Tracing a leak...any advice?

DaveF

Club Member
My 260Z is letting in water when I wash it. I thought it was coming in through the sunroof channel, but it doesn't appear to be the case.
Is there a common fault / route for water to find its way in? The images below show where it dripped from, but it's also got in directly onto the carpet inside the front of the sill....without dripping down from the dash.

IMG_20211019_152710.jpg IMG_20211019_172556.jpg
 

jonbills

Membership Secretary
Site Administrator
Hmm...I don't think so, but I'll check tonight - thanks. Do you think that's the culprit?
Maybe :) they go on the front corner of the door by the dash, but water would still have to get past the main door seal, so not sure.
 

DaveF

Club Member
Maybe :) they go on the front corner of the door by the dash, but water would still have to get past the main door seal, so not sure.

Yeah, they look like a good idea for sure - I'm checking (and will probably fit it they aren't there). No water coming in from the drivers side though, which is strange. I was wondering if it could get in through the bulkhead or vents ?
 

jonbills

Membership Secretary
Site Administrator
There aren't meant to be any holes through the bulkhead, but rust or repairs can sometimes make them.
It might be worth taking the cowl off that cover the wiper motor etc, and see if you can find any holes there.
(it's only the wipers and 4 screws at the leading edge you need to remove).
 

richiep

Club Member
I'd bet money on this being from the bottom corner of your windscreen. Z windscreens are not (or, as standard, not) bonded in. That includes both the seal to the body side, and the glass to the seal. What happens is that water pools on the seal in the bottom corner and it seeps in under the glass and then drips down inside. Pour water on that corner of the screen and then see if it pools on the seal inside shortly afterwards. Given where it is pictured running down the side of the dash, I'm confident this is the answer.

This is a relatively common occurence; my Fairlady Z does it on the driver's side, although not as dramatically as yours. When I rebuilt the car in the mid-2000s, I actually had the screen installer put some sealant inside the seal to help prevent this, but it still eventually started to do it again.
 

DaveF

Club Member
There aren't meant to be any holes through the bulkhead, but rust or repairs can sometimes make them.
It might be worth taking the cowl off that cover the wiper motor etc, and see if you can find any holes there.
(it's only the wipers and 4 screws at the leading edge you need to remove).

Yep, I was thinking the same but didn't realise it would be that simple...Forums are ace!
 

DaveF

Club Member
I'd bet money on this being from the bottom corner of your windscreen. Z windscreens are not (or, as standard, not) bonded in. That includes both the seal to the body side, and the glass to the seal. What happens is that water pools on the seal in the bottom corner and it seeps in under the glass and then drips down inside. Pour water on that corner of the screen and then see if it pools on the seal inside shortly afterwards. Given where it is pictured running down the side of the dash, I'm confident this is the answer.

This is a relatively common occurence; my Fairlady Z does it on the driver's side, although not as dramatically as yours. When I rebuilt the car in the mid-2000s, I actually had the screen installer put some sealant inside the seal to help prevent this, but it still eventually started to do it again.

Thanks - I'll try that. The rubber looks a bit tired too and I did wonder about getting a new one and having the windscreen removed and replaced with a new seal
 

nospark

Well-Known Forum User
It's probably coming from where the others suggested. What you need to also do is remove your windscreen cowl (the slatted metal piece in front of windcreen) to check underneath. Check that the drainholes at either side and also that there is no drainage obstruction around and behind the heater air box. There have been cases where this area can get clogged with water then pooling over the bulkhead seam of the car and then under the very front of the carpets. Wet carpets lead to rusty floors.
 

DaveF

Club Member
Checked last night and the door rubbers seem OK, although the passenger side one is getting a bit stiff. Think I'll order a new pair just in case. The job for this weekend is to take the windscreen cowl off and see if there's anything apparent under there.....then it's time to go around with a cup of water! The joys of classics eh EXTRA:)

Thanks for your advice everyone - very helpful.
 

Fairlineguy

Club Member
I suspect as has been mentioned it’s your screen that’s leaking I always get my screen guy to run his sealant gun around the rubber screen seal.
Best thing to do is mask of the door and scuttle with tape and plastic and water test with a hose pipe.
 

DaveF

Club Member
I suspect as has been mentioned it’s your screen that’s leaking I always get my screen guy to run his sealant gun around the rubber screen seal.
Best thing to do is mask of the door and scuttle with tape and plastic and water test with a hose pipe.

That's the plan too - seems there are three possible culprits and I'll check each one this weekend. Thanks!
 

Farmer42

Club Member
Easiest solution is not to take it out in the rain or wash it with loads of water. It also prevents tin-worm then as well!! Otherwise as Richie said, pour a small amount of water on the seal and listen for the fizzing noise!
 

DaveF

Club Member
Easiest solution is not to take it out in the rain or wash it with loads of water. It also prevents tin-worm then as well!! Otherwise as Richie said, pour a small amount of water on the seal and listen for the fizzing noise!


All very true! I was thinking I should use wet-wipes
 
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