High Oil Pressure on 4.3l Mercruiser

[tahoejag]

Is it normal to have oil pressure readings of 80 while running at or near WOT (4K +)? Midrange cruising speeds reads 60ish. Engine runs smooth, temp reading is 170-175ish, which imo normal. Oil dipstick is within the OK range.

 

[Volphin]

Re: High Oil Pressure on 4.3l Mercruiser

That seems a little high. I think you try to put a calibrated gauge on the engine and see what it really is. High oil pressure can be indicative of water in the oil as well. It won't show on the dipstick though...

 

[tahoejag]

Re: High Oil Pressure on 4.3l Mercruiser

That seems a little high. I think you try to put a calibrated gauge on the engine and see what it really is. High oil pressure can be indicative of water in the oil as well. It won't show on the dipstick though...

Volphin....last fall I did the oil change b 4 storage. During winter months I had a catasrophy that the bilge filled up with water up to the engine and froze (long story). So beginning of season I again changed oil just to be on the safe (any water intrusion, in which I did not see any). After a few runs out this season, I discovered it was low so added oil.....Ooops, too much! So I drained some out (which indicated no water in the oil) and to bring it back to the ok zone on the stick. (I have the factory drain hose system on engine which is convenient). Now unless this drain system is not at the very bottom of the pan, there could be a bit of water below the drain system??? Which brings up another ? of how to remove that oil.

Also how would one hook up an oil pressure gauge to verify correct oil pressure?....just go off of the one on the dash? Thanks for any input!

 

[Volphin]

Re: High Oil Pressure on 4.3l Mercruiser

Remove your sender (behind the intake manifold next to the distributor) and screw in a gauge from an auto parts store like NAPA. Start engine and observe the reading.

 

[Volphin]

Re: High Oil Pressure on 4.3l Mercruiser

Oh, and if you have drained the oil, there will be almost nothing left in the pan.

 

[tahoejag]

Re: High Oil Pressure on 4.3l Mercruiser

Volphin...thanks! will try the gauge in place of sender. it sounds like the drain hose system is adequate then (that tells me there is was no water intrusion).

 

[agallant80]

Re: High Oil Pressure on 4.3l Mercruiser

Mine ran around 80

 

[tahoejag]

Re: High Oil Pressure on 4.3l Mercruiser

RESULTS - Put on muffs. Disconnected blue wire from gauge sending unit to see if gauge was working. Gauge zero'd out. Reconnected wire, gauge worked. Ran motor up to aprx 2k for a moment.....gauge pressure read just above 60 at 2k and then dropped to just above 40 at idle. Ran it on the water....at 4k to 4500, gauge read just over 60.

Diagnosed as bad connection at the sending unit. Will continue to run it and have fun with it!!!!

 

[agallant80]

Re: High Oil Pressure on 4.3l Mercruiser

Huh, Mine always ran at 80 when the motor was really spinning. I wonder if this is a common issue. I figured it was normal and left it alone. Figured high oil pressure is better than low. Guess it does not matter any more seeing as I traded the boat this winter.