1998 Mercedes SL320 engine cuts out after about 10 minutes into journey and will not restart until engine has cooled.

open the hood, look at the strut tower, you well see the three (3) bolts that hold the strut in place, do you see a lines on the center of the strut,? no, you have regular suspension?, if yes then you have air suspension.

well it sounds like a fuel problem i would check my fuel pressure first now if a code came up find out what it means and address it and make sure you have fuel in the tank

Bring to auto parts store and have them check for any codes stored in the computer and go from there, There are far too many options to list here.

gas or diesel..

check the fuel press.

intermitten problems are the worse, when it wont start check fuel pressure with a gauge, and then check for spark, i have spent days on problems such as this, what you have to find is what is missing, fuel ,spark, is maybe coolant leaking into one or more cyls, i have seen air in the fuel system that only cause problems when under hood temp is high, open the hood and it cools enough to to start, hope this helps

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http://stores.ebay.com/Fancy-Motorcars?_rdc=1

hi,seem fuel pump relay is mulfunction,better to your fuel pressure,or maybe the excess voltage protection relay is mulfunction,fuel filter should check also,ty

you say the engine shuts down when it gets hot if it runs rough before doing so it could be the coolant temperature sensor allowing the engine to  overfuel  if the engine cuts out in a couple of seconds but sounds smooth it could be the fuel pump , if it cuts out instantly its electrical.

Check out the crankshaft position sensor