Malibu Boats m5di strange oil pressure issues

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I know this is a boat engine, but the engine is really an L83 Chevy 5.3L marinized by Malibu / Axis boats.

The boat is brand new and would idle at 40psi and over 2000rpms would go up to about 60psi all normal.

The dealer came out and did the breaking service, where they replace the oil filter / oil / check for metal shavings in the tranny, etc.... at 25hours.

After this service, we noticed the oil psi gauge reading much higher.

Cold crank, idle 60psi
Engine warm (160F), idle 60psi
Engine warm (160F), 2000+rpm pegged at 80psi (highest the needle goes).
Engine warm (160F), about 25mins after running it 2000+ rpm, idle drops to 40psi
Engine warm (160F), about 45mins after running it 2000+ rpm, psi seems to level out back to 60psi.

I informed the dealer and they reached out to malibu and said high PSI reading happen when engine is overfilled. So we drained about 5.5qt (8qt total) on the lift using a dipstick pump, and refilled making sure not to pass the FULL line on the dip stick. Even with the dipstick reading 1/2 way between ADD and FULL same readings.

The dealer also informed me yesterday that they have now seen this on several other new boats after doing the break in service.

The dealer replaced the oil filter during the breaking service wit ha Hgnst filter, so I was thinking of replacing that with a WIX or NAPA version of the filter.

The manual for the engine / engine oil cap both state to use 5w-30, while i know the L83 engine from chevy says 0w-20.... but oil being hydraulic i dont think that would affect PSI?

Grasping at straws here, dealer said no issue running it as long as the pressure normalizes, but they are continuing to inquire with the manuf.
 
The pressure gage for the 5.3 is normally mounted on the intake manifold, driver's side. The variance of the oil pressure between idle and higher RPM is controlled by an electrical solenoid. Close to the crankshaft pulley (edit) is an electrical connector that some folks have reported can get damaged.

I don't know where the solenoid is but this should be checked. It's possible it went into a failsafe mode and is causing too high of an oil pressure. That's it for my knowledge on the oiling system. These changes were made in 2014. Good luck and please report back.

Go ahead and change the filter. It can't hurt.
 
Last edited:
Originally Posted by maxdustington
Nice bote. Keep the 5W30, change the filter. I would use whatever AC Delco is specced for the L83 just to be sure.

Start documenting everything. High oil pressure = overfilled seems like they are trying to blow you off. The dealer f'd something up during that first service.


if it was a normal dealer i would believe that, they arent blowing me. We are all friends and they are genuinely concerned and interested now. Will try the filter.
 
Originally Posted by agarabaghi


The manual for the engine / engine oil cap both state to use 5w-30, while i know the L83 engine from chevy says 0w-20.... but oil being hydraulic i dont think that would affect PSI?



Oil can certainly affect pressure. If they put 20w-50 in it, that could definitely explain why you are seeing much higher pressure now for example.
 
Originally Posted by OVERKILL
Originally Posted by agarabaghi


The manual for the engine / engine oil cap both state to use 5w-30, while i know the L83 engine from chevy says 0w-20.... but oil being hydraulic i dont think that would affect PSI?



Oil can certainly affect pressure. If they put 20w-50 in it, that could definitely explain why you are seeing much higher pressure now for example.


Which is why I personally drained it and put 5w30 back in last night, the dealer also said they did another boat and put 5w30 in as well and it is now doing the same thing.
 
Originally Posted by agarabaghi
Originally Posted by OVERKILL
Originally Posted by agarabaghi


The manual for the engine / engine oil cap both state to use 5w-30, while i know the L83 engine from chevy says 0w-20.... but oil being hydraulic i dont think that would affect PSI?



Oil can certainly affect pressure. If they put 20w-50 in it, that could definitely explain why you are seeing much higher pressure now for example.


Which is why I personally drained it and put 5w30 back in last night, the dealer also said they did another boat and put 5w30 in as well and it is now doing the same thing.



Bizarre! You could definitely try another filter, but I have a hard time picturing it causing such a difference. Did the OEM tell you what viscosity was used for break-in? Maybe it was 0w-16
lol.gif
 
Originally Posted by OVERKILL
Originally Posted by agarabaghi
Originally Posted by OVERKILL
Originally Posted by agarabaghi


The manual for the engine / engine oil cap both state to use 5w-30, while i know the L83 engine from chevy says 0w-20.... but oil being hydraulic i dont think that would affect PSI?



Oil can certainly affect pressure. If they put 20w-50 in it, that could definitely explain why you are seeing much higher pressure now for example.


