Cooling System Repair This should be a STICKY!! - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 07-01-2005, 01:01 AM   #1
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Default Cooling System Repair This should be a STICKY!!

After many problems with over heating i decided to get peoples input and put together this thread. From personal experience this will help a lot of people out and now i will post pics later when i have time.....


Your General Motors car with a transverse-mounted engine(OR THE ALMIGHTY 3.8 N/a or */C ) has been running hotter than normal. The car has begun to lose it cool in bumper-to-bumper city traffic, overheating on a few occasions.

After a quick check, you can’t find any coolant leaks, so you decide the root of the trouble has to be a clogged radiator. Although you’ve never removed a radiator, you are confident you can handle the job. But as you are about to find out, there is a right way and a wrong way to do it. I learned the HARD WAY

In the following pages I will guide you through diagnosing cooling systems and the delicate job of removing a radiator and installing a new one. Along the way I will point out several common errors made by beginners.

The primary rule when it comes to radiator repair is to diagnose the cooling system before doing any repair work. Just as a good physician will determine a patient’* disease before operating, you must become a radiator doctor to figure out what is at fault before lifting a wrench.

When a radiator is operating properly, it extracts the engine’* waste heat from the coolant and transfers it to the outside air. To do that, coolant must flow freely through the radiator tubes. Are must also flow freely over and around the radiator’* individual tubes. At highway speeds fresh air is directed to the radiator, but when the going gets slow, the radiator fan must force cool air through the radiator.

Everyone knows that when the ore’* surface becomes covered with dirt and debris, or the radiator’* internal tubes become clogged with corrosion, heat quickly builds up, resulting in the familiar clouds of billowing steam vapor that accompany overheating. But in my experience as a shadetree I’ve found that clogged radiator tubes are often blamed for poor cooling-system performance, whether they are at fault or not. Based on that often erroneous assumption, would-be mechanics remove the radiator without knowing the true cause of the problem. That is what you are about to do.

Pressure-test the cooling system by pumping it up to operating pressure while the engine is cold. Leaks can be safely traced without risking being sprayed by hot antifreeze or being burnt by hot engine parts.

You start out by opening the petcock at the base of the radiator, draining the coolant into a pan. After putting the pan aside, you disconnect the upper and lower radiator hose clamps The upper hose slides off with no problem, but the lower hose is stuck fast to its connector. You think you might be able to pry it free with your largest screwdriver but you only succeed in mangling the soft brass connection pipe. On your last swipe the screwdriver slips, scoring the core’* surface and leaving a deep groove. You aren’t too concerned, though, because the radiator has to be repaired anyway and a few extra leaks won’t make a big difference.

When hoses are difficult to remove, the best way to get them free is to cut several slices in the hose, near the connector. I did this out of frustration but it works..... In this way the hose can be pealed away without damaging the connector. In any event you should replace old hoses and clamps.

Your next area of attack is the transmission-coolant lines. Using only an open-ended wrench you try to loosen the fittings, but the upper fitting holds tight. As you force it, the fitting’* brass nut becomes rounded. (ALWAYS!!!) So you clamp vise-grip pliers onto the nut. The fitting still holds firm, but he soldered connection between the tube and the radiator shears off.

Whenever you disconnect a fitting from a radiator, use a tube nut wrench that wraps around the fragile nut to protect the fitting. It is also a good idea to use a backup wrench whenever possible. As for tough-to-remove fittings: Do not force them; try using a small tubing cutter to cut away a straight section of the pipe. Later, you can install a compression fitting to reconnect the tubing. At this point it’* a good idea to plug the transmission lines to prevent transmission fluid from draining out. And always check the transmission-fluid level after the radiator is reinstalled.

Once you disconnect all the hoses and tubes, start to unbolt the radiator. Remove the fan shroud if it might get in the way later.

