Catalytic Converter - Overheating
Number: J82/25Date: May, 1982
Subject: Catalytic Converter Overheating
Models: XJ-S H.E.
Both the down pipe catalysts of the XJ-S H. E. model have a heat resistant purple paint mark on the outlet cone of the catalyst. This paint mark will turn black and become glazed if a catalyst has severely overheated. The rear catalyst could also become partially blocked and cause a high exhaust back pressure, thereby forcing exhaust gas into the air injection rail, resulting in overheating of the rail.
Catalysts exhibiting this change of paint color and the respective rear catalyst should be changed.