Merc 4.3L Extremely High Oil Pressure

[scockey]

Hello to all. I have a 2003 Searay 182SRX w/ Mercruiser 4.3L 190hp Alpha One. The engine has recently developed a very high oil pressure situation. So here is a run down and I would like to know what I should do next.

At idle, I am seeing about 60 PSI. At 1/3 throttle the pressure is up to 80 PSI (max of the electric gauge) and at about 1/2 and above the pressure climbs all the way up to 90 PSI.

I changed the oil and changed the filter (old one was a Casite, new one is a K&N) and still have the same issue. I have checked the pressure with a mechanical oil pressure gauge as most of the posts suggest and have gotten the same readings as my electric gauge.

I am going to try to call Mercury and any service shops that I can, but I am running out of possible things to check without having to start tearing apart the engine.

The only other thing that I can think of is that the bypass pressure valve is stuck, but I don't know how I would check this.

Any help would be greatly appreciated.

 

[WAVENBYE2]

Re: Merc 4.3L Extremely High Oil Pressure

Could be more than this.

 

[Don S]

Re: Merc 4.3L Extremely High Oil Pressure

The oil filter bypass valve is in the oil filter boss on the bottom, port side of the block. You probably have ta remote filter adapter on it now, but you may even have a filter there. Did this problem start suddenly or build up over time? Did it change when you changed oil or filter one time?
ALso, there is a pressure regulator in the oil pump itself that could be the problem........... and you know where the pump is.

 

[DreamBoater]

Re: Merc 4.3L Extremely High Oil Pressure

I would also think the pressure chk valve in the pump is sticking but you would have to pull the pan and pump to resolve it. a little to much oil pressure is not bad but you have enough to start blowing out seals in the motor which is not a good thing. Good luck with it.
Scott

 

[Don S]

Re: Merc 4.3L Extremely High Oil Pressure

What seals would/could blow because of high oil pressure?????

 

[scockey]

Re: Merc 4.3L Extremely High Oil Pressure

I bought the boat this spring with 80 hours on the engine. It was kept on the trailer for use at a fresh water lake and was traded into a dealer for a larger boat. When I bought it everything on the engine/drive looked spotless. I know have 105 hours on the engine. I started keeping an eye on the oil pressure after I had the alarm beep one single beep once in a while (like 1/2 hr or more) while towing wakeboarders or tubing. After I noticed the pressure was high I changed the oil (Merc 25W-40 FCW rated) and changed the oil filter after that. That was my first oil change. I can't say I was impressed looking at the Casite filter when I got it off. I believe its one that the dealer put on when they supposedly changed the oil and impeller before I bought the boat.

So its not a suddenly developed problem, but was not evident when I bought the boat. I do not have the remote filter but wish I did. Is there an easy way to check/replace the bypass valve with out pullling the oil pan/pump?

 

[Tail_Gunner]

Re: Merc 4.3L Extremely High Oil Pressure

GM motor's alway's post crazy high oil pressure number's, listen close to Don.

 

[ramster]

Re: Merc 4.3L Extremely High Oil Pressure

Try a mechanical oil pressure gauge, make sure it's not your sending unit. I don't think it would be the bypass, that only by-passes the filter, I have it welded shut on my 350 chevy, so all the oil goes through the filter. When my motor is hot it idles at 40 psi, and at cruise speed it runs around 75psi, that is with a Z-28 spring in a standard pump. My vote is bad sending unit.

 

[95yj]

Re: Merc 4.3L Extremely High Oil Pressure

Except that he already verified with a mechanical pressure gauge. Unfortunately he's probably gonna have to pull the oil pan to solve the problem. I'd check the bypass valve first only 'cause it's easier to get to, but its job is only to bypass a plugged oil filter. If the oil pump isn't the problem, then it's a blocked passage somewhere and that can mean tearing down and boiling the block.

 

[Tail_Gunner]

Re: Merc 4.3L Extremely High Oil Pressure

Ohh for christ sake's , let Don deal with this Issue and watch and learn a little bit............ sorry

 

[mkpj1]

Re: Merc 4.3L Extremely High Oil Pressure

I vote for pump pressure regulator stuck closed or partially closed. Bypass doesn't sound viable to me as both your filter and bypass would have to be clogged some? You have a new filter and your oil looks good.

I'm assuming no knocking right? A spun bearing can do this too.

Racers used to increase pressure from the pump to improve oiling at high RPMs but it sounds like your running high at what is considered low rpms- 90 at ~3000. Racers don't even do it anymore as it' been found to decrease horsepower more than anything else. It also heats up the oil and aerrates it decreasing it's protection. Get high enough and you will starve the bearings and can at high enough damage or blow off the oil filter. I've seen it happen. Hope your not using a fram. I mean we're talking 150 + but your running 90 at ~2500-3000.

IMO, Bite the bullet and get it to specs as I did not get the idea Don considered the high oil pressure okay?