E-Type V-12 Cooling System Flush Proceedure

Thanks Jay for the heads-up. It looks like that modification has already been made - an ignition amplifier has been located forward as you suggested. The original one is still in the vally, for looks.

I did find that the radiator cooling fans were not kicking on reliably. I jumped the Otter Switch (with the ignition on) and the fans did not come on. After investigating, two of the 5 wires on the radiator coolimg fan relay (Relay No. 177 in the Service Manual Wiring Diagram), were crossed. After convincing my wife to reach way up under the radiator shroud to switch them, the fans come on now when jumping the Otter Switch. I will field test it tomorrow by letting the engine get to temperature.

Interestingly enough, one of the wires that was crossed on Relay No. 177, leads to the transmission kick-down switch. Maybe that will sort out the kick-down (or lack of it) we are currently experiencing.

I did try turning on the A/C to check the A/C cooling fans' override relay (Relay No. 193), but the fans did not come on with the engine cool. Nor did the A/C Compressor Clutch activate. It looks like the A/C relay is an aftermarke one, with no visable terminal indications (C1, C2 &W1) in sitsu. It also has 5 prongs on it, with 2 of them not used. I will pull it tomorrow and see if there are any terminal indications, if not, will bench test it to get the wiring sorted.

There is a lot of info on this topic on this forum - VERY VERY helpful! I will post my findings on theA/C radiator cooling fan override relay when I have it sorted.

Hope your car is running smooth, and thanks again!

Hi Tom,

I believe you do know the previous Owner - What a great guy! I had been in touch with him about the car, and the ultimate purchase of it from him, since May, 2012. And he is extremely knowledgeable. In getting the car ready for sale he relegated the overheating issue to a shop that he ultimately was not too impressed with. He told me they did some work, only to have the car come back "not running better, but worse," so he took it off of the market, refusing to have them touch the car again. I saw the car online and asked why it was taken off of the market. He was very honest with me. He and I brainstormed and came up with potential things that could be the issue, but he needed to focus on other things, lacking a good mechanic readily available that he could rely on for that car. I ultimately purchased the car from him with full knowledge of what I might be getting into.

He did, however, test the car to make sure the shop, and another friend who was helping him out, didn't do any real harm with overheating that V-12 (i.e. head gaskets, valve seats, etc.), and was relatively sure nothing had escalated to that point.

He and his late wife really cared for the car, and it shows. He shared with me who the first Owners of the car were, and the history of all of the things he had done on the car. He was unbelievably accommodating with us during the sale and in assisting in transport. We will be diligent stewards of their efforts on this very special and unique car!

On another note, the Jaguar Driving Experience is here in Central Florida this week. My wife and I spent 3 hours there this morning and test drove just about everything Jag has. What a blast - My wife beat me on the Auto Cross course by 0.18 seconds! I told the instructor it's because she weighs less than me!!!

That was a great story, well written! you had me on the edge of my seat the whole way thru!
I am glad its looking to be a simple fix. I am sure there were a few sleepless nights worrying about what you got yourself into.
Hopefully the new cat wont disappoint you. I look forward to the further adventures !
Bob F

Based only on the color of this car, and the fact that it came from the Sacramento region, I'm fairly certain that I am acquainted with the previous owner and his late wife.

Since I know that he doesn't "do" the internet, I would like to make a couple of comments on his behalf.

I am aware that he is a very knowledgeable mechanic but, probably due to his large collection of automobiles, this cooling system problem was somehow overlooked as he disposed of his collection. Although his wife's favorite brand of auto was a Packard, this was her favorite among their Jaguars.

I hope that this auto gives you many years of reliable service.

Gentlemen,

As promised, I am reporting to all the status of our new 1971 V-12 E-Type. We were told the car has a serious overheating problem, which was the catalyst to the beginning of this thread.

You are not going to believe this.... We took delivery of the car from Northern California to here in Kissimmee, Florida, a few days ago (Saturday Morning). I gotta say, the car is beautiful! We had it shipped via Horseless Carriage. Got it unloaded and had to make the decision to either push the car 1/4 mile to my garage, call a tow truck, or, yes, see if it starts and idle the car gently, but quickly, to the house before it overheats. So, I elected to start the car and idle it to the house. NO OVERHEATING PROBLEMS...yet. Was keeping my eye on the temp gauge, as well as shooting my laser Temp sensor all over the engine, t-stat housings, radiator, hoses, etc, to see if/where this car was overheating. It wasn't! YEAH! Right? But then... Steam, Hiss, Water, and a little puckering below the waist. So I'm looking for the leak and can't see anything thru the steam. Shut her down. Keep checking temperatures w/ the laser, not overheating.... hmmmmm. OK - it's got to be somewhere, the front of the engine is wet near the water pump, so I started it back up to warm it up enough to see the water show. Ah-ha - there it is!

I can't believe where it is coming from! It's actually coming from under the right-bank t-stat housing... hmmm, why? I'll tell you why, and this is what I cannot believe, somebody removed the t-stat housing, presumably to change the t-stat, and actually reinstalled it with a small hose retainer clip UNDER the t-stat housing. The clip is supposed to be there, but attached ABOVE the housing, with one of the t-stat housing bolts. I'm thinking it can't be that simple. So I reposition the clip properly, tighten the housing down, start her up and presto - overheating fixed!

