Replacing A Radiator

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DISCLAIMER:This information is provided as-is. You assume all risks of following any of these instructions. I'm not to be held liable for any error in the information presented here or any consequences or damages resulting from any use made of the information and images in this article.

This article will hopefully show you how to replace the radiator in a 1987 base-model Pontiac 6000 with a 4-cylinder (4-Tech) 2.5L engine. A BIG Thank You to many of you who have helped with this article.


What You'll Need
  • 1/4" and 3/8" drive ratchet set with both metric and SAE sockets
  • 1/2" combination box/crescent wrench
  • 8mm crescent or battery wrench
  • Flathead Screwdriver
  • Regular and needle-nose pliers
  • A couple medium-size adjustable crescent wrenches
  • A couple plastic bins to catch fluid (dollar store ones work nicely here)
  • Funnels. Recommended is the Lisle Spill-Free Radiator Funnel Kit
  • Bar's Radiator Stop Leak to seal hoses (recommended if your not sure if your radiator hoses aren't self-sealing)
  • 2 gallons 50/50 antifreeze (green, not orange): Means 50% antifreeze and 50% water. You will most likely have to mix this yourself.
  • 1 quart Dextron III transmission fluid (as a precaution)
  • WD-40
  • PB Blaster
  • Gloves - Mechanix gloves are recommended.
  • Zip-Lock or thick plastic baggies and baggie ties.
  • Radiator, upper and lower hoses, and two hose clamps (I got mine from AutoZone)
Choosing A Radiator
If your car has air conditioning, you'll have to choose a radiator built for it. Look for the letters A/C when looking for a radiator. Don't confuse this with Heavy Duty, which is usually only for more high-performace and racing cars. If in doubt, always check with the retailer you plan to buy from before making a purchase. Be sure you provide the car's year, make and model, as well as the engine specifications (ie. Dryden is a 2.5L 4-cylinder automatic). Most radiators are aluminum with plastic caps or tanks (this is the sides of the radiator where the antifreeze and transmission coolant go in). These are the best because they are less likely to rust out than the original. However, you must take extra caution when working with an aluminum radiator during installation and handling due to the fact that the fins bend easier. Once installed, however, this should not be an issue. Look the radiator over when you get it. Some mashed fins are normal as long as they aren't too numerous and there's no actual breaks in the radiator. Get a radiator with some kind of warranty, lifetime preferred. Some radiators have a core charge when you purchase them. This means you can bring back your old one and get the core charge back. Ask when you make your purchase. If they do not accept the radiator back, then there will be no core charge. However, you'll need to dispose of the radiator yourself. Try calling some junk yards to see if they will accept it. Dispose of the old radiator and antifreeze safely according to local laws. Never reuse the antifreeze!


Your Working Environment


The ideal working environment is in a comfortable garage in warmer weather or at least heated/air conditioned. Realistically, not many have this luxury and often it seems radiators go in mid-winter. I had the misfortune of not being able to afford a mechanic to put the new one in, and so I had to do this myself in between 12°F and 19°F weather (I did catch a cold as a result). If you have to work in the cold, bundle up in layers and take frequent breaks, going into a warm bulding and drinking hot liquids. Work slowly and don't expect to get everything done in one day (unless you have someone to help you).
Disassembly
  1. Remove the air intake and set it aside. This is the large hose on top that goes from the air cleaner assembly to the front of your car. Carefully pull the end that is in the front of your car and observe how it went it. Now loosen the screw from the clamp where the intake joins the air cleaner assembly and carefully pry the intake off. Set it aside or in your car/trunk.
  2. Remove the negative battery terminal using an 8mm cresent wrench or battery wrench. It's a tight space in there so be careful. Always remove the negative terminal first! Then remove the positive battery turminal. You must unhook the battery because you'll be working around the fan and other items and don't want anything to turn on. The fan is said to be able to activate at random under certain conditions. Best play it safe.
  3. Place a plastic container under the driver and passenger sides of the car, under where the hoses are. As you work, antifreeze will spill all over things, but that is normal and will safely burn off when you start the engine after installation. Remove the top hose (driver side) by unscrewing the clamps. Let the fluid drain out of the thermostat and radiator. Do this for the bottom hose (passenger side) as well. If you can't get the bottom part of the bottom hose off, you can leave it on as you will still be able to remove the radiator with it attached. But you will need to remove the hose from the water pump area of the engine (this is under the alternator, by the intake manifold). You may want to try using a ratchet wrench to do this. You can use baggies and baggie ties to close off the areas where the hoses attached once the fluid has completely drained. It may take awhile, depending on how much antifreeze you lost from the radiator in the first place.

