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premis 11-26-2012 01:21 PM

DIY _ thermostat Replacement
5 Attachment(s)
Here is a DIY for replacing thermostats. This was done on an LLY truck, but I would imagine it is the same or similar across all platforms.

The thermostats are both located near the front center of the engine in between the alternator and AC compressor. Note, I removed my turbo noise suppressor, if you haven't you will need to remove that before starting. If you haven't already, drain a little bit of coolant (maybe 1 gallon). There is a drain valve on the bottom of the radiator on the passenger side. REMOVE THE SURGE TANK CAP FIRST to remove pressure from the system, then replace surge tank cap and remove drain plug. This will allow somewhat of an air-lock so the coolant will drip out instead of spray.

1. Remove the turbo noise suppressor bracket and the wires held to it.

2. Remove the 12mm bolt holding the black coolant pipe to the thermostat housing

3. Remove the four 12mm bolts in the thermostat housing.

4. Now we need to loosen the black coolant pipe so we have some play in it. First remove the 12mm bolt holding the black coolant pipe to the drivers side head.

premis 11-26-2012 01:25 PM

5 Attachment(s)
5. accessing the 2nd bolt on the coolant pipe is a PITA. First, unplug the two large engine electrical plugs. Then use a torx bit (I think a T-20) to remove the lower plug from the metal mount. Next LOOSEN but DO NOT REMOVE the bolt that is under the intercooler tube near the firewall that holds the electrical connectors to the head (see picture below)

6. Now remove the two remaining bolts holding the electrical connector bracket down.

7. With those two removed and the third loose you should be able to wiggle the bracket out of the way enought to loosen the 2nd bolt holding the coolant pipe to the head.

8. Now gently wiggle the thermostat cover loose, you may need to give it a light tap with a RUBBER hammer. I decided not to unattach the black coolant pipe from the thermostat housing, I was able to work around it. You can if you want, it's your choice. Once the thermostat housing is removed you will be able to see the thermostats.

9. Take the two old thermostats out and be sure to clean out all of the old rubber gaskets on the thermostats.

10. Install the new thermostats (the longer one in the front) and reinstall. Make sure the drain holes on the thermostat are to the rear of the truck.

Remove the bleeder screw on top of the thermostat housing (circled in picture).

Add coolant to the coolant tank on the passenger side between the air box and battery. Mine took about 3/4 of a gallon.

When full, coolant will come out of bleeder screw, when this happens, replace bleeder screw and top off tank to appropriate level.

Hope that helps! It's a pretty easy task, only takes about 1 1/2 beers :drink

Lmholmes11 11-30-2012 02:33 PM

Thanks for the write up. Whyd you decide to replace them? Overheating?

pbarone_iv 12-08-2012 04:09 PM

i just replaced mine based off your directions... thanks a bunch! made it real easy. only thing to change is that the torx screws are t27 not t20.

thanks again

nmeyer414 01-05-2013 01:13 PM

thanks for the write up, i am about to do mine and will let you know how it goes

nmeyer414 01-05-2013 06:30 PM

so, for me the time was 1.5hrs, 3 beers (i drink them kind of fast!). great write up, helped alot. the only thing that i did differently was removed the oil fill tube, so that i could get to the housing and bleed screw easier.

TiMe_1 01-11-2013 08:06 PM

Used this to do mine on my 06 LBZ last weekend. Wasn't hard at all. Couple bolts were a pain to get to but I got it done. Thanks!

rms 01-11-2013 09:30 PM

Excelent pics - bookmarking this.


bubblebutt 01-11-2013 10:58 PM

Only 1.5 beers?? I'll get 2 down before I got the hood open:drink

Marauderer 03-02-2013 07:58 AM

Premis, thanks for the write up. I notice mine not coming to operating temp anymore. And it comes up slowly.

What is the stock thermostat temps??

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