How to Replace Radiator 2004-06 Cadillac CTS

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Hi, I'm Mike from 1A Auto. I hope this how-to video helps you out, and next time you need parts for your vehicle, think of 1AAuto.com. Thanks.

In this video, we're going to show you how to replace the radiator in a 2006 Cadillac CTS. This information is the same from 2004 to 2006 on 2.8 as well as 3.6-liter models.

The items you'll need ainclude a new radiator from 1AAuto.com, 10 millimeter socket, ratchet, and extension, Phillips and flat head screwdrivers, pliers and side cutters, pick tool, drain bucket, T45 Torx bit, GM disconnect tool J44827 or equivalent.

We'll also show you how to do that with a screw-type hose clamp, a drill and drill bits, a tape measure, a marker, a funnel and 50/50 Dexcool antifreeze as well as a jack and jack stands.

We're removing this under body pan in order to gain access to the space between the back of the radiator and the front of the engine. You'll need a flat blade screwdriver to remove these clips. Our vehicle is missing some, so you may find that you have more for some in places that we don't. Our vehicle also has a different style clip: two here and one on each side at the back of the pan. These can also be removed with a flat blade screwdriver, but I find it's easier to carefully grab them with a pair of pliers. You don't want to pull on them too tight because you can crush them. If you get a good grip, they pull out pretty easily. Once all the clips are removed, pull down and back to remove the pan.

On the bottom driver's side of the radiator, we have the lower radiator hose. This particular vehicle does not have a drain plug on the radiator, so we're going to place our drain bucket under here. Use a pair of pliers to slide the clamp back and out of the way. We had to lower the vehicle to get closer to the drain bucket. Now we're going to carefully pry the hose back off of the radiator and allow it to drain into the pan.

Remove the oil fill cap. Take the engine cover off. Reinstall your oil fill cap to make sure that nothing falls in there while you're working.

Use a flat blade screwdriver to loosen the clamp holding the intake tube to the intake manifold at the throttle body. Remove the electrical connector to the map sensor. Move the connector out of the way. Disconnect the PCV breather at the back of the intake tube with the flat or Phillips head screwdriver, loosen the two screws at the top of the split in the air box. Pull back and release the air box from its clips. You may have to remove the air filter. Release this whole runner from the vehicle.

Push down and release the electrical connector from the fan. Pop the clip out that holds the harness on to the fan shroud. Hang that out of the way. Do the same thing on the other side.

Using a 10 millimeter socket and ratchet, remove the three bolts holding the other half of the air box into the engine bay. Lift up, disconnect the hose from the other half of the air box, and remove it from the vehicle. Remove the rubber insulation from under the air box. Remove this Phillips head screw from the side of the fan shroud. You may be able to get in there with a stubby Phillips head screwdriver, but we're going to use a Phillips bit and a small ratchet. Remove these three 10 millimeter bolts from the top of the radiator fans. Disconnect the retainer on the wiring harness on the passenger side of the fan shroud. Lift up, pull toward the driver's side to release the fan shroud from the retainers at the bottom. Pull the fans out through the driver's side to remove them from the vehicle.

These transmission cooler lines located in the bottom of the radiator are a quick disconnect style and required GM tool, J44827 or an equivalent quick disconnect tool. If you don't have access to one of those, we're going to show you kind of a cool do-it-yourself way to make the tool and get those lines out.

You're going to need a small screw style hose clamp. You'll need to undo the clamp with a flat blade screwdriver. Open up the clamp and use a pair of side cutters to cut the screw and off. Now you want to take and wrap this piece of clamp around the hose, make sure it's nice and tight that you have a nice smooth bend to it. Make this process a lot easier for you, the smoother it is. You can even use the slide job pliers to squeeze it on there to make sure it takes the shape nicely.

Now you want to leave a small gap between the two pieces, so take your pair of side cutters again. Cut off the excess piece of clamp. Make it nice and round again with the pliers. This is going to have to squeeze together a little, so make sure that you do have a little gap there.

Now we're going to push the line fully in. Squeeze the gap then. Once you've got the clamp in as far as you can go, push it into place and pull the line out. Be sure you have a drain bucket underneath it to catch the transmission fluid. Use the tool you made earlier from the radiator clamp or the proper GM tool if you have it. Once the clamp is inserted, remove the line and allow it to pour into the drain bucket. To disconnect these transmission cooler quick disconnect fittings from the bottom of the radiator, you'll need GM special tool 44827 or equivalent. Say three eighths quick disconnect tool. It's going to snap around the line, push in on the line. Insert the quick disconnect tool into the gap. Remove the fitting from the cooler. Place the line with the open end facing up to prevent it from draining anymore transmission fluid.

