My Radiator Replacement Step-by-Step Guide on 2000 Pontiac Bonneville SLE
I just had to do this last weekend and like many amateurs who had never done this exact repair before, I spent hours googling how to do it, only to find there was not enough detail for a typical first-timer like me. So after I managed to do it over too many hours, I wrote up the below step-by-step guide to help out others like me doing this for the first time. But first a little back story.
My 2000 SLE started leaking coolant pretty good at a gas station two days ago. The radiator had a hairline crack at the driver side radiator hose fitting, and I could see the coolant spitting out. I had it towed home and went to NAPA for parts, so I could start replacing it that same day, Friday the 13th with a full moon. More on that combination later. The old radiator had writing on it showing it was installed six years ago. Just two weeks ago I had put in a new Felpro Lower Intake manifold gasket, the upper gasket and plastic plenum, new thermostat and green coolant, and various new sensors and it had been running great. I had not done a radiator before, and spent much time googling up advice. Below is how I did it, with more detail than I found elsewhere, so it may help someone else do this in less time than it took me.
And less aggravation. It was lightly raining when I started before dark, thinking I would have the job done in a couple of hours, so I moved my ABC brand pop-up commercial quality canopy from the back deck to the front driveway over the car so I could work dry. I zip-tied a five-gallon bucket to each leg of the canopy and filled them with water, so about 40 pounds at each leg, which seemed sturdy enough in a light rain in Florida. Nope. An unexpected 70 mph storm front blew in about 5 a.m. and I heard what sounded like my canopy being blown away. Sure enough when I went out into the dark pouring rain, my canopy was 50 feet away in the street wrapped around my mailbox. I managed to squeeze the frame together so I could pick it up and get it and the fabric top into the backyard. The wind just undid the zip-ties on my water buckets – live and learn through my stupid mistakes. And my flying canopy put a long scratch on the left fender of my Lincoln Town Car for good measure, this being the night of both a full moon and Friday the 13th, a night anyone not a fool like me would have taken down their pop-up canopy. Now on to the step-by step:
1. Remove lower plastic splash panel under radiator. It’s pretty quick and makes access easier. A lot of the plastic retainers will break, but new ones are $5 for 25 at Amazon.
2. Loosen radiator petcock on driver’s side on bottom edge of radiator, long 11/16” socket, to drain fluid into a drip pan. It drained about 1.5 gallons, which I did not reuse. Drains almost straight down without splash shield.
3. Remove the four radiator support brackets on top of the radiator support. Left and right ones are squarish heavy metal brackets that go over plastic pins at top of radiator, and then there are two center braces, each about 1” wide by 6” long; all use 10mm bolts. Pull the flat black rubber cover over radiator off; it has a flange that presses into the top of the radiator.
4. Remove the radiator support bracket to have easy access to everything else. This is the four-foot long rectangular, curved metal piece. There are 4x 15mm bolts holding it on. To remove the driver’s side bolt, you have to first move the intake airbox out of the way; 2x 8mm bolts on top of it. (I did not remove the support bracket before I removed fan and had a terrible time trying to get the fan out.)
5. Remove the 2 radiator fan bolts, 10mm, one on each side, and the 10mm bolt holding the metal bracket that keeps transmission fluid cooler lines in place at bottom passenger side of fan unit. Unhook electric connector from each fan by prying up holding tab on bottom of each fan and pulling off. I had to use a mirror to see how to disconnect them. Fans should then lift straight out.
6. Remove the upper and lower radiator hoses. Both were old looking, so I replaced them with new ones while I was there. Actually, to my eye, they both go into about the middle of each side of the radiator, so I could not tell NAPA which was upper and which was lower. I call them the driver side (radiator to thermostat housing) and the passenger side (radiator to water pump area where serpentine belt is at. Not sure why NAPA kept asking as I wanted them both.
7. Unhook upper and lower transmission cooler lines going into passenger side of radiator by removing the small E type clips hidden under the plastic covers (which slide out of the way), pull out with e-clip removal tool (one came with my new radiator) or use pick tool to grab one end of clip and work it out. Once clip is removed or loosened with tool, the cooler lines should pull straight out, might take a little force by hand. I could not get lower cooler line clip removed, so I unscrewed the tube holder from the radiator first (18 mm open end or line wrench; a size I had never needed before for anything, so had to run to Home Depot to buy it), then removed the cooler line from the holder later on after radiator was out and had more room to work on it. You can use a pick-type tool to grab an end of the e-clip and rotate and pull to remove it.
8. Remove the two 10mm bolts holding the air conditioning condenser (looks like another radiator) to radiator. The one on driver’s side is shorter than one on passenger side, so remember which is which. I put all removed bolts and parts into separate and labeled Hefty Brand Freezer bags with slider closers as I went along and am glad I did. You can then pull up the radiator and condenser together a little bit and tilt it back a bit to get easy access to the bolt on passenger side. Notice how the condenser has metal edges that slide into little plastic support brackets built into radiator on each side, driver’s side bracket a bit higher than other side. Then you should be able to lift radiator straight out. Compare sizes and mounting brackets to new radiator to make sure they are the same.
9. My new Spectra Premium radiator was $170 in stock at NAPA, cheaper on Amazon if you have time for shipping. It came with two new fittings (same size top and bottom) that hold the transmission cooling lines, which I screwed in hand tight and then a little more with the 18mm wrench.
10. Reinstall parts in reverse order, more or less. I used a torque wrench to tighten some of the bolts using AllDataDIY specifications which had an obvious error, but I could not find the GM torque specs.
11. I put in new radiator first and lined it up with connection points to condenser, which took a little wiggling around to line up and have radiator drop onto rubber receivers at each side of radiator. Make sure condenser also slides into holding brackets on each side of radiator. Install the two condenser to radiator little bolts at 115 inch/pounds (not AllData’s 115 foot/pounds); easier when tilting radiator and condenser back and up a little bit. Once all is lined up, I attached the two cooler lines to the new fittings on radiator; the lines will just push straight in past the retaining spring/e-clip so you don’t have to remove the spring. I put a little motor oil on each line to help slide in.
12. Then attach fan unit. Two bolts, one at each side, and then the bolt and bracket at bottom on passenger side that hold the cooler lines in place all at 71 inch/pounds. I had to move the lines a bit to fit under the bracket. Before I reattached the electrical connectors to each fan, I hit the sockets and connectors with spray electric contact cleaner and then Permatex Dielectric grease.
13. Reinstall the big radiator support bracket and supporting braces and move the airbox back into place. I don’t know the torque, just snugged them in.
14. I then dry fitted the two new NAPA radiator hoses from radiator to engine to get the right angles so hoses were not pinched, and set up new worm gear NAPA hose clamps so I would have easiest access to them for tightening. I used a silver felt marker to mark hoses where they fit best, then removed hoses and dabbed some Permatex 2 non-hardening form a gasket goo on the four fittings for the radiator hoses, then reinstalled hoses and tightened up all four clamps. I don’t know the torque for the clamps, so just pretty tight with a socket wrench. The radiator passenger side was the hardest clamp to line up to tighten, eventually using a long 1/4” extension shaft coming in from top at an angle.
15. Then fill up radiator and cooling system with coolant and bleed it. Before then I removed the coolant reservoir and cleaned it out good with soap and water to get rid of 20 years of crud in there. I used excellent guide from the facebook GM 3800 tips motor site,
https://www.facebook.com/GM3800Tips/pos ... __tn__=K-R16. Three days and many miles of driving later, everything looked good, no leaks at all, coolant temperature perfect.