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Grant, I’m looking into this for mine, noticed that my clutch unit is not doing its job well and basically the original setup is just basically s**t. Looking at your drawing for the wiring , from what I notice your left fan only switches on with the AC all other cooling is done with the right fan, wouldn't it be better to have both fans cooling the motor not just one? I was thinking I would probably run double wires from the right relay to both fans and then as shown your left relay to the left fan switched by the AC unit. That way both fans cool or when AC on left runs.
Katoh
I have done exactly Grant's mod. 90% of the time the main fan is not needed to cool the car adequately. At anything above 30 mph airflow is doing more than the fan ever can. So an electric fan controlled by the thermostat in the water pump intake saves fuel and also reduces noise, as you will notice. In traffic, if the car starts getting hot the main fan will cut in as needed.
The only problem I had was in traffic it tended to switch on and off too frequently as surges of hot water arrived then stopped, which tends to knock out the relay and the fan motor. So I replaced the OEM thermo switch with one from a Fiat that switched on at 90 and off at 85, but not everyone has this problem, Grant never did. I also did what Grant did on his own car, which was to install a cabin manual switch as well, activating a second independent relay, so if the automatic system failed for some reason, or I just wanted the fan on, I had a manual backup.
Greg
Last edited by Greg in France; 02-29-2016 at 01:50 AM.
The only issue with 2 fans basically on call all the time is you will 100% need to do the 110amp alternator upgrade.
This I did anyway, and that was nothing to do with the fan fitment.
The integrity of the radiator is the main key to the success of the thermo fan install. If the radiator is suspect, or has not been internally cleaned, in the last 5 years, that will need doing for the thermo fans to be as successful as they should.
I went the one fan thermo right off the cuff, it just sat well at the time.
Originally mine was +ve HOT, but I switched it to Ign HOT by the second day, as the long run on of the fans simply is "Un-Jaguar" and not really required.
When my a/c is ON, the LH fan runs (everyone knows that by now), and the RH thermo fan NEVER comes on. The RH can come on if needed, and IF it was needed with the a/c on, it can still do so without fuss.
This has been tested in our 44c summer a while back, in peak hour traffic crawl, that RH still did not come on.
The manual switch inside the cabin is a 2nd wire on the EARTH terminal of the RH fan relay, so I can simply switch it to activate the earth of that relay, and thus bring that fan on. I went that way coz I dont like running "active power" wires inside the cabin unless push comes to shove.
The cycling Greg mentioned I did get in the early days, and I found the switch in the lower hose casting was a tad flaky, so I stole one from a S3 at the wreckers, and its still there now. It is 85c spec.
The correct thremostats, as in "length" and temp (I run 82c Falcon stats, with a 3/32" hole drileld), and pressure cap integrity are the make or break of the V12 cooling system, thermo fans or mechanical fans. Cap pressure blow off is as flaky as pollies in Canberra, and that caused me more grief than needed, but once I found a header tank cap that actually blew off at 13lb, as stamped (I tested 12 caps before finding a good one), lots of issues disappeared.
I dont run the foam packing around the radiator, and never had issues, BUT, as I mentioned a lot of times, that STUPID foam on top of the transmission (inside the tunnel) needs to be addressed, as it has probably dropped and sitting on the trans, and that will block exit air from the engine bay significantly.
Since Canberra does not have a peak hour snarl, I would go one fan, but really, unless all that other stuff is up to the task, it may need the 2.
Last edited by Grant Francis; 02-29-2016 at 02:46 AM.
Greg nice idea about the manual switch on the second fan, definitely keep that one in mind but you makes sense about the rest
Grant, if you and all the others in Oz stop sending us hot air flatulent pollies up my way I wouldn’t have this bloody problem, Canberra would cool again to an alpine climate, not the stinking hot **** we have now caused buy the full of hot air wing bags that are given to us, LOL!
Back to the point, I only flushed and cleaned the system a year a ago since then its only done literately not even 100km, it was running super cool, but just this afternoon it went to the top on the N and looked to climb further, 97deg on the thermo housings is way too much, me think. This was only after a 5km run on a mild afternoon.
The Foam around the box could be a possibility, by the way it looks like a mongrel to remove without removing motor and box.
Thanks for the help
The hottest my car has been in was 36C, but with a clean rad and fan clutch in good condition the factory design kept the car cool.
