1968 Corvette: Service Bulletin: Cold Start Failure

Subject:   Cold Start Failure
Model and Year:   All 1968 Vehicles Incorporating V-8 Engines
Source:  Chevrolet Dealer Service Technical Bulletin
Bulletin No:   68-T-31
Section:   VIm
Date:    March 5, 1968

TO:  ALL CHEVROLET DEALERS

Incidents of fuel pump freeze-up and failing to supply fuel have been encountered on some 1968 vehicles equipped with V-8 engines.  These failures usually occur in areas which encounter rain and overnight sub-freezing temperatures.  The fuel pump becomes inoperative when water enters through the atmospheric vent holes and freezes.

To prevent the above condition and to provide a drain, all V-8 engine fuel pumps are being revised by relocating the atmospheric vent holes from near the mounting flange to near the crimp flange.  Refer to Sketch on Page.

A good indication of this condition could be a fuel pump that operates satisfactorily in above-freezing temperatures, such as being stored inside, but does not operate after setting for a period of time in sub-freezing temperatures.  A simple check can be made on vehicles not subjected to above-freezing temperatures by removing the air cleaner, stroking the throttle rod, and observing for fuel discharge into the carburetor venturi.  If there is no fuel discharge, remove the fuel pump and allow it to than and drain.  To prevent recurrence, drill two 1/8" holes as shown in sketch.

Chevrolet Motor Divison
General Motors Corporation