2013 4.3 liter valve noise after oil heats up

[PAoutdoorsman]

I have a 2013 GM 4.3 liter (Volvo Penta 4.3GL - 190hp 2bbl carb) in a Hurricane Sundeck Sport 188 boat - with 190 original hours. It will get a valve train tap/rattle on the left side of the engine towards the front. Sounds like the left front cylinder. This correlates with a drop in oil pressure, and a fluttering of the oil pressure gauge needle. On first startup and easy running, oil pressure is strong (40 psi +). The issue generally presents itself after a 10-15 minute full throttle run, or when towing a skier/tuber for a time (engine under heavier load). It can first be noticed in the oil pressure drop (20'ish psi) and fluttering needle, then when rpm's are reduced to idle the chatter is strong, oil pressure remains about 20 psi and the gauge continues to flutter rather than hold steady like it does when the noise is not present.

This problem presented itself several years ago, but mostly went away with a switch from dino 10w40 to synthetic 10w40. Now it is doing it even after a fresh 10w40 synthetic oil change.

Could this be a collapsing lifter?

 

[spasm3]

Noise when oil is hot, drop in oil pressure, and noise. I'm thinking main bearing.

 

[JHZR2]

Is this the old school iron 90 degree 4.3?

My 98 s-10 with the correct old school 4.3 starts with 60ish psi, drops lower at hot idle, and the gauge will fluctuate a bit at idle. Has always done this since new. The gauges are electric but real, not buffered.

In my Mercedes diesels, fluctuation of the gauge (which is directly piped from the oil filter assembly to the gauge) means that some o rings in the filter system are shrunk. Since this too is a real gauge, it starts over 3bar, and drops to 1.5-2 bar at hot idle.

So I’m not sure I’m hearing anything inconsistent with a real unbuffered oil gauge.

I would wonder if a hydraulic timing chain tensioner could be the cause of the noise? Needs a bit more viscosity and pressure to keep everything tight and quiet…

 

[BigCahuna]

If it were my boat, I'd pull the valve cover on the offending side and take a look around. Might be a loose rocker arm. Then, being it's a 10 year old engine, that spends it's life being hammered on, I'd change the oil to 20/50 mineral oil. Your oil pressure should go up when it's hot, and it should sound quieter. Being you won't be running it in the winter months, it shouldn't' be a problem. Then next winter you can decide if you want to pull it and fix it, or replace it.,,,

 

[JavierH19]

Use a thicker oil for the time being. But you have some issue. You easily should be getting 35+ psi with a 40 grade. The fact that you're getting 20 means something.

 

[PAoutdoorsman]

@

Is this the old school iron 90 degree 4.3?

I believe you would say it is. Here is the a summary of this engine:

Gasoline Sterndrive package only - This engine is no longer in production, but there are some engines still in builder and dealer inventory. The 4.3GL has been in production at Volvo Penta only since 2007, but it's based on a veteran V-6 block that's been successful for 25 years, since GM introduced it as a Vortec truck engine in 1985. Over the past quarter-century, millions of these engines have been built for on-road, off-road, land and sea applications (maybe even air, too), and it has proven to be reliable and long-lived. Volvo Penta's marinized 190-hp GL version is basic, with a two-barrel carburetor, no EVC, no catalytic converter. But the company says it's both quiet and virtually vibration-free, thanks to a center-mounted balance shaft.

 

[PAoutdoorsman]

Use a thicker oil for the time being. But you have some issue. You easily should be getting 35+ psi with a 40 grade. The fact that you're getting 20 means something.

Hypothetically speaking, if a lifter was failing and not holding pressure, would oil bypass and cause a drop in pressure?

 

[BigCahuna]

No. A lifter that doesn't pump up and stay pumped up, will hammer. No effect on engine oil pressure. I would try running that engine at 1/2 or 3/4 throttle until I got it serviced. At the point it's hammering, you might have already wiped out a lobe.,,,

 

[JavierH19]

You said chatter but what do you mean exactly. do you hear any ticking or knocking.

 

[BigCahuna]

Op, you never said if the engine is raw water cooled, or freshwater cooled. I'm gonna assume it's raw water cooled. How's you water temp, when your running it hard ? I'll guess you have a 160 degree thermostat in there. I have the 4.3 in my old pickup, and the oil pressure is right on 40 psi when cold, but drops to 20 psi when it's warmed up. Engine is super quiet at that pressure, so I'm not thinking that what causing your problem. Check all the cheap easy stuff first ,before throwing alot of money at it.,,,

 

[PAoutdoorsman]

You said chatter but what do you mean exactly. do you hear any ticking or knocking.

I would say it is a high clearance valve tick.

 

[PAoutdoorsman]

Op, you never said if the engine is raw water cooled, or freshwater cooled. I'm gonna assume it's raw water cooled. How's you water temp, when your running it hard ? I'll guess you have a 160 degree thermostat in there. I have the 4.3 in my old pickup, and the oil pressure is right on 40 psi when cold, but drops to 20 psi when it's warmed up. Engine is super quiet at that pressure, so I'm not thinking that what causing your problem. Check all the cheap easy stuff first ,before throwing alot of money at it.,,,

It is raw water cooled with a 175 degree thermostat. Temp climbs to 175 and the gauge never seems to move off that mark while operating.

 

[PAoutdoorsman]

@BigCahuna, just thinking about your question some more. It is cooled by the lake water - whichever you would consider that - draws it in through the outdrive and dumps it out via the exhaust.

 

[Number_35]

@


I believe you would say it is. Here is the a summary of this engine:

Gasoline Sterndrive package only - This engine is no longer in production, but there are some engines still in builder and dealer inventory. The 4.3GL has been in production at Volvo Penta only since 2007, but it's based on a veteran V-6 block that's been successful for 25 years, since GM introduced it as a Vortec truck engine in 1985. Over the past quarter-century, millions of these engines have been built for on-road, off-road, land and sea applications (maybe even air, too), and it has proven to be reliable and long-lived. Volvo Penta's marinized 190-hp GL version is basic, with a two-barrel carburetor, no EVC, no catalytic converter. But the company says it's both quiet and virtually vibration-free, thanks to a center-mounted balance shaft.

That does sound like the old 4.3/262 from the mid-'70s, essentially 3/4 of a 350 SBC (and thus the 90° V6 configuration).

It should be straightforward to remove the intake manifold and replace the lifters if required.

 

[BigCahuna]

@BigCahuna, just thinking about your question some more. It is cooled by the lake water - whichever you would consider that - draws it in through the outdrive and dumps it out via the exhaust.

That makes it raw water cooled. Nothing wrong with that type of cooling ,very common.,