Which is why I personally drained it and put 5w30 back in last night, the dealer also said they did another boat and put 5w30 in as well and it is now doing the same thing.



Bizarre! You could definitely try another filter, but I have a hard time picturing it causing such a difference. Did the OEM tell you what viscosity was used for break-in? Maybe it was 0w-16
lol.gif



I assume they come pre filled from the Manuf in TN, as the dealer does a breaking for 2 hours, then the owner can use the boat for 15-25hours before needing the first service.

After they they recommend oil and filter every 100hours or once a year.

Im gonna try the napa filter at this point since its the only part i havent done my self. Its cartridge style at the top of the engine so it should be easily done with out needing to drain the whole engine again.
 
Originally Posted by agarabaghi


I assume they come pre filled from the Manuf in TN, as the dealer does a breaking for 2 hours, then the owner can use the boat for 15-25hours before needing the first service.

After they they recommend oil and filter every 100hours or once a year.

Im gonna try the napa filter at this point since its the only part i havent done my self. Its cartridge style at the top of the engine so it should be easily done with out needing to drain the whole engine again.



Keep us updated on the results, I'm interested.
 
Originally Posted by Snagglefoot
Some pics would be cool.
smile.gif

Yeah, I looked up the engine code and the boats that came up were some super nice ski boats.
Originally Posted by agarabaghi
Which is why I personally drained it and put 5w30 back in last night, the dealer also said they did another boat and put 5w30 in as well and it is now doing the same thing.
5W20 time I reckon. I guess the days of throwing the owner's manual out the window in regards to oil specs are over. I thought the 5.3 could run on anything?!
 
I was under the impression with Oil being hydraulic ... psi would not be affect with slight variance in weight 5w30 vs 5w20 ... as long as the pump can handle it. The L86 version takes 5w30 from the manuf but the LT4 (L83 with a supercharger) takes 0w40.

I got the filter but I am tempted to try 5w20 or 0w20 though I don't think 0w makes much of a different in FL.

Pics of the boat?

[Linked Image from i.imgur.com]


[Linked Image from i.imgur.com]


[Linked Image from i.imgur.com]
 
The PSI you are seeing is the system resistance to oil being pushed through it. Ergo, the more viscous the fluid, the higher the resistance. This is why oil pressure drops as the oil heats, as viscosity reduces.
 
Originally Posted by agarabaghi
possible.... no one knows why. Seems weird it would take so long for oil to get to it's 30 viscous state


30 is just a range of hot viscosity numbers @ 100C. Different engine and oil cooling designs will take longer or shorter to get the oil to its operating temperature, which will vary based on OEM spec. Some engines will not get the oil to 100C, some will get it higher than that; often significantly so. This also of course depends on operating conditions.
 
Yea could be. which means the manuf spec would be wrong then. Ill have to double check running something like 5w-20 or 0w-20 wont void my warranty.
 
A sweet inboard being towed by a Rover...a man after my own heart! Nice boat, enjoy.

Also curious as to the cause. Hengst is a quality filter, cannot see it being too restrictive for the application (assuming the sensor is upstream of filter), but stranger things have happened...
 
Found out from GM Authority, that if the wiring to the oil control solenoid gets damaged, it goes into the high pressure mode. Look for any damaged wiring near and behind the crank pulley. Also, I believe there is a sensor near the crank pulley that lets the sensor know the RPM of the engine. Any chance the tech was monkeying around the front of the engine?
 
Originally Posted by Snagglefoot
Found out from GM Authority, that if the wiring to the oil control solenoid gets damaged, it goes into the high pressure mode. Look for any damaged wiring near and behind the crank pulley. Also, I believe there is a sensor near the crank pulley that lets the sensor know the RPM of the engine. Any chance the tech was monkeying around the front of the engine?


No reason too, this engine is fitted with a front end accessory for cooling the transmission and oil making the stock location for that solenoid either moved or behind it all.

[Linked Image from i.imgur.com]


Also if that wire was damage I feel like it would do the same thing the whole time and not actually let the psi drop eventually.

Gonna see about running 0w-20 and warranty issues.
 
I'm not a 20 grade hater, I use it myself in my Jeep, but I wouldn't use it in a boat. No way.

Almost certainly this is caused by the filters or the oil they've used, and how do we even know this is a problem? The Jeep sees 100 psi at cold start even with 0w20. Hot idle once it kicks into low pressure mode, more like 32 or so. If you hot numbers are normal I wouldn't worry about it one bit.
 
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