Yukon 4WD V8-6.5L DSL Turbo VIN S (1997)
Fuel: All Technical Service Bulletins
Engine - Extended Cranking Time During Hot Restart
File In Section: 6E - Engine Fuel & Emission
Bulletin No.: 87-65-25
Date: September, 1998
Subject:
Extended Engine Cranking Time During Hot Engine Restart in High Ambient Temperature Conditions (Allow Engine to Idle Prior to Shutdown)
Models:
1996-99 Chevrolet and GMC C/K, G, P Models
with 6.5L Diesel Engine (VINs F, S, Y - RPOs L65, L56, L57)
Condition
Some owners of diesel equipped vehicles may comment on an extended engine cranking time during a hot restart in high ambient temperatures of 38°C
(100°F), especially when pulling a load. This condition normally will occur after the vehicle has been shut off at full operating temperature and then
restarted after approximately 15-90 minutes. It is sometimes called a "hot soak". No other driveability symptoms have been noted and the MIL is not
illuminated.
Cause
Viscosity of the diesel fuel following a hot soak becomes too low to be properly pressurized by the fuel injection pump on restart during these periods of
high underhood temperatures. This lower pressure is insufficient to pop the fuel injection nozzles and properly deliver fuel to the engine.
Correction
If the ambient temperature is 38° C (100° F) or greater, especially when pulling a load, customers should allow the vehicle to idle for 5-10 minutes prior
to shutting off the engine. This will allow the engine temperature to stabilize and minimize hot restarting time.
