Yet Another 4.108 Oil Pressure Problem - Help?

[dougal]

I'm hoping this is just a gauge or sender issue, BUT...
On startup, pressure gauge needle leaps across and LOCKS on the max stop. As engine warms, it eventually drops, but will show high if revved. Tried various different oils, and thoroughly flushed engine.

Fear suggests it might be the pressure relieve valve. That would involve an engine removal. Very hard on my boat!!!!

Anyone in the UK know where I can get a mechanical gauge and connectors (1/8 npt??) to test it? Tried the normal Perkins spares outlets, with no luck;-(

There's no more blue smoke than usual, which I'm hoping means the pressure is not 'real'.

[HappyMdRSailor]

Uh...

Auto parts (sorry... spares) store... $15 us... ???

[dougal]

Originally Posted by HappyMdRSailor

Uh...

Auto parts (sorry... spares) store... $15 us... ???

UK not US ;-)

[HappyMdRSailor]

Originally Posted by dougal

UK not US ;-)

I didn't want to do the math and depress you with the plunging Sterling...


Amazon has tons for the price of a good pint...

[dougal95]

Originally Posted by HappyMdRSailor

I didn't want to do the math and depress you with the plunging Sterling...


Amazon has tons for the price of a good pint...

Wow! Really? The one place I never thought to look. And to think they use to be a book shop;-)))

[dougal]

Ok, so here's the next question...?
My engine gauge panel (original Perkins) only has an oil pressure gauge. There's no low pressure warning light OR audiable alarm. YET, looking at the pic, there's a second sensor on the engine block. Is that for a light/alarm? If so, then could someone give me at least a rough idea of how to wire this up?
Many thanks

[HappyMdRSailor]

Originally Posted by dougal95

Wow! Really? The one place I never thought to look. And to think they use to be a book shop;-)))

Oh man... Amazon is my go to.... Not sure about UK service... But join prime and everything that qualifies comes 2 day @ no shipping charges... Traveling??? Ship to a "drop box" location... At my boat in CA, I can have a part delivered to the 24 hr liquor store around the corner and pick it up at 3 AM if that's when I get off the plane... no charge...

Originally Posted by dougal

Ok, so here's the next question...?
My engine gauge panel (original Perkins) only has an oil pressure gauge. There's no low pressure warning light OR audiable alarm. YET, looking at the pic, there's a second sensor on the engine block. Is that for a light/alarm? If so, then could someone give me at least a rough idea of how to wire this up?
Many thanks

Dunno... Gotta be an alarm that isn't hooked up to a horn (ie engine harness connected, but nothing past the engine), or isn't working...

looked at my 4-108 manual.. no love there...

[cookwithgas]

I had a similar problem with my Yanmar. My neighbor who owns an auto repair shop told me to pull the sending unit and bring it to an auto supply store and get them to look in the back for one that looks just like it. I did that and everything it has worked flawlessly for two years. The Yanmar sender was $50 US with a two-week delivery, and the auto store replacement was $7. If you want to install a mechanical pressure gauge (and add several new leak points) it might give you peace of mind but I wouldn't do that. If you have the room, you could plug a small gauge into the sender port and start the engine to verify that you have good oil pressure, then remove it and reinstall the sender.

Good luck!

[dougal]

Originally Posted by cookwithgas

I had a similar problem with my Yanmar. My neighbor who owns an auto repair shop told me to pull the sending unit and bring it to an auto supply store and get them to look in the back for one that looks just like it. I did that and everything it has worked flawlessly for two years. The Yanmar sender was $50 US with a two-week delivery, and the auto store replacement was $7. If you want to install a mechanical pressure gauge (and add several new leak points) it might give you peace of mind but I wouldn't do that. If you have the room, you could plug a small gauge into the sender port and start the engine to verify that you have good oil pressure, then remove it and reinstall the sender.

Good luck!

Thanks, it was the latter I planned to do. I won't leave a mechanical gauge in place as, like you said, just another place to leak from;-)

[leftbrainstuff]

Confirm with another gauge and sender. If you add a mechanical guage add an isolation valve.

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[Lepke]

The unused switch on the oil line is probably a NC (normally closed) switch that probably opens at about 5-15 psi. With a test light or an ohm meter check it with the engine off and on. If it's NO (normally open), it was probably to turn on an alternator.

[bowenst7]

This happened to us on a trip after switching to a heavier oil... the pressure relief valve got stuck open for a while..after changing oil back to multigrade the problem went away. I have read elsewhere that by poking down the oil galley that goes to the pump with a wire the pressure relief valve, if stuck open might be jiggled back into position but I did not have to do this nor do I know if it may work.