I've had this before. I thought I was over it. I guess because I now live about 2 miles from work and never take the car on really rough traffic, I though I was good.

Went to a Starbucks drive thru to avoid getting out of the car in the 100-feels like 110 heat. Some idiot has a trainee making coffee at the drive thru and it takes me 30 minutes to get my coffee. At about 20 minutes of sitting in the drive thru the needle passes N, keeps on going and going to halfway between N and H, A/C stops cooling etc etc. once I get back on the open road needle goes back to N, AC cools etc.

If you are a longtime member here you know that I have replaced every component of the cooling system, rodded the radiator, have an undertray, have a new NOS sender, new fan clutch and so on. Yes the AUX fan is on. There is nothing left to look at.

This is common weather in Houston. Do I need to replace the clutch fan with an electric fan? I don't want for this to happen again.

 

I had similar problems with overheating with an E Type, and it turned out to be the block was contaminated with minerals that came out of the hard water I had. I can only assume that the coolant was mixed with tap water, not distilled water and the minerals deposited in the block. My E Type got to the point that if it was hotter than about 22C outside it would overheat and there was noting I could do to bring the temperature down.

What I did was to drain the coolant, flush and drain with water several times to ensure all the glycol was gone and then filled it with vinegar. Ran it up to temperature and made sure the thermostat opened. I drove it a bit to get everything well circulated and then let the engine cool.

I drained the vinegar solution into a large rubbermaid tub and it looked like milk coming out, there was so many minerals in the vinegar. My tub was about the dimensions of the engine, probably 18"x30" and after I let the vinegar solution sit overnight I had a layer of minerals in the bottom 1/2" deep.

After draining the vinegar, I filled and flushed the block and rad again about 3 times with water to make sure it was all clean. Then refilled with fresh coolant and my temperature gauge stayed at the thermostat temperature no matter what the outside temperature was.

This was easier to do on an XK engine, since there is a plug to drain the block as well as the radiator, I got more minerals out of the block drain than I did from the rad drain plug. I have no idea if the AJ16 engine has a block drain or not.

I used vinegar since it was cheap and effective, and at the time my Mom worked at the university and her boss was a Ph.D. in Chemistry. He said the vinegar would be safe for the mix of iron, copper and aluminium in the XK engine's cooling system, but with a warning that it would react very strongly and exothermically with the glycol, so make sure all traces of coolant were cleaned out before adding vinegar.

 

Thanks for your reply.

I will look into this, but the car has always had distilled water. In it. It was my grandpas before it was mine and he's always made sure that nothing but distilled water is used. Even when the radiator was rodded out they told me it was pretty clean.

 

Spike
Has the car ever done this before in similar circumstances?

Does it have a pusher fan in front of the rad? I have a feeling some of your model do. If no, maybe fit one, if yes, is it working properly? If it is there, and it is working, perhaps replace it with a more modern fan?
Greg

 

Not sure this is a problem. Both of my AJ16 XJS' did this.


Highway speed, needle stays on the N, with or without the AC on.


In heavy stop and go traffic on super hot days, the needle would float somewhere between N and H. I think the engine coolant sensor told me I was running it at about 214F...maybe 216F, but no higher than that.


I think I was involved in a thread where everybody seemed certain that the danger zone for engines started at 230F?


In any case, I do find that running the AC during the stop and go traffic definitely increased the coolant temp, whereas turning it off, brought the needle much closer to the N.


Does that help?

 

Thanks Vee. It always helps to hear from another AJ16 guy.

When your car got hot, did the A/C stop cooling too?

My car is a weekend car, but I want to be able to drive it anywhere. I can't be afraid to I'll get caught in a stop and go situation where the car will get hot and the A/C will stop working. If this is normal for these cars, there has to be a way to solve this problem, even if it means getting a better alternator and installing an electric fan from another Car.

 

It definitely does not do as good a job at cooling as when I'm on the highway. I've been meaning to run a thermometer and check what the temperature of the air is when I'm in stop and go traffic versus when I'm on the highway to make sure it's not my imagination.


I'll get around to it sometime too...

 

Mark,

I know that you've had the rad rodded, but what state are the cooling fins in teh lower third of the rad? This is the most common cause of high temp running at standstill on our AJ16 cars. If the rads are less than perfect, the system seems to struggle at idle and with air con running. When moving, the problem usually goes away.

Paul

 

i do know what you mean about temperatures ,, i'm in Austin and it is 100+, 110 index , cooling these monster V12s is difficult at best!

there is a post here going on about electric fans , and no fan shroud, i dont know what his average ambient temps are , but know what his is doing would not be enough around Texas!

i have two electric fans and shroud, my gage goes up to high N and measured DIGITAL 200F, in traffic, no A/C!

also I'M old school , i like 180/185F , i wont live long enough to wear out the engine because of low temps!

 

This relates to V12 XJ-S and V12 with lucas ign. up to mid 1989. The centrifugal weights in the distributor freeze and the engine will heat up very excessively and cause little things like dropping valve seats to occur I don't let mine get above the N. Prefer it to be at the bottom of the N. If you go to Jag lovers and download 731 pages of experience in a book it explains it all. This is a book on the XJ-S but will apply to all V12's When the weights are free advance occurs when it should etc. Engine is much happier.
jack 314jjwalls

 

Well I need to start taking steps to installing a proper electric fan set up in this car. I imagine step 1 is find an alternator that can deal with this. Then I need to find a modern double fan setup that will fit this car. Originally I had thought about an after market SPAL fan setup and make it fit on the original fan cowl to keep things looking original, but I no longer give a damn. The wiring is the easy part. Since I have the AUX fan coming on with the compressor directly, I can use the radiator temp switch to control my new fan.