The PO had put in a twin electric fan and I took it out because the alternator couldn't keep up at idle in traffic. It was easier to put in the mechanicl fan than upgrade the electrical system. I didn't think the electric fas the PO put in were that great, so I would be pulling them anyway; might as well go back to something that I knew worked in my climate.
possible, you would think if one thermostat sticks you would have a temperature differential? Both housings where up to 98C yesterday.
One thing I do like about the twin fan configuration is that we can loose two fan belts, and move the alternator up where the air pump goes, much neater. My nephew is an engine re-builder, he has a set of fans I can have for the right price.
Question did you gentlemen take the Rad out to do the conversion or left it in place? How hard is it to remove all the foam and crap around the gearbox without removing it?
If you got 88c (standard) stats fitted, then 88 + 12 = 100 when the stats are FULLY open and the system is OUT of control.
82 +12 = 94 when fully open, and out of control.
Not knowing what temp stats you have in there is the fuzzy bit, then my favourite bit, are they LONG enough to close that by-pass port, coz if they dont close those ports, the thing will be hissy forever, no matter how many fans you fit.
Removing the foam with the trans in place is simple, gravity helps a lot, refitting a newer modern spec insulation pad is NO GO. Remove the engine, do it properly, should take no more than 2 days.
Thermo fans with radiator in place is simple also, and that I mean seriously. Getting the old junk out will be "special", and blood will be let.
Careful with the top mounted alternator, that RH stat housing is right in way mostly. Then the fact that the a/c runs a 13 section belt, and the alternator an 11 section belt, a 13 section pulley for the alternator will be needed, and they are NOT popular.
Look forward to reading about part2, do you need to replace the foam insulation around the gearbox? The reason I ask I have another Motor with a Manual box that I will eventually transplant, this could be years away as its not on the high priority list, as for now if I can keep it going its great, so I come back to the point in the meantime if I remove the foam will it cause any other issues if there is nothing there?
Thanks again.
The foam missing is no biggie, just heaps of HEAT transferred into the cabin from that area, and I mean a HEAP. There is still heat getting in with the standard foam, and the newer stuff, so the engine bay heat exiting via that area is enormous.
This, I theorised back in 1994 with mine, and when the engine was out, and the newer, thinner insulation pad fitted, I did notice less heat in that general area inside the cabin.
I used a material that the "hot rodders" use, and then a thin aluminium sheet that I profiled to "pop in" and hold it all in place, AND, give a very smooth surface for that engine bay air.
Also remeber, I removed the trans cooler from the radiator, and fitted a standard V8 spec air flowed unit under the front bumper bar rubber.
Then, just for giggles, I removed the V pulley pack from the crankshaft harmonic balancer (4 bolts), and had the first V removed, no going back now, and less weight, more speed, sweet.
Over the years I continued to do little things here and there, and kept few snaps, as I never thought anyone would be interested, and no digital cameras then either. Its all in the brain, haha, and I will keep putting it all to Word, as I get time.
Ask away if something is "missing", as I do tend to assume too much at times, and need to be TOLD regularly, and that is what wives are for, NO???.
If I think of anything else I will add to this.
Last edited by Grant Francis; 03-01-2016 at 02:02 AM.
I have been thinking, if the temps are too hot even at unstressed speeds, it has to be a coolant circulation problem, and if your two fans are turning at all, I doubt they are the cause if last year, after all the new stuff, it was OK. It just could be the main mechanical fan viscous coupling completely shot I suppose, but if the OEM electric is turning, and it is not boiling hot outside, a bit unlikely. So "just" a matter of finding it; a list in case you need one:
Check coolant levels and start the car and see if, when warmed up the top hoses are getting hot. If not thermostats first thing to check and that the housings and cross pipe are clear.
If the top hoses are getting hot, check if the bottom hose is warming up. If not either look for a pump intake blockage, a rad/ rad outlet blockage,
If all the above check out OK on dismantling and testing, then the pump is the cause, or the water manifolds have somehow got themselves blocked so circulation out of the head is a problem.
Greg
Last edited by Greg in France; 03-01-2016 at 04:15 AM.
Ask away if something is "missing", as I do tend to assume too much at times, and need to be TOLD regularly, and that is what wives are for, NO???.
