High Oil Pressure Issues

Hi, I recently purchased a 1998 Four Winns with a VP 4.3L GI engine and I put it in the water last week. All went well, until the second cruise then the temperature spiked and I had to shut down the engine. I did a bunch of research and concluded that it was most likely the raw water impeller. Sure enough it was toast. I replaced the impeller and the coolant temperature doesn't even move. I had to disconnect the temp switch wire to remove impeller parts from the thermostat housing. I'm not too concerned about the engine temperature because it feels warm compared to before. What I am concerned about is the high oil pressure when I am running > 3000 rmp. The gauge reads into the red (no numbers on lines on the gauge- red area for low pressure and a red area for high pressure). At idle the pressure is in the normal area, but as I accelerate it keeps on increasing. Any thoughts??? I read that I should hook up a mechanical oil pressure gauge, but I don't own one. Could it be the pressure relief valve or the oil filter or even the oil weight? I didn't notice the oil pressure previously so I don't know if it was an issue when my engine was overheating.

Any help would be appreciated.

Ron

Re: High Oil Pressure Issues

Take the time to toss a real gauge on temporarily and go from there. Then there is no question on what you have, could just be a bad sending unit or gauge. IMHO
Will add this my fresh 4.3 has 50 hot idling and 70 hot running 4k thats at the dash, so it could be out a little.
Bob

Re: High Oil Pressure Issues

You can get a oil pressure "test kit" from harbor freight for little $. Or auto zone and similar do loner/rentals with tools.

Re: High Oil Pressure Issues

Thanks for the responses. I purchased a oil pressure test kit from Harbor Freight and hooked it up this afternoon. This is what I found. At initial start-up the mechanical pressure gauge was reading 50 psi and the VDO gauge was reading 3/4. I reved the engine up to 2000 rpm and the mechanical oil pressure test gauge read 65 psi and the VDO gauge was in the red. Both these pressures were taken after initial start-up so the oil would have been cold. I'm thinking that these pressures are too high. What do you think????

Could it be too much oil? Oil weight? Could it be the oil pressure relief valve or clogged oil filter?

Also, since the VDO pressure gauge was working even though I disconnected the lead does this mean that I have a dual oil sensors? When I looked into buying new oil pressure sensors, there are two different types single and dual - what's the difference?

Any help would be appreciated.

Ron

Re: High Oil Pressure Issues

rdufeu said:

Thanks for the responses. I purchased a oil pressure test kit from Harbor Freight and hooked it up this afternoon. This is what I found. At initial start-up the mechanical pressure gauge was reading 50 psi and the VDO gauge was reading 3/4. I reved the engine up to 2000 rpm and the mechanical oil pressure test gauge read 65 psi and the VDO gauge was in the red. Both these pressures were taken after initial start-up so the oil would have been cold. I'm thinking that these pressures are too high. What do you think????

Could it be too much oil? Oil weight? Could it be the oil pressure relief valve or clogged oil filter?

Also, since the VDO pressure gauge was working even though I disconnected the lead does this mean that I have a dual oil sensors? When I looked into buying new oil pressure sensors, there are two different types single and dual - what's the difference?

Any help would be appreciated.

Ron

Click to expand...

"Dual" is for when you have two helms (and two gauges)..."single" means just that, one helm and one gauge.

Happy boating!

P.S. Until you change the oil to what your engine is specified for, you are asking us to use a crystal ball as to if you have the wrong weight currently in the engine!

Make the oil change...with a new filter...and see what you have!

Happy boating!

Re: High Oil Pressure Issues

Does anyone have the oil pressure specifications for a 1998 4.3L GI VP engine? Next time I take the boat out I want to measure the oil pressure when the engine is at operating temperature over a range of rpms.

Thanks

Ron

Re: High Oil Pressure Issues

Oil Pressure (at 2000 rpm) Minimum 30 psi (207 kPa)

Minimum Oil Pressure At Idle 4 psi (28 kPa)

Re: High Oil Pressure Issues

All this is moot until an oil/filter change takes place.

Re: High Oil Pressure Issues

Sure previous owner didn't fill it with 79-90 or 90-140 gear lube to mask an engine problem?

That used to be a favorite scam of used car lots and is still popular with the criminals that run Buy Here Pay Here car lots.

I know first hand that 3 quarts of Valvoline 50 weight Racing oil and 4 cans of STP Oil Treatment will make a bad rod bearing quiet as a mouse......for a little while.

Re: High Oil Pressure Issues

If the gauge still worked after you disconnected the sensor, you disconnected the wrong sensor.

What are the pressures with warm oil?
What oil do you have in it?

Re: High Oil Pressure Issues

180shabah said:

If the gauge still worked after you disconnected the sensor, you disconnected the wrong sensor.

What are the pressures with warm oil?
What oil do you have in it?

Click to expand...

I removed the wire/sensor just above the oil filter and connected the mechanical gauge to the hole. Are there two sensors on this engine or did I disconnect the wrong sensor?

I haven't tried with warm oil yet - I've been out of the country all week. I'm not sure what weight oil is in the engine - I would assume 10W30 since I purchased the boat from a dealer who had serviced the boat for years.

Re: High Oil Pressure Issues

50psi on a cold start is normal,I was priming the oil pump on a mercruser crate engine this week and had over 50 psi using a drill and mechincal gauge

Re: High Oil Pressure Issues

ENSIGN said:

50psi on a cold start is normal,I was priming the oil pump on a mercruser crate engine this week and had over 50 psi using a drill and mechincal gauge

Click to expand...

Thanks!! That's what I wanted to know. I also talked to a service mechanic and he said that the pressures were normal and could go as high as 80 psi. I guess I was worrying about nothing.

So if I wanted the gauge to read more accurate, could I add a resistor inline to the electronic gauge to reduce the voltage drop or could it be the sensor (which I could also replace) or just live with it, knowing that the gauge is reading high?

Ron

Re: High Oil Pressure Issues

Adding resistance is going to make the gauge have a higher reading if you put it in series with the sender. I've never had any reason to do this.

Re: High Oil Pressure Issues

ENSIGN said:

Adding resistance is going to make the gauge have a higher reading if you put it in series with the sender. I've never had any reason to do this.

Click to expand...

Higher resistence = lower reading
zero resistence = pegged gauge

Skip the resistor, you have verified your real pressure, note the location on the gauge and watch for a drop.