high oil presure

[zoop]

I have a 1979 mercruiser 120 . When I start it up it blows the seal on the oil filter . Just changed the oil 30 sae as recomended. Then tried <br />5w 3o to se if thinning it out would help. still blows the seal in the matter of seconds when it fires up. When I pulled the filter I pressed the relief an it seem to be free. But I don't know what is behind it.What could be stopped up???<br />Thank you

 

[LubeDude]

Re: high oil presure

Are you sure you dont have two filter gaskets on there. It wouldnt be the first time its happened. I dont see how else this could happen.

 

[Don S]

Re: high oil presure

If it worked fine before you changed the filter, and you don't have a double gasket, then put on a different filter. there is someting obviously wrong with that particular filter.

 

[Silvertip]

Re: high oil presure

Did you just buy this rig? Did this problem pop up after an oil change? As LubeDude says, first seal stuck to filter housing instead of coming off with the filter. Wrong filter is a possibility. Stuck relief valve in oil pump.

 

[zoop]

Re: high oil presure

No there is not a double gasket. But I will try another filter. Life would be to easy if that were all it was. Open for all suggestions<br />Thanks alot for the help .

 

[Don S]

Re: high oil presure

Was the oil pressure ok and not blow out the oil filter BEFORE you changed the filter...... like the last time you ran it?????

 

[Wellcraft 89]

Re: high oil presure

Is this the first spring start up? <br />If so,a crankbearing could have spun blocking oil passage.seen it before! <br /><br />Rich

 

[Reel Poor]

Re: high oil presure

Im with Upinsmoke<br /><br />A stuck pressure relief valve in oil pump.<br /><br />Oil pressure high enough to blow out of oil filter gasket is also high enough to bend the oil filter over, as if trying to pull the threaded hole out of the bottom of filter. Look at threaded end of filter and see if thread hole is still parralell with the gasket sealing surface of filter. As bent filter unscrewes it may also wobble around.<br /><br />Was there any water in the oil you drained out?

 

[trog100]

Re: high oil presure

i think its a faulty filter.. try another one.. only guessing at the most obviouse cause thow.. its not something that should happen..<br /><br />trog100

 

[SeaRay Dude]

Re: high oil presure

Hi guys, I'm a retired auto mechanic and have ran into this on car engines in the past, a couple things that will cause it are double gasket on the filter or A stuck pressure relief valve in the oil pump. Heres a little story to go with this, while I was in trade school many moons ago the teacher explained to the class how you could increase oil pump pressure by stretching the spring. I had brought a car to the school to rebuild the engine but that meant it became a class project with many different hands on it. unbeknownst to me one of my classmates decided the oil pump spring should be stretched, well when I got it all together and fired it up..suprise surprise.. it not only blew the rubber ring but it blew the filter apart. Needless to say I wasn't impressed and had to bite my tongue to keep from cursing out loud, I had to lift the engine pull the pan put a new oil pump in and put it all back together. I put another new filter on added oil and this time things went the way they were suppose to...

 

[zoop]

Re: high oil presure

I just want to thank everyone for there imput. <br />This boat sat the last part of last year with <br />wiring problem and this is the first attempt to <br />get it running this spring. Fixed the wiring and ran into the oil presure problem. I just put a new filter bought from a dealer and it still blowed the seal around filter . But when it fired<br />I didnt see any oil presure on the gauge. Does this point toward the spun bearing or oil pump.<br />Motor only runs for seconds before blowing .

 

[LubeDude]

Re: high oil presure

Im not familliar with the 120, but if the oil pump is lined up with the main bearing that may be spun, (oil cant pass through), then you would experience what you are saying. High preasure in the filter, and NO oil preasure anywhere else. Doesnt sound real good.

 

[trog100]

Re: high oil presure

there should be a pressure relief valve built into the block.. this should blow off about 70 psi.. it comes before spun bearings and is pretty early on in the oils path as it goes thru the engine.. <br /><br />i dont go for the spun bearing theory to be honest..<br /><br />i am bit vague on where the block release valve is exactly i cant remember whether it come before or after the filter.. if it comes before it should blow off before the filter fails.. it it comes after its straight after (off the main oil gallery) and should still blow off..<br /><br />i am reasanbly sure the gauge gets it pressure reading from the main oil gallery..<br /><br />the pump feeds oil to the filter which is at the beginning of the circuit.. from there it goes to the main gallery.. from the main gallery it feeds the various drillings that lubrcate the engines bits and bobs..<br /><br />most of it gets fed to the crankshaft main bearings.. from the main bearings it gets fed to the big-end bearings and passes out thru the sides of said bearing and back into the sump.. the resistance (clearance) of the main and big-end bearings is what produces the actual oil pressure..<br /><br />one spun bearing would not increase the overall oil pressure by that much and if anything at the far end of the oil circuit did increase the overall oil pressure the pressure release valve should blow off..<br /><br />so we are right back to a blockage at the filter itself.. quite how a blockage could occur back there i aint got the faintest idea..<br /><br />basically your engine is getting no oil where it matters whatsoever.. it cant get out that filter.. or at least not very far past the filter.. it aint making the main oil gallery else the oil pressure gauge would show oil pressure.. and either way the pressure relief valve should blow off..<br /><br />trog100

 

[zoop]

Re: high oil presure

What I believe may be the release is right behind the oil filter in the block. It appears to be a disk with spring tension behind it. That is free . I can push it in with my finger. There is one 3/8 inch hole and the the disk which is about 3/8 in diameter and the opening that the oil filter screws on. Can I hit any of these with air maybe to see if there is a blockage???

 

[trog100]

Re: high oil presure

there are two safety kinda releases one is for blocked filters.. this simply bypasses the filter if it isnt changed often enough and gets clogged up.. this simply makes sure the engine is always being lubricated even if the oil aint being filtered..<br /><br />the other one.. or at least all the ones i have ever seen or looked at up close is a hollow cylindrical piston shaped thing about half an inch wide with a shamfer on the end and held down by a coil spring.. normally there is a large nut enabling its removal complete with spring for replacement of checking..<br /><br />this is the one i mean.. i have never seen one do it but it could seize solid and not be working.. its job is to relieve excess oil pressure due to cold thick oil so as pump drives dont shear or other damage get caused..<br /><br />to the best of my knowledge all engines need such a device and have one.. thow it could be of a different design or type to what i described.. i am not familiar enough with your particular engine block to know exactly what the thing u described does.. thow it does sound more like a filter bypass device than a main pressure relief valve..<br /><br />trog100

 

[zoop]

Re: high oil presure

Thanks for the info. My next step is to purchase a mercruiser manual and look for location of the releases . I will post what I find out <br />This is a great site .