Remove these two 10 millimeter bolts securing the A/C condenser to the front of the radiator. Remove the 10 millimeter bolts securing the transmission cooler line to the rear lower part of the radiator. Move the expansion hose out of the way. Lift up and remove this plastic cover from the radiator support. Using a pair of pliers, remove the clamps for the expansion line. Remove the line from the radiator. It may help you to twist this to break it free. Place that off to the side. Remove the upper radiator hose. Remove these four 10 millimeter bolts securing the upper radiator supports the vehicle. We're going to use a 10 millimeter socket and ratchet.

We'll lift up and remove this from the radiator now. Remove these two 10 millimeter bolts at top of the radiator securing the AC condenser. We're going to need a 10 millimeter short socket and ratchet. Using a pair of side cutters, pop out the plastic clips holding the radiator shroud to the radiator. Repeat this step on the opposite side. Lift up and remove the radiator from the vehicle. Be sure to keep it lean toward you to keep any residual fluids inside the radiator as you remove it from the vehicle.

Here we have our old part that we removed from our vehicle and our new part from 1AAuto.com. As you can see, the parts are identical in mounting locations at the bottom here. We have the same quick-connect transmission cooler fittings at the bottom, same lower radiator hose connection as well as the top, and the same upper radiator support studs at the top of the radiator tank. We have the same locations for the captured nuts which you will have to change over from your old radiator in order to be able to install the radiator into the vehicle as well as the fans and the A/C condenser.

What happens with radiators is road debris can get kicked up and peeing over the fence like you see here. They can also create small holes in there, causing the leak. If the fence become peened over like this, it can block air flow across the radiator and create an overheating issue. They also become rusted out and can leak for that reason or they can build up with debris and sediment from improperly maintained coolant causing a blockage or low flow, also creating an overheating condition. If your old radiator has become peened over or clogged and isn't flowing properly or has a hole in it from rust and corrosion or a road debris, this new part from 1AAuto is going to go in direct fit just like your original equipment and fix you up right.

We're going to have to change these captured nuts over from our old radiator to our new ones so we can install our fans and our A/C condenser. There's a small lock tab here on the top. You're going to push down to get that passed the plastic retainer. Pop the captured nut out. Repeat this process to remove the rest of the captured nuts from the radiator. The captured nuts have a small lock tab on one side. When installing into the radiator, you'll want to make sure that that lock tab is facing out from the radiator toward you the way you push it in, until that tab walks in the provision in the new radiator.

Now these can take a little bit of force, so you might want to use a small flat blade screwdriver to push it in. Once it clicks, take a pick. Just give it a little wiggle. Make sure that it's not going to come out of there. For this particular radiator, we're going to have to drill four small holes into each side to allow us to insert the plastic retainers for our rubber fan shroud. We're going to use a measuring tape. You can see that the inside edge of the hole is the 16th of an inch away. The center of the hole is about a quarter inch from the edge of the fins and from the top of the tank down is a half an inch.

On our new radiator, we're going to go a half inch down from the bottom of our tank and a quarter of an inch to the center. We're going to use a sharp center punch. Careful because this is only aluminum. Just going to tap a small pilot. Use 13/64ths drill bit. We'll also have to reuse the rubber mounts on the bottom of the radiator. Simply pop off by hand, pop onto the new radiator.

Now we're ready to reinstall our radiator into the vehicle. Reinstall the radiator into the vehicle. Be sure that you line up the rubber bushings on the bottom with the holes in the sub-frame. Snap plastic clips for the shroud back into the radiator. You may have to stand up the A/C condenser a little bit. Lift up on the A/C condenser and align it with the top holes in the radiator. Lift up on the A/C condenser. Start your two 10 millimeter bolts into the captured nuts at the top of the radiator, tighten down those two 10 millimeter bolts with a 10 millimeter socket and ratchet. Remember, these are just plastic, just get them tight. Don't crank them on too tight or you can break the brackets.

Reinstall the upper radiator supports. Line up the holes and start for four 10 millimeter bolts into their appropriate slots. Tighten them down with a 10 millimeter socket and ratchet. Route the hose to the expansion tank under your radiator support. Reinstall it onto the new radiator. Open the clamp with a pair of pliers, slide it on and release. Reinstall your upper radiator hose.

Remove your transmission line from wherever you've secured it to. Try to keep it facing up right until you're ready to install it to prevent the loss of fluid. Slide it back in the fitting. Push straight in until it clicks. Be sure that the fitting is in there and it's not going to come back out. Do the same for the other cooler line. Keep it as vertical as possible. Push it in until it clicks. Wiggle it to make sure it's not coming back out.

Reinstall the 10 millimeter bolt that secures the passenger side transmission cooler line to the bottom of the radiator. Reinstall the lower radiator hose. Use a pair of sliding lock pliers to open up the clamp and reinstall it onto the end of the hose. Install the two 10 millimeter bolts securing the bottom of the A/C condenser to the front of the radiator. Tighten those down with a 10 millimeter socket and ratchet.

