Smoke screen option

I recently bought a new to me 1990 XJS12, love it. I’ve beenbabying it for a couple weeks (driving it very gingerly) as it was in storagefor 4-5 years when I bought it. Also the clutch fan would hit the fan shroud ifyou accelerated hard (shroud bent from under car) fixed now.

So this morning , on my way to work, I was showing off a little with my son in the car, and accelerated to the max and………..smoke screen option was engaged.

Looks like a water line on the right side let go, but not the main rad line, something lower and it sprays on the side of the engine andthe exhaust.

I didn’t even get mad! I have waited a long time to get a v12 and now I have one.

 

There are four main possibilities, all relatively easy to fix. First a photo:



This shows the water rail, a pipe that runs between the front water manifold casting (the one that holds the thermostat) and the back one. This system is the path for hot coolant to exit the engine. It exits the head into the casting and exits the casting into the pipe. In the photo the intake manifolds are removed, but the pipe can be seen under the intake runners if you look carefully.

1. The pipe itself (blue in the photo, rusty black on your car, no doubt) may have rusted out
2. The seal that seals the pipe into the casting at each end may have failed
3. The gasket between the water manifold and the head may have failed
4. On the rear manifold there is an exit that allows water to the heater valve. The flexible hose between the two may have failed.

The water manifolds and the pipe can be removed by undoing their bolts without having to remove the intake manifolds. You could of course have a fracture in the castings or the thermostat housings, or a failure of one of the short hoses that link the cross pipe to the housings.



Greg

 

Or maybe...maybe he DOES have a secret smoke screen option.

Assuming he doesn't, Greg is probably right. Car was working fine until you accelerated hard, put enough pressure on the collant system, and something gave way. I'm curious if it's leaking coolant all the time now, or only when you accelerate or accelerate hard.

 

Ha! Ha!
Thanks a lot for the replies. The picture is very helpful.
The coolant continued to run out of the engine when it was shut off. I assume it is rather low now
Last week I spotted a post about changing all of the coolant lines(7 or 8 of them) where they were, and how long it would take. The post said two days.....for real!

 

Thanks, Greg In France
You say these are relatively easy fixes. Oh boy! I think I'm outa my league!

 

Maybe, maybe not. identify all the parts on your car then run the engine and ascertain where the leak is coming from, let it cool. At worst you will need 2 pipe seals, four water manifold gaskets, one new hose to the heater valve, and one new pipe. All pretty cheap, all available from Jaguar Classic Parts or most vendor specialists. Get a small socket set with 1/4 inch drive and undo the four bolts on each manifold, at the top of the manifold in the photo (you can get to these either under or through the inlet manifold runners once you remove the air cleaner trumpet box), remove the rad hose and loosen the cross-pipe hose to the thermostat housing, and lift off the pipe, manifolds and thermostat housing as one.

Bung on the new bits and refit! Then better do the other side, then all the other hoses you have not done!

 

the heater hoses run back in that area as well and could also cause a leak onto the exhaust.

 

So how about this...when it's cold, start it with the bonnet open, just let it idle (well, fill the coolant system back up first!). Eventually the thermostats will open, and if you are looking at the engine when they do you should be able to narrow down the location of the leak...it'll be pretty obvious when the coolant starts coming out. Then shut it back off, let it cool, and start examining the hoses in that area. If it's not a hose it's a seal or something else that is fixable.

I've recently replaced, with the exception of the heater hoses at the firewall, ALL of the cooling hoses and seals in my '87...and with not much skill and a bit of patience it isn't that bad a job to do. The coolant manifolds come off easily enough, the gaskets are cheap...and wouldn't that be a good time to use some Simple Green and get some of that grease off of it? You'll have learned a lot about the car, have the sense of achievement that comes only with you doing it...and saved a few hundred $$$'s in the process.

Go for it...and good luck!

John
1987 XJ-S V12, 63,000 miles

 

Thanks for the information. I finally got under the hood to really investigate and found that it was actually the top rad hose. It had a small split on the underside that sprayed coolant directly onto the manifold.
I ran to the local auto parts dealer and "surprise" the had a hose in stock, only $24.

I'm now expecting all future repairs to go as smoothly

I will be acquiring a kit and replacing the remaining lines asap.

 

Are you familiar with the cooling system bleeding procedure? It's critical on a V12.

Cheers
DD