Fixing the 1998 HMMWV

[mrandig]

Fan temperature switch replacement.

I wasn't necessarily having problems with my fan temperature switch, but while I'm in here anyways...


Visual inspection shows this switch has seen better days. It's a little odd that it's so far gone, but whatever.


I'm just using tape so I can see the connectors.


Removal requires a 7/8 wrench.


Righty tightey, lefty loosey.


Even the wires are bad on this one.


The wires are actually worse than I just thought.


A little scrape of the surface with my plastic razor blade, just to clean up.


Some thread sealant (with PTFE) on the new switch.


I can't read these tiny numbering tags. I'm assuming that, if this is a resistance switch, it shouldn't matter if the leads are reversed. I'll look into it further after this post.


Tighten accordingly. The TM-20 doesn't give a torque spec here, but I wouldn't go to hard. Remember this is a 7/8" wrench, so it's easy to over-do it. A cracked crossover would be a bad day.


For cleaning the electrical connections, I'm now using Deoxit D5. I ran out of my usual QD spray, so I'll need to hit the store soon.


Dielectric grease on the insides of the connectors. This looks like way more than it actually is.


I think we're done.

 

[mrandig]

Lower radiator mount replacement.

As I'm replacing the radiator, I'm also going to replace the radiator mounts.

The lower radiator mount is shown in the picture. I'll do the two uppers when it comes time to put the radiator in.


At first, I started with a pry bar, but I began to feel like I was just trying too hard. Almost like taking a shotgun to go fishing.


Then I switched to a big screwdriver.


Finally, the mount came out when I used both together.


Here's the new mount ready to install.


A little dish soap for ease of installation.


Pops right in.

Done.

 

[mrandig]

Coolant hose replacement.

Well, it looks like we're almost back to where we started. It's been one hell of a detour.


To be honest, one of the reasons I was waiting on paint was to do the lower tube. It almost looks too nice now.

We'll have to see how it holds up with use, cause that tube is going to get hot.


Because a lot of these connections can be fussy, and some even brittle, every hose gets some dish soap on the inside prior to installation.


As a general rule, all hose clamps less than 1/2" were torqued down to @15 in/lbs. Anything 1/2" and over was torqued down to 30 in/lbs.


Lower water pump hose installed.


Lower water tube installed.


Lower radiator hose installed.


Lower radiator hose routing.






Lower surge tank hose and clamps.


Lower surge tank hose installed at water tube.




Lower surge tank hose installed at surge tank.




In addition to the lower surge tank hose, there's also two upper hoses.


One of the upper hoses goes to the water crossover, the other goes to the top corner of the radiator.


These new hoses are silicone and are softer than rubber. The existing clamps were having problems tightening correctly, so they had to be redone.


All hoses are complete. At least until the radiator goes in, then they'll just need to be connected and tightened up.

 

[Coug]

So far so good - the paint is a great match. I feel like painting everything I can at the moment, but I won't.

I got mine from QTM Parts on ebay. I think the price is a little higher, but probably not even a dollar more. I haven't compared shipping costs, so that may make the difference. It did show up quickly.

Not sure if the newer paint cans suffer the same issue, but the older cans they used seemed to have issues if they sat for too long, even brand new. Purchasing directly from Rapco is the easiest way to get the freshest cans of paint.

 

[mrandig]

Idler pulleys, water pump pulley, belt tensioner, and serpentine belt installation


For this post, I'm going to do the serpentine belt and all of its components, including pulleys and hardware.

First are the upper idler pulleys; there are two smaller ones.


Installed and torqued to 37 ft/lbs. (GM spec).


Next is the larger pulley. The long bolt will go into a bracket attached to the right cylinder head. Installed and torqued to 37 ft/lbs. also.


There's also a long spacer that the pulley will need to go through.


All three pulleys installed.


Next, we'll do the serpentine belt tensioner.


I'm torquing this tensioner to the same 37 ft/lbs.


The water pump pulley gets installed next.


There's a total of 8 holes. The inner 4 are for the water pump pulley, the outer 4 are for the fan.


The pulley will only fit one way, so you'll likely have to install the pulley and then spin the pump to align the holes.


Loctite comes next. I'm using blue 243, which is a general purpose threadlocker that provides a medium-strength bond. It can be removed with hand tools if there is ever a need.


Does everyone know Loctite expires? Of course, as soon as I noticed this, I immediately threw this bottle away and bought a fresh one.


The water pump pulley bolts need to be torqued to 17 ft/lbs.; but there's no good way to do this, as the pulley will keep spinning. Once the belts installed, then it's easy.


Move the tensioner clockwise to allow installation of the serpentine belt.

Route the serpentine belt around the crankshaft pulley, under the two upper idler pulleys, around the alternator pulley, power steering pump pulley, water pump pulley, and tensioner pulley.


Release belt tensioner.


That's about it for the moment.

I'm going to wait until everything else is done before putting the fan and clutch back on. We'll do that when it's time to put the new radiator in.