Jaguar S-Type Water Leak, Water in Boot
On the S-Type, water in the spare wheel well nearly always comes past the boot lid seal or the welded seams it crosses at the sides of the opening, with the rear lamp gaskets next. A wet front footwell usually means a blocked scuttle drain. I'd find the entry point with a talc and hose test before buying a seal, and dry the well quickly, because the rear electrics live there.
How bad is it · Safe to drive
Safe to drive, but find it and dry it out soon
The leak itself does no harm to driving. Standing water in the spare well reaches the rear fuse box and modules, which leads to a flat battery and warning messages if it is left.
Which one applies to yours depends on your symptoms, your model year and what has already been done to it.
Likely causes, most common first
Read the check cost before the odds: a free check that rules a cause out beats a likely guess that costs money.
Water around the spare wheel: the boot lid seal
The boot seal clips onto a pressed metal lip, and on these cars it often doesn't press hard enough against the lid. Water driven under it while you drive runs down the inside of the opening into the spare wheel well.
A puddle under or around the spare wheel after rain or a long wet drive. Hosing the car while it stands still may leave the boot dry. A leaking seal can also drag on the lid, so it no longer lifts when the release button is pressed.
Fold the rear seat, close the lid and look from inside the boot in daylight for light showing past the seal. Lift the boot floor and follow any water tracks down the back panel to see which side they start from.
Worth trying: pull the seal off, lay a bead of sealant along the top of the lip or in the channel inside the seal, and push it back on. Alternatives: build the lip up with a layer of tape so the seal grips harder, or fit a new seal, roughly 100 USD at a dealer. A seal worn in one spot can also be refitted turned round the opening so the worn part sits higher.
New seal and still wet: the seams at the sides of the opening
Down each side of the boot opening there is a welded joint with a small notch where two panels meet, and the seal crosses it. Water finds that low point under the seal and runs inside the rear wing to the spare well. Later cars got a butyl filler on that seam from the factory; earlier ones often lack it.
The leak carries on after a seal change or after the lamps are resealed. It is often worse with the car parked nose-down, when water pools at the weld about two thirds of the way down the side.
Lift the seal on each side and look at the seam where it crosses: bare joints, gaps or rust between the sheets. Check the joint in the gutter channel above each rear wing and the area next to the boot lock as well.
Worth trying: clean the seam and lay flexible bituminous or butyl sealer an inch above and below the joint, then refit the seal. Bituminous stays soft and comes off easily later; silicone hardens and is a pain to remove.
Water behind the trim at the back corners: rear lamp seals
Each rear lamp unit sits on a thin foam or rubber gasket and is held by three fixings: two nuts and one plastic push fitting. If the push fitting springs loose or the gasket flattens, rain runs behind the lamp and down into the boot.
Damp boot side trim or carpet behind a rear lamp, or water at the back corners of the well rather than the middle.
Take the trim off behind the lamp, have someone run a hose over the rear window and lamp, and watch the back of the lamp from inside. A dusting of talc on the dried panel shows the trail clearly.
Worth trying: make sure all three fixings are tight and the push fitting is home, then reseal the gasket, or run a bead of black sealant round the outer edge of the lamp.
Dry seal and seams: boot vents and blocked drains
There are air vents either side of the boot behind the carpets, and the exhaust heat can distort them. A distorted vent lets spray in, and the drain plugs in the floor don't sit at the lowest point, so the water stays.
Water in the well even though the lid seal, seams and lamps test dry. A flooded well can also bring false alarms and a flat battery. Electrical faults that come and go are a reason to lift the boot floor even without a visible leak: a fuse box and modules sit by the spare wheel.
Pull the side carpets and look at the vents for warping and water marks. Check the drain plugs and the small holes in the rib in the centre of the well for a covering of tar-like tape.
Worth trying: replace and seal the vents, and clear the drains. A small hole, about 1/8 in, punched at the lowest corrugation near the battery lets water out before it reaches the electrics, but it doesn't stop the leak.
Wet front footwell: blocked scuttle drains
Rain on the windscreen drains out through the scuttle under the wiper cover. When leaves and seeds block that drain, the water backs up into the heater intake and finds its way into the footwell. On the left side it can also reach the control module behind the glovebox and cause fault messages.
A wet carpet in a front footwell after heavy rain or a car wash. Water tipped into the scuttle intake turns up on the floor within a few minutes.
Take off the wiper arms and the scuttle cover and clear the drains. Then take out the cabin filter housing and look at the seals round the ducts, the heater and A/C hoses and the cable grommets in the bulkhead.
Worth trying: clear the scuttle drain and intake duct, reseal any loose grommet or duct seal, and dry the carpet and underlay fully. Check the module behind the glovebox for corrosion if warnings have appeared.
Dripping from the roof light: sunroof seal or drains
The sunroof tray has four drain tubes, about 5 mm across, one at each corner, running down the front and rear pillars. If a drain blocks or the glass doesn't close fully onto its seal, the tray overflows and water drips out at the interior light.
Drips from the dome light or headlining after heavy rain, sometimes onto the gear lever.
Open the roof and look into the front corners of the tray; tilt it up to see the rear ones with a torch. Make sure the glass closes all the way.
Worth trying: clear the front drains with a cotton bud and the rear ones with a length of wire. Compressed air works, but go gently so the tube doesn't blow off its outlet. Dry the light housing before refitting it.
The order to check them in
The point of the order is money: each step either rules a cause out or makes the next one worth doing. Green is free, amber costs a little, red is the one to arrive at last.
Where the water is
Lift the boot floor and the front carpets and note where the water sits: spare wheel well, a back corner, a front footwell or the headlining. Each points to a different source.
freeWater test with talc
Dry the area completely, dust the suspect panels with talc, close up and soak the rear window and boot with a hose. The first trail in the talc leads to the source. If it stays dry, try again after a drive in the rain.
freeBoot seal and lip
Look for daylight past the seal from inside the boot with the seat folded. Reseat it on sealant or tape, or replace it.
free to checkSeams at the sides of the opening
Lift the seal where it crosses the welded joint on each side and at the lock, and fill any gap with flexible seam sealer.
a tube of sealerRear lamps
Check all three lamp fixings and the gasket, then hose over the lamp while you watch from inside.
free to checkBoot vents and drains
Behind the side carpets, check the vents for warping and the floor drains for blockage.
cheapScuttle drains for a wet footwell
Remove the wiper arms and scuttle cover, clear the drain and intake, and check the bulkhead grommets and duct seals.
a few hoursProtect the electrics
Once the leak is found, dry the spare well and look at the rear fuse box, connectors and modules there for green corrosion. Water in the well is a known cause of a flat battery and odd warning messages on these cars.
freeWhat it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar S-Type Rear Light and Brake Light ProblemsDim rear lamps and failure messages, including corrosion from a wet boot.
- Jaguar S-Type Battery Drain, Battery Flat OvernightWhen water in the spare well starts flattening the battery.
- Jaguar S-Type DSC Not Available, ABS FaultWarnings that can follow water reaching the module behind the glovebox.
- Jaguar S-Type Wipers Not Working, Wiper LinkageWater under the wiper spindle caps seizes the wiper linkage.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
Ratings, fuse numbers and torque figures vary by model year and market. Read the legend on your own car before pulling anything, and use the figures in the manual for your car, not the ones in a video.
Check your VIN: exactly which car you have and which bulletins apply to it.