Hydraulic fan issue - looking for help

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Dukester

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My wife's 2002 LS V8 overheated on Saturday. I checked the following:

1. Degas bottle coolant level low after overheat, but didn't take much to top it off.
2. Ran engine and bled coolant system to check for air bubbles, didn't get any significant amount of air out of the system.
3. Checked the fluid level of the hydraulic fan and it's ok.
4. Started car with AC off and cooling fan blowing on low. Kicked in AC and fan shifted to high.

So at this point I figure what the hell, so I go ahead and swap the thermostat. After changing the thermostat, I drive around about 30 minutes around the neighborhood with no troubles. I took the car to work today and drove the long way around, put about 45 minutes of mixed road/highway with no temp issues until right at the end when it started to get hot again.

When I got to work I popped the hood and now that the car is hot and has been running a while, the fan doesn't spin up to high when the AC is on.

So I figure I've got one of two problems:
1. The hydraulic pump internals are worn and when it get's hot it can't generate the needed pressure.
2. The solenoid for the high speed system fails when the car is hot.

I'd like to try replacing the solenoid first, but I don't have a manual, so I was hoping someone could look up the procedure for me.

Thanks,
Duke
 
If you do have to get into it and repair the fan or water pump, be sure to replace the belt, whether you need to or not.
 
The pump itself is a bear to remove. There are a few threads on this - so no sense repeating it again - but you have to buy a 10mm gear wrench to get to the bolts and loose/tighten one-then another-then another,... bit by bit.
 
Well, it's been a few weeks, but I figured I'd come back and update the thread.

QuikLS, I actually did a fair amount of searching on the hydraulic fan issue, but while I found a lot of threads with people talking about them, I didn't find much with actual repair info. The search doesn't have a 'use all terms' option, so when you search for 'hydraulic cooling fan' the search result is not as useful as you might think.

To add a couple of diagnostic details I didn't have the first time. I figured out the car was only overheating under a certain circumstance. If you started the car and drove in stop and start traffic, you could drive an hour with no overheat and the fan would run fine. The problem came in if you got on the freeway and drove over 60 for a while then slowed down. The car is fine on the freeway (lots of air flow), but when you slow down again and get back into traffic, the car would overheat and the fan would not go back into high. Once stopped and the car cooled down again, it worked fine no problems.

So this reinforced my feeling that I had a bad actuator and not a bad pump. I originally intended to go ahead and change the pump and the actuator, but after getting into it, I decided to just change the actuator for the time being as I didn't have the proper puller for the pulley on the pump and couldn't figure out any different way to get that top front bolt out.

So basically I ended up gettting the pump exposed and just changing the actuator.

What I did to get to the pump:
1. Put car on ramps to get good access to bottom.
2. Remove plastic air intake and plastic guards on bottom of car under the radiator and under the alternator.
2. Drain the radiator, disconnect upper radiator hose and set aside.
3. Unbolt receiver dryer and set aside.
4. Disconnect DCCV connection and unbolt DCCV and set aside.
5. Disconnect high pressure hydraulic fan line and drain fluid into cup (this is a slow process as it has to bleed through the pump).
6. Unbolt the fan shroud (two bolts one on each side at top, bottom just slots in) and unclip the fan return line from the two shroud clips to give yourself some slack.
7. Lift out the fan shroud out and lay it on top of the engine.
8. Remove belt from alternator and hydraulic pump.
9. Remove alternator (don't forget to disconnect the battery).

At this point you'll have a good sightline to the pump from the bottom and to the pulley from the front. Here is where I ran into trouble. Getting the bottom two bolts out of the pump was no problem, you can use a regular socket with long extension. The top back bolt was also doable with gear wrench that QuikLS mentioned (pricey, but if you do your own work, you should have a set of these). The front bolt gave me some trouble though, I just couldn't get to it from the bottom and the fan pulley is in the way in the front. So if you had the pulley remover, you could remove the pulley and then get the front bolt out from the front side. Since I didn't have the right puller, I settled for just replacing the actuator as I was pretty sure that was my problem anyway.

On a side note, if I had to replace an alternator again, I'd also remove the hydraulic fan shroud. It makes getting to that top alternator bolt a breeeze.

After replacing the actuator, I reversed the steps to reinstall everything. Before you put the high pressure fan line back on, make sure to replace the teflon seal ($2 at the Ford place) and prime the motor and pump with fluid. To prime the motor, I just filled the HP inlet with fluid and spun the fan by hand until it drew fluid. Spin it forward and back until you don't get any air bubbles when spinning it backwards. Then refill the reservoir and spin the pump pulley by hand until fuid starts to drip out of the HP line. Once you have done that just reconnect the HP line.

Overall, this is a big job, but doable if you have the time required. They quote about 5 hours for the shop and I worked on mine about 8 hours total.

Duke
 
Yeah, seems the job is a bear for everybody. After looking at it, I still think it would be easier to pull the pulley with the pump mounted and go for the top front bolt from the front.

Car seems to be running fine and fan has both high and low speeds. But since it was only failing after about 30 minutes on the freeway, I still have to take it out on the freeway and see if it stays cool after stretching the legs a bit.

Duke
 
what part did you replace? and if you could the part number
Thanks
dAN
 
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