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I finally found the reason that my wife's 92 BMW 525 has been loosing coolant at about a quart/month. The car began a steady missfire and a quick check/replacement of the plugs turned up the problem. There is a very slow weeping of coolant into the #5 spark plug cavity. The water/foam finally got high enough to short out the plug. So who would pull the head to get it sealed?? Or, who would put in some brand of stop-leak?? Does anyone have a positive experience to share regarding use of a coolant sealer? It can't possibly be Bar's Leak (a varnish like product), but for such a slow leak I just can't justify the expense of pulling the head. The car runs great after the new plugs.
Charlie Guthrie

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1998 BMW Z3
1987 BMW 325is
2000 BMW
1996 F250 Turbo Diesel

Subaru sells some stuff in a small blue can specifically for the 2.5RS, they call it cooling system "conditioner". According to all accounts it's a pretty mild stop leak more than anything else. That might be just the ticket for such a small leak.

--Kevin H.

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2003 WRX (again!)

One vote for pulling the head. But I'm funny like that.

This sounds like a problem that will just continue to get worse. I'd fix it now before something catastrophic happens.

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

I am with Mike on this one. I prefer doing the full job and not just putting it off until something worse happens.

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2010 Honda Fit Sport
Couple of bicycles

Sometimes stop leak additives don't just stop up the leak!!!! they sometimes foul the radiator core and also the heater core plus any small passages in the block or head. I've used that crap and been sorry for it.
Whitney is spot on, pull the head
B2

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2004 C5(415whp,390ft/lbs),
1997C5,1997Trans Am, 1986 C4,
1990 Miata, 1976 MGB,1997 Protege, 1989 MR2

I rebuilt an engine once and when I was done the only problem I had was a slight leak between the head and block. I pulled the head that was leaking and very carefully retorqued it with a new head gasket. It still leaked. My father suggested trying some stop-leak. I put it in and it stopped the leak and did not cause any other problems. I sold the car a couple of years later and it was still running fine.

It's been too long ago to remember what brand it was. I do remember that it was a small bottle of what looked like plastic pellets in a dark brown thick liquid.

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Mitch Moore

That's Barr's Leak. Back in the day I had an engine builder tell me that he recommends the stuff in any motor used for racing, even freshly built ones. I used it for years in my rally car and never had a problem. I did get a stick through my radiator once and it barely leaked.

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Carl Fisher

Be Cool to the Pizza Dude:
http://www.npr.org/templates/story/stor ... Id=4651531

I know certain manufacturers use Bars-Leak or similiar on the production line.

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Rich
http://www.v8mongrel.com/

The factory shop manual for my '72 Jaguar E-type V-12 recommends 2 bottles of Bars-Leaks to be added whenever the coolant is changed. But we all know how diligent the British were in assembly of the car!

Charlie, one word.....pepper!

If it were me I'd try the radiator stop leak first because 1st, I'm just lazy and 2nd its just the daily driver so won't see the "abuse" we give our track cars.

But, since its the wife's car I guess you have to balance the above against the possibility of her getting stranded somewhere unpleasant. Perhaps not worth the gamble!

Ron