a garden hose until it runs clean. Depending on what’s in there you might have to use some cleaners but can be saved almost every time. This is a minor problem and can be driven along on all day until fixed.
B) There really isn’t a B in this case because it doesn’t cool down the car in a critical way unless your overheating and turn it on to help its big brother out.

Head Gasket: This isent so much a part of the cooling system but it plays an important role in it. This guy keeps the space between the block and the head sealed up nice and tight keeping all the fluids in there respective place. A hole or tear in this guy can polute your oil, coolant, or the wonderfull white smoke from the tail pipe. This has been covered a bunch of times so I wont drag this out.

I'm going to add some more information to this a little later and welcome suggestions to the same effect!

Now lets get into some of the misc stuff with the cooling system.

Air Bubbles: We get these when we drain or occasionly when we flush the cooling system. One of these guys can be disaster to the cooling system if not taken care of quickly. To do this let the car run for 10 - 15 mins until it gets warm with the rad. cap off. The radiator will want to spit up coolant and water everywhere thats fine, just keep filling. Finally when it stops and it doesnt over head turn off the car, fill up one more time and your good to go.

Oil: Oil cools down the motor more then the radiator. Why? because oil takes away all the friction from the piston rings and the wall. Remember the old pensoil (sp?) commerical where they were talking about that, well its true. If you have no oil in the car the radiator isnt going to save it not a day in its life.


<U>Thanks to luserkid for the added information amoung other misc help.</U>


Modified by nocturnaldragon at 1:36 PM 7/26/2005

 

God that took me a long *** time to read. It also hurt my eyes because it was all close together. I think what really got me was that i just woke up and got this to read

Anyway very good thread. To get more into complicated things that you forgot is oil. Oil cools down the motor more then the radiator. Why? because oil takes away all the friction from the piston rings and the wall. Remember the old pensoil (sp?) commerical where they were talking about that, well its true. If you have no oil in the car the radiator isnt going to save it not a day in its life.

Also headgasket is very important as what was the massage here. But headgasket is to help tell the oil and coolant where to go and not to crash into each other. When that happens you have to drain the radiator and block and get a new headgasket.

And finally i cant believe you missed this, but air bubbles. Air bubbles are a cause of you to think your over heating then you think your fine. When you get an air bubble in the lines more then likely youll over heat with the quickness. To fix that you need to bleed the system.

To Bleed: Let the car run for 10 - 15 mins until it gets warm with the rad. cap off. The radiator will want to spit up coolant and water everywhere thats fine, just keep filling. Finally when it stops and it doesnt over head turn off the car, fill up one more time and your good to go.

Other then the left out stuff great write up

 

Awesome thread, this will come in handy to a lot of people.