D^2, Living in TeXaS,it probably doesn't even get cold enough there for your car to need the hot-air shroud that is on the exhaust manifold. It is used when the outside air is very cold,thus causing a lean fuel condition(vs. too rich). When the outside air is very cold,it is more dense and provides more Oxygen. Unless the carb is richened-up when the outside air is very cold,there will be a lean-idle skip or stumble. The choke will be open when the engine is warmed-up...but super-cold air will be entering the carb. In cars equipped with this hot-air shroud,there is a flapper-door in the aircleaners snorkel. When the air passing thru the snorkel is very cold,the flapper-door shuts off the supply of outside air and only allows the heated air from the shroud atop the exh manifold to enter the snorkel. The flapper-door is something that is overlooked when a car is being diagnosed for running overly rich. If it is stuck shut all of the time,a car is being fed super-hot air all of the time. ...but hey,at least there won't be any carburetor ice! Steve(bizzy with projects)from Albany,N.Y. '75 Imp 4dr <--checking on American Collector Car Ins. No time to drive. '79 440 powered 35 ft RV <--steel beams being added/welded in the roof. _______________________________________________________________ ----Original Message Follows---- From: dardal@xxxxxxxxxxxxxxx Reply-To: mailing-list@xxxxxxxxxxxxxxxx To: mailing-list@xxxxxxxxxxxxxxxx Subject: IML: Rattling heat shield Date: Sun, 19 May 2002 23:14:04 -0500 (CDT) Hi all. My 68 Lebaron is motivated by a 69 440 from a New Yorker. This engine has the 69+ air cleaner along with the left manifold heat shield (that supposedly feeds hot air when the engine is cold). Well, at low rpm when hot, the shield is rattling (over 1500 rpm or so, the frequency is too high and the rattling stops). I replaced one of the bolts that was missing (connecting the upper and lower part) and the intensity of the rattle and/or the rpm that it occurs slightly changed. The part is not securely attached on the head. All you 69+ owners, can you tell me how to secure that part and/or keep it from rattling? Thanks D^2 _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.