    TIP: If your clamps are rusted, try using PB Blaster overnight to loosen the rust, then squirt WD-40 and let set about an hour before attempting to remove. How much you need will depend on how badly rusted the clamps are. This goes for any bolts, screws, clamps, and fittings you may encounter.




  4. Now you have clear view of the transmission cooling lines. You want to loosen the screw-like clasps from the rubber hose with needle-nose pliers or a small socket and ratchet wrench. Slide the clamps down the rubber hose a little. Be sure you have that pail under this area as some transmission fluid will leak out. Do the outer line first, using a pair of pliers to gently wiggle the rubber hose back and forth while putting downward pressure. If you do it carefully enough you can remove the hose from the aluminum line. Then do the other one. Let the aluminum lines drain but the rubber hoses can be positioned aside in an upward fashion so nothing drips out. You can also put baggies on the hoses and lines once they've stopped draining if you want. Move the battery wiring from between the aluminum lines.
  5. If you look up near the radiator cap, you'll see another small hose that leads to the reservoir where you fill the antifreeze. You can use a pair of needle-nose pliers and pull the two clips (one is two prongs and another is one) to loosen the clasp. Move it down the hose a little, about an inch. Then with pliers, gently wiggle the hose off. Nothing should come out if your reservoir is empty and the fluid in the radiator is below that hose area. If not, some will leak out.
  6. Go back to the driver side, as now you'll unhook the wiring from the radiator fan. This is located just under the radiator fan motor. In the picture below you will see it's on there with a clasp over the connector plug and socket. This is on the bottom and you can't see it. Get a screwdriver and you'll be able to know by touch where this clasp is and be able to get the blade under the clasp. Carefully pry that down a little and at the same time try to wiggle the plug loose. Be careful! I've heard of those clasps breaking off! Do not remove the bolts from the fan yet.
    Note that there is a wire that is leading under the car underneath the radiator fan. This is actually connected to the frame of the car and will not need to be removed.


  7. Loosen the bolt from the center of the metal motor mount. Do not remove the bolt. This is where another bar on the passenger side goes down into the frame. Be careful not to strip the nut. You can use a couple adjustable crescent wrenches for this. After that you can remove the bolts on the front frame of the car. Below shows these bolts and how the one front bolt is almost hidden behind the grille assembly. You can use a crescent wrench instead of a socket wrench to remove this and not have to remove the grille. Move the plastic motor mount piece upward and away from the radiator. If it won't move don't force it! Just loosen the motor mount bolt a little more. The engine should then tip backwards.


  8. Now you have room to work to get the fan out. Take out the bottom bolts first. You may need to get under the car to do this. However, if you are not able to (due to working outside in inclimant weather, for example), then you can still get them out from the top. Work on the driver side one by standing at the driver side fender. Work on the passenger side one by reaching in by the exhaust manifold. This is a very tight squeeze and will take awhile to loosen the bolts, especially if they are rusted. Use a ratchet wrench for this job and work slowly. Then remove the top bolts from the fan. Save them in a baggie and remove the fan. You can clean the fan using some SoftScrub or similar cleaner and a rag, and then rinsing it clean. Be careful not to get anything in the motor itself. Let the fan dry completely.
  9. Now remove the bolts from the top of the radiator on the front of the car. You can tell which bolts are holding the radiator assembly down. Usually a 13/32" socket will work on most of them. Be careful as there are rubber U-shaped mounts on the bottom sides of this plastic top piece. Don't loose these. The radiator is now ready to remove. Go slow and try to tip or turn as needed. Be sure you have pails under the car to catch fluid because now stuff is really going to come out! If not, you got lucky. Especially if you happened to have completely removed the bottom hose. If you didn't remove the bottom hose, you'll want to tip the radiator a little to and move the hose away from other objects until the radiator is free. Be sure that the bottom U-shaped mounts are either still in the car where the radiator was or that you can locate them. These postition the radiator.