What the previous owner perceived as a horrible overheating/boil-over issue was a two-minute fix. Dont know who his mechanic was but, ..

BUT THEN.... just when I was testing it further, bringing it all the way up to temp, a wall of thick smoke emerges from just in front of the firewall, in the engine compartment. Crap! Shut it down quickly. Look under the car and it is weeping a sludgy redish fluid, about 3/4 cup worth. Now I'm thinking the radiator blew internally, and there is yucky silty antifreeze mixed in with automatic transmission fluid.... Put the car on the lift, removed the exhaust heat shields and find nothing leaking. After a good nightÔÇÖs sleep, I deduced that when the car was brought down from the previous Owner's garage in California to the Hauler, he hired a flat bed tow truck for the 1/2 mile journey. I'm betting the flat bed tilted the car so far backwards that it spilled automatic transmission fluid out of a vent and onto the heat shield, where it blended with accumulated dirt on the shield and then sat for 3 weeks while in transport to Florida. When I started and heated up the exhaust system, it was quite a show!

Transmission fluid is clean, oil is clean, and antifreeze is clean. SHEW!!!!!!!

Checked the electric fans for proper operation, temp cut-in, correct rotation direction... Properly topped off the carbs w/ oil, topped of the brake fluid. Motor Oil is fresh & clean.

I have taken her out for baby step runs. First to the corner store a mile away to fill it up with fresh gas. Then to another corner store further away (celebratory beer run w/ a buddy), then to a meeting thru traffic on Monday, and finally on a 12 mile journey on the highway, ea. way. No overheating issues, but she does miss-fire a bit on the highway. Will be changing plugs, wires, cap, and rotor soon.

I truly am relieved that things have worked out. I am still going to flush the cooling system and change the radiator to the new aluminum radiator that came loose with the car. I have a month or so of mild weather down here until I believe the car will benefit from it.

Thanks to everybody who generously gave advice. Hope my story was entertaining!

... new avitar

Thank you too Brian - all great comments - this Forum is teriffic!
I will report in once I have it fixed.

Thanks William,
Yes, I have aligned myself with some really great people here in central florida at our local JCNA club.

Thanks Jay - I hope it's that simple! I will advise in a couple weeks once the car arrives from CA.

Thanks Bob for your kind reply - very good info! I am told the car will boil over, so I'm thinking the radiator may be full of silt, or the fans may be running backwards, or, or, or,or! Will sink my teeth into it. I do have a laser temp guage and will surly break it out before I go nuts replacing things for the sake of replacing things.

Hi Tom - I'll see you tomorrow at the Holiday Party! The car looks a lot like yours, but it has the Suede Green Interior. I believe yours is Biscuit? Our car is still in enroute, in enclosed transport, coming in from the Sacremento CA area. I called to check on it yesterday - in Kansas.... Will change trucks in NJ at their storage facility, then head to FL on their next FL truck. Using "Horseless Carriage." Was hoping to have it for tomorrows party, but there will be many more opportunities to run around in it.

Merry Christmas Danny, stop by and see me after the holidays. I can go over what you need to do & how to do it. Can't wait to see your new car.
Tom
Technical Advisor Jaguar Club of Florida
407 298 1358

I know that my 6 cylinder read hot when I bought it, reading in the red when everything was normal. Turned out to be the sending unit on the top of the intake manifold. On my V12 circa '86, the same style sending unit is on the right manifold. If your car's gauge is in the red and the coolant is not boiling out of it when running or especially after key off, suffice to say you have only an instrumentation issue somewhere .

Everyone have a joyous and safe Christmas and New Year

PS,, Merry Christmas to everyone

This car is certainly going to need work to make is usable & safe. Check your local club and find a good mechanic who can examine the car for you and tell you what should be done, You can then decide what you can do!

Danny, congratulations on the new car!!
I would recommend you do a little checking on the car before you assume its actually hot. I have a 69 (6 cyl) that was my dads car , he always claimed it ran hot, and wouldnt drive it much because of that. but when I got the car I started looking for a cause. I bought one of those laser temp things and took measurements all around the engine when it was hot, some may argue the accuracy of a cheap laser thermometer, but it gave me close enough readings to see that the engine wasnt really "hot".

my temp gauge would read in the red zone, however the temp readings at the temp sensor in my manifold were never higher than 180 degrees.

so my next step was to check the gauge for accuracy. If you arent familiar with how the older jags ran the instruments there is a small voltage regulator on the back of the gauge cluster.
it looks like a small lucas relay, but what it really is is a bi-metal voltage regulator that is not very accurate, there are a load of links on the theory of operation, but what I would do is replace it if its the original part with a new version from XK's Unlimited. it is P/N 08-9965.
it will set you back about 20 bucks.

once I replaced that my temp gauge stayed in the normal, and as an added benefit my fuel gauge started behaving again.

that may not be the complete cause as your car could indeed have other issues, and a flush of the system is a good idea if you are unsure of how old the antifreeze is. but I know for me the simple replacement of that old voltage regulator brought everything into check.

Bob