So gents,

--What is the best upgrade alternator I can buy for this car to handle the e-fans? I imagine it needs to have the same shape and size of pulley so it can be dropped in?

--What modern, even current Jag can use fans from to fit into my XJS? I would really like the part to be Jaguar for nostalgic reasons, but if there is another proven solution I do not care

Thanks for your help

 

Spike
The 115 amp alt fitted to later XJSs will go in fine, just needs the pivot bolt changing to 10mm diameter and the bracket holes for that bolt enlarged.


Grant and the Aussies swear by the Aussie Ford Falcon twin setup, apparently drops straight in, shroud, fan supports and all. A search on Aussie ebay gives loads of hits, and Grant will no doubt advise too.
greg

 

Thanks Greg. My car is a 95 AJ16. It has the last alternator they fit in there. And I think the Ford Falcon set up is for the V12's only. I want to be able to fit the most powerful thing I can in there I can find though. The alternator needs to handle A/C on, lights on, new electric fans and current aux pusher fans. I don't think the current alternator will do the trick. Just for my peace of mind I would like to fit the best quality , most powerful alternator that can fit in my car.

This won't be a cheap project because I will not be buying any used parts, which sadly means that my new top will have to wait, but being dressed in a business suit in 110 degree weather on a XJS that couldn't blow cold air anymore on a Stsrbucks drive-thru at lunchtime was a one-time experience for me.

 

Mark,

You could fit the twin electric fans that were fitted to late XJ40 6 litre cars.

Paul

 

Thanks for your reply. Would that XJ40be as powerful as something from a modern car? Or this

https://webstore.spalusa.com/en-us/p...pksl-dual.aspx

Right now I have two aftermarket pusher fans in front of the condenser that run of the original aux fan wiring and have been modified to come on with the compressor. If I get electric fans to replace the clutch fan, then I will remove one of the pusher fans and that leaves me at stock amp draw for the most part. So the question I guess is what can the existing alternator handle?

 

Anyone got any ideas on a good alternator replacement for my 95AJ16 ?

I have a 120 amp alternator in there now, since that's what the replacement AJ16 bosh alternator I got came rated at, but I will want a beast of an electric fan in my car. Can anybody point my in the right direction to upgrade this thing?

 

Spike
That SPAL link looks the business. See what volts your alt produces at tickover, and in traffic etc, and on the run, by buying one of these type of things and shoving it in the cigar socket:
https://www.amazon.com/TOOGOO-Cigare.../dp/B0092KVYGI


If your alt really is 120 amp that will be LOADS strong enough. If your cannot keep up, it is duff or the tickover is too slow to spin it up enough. The main thing is getting it spinning fast enough when in traffic to produce enough current to keep the volts up and the fans going full blast. In the end I fitted a solenoid that opens when the main electric fan kicks in and raises the tickover a few hundred RPM. Item 11 in this diagram (loads second hand):

Aircleaner-Rh-5.3 Litre - Parts For XJS from (V)139052 to (V)179736 | Jaguar Classic Parts UK
I realise you have a 6 cylinder car, but one of these can easily be rigged up into the inlet I would think. As you say in the other post, it is just a matter of getting enough power into the fans and big enough fans. Two each side of the rad should do it!
Greg

 

Hey guys OP here.

Still trying to figure out the best way to get this done.

The Alternator is 120 for sure, but I am not taking risks. I want an upgraded one for sure.

Ironically the electric fan on my X type failed, and this in turn led to immediate overheating when the A/C was on.

I saw a very low mileage wrecked F type and considered getting the alternator and fan from that car, but I kind of chickened out because I don't know if it could be made to work in my XJS. Just liked the idea of putting Jaguar parts in my XJS.

But I think the best option might be a fan from a XK8. I am going to look into that See it they could fit.

 

Spike
If you have two pushers in front of the condenser, and a 120 amp alt, something else is wrong. Assuming the pushers ARE pushing (it has been known...) and are decent high CFPM rated fans, they should keep a good condition condenser working properly. A 120 amp alt will do everything, as long as you fit a fast idle device to come on with the aircon to give you enough revs in traffic stops to produce current. My car's 115 amp alt does everything no bother at all, BUT you need a few extra revs, hence my earlier post about this matter.
So before going into bigger alts, it might be worth your considering:

• a new-style parallel-flow condenser which are more efficient than the Jaguar type, and readily available in the USA, I understand,
• a fast idle device,
• as you mentioned, the most powerful electric fan(s) you can find to replace the engine driven one which will not be doing anything significant in traffic stops, and
• a new radiator, maybe a Wizard if they make one for your model.

I rather feel this list would totally solve your problem, which nothing else will.
Greg

 

Greg-

I actually have an aluminum parallel flow condenser. The car cools well until it gets stuck in stop and go traffic in 105 degree heat for 20 minutes. The mechanical fan just can't keep up.

The extra amps I want are just for my own peace of mind. I don't want to be somewhere late at night with my lights on, a/c on and all fans on and have the car die.