My 2004 3.0L base S-type is exhibiting a coolant leak. Despite the absence of overheating incidents—attributable maybe to a limited commuting distance of 15 minutes a few times weekly—I need to replenish the expansion tank with about 50% of its capacity every few days. The expansion tank itself is intact, and the frontal region of the engine bay remains dry, suggesting that the water pump, thermostat housing, and associated coolant pipes in the radiator vicinity are not contributing factors. I have observed coolant dripping from the joint of the transmission bell housing and the engine block. To eliminate the possibility of coolant traveling via gravitational flow along the under-engine cover, I have removed it, confirming that the dripping originates from the rear of the engine. However, I am unable to detect any coolant leaking from anywhere above, leaving me stumped regarding the source.

I am aware that in the V8, there's a coolant hose located within the engine valley that is prone to leakage; I am curious if a similar component exists in the V6?

I am about ready to scrap this car as I'm also facing having to replace crumbling upper front strut mounts which I've been quoted 4 grand to repair but was going to attempt myself. But with this coolant issue, it may be time to just call it a day.

Any advice welcome

 

Get thee a cooling system pressure tester. This is the doohickey that looks like a bicycle tire pump and connects in place of the reservoir cap. You manually pump up the cooling system to the rating on the cap. If there are any external leaks in the cooling system, you will be able to find them.

The big advantage of the pressure tester is you put the system under much more pressure than merely running at idle. Many leaks will not be apparent at the reduced system pressure present at idle. Plus you can poke around the engine with no danger from moving parts.

If you'd rather not spend the money to purchase a tester, some auto parts stores have free loaners.


Are you talking about the rubber-like mounts between the sheet metal towers and the struts? If so, $4000 seems WAY out of line!

 

Thank you for the suggestion, I've ordered one


I videoed the dripping coolant but I doubt it helps. From above in the engine bay, everything is dry, including the pipes going to the cabin heat exchanger.

And yes the 4 grand is just for the foam rubber tops of the struts. Honestly, I feel the quote was their way of telling me they didn't want the work after insisting they'd only give me a quote if I paid for a diagnosis. Which like a fool I did, even though I already knew what the damn issue was. The problem is I've tried to get other local shops to look at the car for other issues and they were honest enough to tell me they wouldn't touch a jaguar. So I was just going to get some used struts and do it myself

 

Greetings Gary,

Suggest you read my thread in the Diesel forum "Massive Coolant Loss . . ."
Yes, I know it's a different model and engine, but consider the too-often overlooked . . .

On all Jaguar OHC V6 and V8 engines oriented north-south, no matter what fuel they chew, the timing case casting and cover for the upper chain creates an effective "dam wall" at the front of the Vee. Any coolant loss, especially around the hot outlet from engine to radiator, can travel nowhere other than back along the Vee to exit near the firewall, leap like Eddie The Eagle down over bell housing and even start dripping around either side of the transmission. This has proved a "gotcha" for so many who go searching for a burst Welsh plug at the rear, or wonder why their transmission is leaking hot coolant!

If you read the write-up, you won't ask how I know! Good news is that, in most cases, a straight forward DIY fix to replace leaking parts.

Cheers and best wishes,

 

Thank you, I'll be sure to check this out too. Hopefully the pressure tester will arrive today and I can see something.

 

4000 bucks?! Were they going to replace them with gold plated ones?
The parts are only £45.00 each for the strut tops
or £125 each for a kit complete with spring rubbers.

 

I got the pressure tester and found leaks on the water pump and the passenger side of the radiator, which was weird as I've not seen any moisture at the front until today, maybe it just evaporated, it was a slow leak. I still could not identify the source of the leak at back of the engine. I took off the top manifold and the top of the block is wet at the back near the firewall but not forwards of it. There was a round depression on top of the engine in this area that seemed wet but I couldn't really get to it. I took a bad photo with an endoscope but I'm not sure if will help lol



And yes I was not expecting the 4 grand price tag, I knew I could get a rebuild kit for the strut for about 100 dollars but honestly spring compressors scare me. So that's why I went to the pros😟

​​​ When I lived in LA getting a shop to look at a jag was never an issue but I'm now in Richmond Virginia and it's a different world. Garages tell me their mechanics wouldn't know where to start with a jag (my wife's VW GTI also). Doesn't say much for their mechanics IMO, cars are pretty much all built and work the same.

Thanks for all your advice

 

[QUOTE=

I am about ready to scrap this car as I'm also facing having to replace crumbling upper front strut mounts which I've been quoted 4 grand to repair but was going to attempt myself. But with this coolant issue, it may be time to just call it a day.

Any advice welcome[/QUOTE]

Here is some real advice you can use. I just replaced the shock tower pads on the front. 4 tower pads come in the box for a whopping $204 from car parts.com Next. You will need some jack stands and a floor jack. You will also need a McPhearson spring compressor if you are just doing the tops. Now if you do not have the electronic damper shocks, you also have another path. At carparts.com you can buy the entire unit assembled. That is the shock, spring and top for $154 for each side in the front and $120 for both of them in the back. It is just a swap. No spring compressor needed. All four wheels...about $400 bucks. These options and prices are from yesterday so they are good.

Best of luck. The worst you could do is save $3600 dollars that some hack was going to steal from you. haha.

 

Great work! Sounds like you are hot on the trail. Fix the known leaks and then test again. Who knows, maybe coolant was getting blown on top of the engine and collecting there.

Changing the radiator is no fun. Pretty tight quarters in there. On my ‘02 V6, the process went a lot smoother after disconnecting the AC condenser and swinging it out of the way. Not sure if this is applicable to the later models.

For the water pump, make sure to get the correct version. I found some physical differences between early and late versions. Most vendors had the wrong info and kept trying to sell me the later version. Probably won’t affect you, but more details here:

https://www.jaguarforums.com/forum/s...3-0-v6-204901/

 

I only see complete struts for the earlier pre-2003 cars

 

On carparts.com the stock number for the tops is Part #: TS171367L It is a Monroe set of 4. The strut assemblies can also be found at Amazon, Advance, and Ebay. All new stuff. At carparts.com I had a 2000 year in there. Sorry for the confusion.

 

[QUOTE=kr98664;2805979]

"Changing the radiator is no fun. Pretty tight quarters in there."

Karl, when the radiator is out, that is when you change the sway bar bushings. whether you need them or not.