Thread: How to replace heater core and water pump

I hop this post can help somebody, but the point of this post is so I remember what I did. So I have a 2006 Pontiac grand prix GT with 120,000 miles. I have had a coolant smell forever in the engine bay, but until recently I never lost any coolant. Also never smelled any coolant in the cabin. Until recently. Two months ago I noticed the coolant was a little low so I had the car pressure tested and the showed me a leak in the radiator. I replaced the radiator and all was good for a month. Then I noticed a coolant smell on the inside and losing more coolant. Also, the temperature fluctuated more than it usually did, but never overheated. Also, for the last few years I have noticed no heat in the winter and a gurgling behind the firewall. I have flushed the heater core several times, and it helps temporarily. So I finally decided today is the day. I was going to tackle the heater core and check everything else. I will go step by step. Also

Step 1 - review all on line posts and Chilton's manual

I think I am going to have to put a lot of replies here because for some reason the return button does not work so I can not start a new paragraph. I am only half way done with the procedure, and this is not the order I did it, but I now know how it should be done.

Step 2 - Remove the center console. This is done by removing the screw in the shifter and taking the handle off. It is a Phillips screw. Then put the seats back and remove a bolt on each side of the console. Then put the seats forward and remove the 2 bolts at the back of the console near the floor. Then put the key in and shift the car to L. The console will then come up and out. There are two clips that it must be popped out of. Then put the car back in park and remove the key.

Step 3 - If you have rear air you have to do this. I tried not to and broke the outer cover for the heater core. So If you have rear air you have to pull the carpet back. To do this you have to take out the seats. Unbolt the seats by removing the bolts that hold down the rear of the seats. Then pull the seats back to free them from the front hook/latch. Once the seats are free disconnect the battery. Then unhook the electric from the bottom of the seats. Then the seats can be placed outside the car. Then pull the carpet back. You will have to remove the trim pieces the cover the sides of the carpet. You need to get the carpet over the shifter in order to remove the ducting. Once the carpet is back you can just lift out the ducting.

Step 4 - remove the trim piece around the radio. You have to first remove the trim around where the key goes. It just pops off, then the trim pops off. Then unbolt and remove the storage compartment on the bottom

Originally Posted by Scottydoggs

heater core is fun.

remove the console and then start taking every gold colored bolt out of the center section under the dash. once you can see the core, follow the 2 pipes up to the inside of the fire wall, theres a screw holding it up there, then take it out, and replace it.

if you search around a bit you'll find a few posts covering this job.

It is not fun. My kids have learned several new swear words. Also, I did read all the posts, but none had enough detail, so I am putting in a bunch of detail. Partly to help other people, but partly to help me so I can put it back together. I took off a bunch of stuff I did not need to, and did not take off some stuff that I was supposed to.

Step 5 - remove the black pieces under the dashboard. There are 3 plastic rivets holding these on. Pull out the raised tab and the rivet will come out.

Now you can actually start at teh heater core.

Step 6 - remove the outer heater core cover. There is a great post on this on this site. With the seats out can carpet back there is plenty of room, but you have to lay on you bcak and make sure you have a good light source. You need a 1/4 inch wood chisel and nut drive toremove all of the mounting point. There are plastic rivets that you need to scrape off the head with the chisle. Just take it down until it is flush. Now you can pop off the outer cover

Step 7 same thing for the inner cover. Screws and plastic rivets. There is one that I could not get to without a swivel type extension on my socket.

Step 8 - remove the heater core by just pulling it out. There is a foam piece behind it. Still not sure what to do with it. It has a piece of paper that if I remove I could stick to the heater core, just like the new one I bought. This is where I am at for now. If ayone has any ideas on the foam piece, and whether the paper goes toward the core or away I would appreciate it.

Step 9 - wait for outer heater core cover to come from dealer because you broke it because you did not remove the seats and carpet first time around to get the rear heating duct out.