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Discussion Starter · #1 · (Edited)
So I had the opportunity to change the thermostats in a Duramax van the other day and I did a write up on it. No pictures, but they have a second van and I hope to do the stats in it soon.

So here is the write-up I did. If you feel it needs to get added to a how to folder, that would be great.

DuraVan Stats

Here we have a little How To on replacing the thermostats in your LLY Van if you are so lucky to get own one.

The difference between doing this in a van and a pick-up are extreme. The location of the housing bolts and the placement of the stats is about the only thing in common betwixt the two. Accessing the bolts is where the big difference is.

I’ll start with a short over-view: Remove the alternator to get to the two bolts under the intake. That’s basically it, but I’ll go ahead and detail it out for those that need a bit of help. My customer has two of these and hopefully they will have me do the other one soon. If so, I will take pictures and add them to this thread.

To get the alt. out, you first need to remove the fan shroud. Flat rate for the alt. includes draining and refilling the coolant. It’s not needed, but since you will drain the coolant anyway to do the stats, you may as well drain it down a gallon or so. You only need to get it below the level of the stats.

1. Remove the bolts holding the top of the fan shroud, the surge tank and the air cleaner. Bungee the surge tank over the battery.

2. Disconnect the MAF connector and loosen the hose clamp on the intake accordion hose at the engine end. Lift the left side of the air box, disengage the slot and tab on the right side and remove the air cleaner.

3. Loosen the hose clamps on the boost tube on your right, the boost tube in the center and the vertical part of the boost tube on your left. The plastic boost pipe 90 Deg on your left will need to be pried off. I put a prybar where it bends down, prying up and pushing down on the tube with my right hand to pivot it out of there.

4. Remove the intake heater by using a 5MM allen to remove the four bolts, catching the steel gasket and disconnecting the two wire connector on the back side of the heater. Set it on the fan shroud.

5. The main wire to the intake heater goes to a harness that lays across the top of the fan shroud. Remove the nut holding it to the Buss Bar by the battery, open the plastic clamps across the fan shroud and set it all off to your right. Don’t worry about it being a hot wire, because you disconnected the batteries, right? Right? Yeah. Neither did I.

6. Take the AC line and hook it over the trans and eng dipstick tubes.

7. Remove the two bolts on each side of the fan shroud holding it to the bottom half. This is where they say you will need to drain the coolant to do the alternator. Well, the upper heater hose is flexible, the fan shroud is flexible… the fan shroud WILL come out if you leave the upper radiator hose on, but since you will drain the coolant to do the stats, just pop that upper radiator hose off and make it easy on yourself.

8. Loosen the serpentine belt and remove it from the alternator.

9. To remove the alt. on the van, there is a bracket on the bottom clamping it and that comes off. There are two bolts that mount the alt. and three bolts that hold the bracket on. The bracket is located with hollow dowels so it will need some persuasion to get it off, but it’s not bad. Once the bracket is off, pull the alt. straight out and set it on down, leaving the wires hooked up – the batteries are unhooked, so no worries there, right?

10. Remove the one bolt holding the fuel pressure coupler to it’s bracket and stuff it out of the way to your left. Remove the two bolts and the fuel coupler bracket so that you will have room to lift up the stat housing. One thing that I did that may not be needed is to remove the oil filler tube. The big thing to be careful of here is that you don’t spill coolant down the open hole, so lift the housing first, then if you can’t get to the stats, remove the filler.

11. Now we are ready to get the stats out. Disconnect the temp sensor and reach in with a 12MM socket on a ratchet – ¼ inch drive with a medium long socket worked well for me – and remove the bolts on that side. Put an extension of just the right length on the ratchet and remove the bolts on the right side of the housing and lift it up.

12. Remove old, install new. Reassembly is the reverse of disassembly. The only assembly note that I can think of is when you are reinstalling the alt. bracket, tighten all five bolts, then go over them again. Then do it one more time to be sure that it’s all settled in.

13. Also, note that unlike the pick-up, there is no bleed hole on the housing because the hose is the high spot, but the hose bends down some so you still need to manipulate the hose to get the air out. Also, I have a funnel that attaches to the fill hole, and is sealed. This is a great way to fill the cooling system.

As I mentioned, I hope to do their other van soon and I will take pictures of it as I go and will get them attached here.
 

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In case you did not notice we have a van section here that this type of info would be perfect for.
 

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Discussion Starter · #3 ·
I looked for it but didn't see it. I'll? see if a mod can move it. Thanks for the heads up.
 

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Discussion Starter · #4 ·
After looking again, I found it but I don't find a button to report it to a moderator.
 

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In the lower left corner of each post, there's a little white triangle, outlined in red, with a black vertical line inside it. Click on that to send a message to the moderators for that post.
 

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Discussion Starter · #6 ·
Not on my phone. I do t even have a Quote button. :(
 

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Oh, no idea how to do it on a phone. Maybe you can switch the layout to the desktop one?
 

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Ok. I seen your post here and have to say there is no reason to remove the alternator. My van is a video 2006 lly.
After removing the intake hoses and fan shield....you need to unbolt the vacuum port from top of thermostat housing, remove little bracket below intake. Remove intake heater too. The two right bolts are fairly accessible. Can remove with just socket and extension. The back left bolt needs a wobble socket. And for the front left bolt, remove the coolant sensor and use a wrench from the front to remove.
 
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