Ford Mustang Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
69 Posts
Discussion Starter #1
The GT has developed a leak in the washer nozzles. Washer fluid will leak out and run over the hood while driving. Forum search and Googling the issue doesn't come up with many GT results, but I think I know what the issue is.

Recently I upgraded all the caps to the chrome AM caps. I think the new washer reservoir cap seals better than the stock cap. This seal causes pressure to build in the reservoir.

My first test will be to put the stock cap back on and see if the leaking goes away. If it does...then I have to figure out a way to 'fix' the new chrome cap to allow it to leak out the pressure.

Anyone else experience this problem?
 

Attachments

·
Registered
Joined
·
478 Posts
Sounds like you are on the right track with the increased pressure. It's hot right now, and the increased temp will lead to increased pressures if the seal is "good". The fluid will take the path of least resistance - in this case, out to nozzles. Is there an o-ring or something on the cap? Maybe you could notch it somehow...
 

·
Registered
Joined
·
101 Posts
I'd actually bet its the opposite. New caps probably do not seal as well as the original. Think about putting your finger over a drinking straw. Lift it out of the liquid and the vacuum holds it. Release your finger and it runs right out.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #4
I'd actually bet its the opposite. New caps probably do not seal as well as the original. Think about putting your finger over a drinking straw. Lift it out of the liquid and the vacuum holds it. Release your finger and it runs right out.
That makes sense for an open system. But with windshield washing systems there is a check valve in the line out from the reservoir. The valve is supposed to prevent leakage.

It's possible that the valve is going bad, but I think the over-pressure in the reservoir is defeating the valve's pressure rating. But...I could also be completely wrong.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #5
Just to follow up...

I removed the aftermarket cap and replaced the OEM. Leaking nozzles immediately went away. I left it this way for 4 weeks with no leaks.

I then removed the OEM cap and put back on the aftermarket cap. The leaking nozzles returned.

The leaks happen only after the engine warms up though. So...aftermarket cap with rubber o-ring pressurizes the tank beyond what the check valve can compensate for.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #6
I took the aftermarket cap and drilled a very, very small hold under the lid grip in an unnoticable area (back side of cap when installed).

The hole is just slightly above the level of the o-ring but the o-ring still sealed it when the cap was in place.

So I shaved the o-ring just enough to let the pressurized air escape into the hole.

No more leaking nozzles and no one can tell that a hole exists in the shiny pretty cap!
 

·
Registered
Joined
·
314 Posts
Nice way to solve the Problem, and also coming up with the pressurized tank is quite cool. I understand the facts, but would never thought about this on my own :yup:
 

·
Registered
Joined
·
55 Posts
I just installed the same caps on an 08 GT and had the same problem, leaking out the washer nozzles. The factory plastic cap has a relief hole in the top of it, so I drilled a 1/16 hole through the bottom red dot on the cap using a drill press for accuracy.
It looks like it came that way from the factory. Problem solved.
 
1 - 8 of 8 Posts
Top