My 1994 XJS V12 2+2 is getting some work done. It needs a new water pump. Since they are getting into it, does it make sense to replace the fan with the dual electric type? Also having exhaust work done. Would it be a good idea to save orginal fan (if mod is done) and save OEM exhaust parts of someday someone wants to put back to original? I know we are a long way from being collectible, but do collectible Jag enthusiasts prize original condition over improved mods?
Just curious.

 

Yes all round, and I am tad Biased.

 

Duel electric fans are a great mod on any car.

 

I suspect that plastic fan is cracked beyond belief. Replace it with LKQ? Sure.


But, dual Efans are so slick. My lump delights in a pair.


Carl

 

Just my opinion, I'd forget about collect-ability and build the car that you want to drive. If, to you, that means keeping it in it's unmodified state, that's great, but you'll notice that there are not very many unmodified XJ-S's on the road these days, and there is a very good reason (Lucas) for that. Fix the dizzy, put in dual electric fans, rig up cold air intake, upgrade the alternator, ditch the air pump, get the injector wiring out of the valley...in short, do about everything the Palm suggests, and my guess is that you'll have a car you'll be much happier with. It won't be a pristine Jag, but as I said, there is a reason you don't see those on the road these days...

In any event, have fun with it!

John
1987 XJ-S V12

 

Thanks, pretty much decided to do the cooling fans, air intake, hi flow cats, and dizzy mod now. Will wait on the rest. Just need to decide if I want the integrated transmission fluid cooler with the dual electric fans or not. An extra $100, but they claim it will drop coolant temperature an extra 10 degrees on a hot day. Will probably do it. Thanks again to everyone on here willing to help a newbie out.
Mike

 

As a counter point point, the PO of my car (also a 94 V12) put in the electric fans. However, not all fans are created equal and these apparently were the crappy ones. They filled the space, but I was fighting a temperature gauge that would steadily climb in traffic if the outside temperature was over 25C and I kept the AC off. It sucked a lot of power, the voltmeter dived into the red whenever the fans came on, and the car had a 120A Bosch alternator.

I ripped all that out, went back to the original mechanical fan ( black blades) and now my temperature gauge doesn't move. Standing beside the car with the hood closed I can feel the hot wind coming out from under the car as it sits there, so I know the fan is moving plenty of air. The voltmeter doesn't move now either and I can have the AC on in traffic. I'm very glad to have put it back the way the factory intended.

 

I'm pretty sure the V12's already have a separate transmission cooler, doesn't it?

 

The vast majority of Jaguar enthusiasts I know are OK with mods. But make sure they're sanitary. It's the hatchet-jobs that rankle...and can make the car harder to sell down the road.

Cheers
DD

 

Why modify the dissy, I've had my Marelli for 8 years and 10,000's km in it no problems if you keep the maintenance up, ie replace the spark plugs, poorly maintained ignition is what causes the Marelli meltdown.

Fans, cats and intake yes do them.

Use good quality e-fans, OEM fans from a V8 work well, I used fans from a local Ford which fit with minimal mods. I've also heard good things about the SPAL fans.

 

When I first purchased the car, I had it checked out by a Jaguar mechanic. He gave it a clean bill of health after fuel filter, oil change, and other odds and ends. That was about 11 years ago. Shortly after I got it back, I had the one bank of cylinders drop out. Granted, the mechanic in question probably missed the distributor problem. However if you have the experience of seeing one side of your exhaust (cats) glowing cherry red and throwing off sparks, it might tend to make you paranoid. I don't see the downside of doing the Kirby Palm fix (page 159 I think it was).
On the other subject, I hope I have good luck with the dual electric fan mod. I need to decide between the one to purchase. I know I could get by cheaper, but I am not yet a DIY kind of guy. So I plan on purchasing a prefabricated kit. It seems that the majority opinion favors the el3ctric fan mod.Hope I don't regret it.
Mike

 

yes, it does. The only advantage of a separate cooler is that the OEM one within the LHS radiator tank can be disconnected, thus preventing the chance of coolant and ATF mixing if the in-tank cooling coil fails.
Greg

