GM: Various Engine Noises During Cold Start, Warm Engine Operation

GM Engine Noises During Cold Start, Warm Engine Operation

The new Small Block Generation 5 engine family incorporates a new fuel system technology known as direct injection (DI).

Model(s): 2014-2019 Trucks with the 4.3L, 5.3L and 6.2L RPO Codes

– L82 – L83 – L84 – L86 – L87 – LT1 – LT4 – LT5

The latest generation of GM full-size trucks incorporate a new generation of technologies not previously seen in full size truck and utility applications. As a result these engines generate noises during cold start and during warm operation that owners of previous generation multiport fuel injection (MFI) vehicles may not be familiar with.


The new Small Block Generation 5 engine family incorporates a new fuel system technology known as direct injection (DI). With DI, fuel is injected directly into the cylinder using a high-pressure fuel system.

DI provides many benefits in improving engine efficiency. In particular, DI improves power, torque, and most importantly fuel efficiency. This technology is included as standard equipment on all Generation 5 engines in the small block engine family, which are the 4.3L V6, 5.3L V8 and the 6.2L V8.

The high-pressure fuel system does have unique operating characteristics; in particular, the noise emanating from the high-pressure fuel pump can result in a subtle ticking noise that is apparent when the vehicle is idling. The sound is more evident when outside around the vehicle, when the hood is open or the vehicle is operated in a drive-through. The sound may be more noticeable during a cold start, but lessens once the engine is warm. A slightly higher pitched clicking sound is the fuel injectors pulsing ON and OFF under the high fuel pressures. These sounds are a normal characteristics of the DI high pressure fuel system.

Another operating characteristic is a slightly longer crank time when the engine is started. The increased crank time is the result of the time required to build high pressure in the fuel system before the engine starts.


The oil pump design has changed from a gerotor gear type pump to a two-speed vane type pump for fuel economy reasons. At temperatures at or below 0°C (32°F), or when the engine has been sitting for a few hours, it is possible to have air enter the pump through normal oil drain back. Upon startup, the owner may hear a short “Rrrrp” or “Rasp” coming from the front of the engine. It is most often heard during a remote start. There is nothing wrong with the oil pump or oil system. No repairs should be attempted for this condition.


The 6.2L engine dry sump oil system may generate a moan noise that may be heard inside the vehicle at idle and/or low engine rpm operation for approximately the first two minutes following a cold start. The noise cannot be heard from the outside of the vehicle.

This noise may be more noticeable on the passenger side of the vehicle and has been described as similar to the sound of running water. The dry sump oil system is hard mounted to the body of the vehicle, and at cold start, the oil moving through the system can transfer the noise to the body. This is a normal dry sump oil system operating characteristic and no repairs should be attempted.

Courtesy of General Motors

You May Also Like

Acura Turbo Engine Service

It is important to check the operation of the solenoids that control vacuum to the actuators.

The 2007-2012 Acura RDX was Honda’s first production vehicle in North America with a turbocharger. The company took the proven K-series engine and lowered the compression ratio from 10:1 to 8:1, and added a turbocharger with the associated plumbing. But, it is a lot more complicated when it comes to managing the boost.

Subaru EJ25 Head Gasket Problems

Most of the EJ head gasket failures occur around the 100,000-mile mark and start as a slow oil or coolant leak.

Honda Electronic Throttle Body Service Tips

Using care and following OEM procedures will help you to avoid unnecessary parts replacement and comebacks.

New Oil Specifications

Many 0W16 oils have a new donut certification mark on the bottle called API SN-PLUS and SN-PLUS Resource Conserving.

Solving Intermittent Overheating

New cooling systems anticipate and influence changes in coolant temperature.

Other Posts

Diesel Air Filter Replacement

Here are some diesel air filter replacement tips in order to keep these vehicles running as intended.

Deciphering Engine Misfire Codes

When the fuel/air mixture ignites, many factors must be met to pass a misfire monitor.

Cabin Air Filter Replacement

There are three major reasons to replace a cabin air filter in the winter.

Today’s Fuel Pressure Diagnostics

Direct injection pressure is measured with sensors, and you’ll need a scan tool to measure the signals