Coolant leak from rear of engine.
 

It started with a "coolant smell" after having the thermostat replaced. I couldn't find any coolant on the floor of my garage, so I just kept an eye on it. After driving home with a low coolant light, I was able to determine that the vent hose from the coolant overflow tank had a pinhole leak, so I replaced it and no more leaks right? Wrong, after a day or two I parked it in the garage only to find coolant running out all over the floor, so I quick jacked it up and was only able to determine that it was running out from the back of the engine down over the transmission. I'm going to have to remove the supercharger ducts and coolers from the top of the engine to determine where it's coming from I guess, I'll keep you all posted.

Best of luck , I believe it's not something major and you can spot it on easily

Yesterday I pulled as much off of the top of the engine as I could, and looked down in there, but I couldn't see a thing. I reached in behind the engine and it was wet with coolant but I couldn't tell from where. I also looked at it from underneath, but couldn't see anything either. So I had a flatbed come pick it up and take it to an independent Jaguar garage to see what they find. I've got my fingers crossed!

Sounds odd that it started leaking at the header tank and immediately went to the rear of the engine. The header tank problem is most likely a bad header tank, they fail at the bleed line nipple. If you did not replace the tank, it is probably still bad. As far as coolant going over the bellhousing, this may be coming from a hose under the intake manifold.

I found a thread yesterday about the coolant hose that runs under the supercharger, and the symptoms perfectly describe what's going on with mine. I think the vent hose from the overflow tank, and the one under the supercharger wore out at the same time. It seems to me that a hard line under the supercharger would have been a better idea.

Good excuse to upgrade the supercharger pulley while you have the supercharger off. Then you won't feel so bad about the amount of effort used to change the hose :-)

This is an unusal coincidence...I don't like car coincidences...the two leaks might have been caused by a cooling system overpressure caused by a bad thermostat working on the two weakest points...I would keep an eye on it. The coolant guage is an idiot light, it can be getting very hot and you won't see it unless its beginning to hit the red range.

Actually, it sounds very similar to what I went through when my R was 4.5 years old. Have a look at your main radiator fan as well. I ran through changing everything to cure an overheating problem, radiator first (due to a crack which was leaking coolant), thermostat, then several hoses that gave way sequentially (so I changed all the hoses that I could get my hands on, prophylactically) and in the end it turned out to be my electric fan that was turning, but not at maximum power (which made it very difficult to diagnose that it was the fan, since it seemed to be working). I had no regrets in changing the hoses as they were going soft already (at 4.5 years of age mind you), but we only figured it out when the car continue to run hot with no coolant lost from the cooling system (a testimony to the seal of the new hoses).

I wonder if the new Jags that appear to have the same engine still use the same coolant hose under the supercharger.

Just had the second hose leak in a month on my 2005 super v8 with about 55k miles. I asked Nalley Jag and some others parts suppliers about prophylactically replacing hoses but the response I got was basically there are tons of them in the engine and they are not cheap, and they don't see that many failures coming in the shop, so I am just having the second hose replaced for now. For those who replaced a bunch of hoses, how did you decide which ones to replace?

I just replaced the lot prophylactically when I got them all together as it wasn't worth the hassle of sending the car in everytime there was a leak and worse, having down-time due to lack of spare hoses from the agent and waiting for the hoses to be air-freighted in from UK (1-2 weeks). Many of the hoses were not in good condition when I had my leaks (at 5 years of age). Of course I had an overpressure problem due to the radiator fan wearing out and not being as powerful as it should have been as well, so that gave added stress to the cooling system. I'm in the tropics, so the weather may be a bit different, but I was told by the Jaguar agent in San Diego that they don't seem to have problems with hoses in the weather there.

Thanks, that is helpful, but how did you select which hoses to replace?

Mine was indeed the coolant hose under the supercharger. I really think Jaguar dropped the ball here, a hard line is definitely needed.

I did all of them that I could lay my hands on, and of course then one below the supercharger would then have to give way....

Just had to replace the water pump on our 2004 VDP. Only 42,000 miles.

Would have been $500, but purchased extended warranty so only $100. I hope the water pump is not a normal problem with these cars. :icon_shrug:

Water pump is unusual at that mileage. Change the coolant, you could be low on pump lubricant in it. I would expect this pump in a system that is maintained to last at least 100K miles.