05-01-2017, 10:39 AM
Sorry for the long delay in reply. It actually had been raining or snowing for months it seems. I got distracted and only got back to it recently.
(1) Buy a stethoscope today and try to listen all over to isolate the location of the noise.
The stethoscope revealed no noises anywhere except when the probe was placed on the surfaces of the water pump housing, and on the timing belt tensioner stud bolt. The water pump provided a gravelly growling noise, and the timing belt tensioner stud produced a higher pitched rough squeak.
(2) Should also perform a spark plug short test to try to isolate whether a specific cylinder is producing the noise.
Shorting each cylinder produced no reduction in sound, only a decrease in idle speed.
(3) Drain and inspect the Mobil 1 oil that is currently in the car for any material. (as well as change the oil filter). This oil is the same oil in the car as when the noise was first noticed.
The oil in the oil filter and oil drain pan was clean and free of metallic particles or grit. I attached a mechanical oil pressure gauge to a port on an oil filter sandwich adapter plate (made by GlowShift) added between the oil filter and engine. I installed an OTC mechanical oil pressure test gauge and Autometer electric oil pressure gauge to the sandwich plate ports. Measured oil pressure at cold start and after warm up (when engine cooling fan kicked in) were 75 psi, and 25 psi respectively. The oil pressure between 3000 - 4000 RPM hot was also measured at between 65-75 psi, which are within the factory specification for this engine.
(4) This weekend I will try to take it for a short drive (with water pump belt reconnected of course) to see if the noise is present under load (lugging). I have never noticed it in the past, and I have pretty sensitive ears.
Above 1000 rpm, the engine produced no unusual sounds at light, moderate, or no load.
I removed the old water pump and bought a new water pump at the auto parts store, but the bearing seemed tight and had a grainy sound when spun by hand. The Suzuki dealer wanted almost $200 for a new OEM pump but I was able to order a new Japanese made AISIN pump online for $60, which was identical to the old water pump. When it arrived, the bearing seemed tight but smooth and quiet. This was installed onto the engine.
The almost new Continental timing belt on the car had zero wear and was re-used.The new Beck Arnley (GMB) timing belt tensioner had some stiction. It also had a slightly grainy feel when spun by hand. I compared it to the original tensioner, which had the same feel. (a sticking motion when slowly rotated). I had a spare used tensioner from my G16B Esteem engine, which had the same part number as the Cultus and it spun freely with no stiction and was completely silent when spun by hand. I installed this used tensioner on the car.
The new water pump, used tensioner, and timing belt was reinstalled, following factory service manual instructions, and the radiator refilled with new antifreeze. I torqued all bolts/nuts back to factory specs with my new inch-pound torque wrench. I left the timing belt cover off so I could observe the components after start up and use the stethoscope again if needed.
After about a 6 minute warm up and engine at base idle, no unusual noises were detected.
Conclusion: I think the timing belt tensioner and water pump bearing failure were responsible for producing the combined noises. It is amazing how useful the stethoscope is when trying to isolate noises! Thanks for the tips!
(1) Buy a stethoscope today and try to listen all over to isolate the location of the noise.
The stethoscope revealed no noises anywhere except when the probe was placed on the surfaces of the water pump housing, and on the timing belt tensioner stud bolt. The water pump provided a gravelly growling noise, and the timing belt tensioner stud produced a higher pitched rough squeak.
(2) Should also perform a spark plug short test to try to isolate whether a specific cylinder is producing the noise.
Shorting each cylinder produced no reduction in sound, only a decrease in idle speed.
(3) Drain and inspect the Mobil 1 oil that is currently in the car for any material. (as well as change the oil filter). This oil is the same oil in the car as when the noise was first noticed.
The oil in the oil filter and oil drain pan was clean and free of metallic particles or grit. I attached a mechanical oil pressure gauge to a port on an oil filter sandwich adapter plate (made by GlowShift) added between the oil filter and engine. I installed an OTC mechanical oil pressure test gauge and Autometer electric oil pressure gauge to the sandwich plate ports. Measured oil pressure at cold start and after warm up (when engine cooling fan kicked in) were 75 psi, and 25 psi respectively. The oil pressure between 3000 - 4000 RPM hot was also measured at between 65-75 psi, which are within the factory specification for this engine.
(4) This weekend I will try to take it for a short drive (with water pump belt reconnected of course) to see if the noise is present under load (lugging). I have never noticed it in the past, and I have pretty sensitive ears.
Above 1000 rpm, the engine produced no unusual sounds at light, moderate, or no load.
I removed the old water pump and bought a new water pump at the auto parts store, but the bearing seemed tight and had a grainy sound when spun by hand. The Suzuki dealer wanted almost $200 for a new OEM pump but I was able to order a new Japanese made AISIN pump online for $60, which was identical to the old water pump. When it arrived, the bearing seemed tight but smooth and quiet. This was installed onto the engine.
The almost new Continental timing belt on the car had zero wear and was re-used.The new Beck Arnley (GMB) timing belt tensioner had some stiction. It also had a slightly grainy feel when spun by hand. I compared it to the original tensioner, which had the same feel. (a sticking motion when slowly rotated). I had a spare used tensioner from my G16B Esteem engine, which had the same part number as the Cultus and it spun freely with no stiction and was completely silent when spun by hand. I installed this used tensioner on the car.
The new water pump, used tensioner, and timing belt was reinstalled, following factory service manual instructions, and the radiator refilled with new antifreeze. I torqued all bolts/nuts back to factory specs with my new inch-pound torque wrench. I left the timing belt cover off so I could observe the components after start up and use the stethoscope again if needed.
After about a 6 minute warm up and engine at base idle, no unusual noises were detected.
Conclusion: I think the timing belt tensioner and water pump bearing failure were responsible for producing the combined noises. It is amazing how useful the stethoscope is when trying to isolate noises! Thanks for the tips!