    Once your radiator is out, get a 1/2" box wrench and carefully remove the aluminum transmission cooling lines from the radiator. Be extremely careful that you don't twist or bend the line itself. Inspect the aluminum lines for rust and cracks. Be sure the ends are open and free from gunk, etc. You'll want to be sure the fittings on each end are loose (but not off). Attach them to the new radiator.
Restoring the Aluminum Lines
The aluminum lines are quite bendable so be careful with them. These are not something you can get at an auto parts store and some dealers probably won't have them. These are lines that have to be specially bent. Once the lines are on the radiator, you can mask off the radiator and the tips of the lines, then spray them with silver high-heat engine paint to make them look newer. You'll want to sand them with 150 grain sandpaper lightly to get excess rust off before painting.




Putting In The New Radiator
  1. Place the new radiator in the car, setting it on the bottom rubber mounts. Be sure they are set in properly. Cleaning this area beforehand will help ensure the radiator is placed correctly. You may want to put the bottom hose (passenger side) on the radiator first before you install the radiator. Carefully tip the radiator and get the hose so that it will easily reach the water pump connection on the engine. Put a clamp on the hose and fasten the top of the bottom hose to the water pump connection on the engine. When putting on the hoses, you may opt to use the radiator hose sealer previously mentioned in the What You Need section.
  2. Put the top on the radiator, making sure that the rubber U-shaped pieces line up. If they don't, you might crack the top part. There's also a rubber piece across the front of the car that the radiator rests against. Be sure that the ends of it don't flop down. You may need to reglue this in place with hi-tack glasket glue. Once the radiator is in place, bolt down the top.
  3. Put the fan in by bolting the top bolts of the fan first, but loosely so it holds the fan in place, but not tight. Then put in the bottom ones loose enough to just hold. This provides some give to align the fan to get other bolts in. Again, if you opt out of getting under the car to fasten the bottom bolts, work slowly and in the same way you did when you took the bolts out. Once all bolts are in, tighten them all good but be careful not to strip them. Hook up the fan motor connector after the fan is bolted in.
  4. Thread the battery terminal wiring between the aluminum transmission lines as it was before you took out the radiator. Attach the transmission cooling hoses to the aluminum lines, being sure they do not cross each other. Fasten them with the clamps.
  5. Attach the top radiator hose to the radiator and thermstat and tighten the clamps.
  6. Attach the reservoir hose (passenger side) to the radiator and adjust the clamp.
  7. Connect the positive battery terminal first, then connect the negative terminal.
Preparing The System
Fill up the radiator to about 2" below the neck. Turn on your heater and set it to the hottest setting and the fan all the way on the highest setting. Start the engine. Let the engine run awhile, allowing the radiator fluid to drop down a little, then fill up to about 2" below the neck again. Keep an eye on it and keep it filled up. Let the car run until the thermostat is wide open. Signs of this can be any one or more of the following: There is fluid coming from the top of the fins when you look in where you fill the radiator fluid. This means the fluid is circulating but it doesn't always happen during this procedure. The top hose may be warm or hot. The best indication is if the car is hot inside from the heater and/or the radiator fan turns on. The car should run about 15 to 20 minutes, usually.

While the engine is idling, the ECM (Engine Control Module or Engine Computer) will need to relearn to run the engine. During this time, the engine will go through frequent cycles of low idle and surging or high idle. Do not step on the accelerator pedal to try and "correct" this! While the engine may sound like it'll stall a few times, it shouldn't actually stall out. It will sound pretty bad though. After a good 20 minutes or so, it should even out and start to run normally at a normal idle speed. If the engine idle does not even out or it stalls, check your IAC (Idle Air Control) to be sure it's operating properly and repair if necessary. Check that your Service Engine Soon light does not come on.

With the engine still running, fill up the radiator to the neck and put the cap on tightly. Fill the reservior to the Add mark.

With the engine still running, check the transmission fluid level. I didn't loose any so I didn't have to fill it, though you may have to.

Now you are ready to drive! It's best to keep some anitfreeze in the trunk, just in case. After a good half hour drive (this also helps the ECM to relearn), let the engine cool about an hour and then check for leaks, and check the coolant levels. Also check the motor mount bolt to be sure it's still tight. If not, tighten it more than you did the last time and check again after another drive.