lost oil pressure today with 50w oil

[crazygn]

Well i started my 350 engine up two days ago and had 43psi of oil pressure with 10-40 oil on start up. I then changed today to 50w oil and on start up it was fine, then a soft tap started and next thing you know the rockers where tapping bad . I looked down and 0 oil pressure now.

I pulled the dist to see if the oil pump shaft broke but it seems ok[ not sure just yet] . It seems like it lost suction or prime and wont pick the thick oil up now.

anyone ever have this problem with 50w oil

 

[Bondo]

Re: lost oil pressure today with 50w oil

I then changed today to 50w oil

Ayuh,.... Why,..??..??

 

[Bt Doctur]

Re: lost oil pressure today with 50w oil

"Well i started my 350 engine up two days ago and had 43psi of oil pressure with 10-40 oil on start up. I then changed today to 50w oil "
Sure you dont mean 20w-50

My question too, why????????

 

[crazygn]

Re: lost oil pressure today with 50w oil

I was told by a few to run it, when it warms up i run around 8psi-10psi at idle. I hoped to just up that a few to make my self feel better. Its an old engine and i was reading that 50w would be better for the old bearings as long as you warm it up first.

 

[crazygn]

Re: lost oil pressure today with 50w oil

sucks , i just spent 2 months getting the boat ready for this sat.

sucks to be me

 

[zbnutcase]

Re: lost oil pressure today with 50w oil

Might have broken the plastic oil pump drive sleeve that Chev uses from the factory, aftermarket shafts have a steel sleeve

 

[84Monaco]

Re: lost oil pressure today with 50w oil

How long did you run it for? Was it overheated when giving no pressure? Have you checked the pressure with an alternate sender/gage?

 

[crazygn]

Re: lost oil pressure today with 50w oil

It only ran with the 50w for a few sec's before it lost oil pressure it never got to warm up. You can hear that it has no oil pressure, the lifters and rockers sound bad- no oil.

Whatever happened , it did it right away with the 50w oil

 

[Bifflefan]

Re: lost oil pressure today with 50w oil

Pull the dist. and look down the hole with a flash light. you should be able to see 2 prongs or a round shaft with a slot cut in the middle. If one of the ears is missing your pulling the engine and replacing the bearings and oil pump.
If they are both there get a oil pump primer shaft and run it on a drill (counter clockwise I think, im not a chevy guy) and see if you get pressure then.
also use a different gauge hooked right to the engine to check the pressure.
Id guess that if you used straight 50 wt it just wont pick it up.
When the engine is old, the pump is too. Thicker oil makes everything work harder.

 

[Silvertip]

Re: lost oil pressure today with 50w oil

Low oil pressure at idle is not a major concern. The old addage is that if you "have some" all is good. There is very little stress on the engine at idle so 8 - 10 PSI is no big deal. 40 PSI under way is just fine as well. Straight 50 weight oil is pretty thick stuff. Use an engine priming tool run with an electric drill to see if you can bring up oil pressure.

 

[myoldboat2]

Re: lost oil pressure today with 50w oil

crazygn, I just bumped a thread from a year ago: Oil Pressure - Mercruiser 140 hp

It's now a year later. My oil pressure still comes up very quickly and is higher at idle than before. My main concern was that the oil pressure took way too long to come up after starting. I'm still running Quicksilver 25W-40 with the Quicksilver oil filter.

I think it was really a matter of cleaning all the crud and gunk out of the oil pan and oil pump screen. From what everyone told me, the oils used 25 or more years ago would build up that gunk, but good oils today shouldn't.

 

[crazygn]

Re: lost oil pressure today with 50w oil

ill check the shaft when i get up so i have some light. thanks for the help guys

 

[Matt89GT]

Re: lost oil pressure today with 50w oil

Mercury calls for only 4 PSI of oil pressure at idle so you was fine, next time if its not broke dont fix it.

 

[crazygn]

Re: lost oil pressure today with 50w oil

thats crazy, oh well thanks for the good info. learn stuff every day even if its the hard way

 

[Matt89GT]

Re: lost oil pressure today with 50w oil

I hope you get your problem resolved

 

[dannyual767]

Re: lost oil pressure today with 50w oil

Pull the dist. and look down the hole with a flash light. you should be able to see 2 prongs or a round shaft with a slot cut in the middle. If one of the ears is missing your pulling the engine and replacing the bearings and oil pump.
If they are both there get a oil pump primer shaft and run it on a drill (counter clockwise I think, im not a chevy guy) and see if you get pressure then.
also use a different gauge hooked right to the engine to check the pressure.
Id guess that if you used straight 50 wt it just wont pick it up.
When the engine is old, the pump is too. Thicker oil makes everything work harder.

This is what I'd do. These oil pump primer shafts are cheap but I'm not sure if you can buy one from NAPA or your local Autozone/Advance Auto Parts or not. I know you can order one from Summit Racing or Jegs but then you have to wait for it to arrive. If you were near me, you could use mine.

However, it sounds like your engine was tired to begin with and a total rebuild is probably in your near future.

 

[bigskiohio]

Re: lost oil pressure today with 50w oil

I am at the lake now and my 120 idles at 600 rpm and around 10 psi oil pressure probabaly shoud be running 40 weight as it is in the 90s . running wot it is 35psi.

 

[crazygn]

Re: lost oil pressure today with 50w oil

Seems the shaft is still on the pump, or it feels that way. I drained the 50w oil and i'am gonna put some 10-40 back in and try to prime it to see what happens. This engine could use a rebuild this winter i just hope to make it pass the summer.

 

[sethjon]

Re: lost oil pressure today with 50w oil

Well i started my 350 engine up two days ago and had 43psi of oil pressure with 10-40 oil on start up. I then changed today to 50w oil and on start up it was fine, then a soft tap started and next thing you know the rockers where tapping bad . I looked down and 0 oil pressure now.

I pulled the dist to see if the oil pump shaft broke but it seems ok[ not sure just yet] . It seems like it lost suction or prime and wont pick the thick oil up now.

anyone ever have this problem with 50w oil

I use 10/40 in every motor I have...cars, boat, go karts and never had an oil related problem. If you used straight 50 its too heavy at start up. Change it out and go back to 10/40. It should make everything go back to normal.

 

[Matt89GT]

Re: lost oil pressure today with 50w oil

I would also check the sending unit and put a manual guage on it.