Reinstall the radiator fans into the vehicle. Be sure to line the bottom slots up with the tabs on the radiator. Reinstall the three 10 millimeter bolts into the top of the radiator. Tighten those bolts up with a 10 millimeter socket and ratchet. Reinstall the electrical connectors to each fan. Reinstall the plastic insulator for the air box. Reinstall the air box. Remember to connect the cooling line to the top. Reinstall the three 10 millimeter bolts. Tighten them down with a 10 millimeter socket and ratchet.

Reinstall the air filter into the air box. Reinstall the rest of the air box and the intake tube. Using a flat blade screwdriver, tighten up the screws to connect the two halves of the air box. Reconnect the electrical connector for the map sensor. Reinstall the boot onto the throttle body. Tighten down the clamp.

Reinstall the cover for the upper radiator support. Reinstall the PCV breather line. Remove the oil cap. Snap the engine cover back into place. Reinstall the oil cap. Reinstall the lower windage tray. Secure it with the plastic clips you removed and the thicker clips in the front. Install a clean funnel into the expansion tank and fill with the 50/50 mix of distilled water and orange Dexcool coolant.

Reinstall the expansion tank cap, and allow the engine to run for 2 minutes, occasionally revving to 3500 rpms. After 2 minutes, shut the vehicle down and allow it to cool. We'll repeat this process several times to remove any air bubbles from the cooling system. Be sure to always monitor your temperature gauge and make sure that it does not start running over the normal operating temperature. Otherwise, you'll have to shut down the vehicle before the 2 minutes is up.

After you filled the cooling system back up, remember we disconnected the transmission cooler lines, which means we'll have to check our transmission fluid. With your vehicle raised, supported, and running in park after going through the steps to cycle the transmission fluid, use a T45 Torx bit, an extension and a ratchet to remove the drain plug on the back of the transmission.

Our transmission fluid is running out with the vehicle running, which means that our level is often where it needs to be, so we can reinstall our drain plug. Otherwise, you would install a hose or pump and fill the transmission fluid until it ran out of the bottom of that all as you saw there.

If you do have to add transmission fluid, you'll use a screw on hand pump set up like this into your jug of Mercon 6 ATF fluid for this particular vehicle. Insert the end of the rubber hose into the fill plug hole and pump the top to pump fluid into the transmission pan.

Thanks for tuning in. We hope this video helped you out. Next time you need parts for your car, please visit 1AAuto.com. Also check out our other helpful how-to and diagnosis videos.

How to Replace Radiator 2004-06 Cadillac CTS

step 1 :Removing the Splash Shield

step 2 :Draining the Radiator

step 3 :Disconnecting the Air Intake

step 4 :Removing the Radiator Fan

step 5 :Disconnecting the Lines

step 6 :Disconnecting the Lines

step 7 :Removing the Radiator

step 8 :Preparing the Radiator

step 9 :Installing the Radiator

step 10 :Installing the transmission line

step 11 :Installing the Radiator Fan

step 12 :Reinstalling the Air Intake

step 13 :Replacing the Splash shield

step 14 :Refilling the Radiator

step 15 :Checking the Transmission Fluid

Tools needed

Shop Products

2004-07 Cadillac CTS Radiator TRQ RDA82668

How to Replace Radiator 1999-2013 Chevy Silverado 1500

Same Day Shipping

Guaranteed To Fit

USA Customer Support

Instructional Video Library

How to Replace Radiator 2004-06 Cadillac CTS

step 1 :Removing the Splash Shield 1:05

step 2 :Draining the Radiator 2:14

step 3 :Disconnecting the Air Intake 2:48

step 4 :Removing the Radiator Fan 4:06

step 5 :Disconnecting the Lines 6:02

step 6 :Disconnecting the Lines 8:53

step 7 :Removing the Radiator 9:37

step 8 :Preparing the Radiator 13:19

step 9 :Installing the Radiator 16:32

step 10 :Installing the transmission line 19:02

step 11 :Installing the Radiator Fan 20:22

step 12 :Reinstalling the Air Intake 21:15

step 13 :Replacing the Splash shield 23:30

step 14 :Refilling the Radiator 23:57

step 15 :Checking the Transmission Fluid 25:10

Tools needed

Shop Products

2004-07 Cadillac CTS Radiator TRQ RDA82668

How to Replace Radiator 1999-2013 Chevy Silverado 1500

Same Day Shipping

Guaranteed To Fit

USA Customer Support

Instructional Video Library

step 1 :Removing the Splash Shield

step 2 :Draining the Radiator

step 3 :Disconnecting the Air Intake

step 4 :Removing the Radiator Fan

step 5 :Disconnecting the Lines

step 6 :Disconnecting the Lines

step 7 :Removing the Radiator

step 8 :Preparing the Radiator

step 9 :Installing the Radiator

step 10 :Installing the transmission line

step 11 :Installing the Radiator Fan

step 12 :Reinstalling the Air Intake

step 13 :Replacing the Splash shield

step 14 :Refilling the Radiator

step 15 :Checking the Transmission Fluid