1994Vmax

iTrader: (4)

I thought I would do this as there is a lot of misinformation spread around on how to change these lines. In this instance it was 2005 GMC 1500HD 4X4 with of course an LQ4. This procedure should follow suit for any other V8 truck of this era and of course is for 4X4's specifically. I read a bunch of supposed techs spouting you have to either drop the front diff down or undo the mount and lift the engine on the drivers side. I can tell you right now, that is completely 100% wrong and is an absolute waste of your time! It's odd that such a simple common problematic component has so many people doing unneeded work to fix them. It's actually a pretty simple job for any automotive newb with some patience. When I checked no one had done them the way I had and posted it, and most posted answers led to extra work for nothing. So here goes!


1. Disconnect and remove the battery from the truck. It gets in the way of the lower line on the radiator. The brace over the battery has 2 10 mm head bolts and the battery hold down is 13 mm. 8 mm takes off the side post connections.

2. Pull the plastic covers off the lines at the rad connection. It's just a small spring clip that holds the line in the radiator. A small pick of screwdriver pops it right out. Do this for the inlet and outlet.

3. Remove both skid plates. It's 8 15 mm head bolts that hold them in place.

4. Go under the truck and remove the one bolt that holds the lines to the engine block. It's just a bracket near the front of engine, directly above the front diff. A 13 mm ratchet wrench makes quick work of it( in theory).

5. Move to the rear of the truck. At this point disconnect the front driveshaft from the yolk on the differential. My truck had 11 mm heads on the bolts in the yolk. Pop the U joint out of the yolk and just move the driveshaft off to the side, no need to pull it from the transfer case.

6. Pull the 2 10 mm bolts off of the aluminum block that holds the coolers lines to engine block.

Now this is specific if you have a clutch fan

Take the intake tube off especially if it's the stock snake as it gets in the way. Pull the fan off the front of the waterpump. Its just a big nut that threads on the water pump. Move the fan forward in the shroud. You do not need to remove the shroud. If you have e fans none of this applies

8. Now unclip the lines off of the radiator shroud/ fans and move the upper line in between the front of the engine and the shroud so it has enough room to swing down under the truck.

9. Now simply wiggle the lines and pull the backwards towards the transfer case. It took me 30 seconds by myself and the old lines were on the floor. Pulling them backwards avoids any clearance issues with the engine mount.

10. Install is reverse. Push the lines back through ( did this alone but a helper would be nice to pull as you push.)

11. Reroute the long upper line up to the top of the rad in the same method as removal. The lower will just come up and fit.

12. Install the spring clips in the radiator first and then click the tubing in place. There is a positive click when the line is seated. Push the black covers back over the spring clips to keep them seated in place.

13. Reroute the cooler line around the block heater cord if you have one. The cord comes out below the cooler lines and needs to as if you pinch it, it will touch the exhaust manifold.

13. Lube the new gasket on the rear cooler block and reinstall the 2 10 mm bolts into place. Reinstall the front driveshaft and both skid plates.

14. Reinstall the 13 mm bolt that holds the cooler lines to the engine block on the front. Clip the cooler lines back into the plastic bracket on the radiator shroud ( my aftermarket OE style replacements aren't bent right and don't fit, go figure.)

15. Reinstall the clutch fan( if necessary) and the intake tube. Install the battery, start the truck and check for leaks. Done!

It's a 1 hour job at the absolute most if you hussle. No need to lift, drop or do anything else. This worked on the HD and I am confident it's the same on any 4X4 1500 through 3500 truck.

I will redo a different set of lines eventually to something better than the original style that leaks all the time. I think 1/2" compression fittings and some braided line would replace the rubber portion nicely and never leak again.

tcoz2000

I have been scouring the internet looking for this info. After reading nightmares about dropping the front diff and pulling the motor mount, I was not a big fan(I'm supposed to leave on vacation tomorrow!).

When laying under there it appeared dropping the front driveshaft MIGHT allow me to work the lines down and out. I will chisel the rust off and have at it in the morning.

Excellent post, if I have any different issues on my 04 2500HD I will update.

Thanks again!

Bit

iTrader: (1)

Everybody does it the other way cause that's what the service manual says. Good job on thinking outside the box.

AUTOT3K

iTrader: (3)

I just did an 03 Avalanche 2500 at work /w the 8.1L
it was alot less involved then yours.
the skid plates had 9 15mm bolts
the bolt on the block holding the clip for the lines was a 15mm, use a ratchet wrench again.
and the only other piece that required removal was the plastic cover on the PCM.
the lines are extremely tight to the front diff so you gotta kinda twist and angle them as your popping them off from the oil filter adapter

1994Vmax

iTrader: (4)

I did it on my 03 and more or less followed my own instructions. That truck was awful to reroute the lines back in. The driveshaft was in the way as usual but you don't need to touch the oil filter so I omitted that from my instructions. Taking off the filter and whatnot may help on one truck and not another but on my 03 that is identical in every way to my 05 it didn't get in the way at all.

The big block trucks probably have more room at the rear is my guess simply because of the difference in mounting the lines.

AUTOT3K

iTrader: (3)

I know when it comes time to do my 2010 it'll be a breeze haha...2wd and room to do whatever I want

1994Vmax

iTrader: (4)

I have to do install of transmission cooler lines on the old 05 as after 8 years and 130000 miles they are finally leaking. I bought GM lines and they are really cheap honestly...... all 3 were only a little over a $100. Dorman only makes 1 of the 3 lines anyways oddly enough.

The GM lines actually fit too...... perfectly. My 03 was super easy to swap the trans lines on..... took maybe an hour but more like 45 minutes. Would be less the second go around.

I could do an install how-to on those maybe as well and then finally take and include photographs for the engine oil cooler lol.