HaHa Ah Yes!!
Just looking at your oil cooler, makes me think, I didnt have a problem until that afternoon and what I did is held it in first and just gave it a little squirt, only a little mind you nothing Illegal or nothing to see here. Could it be the box just pumped too much heat in?
Check coolant levels and start the car and see if, when warmed up the top hoses are getting hot. If not thermostats first thing to check and that the housings and cross pipe are clear.
If the top hoses are getting hot, check if the bottom hose is warming up. If not either look for a pump intake blockage, a rad/ rad outlet blockage,
If all the above check out OK on dismantling and testing, then the pump is the cause, or the water manifolds have somehow got themselves blocked so circulation out of the head is a problem.
good ideas Greg, and I will check all those out in sequence, when I get a chance, but will do it before I do any Mods. Time is just a killer at the moment the lack off!
I did take the bonnet up to someone who was meant to punch flutes in it for ventilation, 11/2 years later no flutes and the same excuse. I think the flutes would of helped.
"A little squirt", in Canberra, fair dinkum. I believe ya, just.
Trans heat can be quick and a sudden, and since that original heat exchanger is in the "topside" radiator tank, the already top hose temps are being heated even more, and that is why I remove those exchangers from the radiators, and also the power steer exchangers on the Jags that have that nonsense.
When I recored my 2 V12 radiators, I had the mob remove that exchanger totally, and plate the tank accordingly, so there is no restriction to coolant flow at all. Basially made them a "manual transmission" radiator.
I really would be removing those "new" stats, and boil them, and measure them, and ensure they open beyond 41mm, disc to disc. If they do, reuse them, if they dont, fit the Falcon ones I mentioned in that doco I sent you.
A quick test that Greg and I discussed some time ago, start the beast, from cold, drive 1/2km immediately (NO warming up in this case), shut it down. Open the bonnet, feel the 2 top hoses, cold I bet, now reach down and feel the 2 metal trans pipes near the alternator, HOT, I bet. So, as I have said for tooooo many years, the trans fluid gets hotter way before the coolant, and operating temp of most transissions is 100C+, do the maths, it is a no brainer to me.
OR, if room is an issue, start it up, brakes on, put it in "D", and sit for 30 seconds, shut it down, do the feel test.
Last edited by Grant Francis; 03-02-2016 at 02:06 AM.
Guys, I also mean to replace the entire radiator wall with a new one with 2 electric coolers. Everything described here is clear.
There is only one thing that is confusing me and I should probably solve it. The A/C fan is out of the game, that's clear.
What remains is the "main" fan, the speed of which is controlled by a viscous coupling depending on the temperature. Is it possible to somehow regulate the speed of the main electric fan depending on the temperature? Essentially a black box, where the input is switching when a certain temperature is reached and then the value (Ohm) of the coolant sensor. And the output is probably the power supply of the fan. Of course, then this box could also solve the overrun of the fan after turning off the engine. Or is it useless to think about this?
These things exist, I think they are called pulse modulators. There is a guy in the USA who makes very reliable stuff. If you search JJJ's posts, he fitted one and it works well. Having said all that, electronic gizmos of any sort tend to have a half life of months at best under the V12 bonnet! SO my advice, FWIW, is to stick to the simplest possible setup, which I believe is:
The Grant Francis main fan control setup using the water pump inlet switch (but use an on at 90°C off at 85°C switch to avoid the fan hunting)
The auxiliary fan on with the compressor
Second backup circuit for the main fan using a cabin switchlight in the cabin
'Fan on' light in the cabin
New fuse box running power from the firewall to the new main fan
Use 70 amp relays or they cannot handle the start load when the relay cuts in
Either buy a radiator with the fan carrier a welded part of it, or build a fan chassis and fit it securely. I have done the latter, but the former is a better solution, I think.
Attached my wiring diagram and some pics Main fuse box handling current from the firewall post, each relay separately fused. small fuse box fusing switches and warning lights etc Two separate 70amp relays, one for the thermostatically controlled circuit marked A, one for the cabin switched circuit marked S.
Here's the AutoCool Guy's product site. Check out the youtube videos. I finally did find out why the Derale PWM was pulled from the market. His website is a little hard to navigate. You have to scroll down to see what he's referencing in his tabs.
09-27-2014, 05:37 AM