Radiators are generally attached with four or six bolts on either side. If they haven’t rusted, they are simple enough to remove. However, it is easy to miss some of the square rubber cushions on which the radiator sits. Sometimes they stick to the bottom of the radiator or to the rail on which the radiator rests, or they may be lost in transit. Make sure the cushions, which protect the radiator from shocks and vibrations, are present before you reinstall the radiator. On this transverse-engine GM car there is an extra from the car’* frame to the front of the engine. You should carefully loosen such a mount and keep it away from the radiator’* surface.

Once the radiator is completely disconnected, it’* time to pull it out. Standing on the radiator’* sides, you manage to angle the radiator safely out of the engine bay. You avoid contact with any sharp edges, like the fan blade, exhaust manifold, or the loosened motor mount. Now you are ready to take the radiator o the repair shop.

The soft radiator core is vulnerable, and once it has been removed, it should be sandwiched between two pieces of corrugated cardboard.

If you are in doubt about there actually being a problem with the radiator, ask the radiator repairer to tell you about any leaks, logs, or defects that were found. Explain that you are trying to solve an overheating problem.

If the radiator flow is restricted, the radiator repairer may suggest removing the tanks to check each tube individually or just replacing the entire core. Often cars with radiators damaged in a front-end collision have core areas that were soldered off. While this technique saves money on the repair bill, it cuts down on the cooling capacity and efficiency of the radiator, making it, in effect, a smaller radiator.

When opening the transmission line fittings, always use a tube nut wrench, and a back-up wrench when space allows. It is easy to damage the fitting’* nuts with an open-end wrench.

As it turns out, the radiator shop’* owner tells you your radiator is free of defects, except those you inflicted during removal. With the core surface so badly cut, the damage done to the transmission-fluid cooler, and the badly mangled hose connection, the cheapest way to get your car back on the road is with a new radiator. The only real defects in the original radiator were those caused by your inexperience.

After buying and installing a new radiator, your car still has the same overheating problem, so you go to a mechanic for help. He starts out with a cooling-system pressure test, which shows there are no leaks. Next he does a combustion-leak test to make sure there are no internal leaks that might allow exhaust gas to bubble into the cooling system. He draws air from the radiator through a blue test liquid. Any trace of combustion gas would make the liquid turn yellow. You engine passes the test.

Everything else, including the thermostat, core plugs, and pressure cap, checks out fine, yet the car still runs hot and begins to overheat in city traffic. The mechanic decides to see if he can duplicate the conditions by running the car n drive with the wheels blocked o simulate city driving. This puts stress and load on the engine and cooling system similar to what you would encounter in a typical traffic jam. After about 15 minutes the engine gets hot, with occasional burst of bubbles in the coolant recovery tank. At that point the engine’* electric cooling fan should be turning to pull cool air over the hot radiator tubes; it is not. On some cars with electric fans, turning on the air conditioner automatically engages the fan, but most of them use a temperature sensor to start the fan. It doesn’t take long to figure out that the engine coolant sensor, which triggers the fan circuit, is defective. Using jumper cables to ground the sensor wire urns on the fan, and the temperature gauge begins to drop slowly. Once the engine cools down, a new coolant sensor I installed. You car now keeps its cool wherever you drive it.

Solving the overheating problem was more complicated than necessary because you didn’t diagnose the problem; and the solution came at a high price. Getting your car’* coolant system under control ended up costing $220. The price of the coolant sensor was only about $20, but you also had to pay $20, but you also had to pay $200 for the new radiator, which you didn’t need in the first place. In any auto repair, diagnosing the problem before you undertake a repair is the key to success.

When all the hoses and tubes have been removed, the radiator must be carefully angled out to avoid sharp objects in the engine bay. (shown with arrows): motor mounts, exhaust manifold, transmission fluid lines.



On many newer cars a coolant sensor operates the radiator’* electric cooling an. If it is defective, the car will quickly overheat in city traffic. Check the water pump by pulling on it and trying to rock the pulley back and forth. If there’* too much play, the bearing May be worn out and the pump should be replaced.
Before attempting any repair work, it is best to know where you stand and what needs fixing. Step-by-stem plan of attack for diagnosing your car’* problem will be time well spent, avoiding costly unneeded work.

