Home Write Ups Engine Electric Fan R & R (WJ)
Electric Fan Removal and Replacement (4.0L WJ)
Written by Cebby
My WJ came equipped with the electric cooling fan. It is commonly known that the 99-00 WJ's suffer from inadequate cooling. Later WJ models came with a viscous coupled engine driven fan tocombat this problem. The only problems I've experienced were due to coolign system failures - primarily the electric fan and the fan relay.
At roughly 75000 miles, my WJ developed some cooling problems. I was getting intermittent fan operation. Since I have a few miles left on my 8/80 powertrain warranty, I take it to the dealer who sold me the vehicle (purchased used with 36000 miles). The dealer replaces the fan relay and tells me everything checks out. At this point they tell me that the cooling system is NOT under warranty. Well, driving home I hit some traffic and watch the temperature climb into the red, - this is in November in the Northeast, so it is not related to the ambient temperature. I blast the heater to bring the temp down so I can limp home (pulling over and shutting down when traffic was getting too heavy).
Back to the dealer two days later. After about 6 hours, the dealer tells me the fan is the problem. I asked if they had replaced a functioning fan relay - "they had no way of knowing" they tell me. I picked up the vehicle prior to them doing any work. 5 Star Crooks...
SO... I found a dealership closer to my house that is reasonably priced on parts and opted to tackle this myself.
- First thing to do is to disconnect the negative battery terminal.
- Drain the coolant. You need to get a length of 1/4" +/- ID hose to push onto the radiator petcock. If not, the coolant will drain all over the valence. The petcock is located at the bottom of the radiator on the passenger side. When loosening this petcock, be advised that it IS NOT a 1/4 turn valve, but a normal petcock that must be unscrewed almost completely (a few revolutions) to drain at any decent rate. Mine was impossible to turn by hand, so I took an adjustable wrench and fitted it to he handle so I could get some leverage.
- Remove the upper radiator hose. This hose uses constant tension clamps. The service manual recommends a special tool for doing this, but I've found that some right angle channel locks work fine - you just have to be careful.
- Disconnect the electrical plug attached to the passenger side of the shroud. This plug has a plug lock like most other plugs in the engine bay. It requires moving the red plastic lock slightly to be able to depress the clip that will permit separating the plugs. This is not an easy task if you have normal to large hands. Prepare to skin your knuckles.
- Removing the fan involves removing the shroud so you can get to the fan mounting bolts. There are (4) bolts attaching the shroud to the radiator. Since I am in the Northeast, I hit all the bolts with some PB Blaster to facilitate removal. The top two bolts are easy to remove. The lower bolts are another matter. The lower passenger side bolt is nearly against the framerail. I've tried a number of tools to get this off. The best soultion I've found is using a swivel head socket. In a pinch, a socket and separate universal joint will work, but the extra length of the universal makes it tough. The lower driver side bolt is nearly impossible to get to. From above, the steering box is in the way. I ended up using a combination of a swivel head socket, 18" extension, universal joint and a 6" extension. I came at the bolt from underneath. Not easy and by far the most difficult part of the project.
- After the bolts are out, the fan shroud and fan can be maneuvered out.
- Remove the fan assembly from the radiator side of the shroud.
Fan mounted to shroud
- Mount the new fan to the radiator side of the shroud. Be sure to route the fan wires in the same way as the fan being replaced.
- Maneuver the shroud and fan into place. Reattach the shroud to the radiator with the 4 bolts. Coat the bolt threads with some anti-seize to make future removal easier.
- While under the vehicle, close the radiator petcock so you don't have an accident when refilling the radiator with coolant.
- Reattach the electrical connector on the shroud to the vehicle harness.
- Reinstall the top radiator hose and constant tension clamps.
- Refill the coolant (reuse as much of the existing coolant as possible depending on its condition)
- Reattach the negative battery cable.
- Start the vehicle and let it idle until normal operating tempurature is reached. You should hear the electic fan kick on around 210°.