 

so any claim by the manufacturer that coolant temp can be reduced by doing the transmission cooler add on to the fan set up is false? I was wondering what mechanism could be at work to increase radiator efficiency. Does the hot transmission fluid somehow impact the efficiency of the radiator as a whole? Didn't make a lot of sense to me. They do mention the benefit of eliminating the possibility of the 2 fluids mixing. The one I am looking at with the transmission cooler is sold by V12S.com.
Mike

 

The coolant immersion stops the ATF overheating. If the gearbox is being worked really hard, then tranny cooling puts an extra load on the engine cooling system. Quite a few cars have no OEM ATF cooler, which is why, maybe, the maker says what they do. FWIW, I think separating the two coolers is a good plan, I have done it on my car, but I took Grant's advice and mounted a cooler behind the front bumper. It is far better to mount the ATF cooler outside of the engine bay than in it, I feel, as the heat gradient will be far better than having the cooler in a hot engine bay with hot air blowing over it from the water rads. Easy to plumb and very inexpensive and very effective ATF cooling. Highly recommended and your garage will find it easy to fit.
Greg

 

Thanks! I will talk to the mechanic, and probably forego the add on transmission cooler associated with the electric fan mod. I will see what cooler he suggests as a stand alone mod located where you suggest. Thanks again for your help. I had not thought about the location with the fans being less than ideal.
Mike

 

I'm a fan of auxiliary ATF coolers but I'm not an advocate of eliminating the OEM cooler in the radiator.

Here's my theory......

The add-on cooler, like any radiator, relies on air flow to be most effective. At idle, with the car motionless, very little cooling is taking place. I always worried that the ATF could overheat if you were stuck in grid-lock traffic or the like. Just think of what would happen to your coolant temp if you're stuck in traffic with no engine cooling fan to pull air thru the radiator.

Therefore I always leave the OEM cooler in the loop, with the system plumbed to direct fluid thru it first and then thru the add-on cooler.

Mind you, I'm not asserting that my worries in this regard are justified. I've never installed a gauge to monitor ATF temperatures under various conditions. In the real world, rather than my imagination, it might be a non-issue.

Cheers
DD

 

I started off like that Doug, but in the end simplified it to just the external. Even in hot summer after a fast run and a slow passage, the AFT inlet spigot on the cooler is not too hot to touch, and the outlet just warmish. So I suspect the worry is a non-issue. Mind you, I do have a larger than standard sump pan, so a bigger reservoir.
Greg

 

Depending in the conditions, the in radiator loop is also a trans fluid heater. The ATF likes to be in a reasonably narrow temp range, too cool is not good either. So on startup the coolant warms the ATF, since coolant warms up faster than the ATF.

 

That was what I always thought too, the cooler was in the radiator to regulate temp more than just cool the trans. If the engineers just wanted to cool the trans a separate radiator seems way easier than a radiator built into the interior of another radiator. No idea how much this matters in the real world though, I know for me it's a fair weather car, I'd guess cooling is more of an issue than warming.

 

In past years, I've added trans coolers to critters with auto boxes. But, never eliminated the OEM in the radiator. But, as Doug says, I've no objective data as to any cooling difference.


Both were trucks and used to two a trailer on occasion. No huge ones, albeit.


That is where an auxiliary cooler is needed as opposed to just regular driving.


And, in my opinion, which is based on no data, it's the torque converter slip that creates the most of the heat.


If indeed a logical or illogical thought progression is used, my suggestion would be to shift to N when possible in stop and go traffic. Do as little idle in D as possible then.


Oh, one more advantage in out front hinged bonnets. If the traffic and heat conditions re really bad, pop the bonnet latch to the safe catch. Added vent can mean a lot.


Each of my present critters does just fine on OEM trans coolers. But, my driving isn't really stressful to their transmissions.


I resisted getting a small trailer for the JEEP!!! It was kinda neat and definitely cheap!!! Getting smarter !!!


Carl