I find myself having to add washer fluid to my wife's XK8's reservoir every weekend, even when she claims that she has not activated the system even once during the previous week. I never see any washer fluid on the ground underneath the car so if the system is indeed leaking, it is doing so while the car is being driven....

My JTIS CD (which covers through the 2004 model year) indicates that the washer fluid reservoir holds 7 litres. I find that hard to believe. My Dodge Ram pickup has the largest washer fluid reservoir I've ever seen in a normal car or truck, and it doesn't come close to holding that much fluid....

Can anyone confirm that the XK8 washer fluid reservoir indeed holds 7 litres? I think that JTIS figure is a misprint....

 

According to the Driver's Handbook it is 7 litres capacity.



Graham

 

When I had the wheel arch cover off to fix the headlights I was amazed by the size of the thing. At least as big as a 5 litre can so I wouldn't be surprised.
They do, unfortunately, spring leaks.

 

As you can see, plenty of places to leak:



The joint from the rubber inlet pipe to reservoir is a favourite but the seals on the pumps can also fail.

Graham

 

Several years ago my wife's recently-sold Lexus SUV's washer fluid system sprung a leak that immediately created a puddle of fluid underneath the front bumper whenever I attempted to fill the reservoir. I traced the leak to a cracked plastic hose connector, which I replaced with a two-dollar brass one from the hardware store. Problem solved....

This is different, however. Whenever I fill the reservoir, it holds fluid with no visible puddles or even drips anywhere. Yet by the following weekend, I have to add at least 4 to 6 ounces of fluid to top it off again. Not a substantial loss (yet), but still quite strange....

 

Do you fill it to the top of the filler pipe? If so, as Graham suggests, the leak will be from the seal where the filler tube (big 'S' shaped thing at extreme left of pic) goes into the reservoir.
Probably flexing/vibration so it waters the road.
If you pull off the cover (only fifteen different types of fastener) you can try the old plumber's trick of wrapping a bit of rag round the joint to see it it gets wet after a drive.

 

I don't want to be the cause of any marital discord but....................are you using alcohol based screenwash?

Graham

 

One other thing to consider is that is you do have a slow drip it is possible that it is being caught in the under tray and never makes its way to the ground.

The way the under tray is shaped, I would bet it would hold about a pint before it overflowed.

 

Steveinfrance,

I typically fill the reservoir to within about a half-inch of the top of the filler tube/cap. Now that I know the reservoir holds enough fluid to fill a kiddie wading pool, I won't be as concerned about keeping it full....



Graham,

The washer fluid I've used for several decades in all of our vehicles lists methyl alcohol (67-65-1) as part of the formula. I assume this is what provides its freezing protection down to 0 degrees F. So what's the problem with a slight bit of alcohol?



ccfulton,

What undertray? Our S-Type has a full engine bay undertray, but our XK8 does not and apparently never did. Just the flimsy plastic alternator cooling duct that I must remove in order to get to the oil filter....

 

There is a plastic piece that spans the front header and has rather triangular ends that fill in between the bumper and the wheel well liner. It covers the area under the reservoir and is shaped such that it would catch a small leak.

They can be damaged, so it could be that yours is missing, but from the factory, the reservoir should be in a more or less enclosed environment, and you should not be able to see it without taking something loose, either the undertray or the wheel liner.

In the pic GGG posted, the black plastic part under the reservoir is the undertray. The sort of stair step shaped thing with one screw hole in each tier. This is what I suggest could mask a small leak.

 

No problem at all with alcohol in the screenwash. I was jokingly hinting at a possible reason why 7 litres a week may be disappearing without trace.

You should have a horizontal black plastic Undertray (item 7) beneath the Front Bumper (item 1). At either end of the Undertray are vertical Wind Deflectors (item 16):



Clearer to see how it fits in this diagram:



Are these missing?

Graham

 

I do not believe those pieces are missing. I've jacked up the front end multiple times since we purchased the car in early February and I always have to ensure that my floor jack gets past the black plastic "shield" to the firm metal crossmember underneath. I call it a shield, not an undertray, because in my opinion a true undertray covers the entire engine bay as the one on our S-Type does....

Thanks for the illustration. I will double-check the presence of this "shield" when the XK8 gets back home this afternoon....

 

I don't expect they are missing as you would have noticed the Front Bumper flexing without them.

I always use Jaguar descriptions when mentioning parts. In this instance the Parts Manual uses the term 'Undertray' for item 7:



In reality. it's even less than a 'shield' to me - just a nasty piece of plastic!

Graham

 

Agreed. I hate having to dodge these plastic parts when looking for solid metal to serve as a jacking point....

 

I've had my XK 10 months now and have never refilled the reservoir!

 

Then you run the risk of eventually burning up your washer fluid pump....

 

The motor has a built in low level sensor which will display a message in the instrument cluster.

I have gone near a year without an appreciable decrease in level so 10 months is plausible. Granted, I do live in a place without weather, so it doesn't get used much.

The elbow in the engine bay is a separate piece from the filler neck and I have noticed that the seal isn't the greatest.

If you are filling to the point of being visible in the neck, it could be that it's dribbling down to just out of sight or even that the engine heat is cooking it away in the elbow.