It is easier to find a coolant leak under pressure, so the fist step is to pump up the cooling system. While this can be one by letting the engine heat up and the coolant pressurize, it is safer and easier to use a pressure tester. (When you find a leak, it is better to be sprayed by cold coolant than to be scalded b hot antifreeze.) The pressure tester consists of a hand pump that fits over the radiator ca and pressure gauge. Do the same pressure test after you complete the job.

All modern automotive cooling systems are designed to operate under pressure to raise the coolant’* boiling point and efficiency of heat transfer. Not only will a leak cause the system to loose coolant, it will cause the coolant to boil at a lower temperature, making a boil-over easier.

Coolant can escape through a number of places; the most common are a leaking hose and clamp. If the pressure test reveals no leaks, check the engine core plugs. Core plug leaks are generally difficult to spot, and you will need to get under the car and search carefully and check each plug. The best clue to a leaking core plug is a greenish drip of coolant you might find clinging to the starter or motor mounts. While under the car, check the water-pump weep hole where possible (found on the bottom of the water-pump casting) for drips or coolant residue.

When you’re stumped, look for more exotic leaks, such as the heater core. Drips of coolant may show up on the floor mat on the driver’* side or may come from the air-conditioner evaporator housing. One sure sign of a heater core leak is the sweet smell of coolant accompanied by a fogging of the windshield when the defroster is used. Examine the coolant-recovery tank and its plumbing for leaks.

The thermostat can be quickly checked by putting it into a pan of water on the kitchen stove. As the water heats up to boiling, the thermostat’* action as the engine coolant heats up to operating temperature. If it opens too soon or remains open, performance, efficiency, and emissions will suffer.

The real trouble begins when the thermostat doesn’t open. Coolant will be trapped in the water jacket and will not transfer heat away from the engine. A loud banging sound usually precedes the geyser of billowing vapor that accompanies overheating.

Next, look at and grasp the water pump’* pulley, trying to rock it back and forth. It should move freely. If it feels loose, the gearings may be worn out.

Remember too that air must flow across the radiator tubes If the airflow to the front of the radiator is restricted by debris on the radiator’* face or a problem with the cooling fan, cooling will be seriously reduced. Older cars will have either a direct-drive fan powered by a belt or one that is activated by a heat-sensitive clutch: Check the belt tension for slippage. On newer cars there is a temperature-sensor control and an electrical fan; both should be checked.

Even after you think you’ve found the source of your cooling-system failure, continue along with the diagnostic checks. Multiple causes could be at the root of your car’* overheating.

PICS WILL BE UP SOON
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Old 07-01-2005, 12:43 PM   #2
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pics coming soon
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Old 07-01-2005, 09:31 PM   #3
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Quote:
Originally Posted by Kennginn
pics coming soon
so wha do u all think of the write up?
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Old 07-01-2005, 09:42 PM   #4
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Its a good write up Kenn, bit long so its hard to follow, the pics will help once you get them up
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Old 07-01-2005, 11:18 PM   #5
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Its a good write up Kenn, bit long so its hard to follow, the pics will help once you get them up
Hopefully these pics get up quicker than that scan tool pic...
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Old 07-02-2005, 03:09 PM   #6
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Its a good write up Kenn, bit long so its hard to follow, the pics will help once you get them up
Hopefully these pics get up quicker than that scan tool pic...
damn bill its coming :goodmorning:
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Old 07-02-2005, 04:58 PM   #7
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Excellent write up, Kenn. How bout some pics, bro?
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Old 01-21-2012, 01:46 PM   #8
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did the car miss? did it ever gave you a code about a missfire? thats a common problem, specially in #4 piston. once your head gasket goes, it will start burning antifeeze and smoking. Thast the story with my bonni. 2002 ssei.
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Old 01-21-2012, 02:47 PM   #9
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Good write up, no offense meant, but you should proof read it a few more times.

Roger.
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