H3 Radiator replacement procedure

[alrock]

This procedure is essentially the same for the 3.5, 3.7 and 5.3, though I've been told the 5.3 does not have the slip shroud on the fan shroud, and that the cooling fan must be removed. Note that pictures from two different radiators are used in this post.

• Remove skid front splash shield
• Drain Radiator
  • Using adjustable pliers or similar, loosen clamp on lower radiator hose and move backwards on hose
  • Pull hose off of lower radiator opening and drain coolant into a bucket
  • Remove radiator cap for faster draining
  • Please note that in the picture below the transmission cooling line fittings are fully removed. Do NOT do this to your new radiator as you may not be able to put it back together. That transmission cooler is "floating" in there and you may not be able to line it up properly. We were just playing with it. 2nd picture shows how radiator should look upon removal.

Ugliness, and only 18 month old OEM radiator

• Unclip transmission cooling lines (automatic trans only)
  • Pull back small black plastic cap on transmission cooling lines
  • Using a small pick or similar, remove spring clip from transmission cooling lines
  • Pull lines out of fitting. The large fitting with the nut should remain in the radiator
  • Allow transmission fluid to drain
  • Do NOT remove fitting as shown in picture. This is for illustrative purposes only. You might not be able to reattach this fitting to the trans cooler if you fully remove the fitting like in the picture below.

• Remove top radiator hose using same procedure as bottom hose removal
• Remove fan shroud
  • Grab slip shroud knob located halfway down on passenger side
  • Rotate it around 90 degrees, grab second knob, rotate another 90 degrees
  • Squeeze clips on either side of fan shroud
  • Tug shroud upwards and out of the truck

• Remove top bolt and bracket and foam, if so equipped

• Detach a/c condenser from radiator
  • Tilt radiator backwards, lifting radiator up a bit if necessary
  • 10 mm bolts, one on each side of condenser, facing the front of the truck
  • Pull condenser upwards about 3/4" to lift it from bottom brackets on the radiator

• Remove radiator
  • Detach front diff breather hose from the right side of the vehicle
  • Detach coolant overflow hose from cap and brackets
  • Pull radiator up and out of the vehicle
• Installation
  • Reverse above procedures
  • We were required to pull out the small nuts used for the a/c condenser and move them from the old radiator to the new one.
  • If you are installing an external transmission cooler (or you have a manual and you got a similar radiator), do not touch the two transmission cooling line fittings. Those must not be touched to ensure the integrity of the radiator. No coolant will leak if you do not use these for your transmission.

• Filling coolant
  • 50/50 mix of Dexcool and distilled water
  • Fill radiator until full
  • Fill overflow tank until full to "Cold Fill" line
  • Leave radiator cap off
  • Start truck and check for leaks
  • Add coolant to radiator, add coolant as necessary
  • When truck reaches operating temp, the thermostat will open and the coolant level will drop. Add coolant mix to compensate.
  • When full, shut off truck and replace cap
• Top off transmission fluid as needed
• Time: 1.5 hours+. Alldata time is 2 hours.
• Capacities and specs:
  • Cooling system
    • Dexcool, 50/50 with distilled water
    • 10 qt capacity. I drained about 7 qts, but needed about 9 to fill it, including the reservoir which had been low due to the leaking of the existing radiator
  • Transmission
    • Dexron VI
    • 1st install we drained less than 1/2 quart
    • 2nd install we drained about 3 quarts, as it kept coming from cooling lines since we weren't working very quickly

 

[Bigunit]

Great write-up. Thank you Alrock. :cheers:

 

[05Mudiak]

Thanks alrock!

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[persius1]

Awesome write up! Put it to use today. :cheers:

 

[beadyeye]

Just got back from dealer after they told me my radiator is leaking so I came here. The guy at the dealership told me that the fan would have to be removed in order to replace the radiator but I don't see it in this write-up. So is it not needed?

 

[zackcrum]

No it isn't. Just remove the shroud

 

[alrock]

On the I5 engine, the shroud is two pieces and the bottom half circles up to the top half. Look for the lever on the side of the shroud and pull it up to the 12:00 position. You'll note in my pics that my fan is in place.

On the V8 you do have to pull the fan.

