2005 Jeep TJ 4.0 Liter Belts/Hoses Service

Servicing the belts and hose on the four liter Jeep Wrangler. Not a difficult chore, and can be done well with inexpensive materials and tools. This job will take a couple hours if all goes well, the time consuming part of the job is getting the materials together.

This is an easy job for the home mechanic, and should be done regularly to prevent catastrophic breakdowns. I’ve owned the Jeep for three years, and the top radiator hose had been ‘soggy’ for a few months. With summer coming up, there’s a high chance of long trips, hot weather and four wheeling. Simple preventative maintenance will go a long way.

There were some nuances to the service job, but this Jeep is a far cry from my old 1984 Volvo DL. There have been some convenient advances in belt/hose ‘technology’ within the last quarter century:

1. Belt Tensioner. This is a neat device that pushes against the belt, keeping a proper tension even as the belt wears out. Be careful not to let this smack into the closed position once you get the belt off of it.

2. Serpentine Belt. The belt doesn’t even go around the fan assembly, thus preventing having to take the fan off for replacement.

3. Hose Clamps. A nicety for sure, screw clamps are just fine, but these allow for consistent and perfect pressure on the hoses, without possible overtightening. These should be replaced during the procedure, they stretch out over time.

1/3 Tools/Materials


You can pick this up at a local auto parts shop, or at the parts department of a Jeep dealer. I got a Goodyear ‘Gatorback’.

Channel Lock Pliers:
These are for the clamps that hold the hoses on.

Two gallons of antifreeze/coolant, two gallons of distilled water. I eventually just used 2 gallons of the 50/50 mixture.

The lower radiator hose, the upper radiator hose, 5 feet of 5/8″ heater hose, 5 feet of 11/16″ heater hose.

I got the 5/8″ hose and upper hose from a local auto parts store. They ordered the bottom hose wrong, and 11/16″ heater hose “doesn’t exist”, so I got those from the dealer (see how nicely the 11/16″ heater hose is shaped). All clamps come from the dealer as well.

2/3 Plans:

Three of the four hoses are easy. The last hose, is not. We’ll do the heater hoses, and radiator upper hose first, then remove the belt to get the lower radiator hose.

3/3 Execution:

0. Drain the coolant. There’s a draincock on the radiator. Or you can use the ‘express method’ and unhook the lower radiator hose from the radiator. Use the channel-locks to squeeze the clamp, and move it off the radiator. Watch for pouring fluid, and don’t burn yourself. Feel free to turn the engine on for a minute (heat on). Make sure the engine is cold before you do this, and only let it run for a minute. This will allow the rest of the coolant to sputter out.


1. Upper Radiator Hose. Use the channel-locks to move the clamps, work the hose off, replace with the new hose. Clamp on. The dealer only gave me one clamp for this hose, and a screw clamp for the other end. They claimed they don’t make anymore of the clamps for ‘that side’. I used one of the old clamps instead of the new screw clamp.


2. Heater Hoses. Same process, make sure to put all nylon sleeves on the new hoses. The 5/8″ hose has to be routed since it’s not preshaped. Just ‘curve’ it so it matches the top hose.



3. Remove the Belt. The top end of the lower hose, the one that connects to the water pump, is nigh impossible to access with the belt on. Use a socket wrench or a breaker bar with a 1/2″ drive. Insert the drive into the body of the tensioner. Push towards the side of the engine with the windshield wiper fluid. This will cause the tensioner to rotate downward, and the belt to come off. Do not allow the tensioner to ‘snap’ back into place, ease it back up.



4. Lower Radiator Hose. You’ve already unattached the bottom end, now for the top. We couldn’t get in there with the channel-locks and used a smaller pair of pliers. Push the clamp down, pull the hose off. We didn’t use a tension clamp on the top end of the hose, it was way too tight. I’d be interested to see if ‘real’ mechanics manage to get one on there, or if they just use a screw clamp like we did. Attach the clamp lightly to the hose before you install it. Make sure the screw head will be facing the front of the engine when you put the hose on. Tighten the screw clamp until it’s ‘hand’ tight.



5. Belt. Route the new belt, you will likely need a friend to hold back the tensioner while you get the belt on. The belt will be very tight because it is new, so you’ll have to muscle it on. The easiest way to do this is to wrap it around everything except for the power steering unit (the top right pulley). Then push it on carefully with either gloves or a flat head screwdriver.


6. Refill. Remove the radiator cap. Fill the radiator with your coolant/antifreeze mixture until it’s at the top of the radiator. Turn on the engine. There are many air bubbles in the cooling system from the new hoses. Leaving the radiator cap off while running the car will allow the air pockets to ‘bubble’ to the top of the radiator. Continue to fill the radiator as the air bubbles out. When you’re satisfied with your liquid level put the cap back on, and you’re good to go. Keep whatever leftover coolant mixture with you in the back seat, and sporadically check the coolant expansion tank. Fill it up to ‘full’ line.

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