One of my tires loses about 1 pound of air every couple of days. However, the leak stops leaking at 25psi. I have removed the tire thinking there is nail or something causing a slow leak. Nothing.

Could it be the valve itself? Anyone else here with this experience?

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Ben
1987 190d 2.5Turbo

Could be the valve and also the rim..

I had a similar problem on my 1971 W113 280SL.
Checked the tire for leaks in a tub of water, removed and remounted the tire, installed a new metal valve and still a slow leak down to about 22-24lbs..
Ended up putting in a tube and no more problems !

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http://i19.photobucket.com/albums/b1...c/GOWIDE-1.jpg
1971 280SL ROADSTER
1988 300CE TWIN TURBO WIDEBODY
1994 E320 CABRIOLET
1999 C43 AMG
2005 G55K AMG
2008 CLK63 AMG BLACK SERIES

Lay the tire flat and slowly pour some water around the bead area. The water will collect and fill the low spot at the tire/wheel interface and enable you to spot any bubbles.

Can also be the valve stem or the core.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

Charge the tyre with air conditioning fluid then use a sniffer or an ultraviolet light. See

http://www.justoffbase.co.uk/Air-Conditioning-Leak-Detection-Kit-Sealey-VS600

also see Adixen.co.uk maybe for some ideas.

Normal engineering crack detection techniques, so called

- dye penetrant

or

- ultrasonic scanning

around the rim.


I know it is very hard to fine small leaks. There was man on Ebay selling a wheel that was replaced by the MB dealer. He/they eventually found the crack in the rim; welded it and was selling the wheel.

Loose valve might be worth checking, but i'm betting on it being a slight bead seal leak. JimFreeh's method is the best check, adding a little dish soap to the water will make it even more visible (and fun for kids!!). While you have the soapy water out, brush a little onto the valve stem and valve.

Good luck.

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Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)

If you can get the tire off, use steel wool to clean off the rim where the tire bead seats. You should also clean the tire bead with the steel wool. Then, reinflate and reseat with soapy water on the bead.

x2 on the valve stem and/or seal

__________________
2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900

Errrr....This seems:

- cost prohibitive
- potentially illegal depending on refrigerant
- not very logical

How about using soapy water? Any tiny leak will bubble up if the water has soap in it.

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Yep soapy water is good if you can't immerse the whole wheel.

It will certainly show any problems if you fill the op of the valve stem.

If the valve is leaking and it is a Schrader valve (http://en.wikipedia.org/wiki/Schrader_valve) don't over tighten the valve. You might get one of those prong shaped security bits to fit (see http://www.peachparts.com/shopforum/showpost.php?p=2715799&postcount=17 for the type of thing I mean)

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

First, overpressure the tire (50? psi). Then throw soapy water over the whole tire to look for bubbles. I've been able to find the smallest of leaks using this method.

In my area tires often develop rim leaks from corrosion. Lay the tire flat and throw soapy water on the rim. Wait a number of minutes and the slow leaks will show up as small patches of foam.