My first post. 2001 Blazer, 118K miles. After a 20 mile trip to the market, I smelled something hot under the hood on the passenger side. Engine coolant was at mid range and no coolant smell. The heat seems to be in the are of the Engine Control Module (?) that sits on top of the coolant expansion tank. Engine is still running o.k. Does not seem to happen while sitting and idling for several minutes. However, when I took it for a short run around the block, the smell came back. The ECM seems excessively hot, but have never touched it before to see if this is normal. Any experience with this?

 

Reference to earlier post on this problem. Found the problem. Heat shielding that protects the plastic heater and a/c box at the firewall had crumbled and fallen down on the exhaust pipe attached to the manifold. ECM still warm, but does have a big heat sync on top to dissipate heat generated under the hood.