 

[WillieMo]

Great write-up thanks!!!!

 

[hellomynameis]

Thanks for this how-to. I just got 90% done with my radiator replacement. I'm stuck with hooking up the transmission cooler lines. I pushed the lines into the fittings on my new Silla radiator and they are seated all the way—I can't push them in any further and they won't pull out. I'm leaking transmission fluid when I start the truck. I didn't see an o-ring in the old radiator and I don't recall seeing any fall. Do I need to go get some o-rings? Is there something else I should be doing to seat these lines?

 

[jphh20]

Check the cooler flange nuts on the sillaradiator. My silla cooler flange nuts were loose and needed to be snugged down.


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[hellomynameis]

Thanks jphh20! That was my problem exactly, I tightened those nuts down this morning and I have no more leaks.

 

[jphh20]

Great to hear, I'm on my 2nd silla radiator. Keep an eye on the overflow tube near the pressure cap. Mine started to drip at times and needed a small hose clamp to seal.


Joe


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[SuperBuickGuy]

great write up but you forgot the moments for cussing breaks - for example, sometimes you can just snap the lines into the transmission ports. Other times, you'll snap them into the port and the spring will launch out of its spot... if they do, first, cuss, then push the line in and push the spring clip in after you've bottomed the transmission line.

Also, you can use an air hammer to get the fan off if you don't have a wrench (tighten it too)

 

[Best4x4]

Yeah I had to use a small hose clamp on the silla radiator as well for the overflow hose. No big deal though, the silla is doing much better than my oem.

 

[AlaskaDan]

How about starting the h3 after new radiarer installed and leaving transmission lines unhooked to flush the old granny fluid. Getting a tyranny fluid change at the same time. Good idea or not?

 

[Airborne]

How about starting the h3 after new radiarer installed and leaving transmission lines unhooked to flush the old granny fluid. Getting a tyranny fluid change at the same time. Good idea or not?

Actually I would like to know this as well. My radiator just started a small leak and I will be replacing soon. I was going to do the trans fluid and filter at the same time how messy would this be to flush it as well?

 

[alrock]

Interesting question. Perhaps put a tube on the intake line to a jug of new fluid with a drain line to a bucket for old fluid. I don't know if the system is pressurized to "pull" fluid through or if it just pushes it through. If it only pushes I think it would be a bit risky, or a bit of a PITA, to drain a quart, add a quart, etc. so that the pump is never dry. In that event you'd still end up mixing new fluid with old fluid, which leads me to doing the safer method of dropping the pan.

Dropping the pan changes out about 1/2 the fluid, plus you can put a new filter in at the same time. If I wanted to really get more new fluid in I'd do two drain and refills, which should get me to about 75% new fluid.

 

[Airborne]

Alex good call. The ATF from redline just gets damned expensive that's why I was hoping for just a true 1-1 fluid swap not the drain/repeat/drain method. Oh well.
And yes the system is driven by the torque converter so it is pushed through, there would have to be a constant supply of atf going down the fill/dip stick tube. Hmm I'm going to brainstorm this and see if it can be done and I will post on what happens.

 

[bpercy]

rad and condenser

I changed my rad today. Took me 3 hours.. I had trouble getting the clips out of the tranny lines at first because of a bunch of corrosion. About 5 mins of scraping each one with the pick before i could get a grab on the clip. Im in Canada (just north of Minnesota border , so salt eats the **** out of our trucks underneath). Anyways, the rad hoses came off nicely, you need wide pliers to do the trick. The bolts that attach the condenser to the rad are a bitch...i couldnt go through the grill and had to use a 10 mm wrench. Getting the rad out was tricky too, because it wanted to keep hitting the condenser lines on the driver side. All in all id say the toughest part is messing with the condenser (air conditioning) bolts and getting around it while taking old rad out and putting new rad in.

I had to take my brand new rad out after i finally got it in place before bolting it done.. because the new rad didnt have threads on the sides for the two 10 mm condenser bolts. So i just took the new rad out and took off my mounting brackets and put the old mounting brackets back on.

This is probably why it took me more like 3 and not 2 hours.. Also i used ear plugs on the tranny lines (good idea) and only lost about 200 ml of Dexron VI.