Hi, my 420 must have a coolant leak, but I can't find it. After a 4-5 mile drive, steam and smoke comes from under the rear edge of the hood when I stop; open the hood and it is obvious this is coming from the exhaust crossover pipe which takes the exhaust from the driver's-side exhaust manifold, and the smell makes it obvious it is coolant. There is a rubber heater hose directly over the crossover pipe, with one of those "flush-and-fill" plastic fittings in it (is this stock?) but I simply cannot find anything leaking after looking really carefully several times, and feeling the underside of the hose with my hand, etc. So far I have not seen a sign of a drip on the garage floor, and the coolant level hasn't dropped noticably.</P>


I removed the computer and looked underneath at the hoses between the firewalls, and again I cannot see anything leaking nor any sign of previous leaks. The heater works fine. Please advise if you have experience with this, or ideas.</P>

 

could be headgasket when the engine is running is there any bubbles in the coolent tank? is there steam comming out of the tail pipe? is there like a mayo looking stuff under the oil filler cap? all these point to head gasket.

 

Hi, I have none of the symptoms you described.</P>


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Found the problem: someone installed a stupid "flush-and -fill" coonnection in the hose; 5/8 inch fittings are too loose for the metric hose, I think. I iwll try to find something to reconnect the two ends of the hose. Either it would stop leaking when hot, or at least i could not find the leak. When cold, the coolant would drip onto the exhaust crossover pipe and, when it get hot, steam and smoke!<IMG src=smileys/smiley1.gif border="0"></P>


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