Pretty sure the water pump is finished since she’s overheating. It was last changed in 2010 so probably well overdue. Doesn’t look terribly difficult, might take a stab at it solo. Any recommendations ? I know the 4.0 v8 is a little more rare then the 4.2 so I’m curious to see if anyone has done one recently.

 

As far as I know ALL 4.0L, 4.2L and the Lincoln LS 3.9L engines use the same water pump? Including the SC and NA versions.
I installed the Lincoln part in my old 2005 STR because they are all around and the aftermarket has released an improved version over the original factory design. So the Lincoln one is cheap and available. My local parts store had one in stock at 9PM on a week night!

With the age of your car you will need a cooling system overhaul at this late date. So don't just replace the water pump as that's false economy and you will soon be back in there fixing additional stuff. Plan on changing ALL rubber hoses (Hey at least you don't have a SC version with many more hoses!). Thermostat too.

Has the DCCV been changed? If not add that to your list. Be sure and flush the heater core good with the DCCV removed. You will have 3 hoses going to the firewall. One to the drivers side. One to the passengers side and the 3rd one is the return from both sides. Flush both ways thru ALL 3 hoses. The S-Type is not known for heater core plugging but it's a good thing to do since it's all open.

Flush and put in new clean coolant and it's just plain Dex-Cool so again available anywhere.

The 4.0L is know for tensioners problems and I hope both the primary and secondary tensioners have been changed already?

As always if you can't DIY the repairs be prepared for a large bill and additional damage to your car from mechanics breaking things! To be fair your car's age will make all the plastic brittle and things will fall apart when you try to disassemble them. So be prepared for that.

None of this is hard but it will take some time and as our friends from the UK say "It's a bit fiddly"! So give it a try!
Plus this forum has many threads on the 4.0L cooling system so time spent searching for those will be worthwhile.
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Indeed I changed the dccv & flushed the heater core about 4 years ago. Most of the hoses and plastic housings have been replaced or changed to aluminum. Changed thermostat yesterday in hopes it was the issue but after listening to the water pump make more and more noises over the last few weeks I’m convinced it’s the culprit

 

The water pump is about the easiest to change I've ever seen. 8 small bolts and it is done. But, while you are going to do this repair, you should replace the thermostat, the housing, and as many hoses as you can plus the serpentine belt and check the idler pulleys for any wear. The thermostat plastic housing is junk and they make a metal one that fits perfectly. In a few hours you are all brand new.

 

Yes it’s much different then the 4.2

 

The water pump fits more engines than I thought?
It also is the same as the LR 4.4L V-8 which I did not know!


Yes I was surprised how easy it was to change after all the hard repairs I had to do on my STR.
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Maybe the radiator if you already did the thermostat recently and water pump little while ago.

 

Yes radiator is going to be my next project. If that doesn’t work I’m thinking the head gasket but car doesn’t drink coolant, produce white smoke or idle rough. Fingers crossed if not it was a good 2 decade run!

 

Um, before you load the parts catapult (Pull!), what are the overheating symptoms you are presently seeing? Gauge reading high? Puking coolant from the reservoir cap? Rough running?

 

Finally got around to changing the water pump although it seems like the old one (2010) was in decent shape. She seems stable now. No overheating although one of the pulleys still squeaks on startup. Will run her a bit this week and see but yea only symptom was a random overheating issue which seems the water pump resolved. The radiator is over two decades old so it wouldn’t hurt to change it they’re pretty cheap.

 

Nvm after further investigation it appears coolant is leaking from the radiator. Passenger side where the metal meets the plastic. Water pump and thermostat were less then $70 bucks so no big deal there. Local parts store has one for $140 so might give her a go this weekend. Beats a blown head gasket for sure. Thx again boys the “dream machine” lives on….

 

You might want to consider a Nissens branded radiator for your S-type. I have used one and Karl here on the forum has used one as well. It is a 6+ hour job for a professional, so you really don't want to do the repair again any time soon...

BTW, my original radiator leaked in exactly the same place when it was saying "goodbye".

 

I'm very pleased with the Nissens brand radiator. The replacement process? Not so much. What a royal pain. I don't know about V8 models, but on my '02 V6 there was lots of stuff in the way.

You'll need to get the front end up on ramps or jackstands, as you'll need access underneath. I didn’t have to remove the bumper cover, just the belly pan. I had to drill out several fasteners as they were seized.

The fan (and shroud) had to come out. I removed mine separately but the factory method may have you remove it as a unit with the radiator, AC condenser, and combo PS/AT cooler.

Tight quarters in there, but I separated the condenser and cooler from the radiator and left them floating in place. Fortunately I didn’t have to disconnect the cooler lines, but not so with the AC lines. What a miserable design. If the AC lines had been redesigned slightly, the radiator could have come out fairly easily without discharging the refrigerant. So if the V8 AC lines are like the V6, plan on doing a full vacuum evacuation and recharge.

 

To make the repair process go smoother, have the air conditioning system refrigerant discharged by a shop with recovery equipment so the lines can be removed.

If the vehicle is a pre-facelift 4.0 litre model, remove the condenser from underneath and carefully remove the power steering/gearbox cooler from the radiator tabs. The flexible hoses to both coolers are normally perished and can break or leak.

This also an excellent opportunity, as others have suggested, to replace the DCCV and anti-roll bar bushes whilst the radiator is out.of the way.

 

Got the radiator switched out today and it was definitely tight quarters. Now it seems either the fan was damaged in the process or decided to start quittin on me. It spins but extremely slow. I’m guessing all the pulling and fussing could have finished it but that fan is probably one of the olderst moving parts on the car. I see a lot of posts about relay or fuse.

 

Removed fan today tested with an old battery and she spins like new so now I’m stumped. Might wire up a switch to turn it on manually or could it be the temp sensor?

 

Two fuses to check, both under the hood:

#5
#25 (This is a big 'un, as Al Bundy would say)

 

Going nuts trying to find fuse 25. Anyone know where it is v8 2002???

 

Inboard side, at the front corner in the front power distribution box under the hood:

 

Ok that’s what I thought was fuse 25 but for some reason it’s labeled 9 I think. I’ll check it out this weekend. Scrapyard has a fan with harness and cooloant pump all attached and in good condition for $50 might roll the dice since I’m leaning towards it being the sending unit on the fan but could there be a way the alternator is causing fan not to come on ?