Oil clogging in oil pump

[55 cadi]

Hello all,

I changed my oil, the oil pan had sludge in bottom, i cleared all that out but there was probably some that made its way through the system, now on occasion my rockers rattle from lack of oil, then usually goes away.

Question is, is there something i can use to add to oil to break up the larger sediment so it doesn't clog the oil pump?

Thanks for all the advise.

Jason

[The Tassie Devil(le)]

I believe there is an oil flushing additive that can be used, BUT, there is a most probable possibility result in some particles of sludge being caught inside the hydraulic lifters  that will necessitate their removal and individual disassembly for cleaning.

These flushing solutions are used following an oil change, and then another oil change is required some short time following the insertion of the additive.

Bruce.

[TJ Hopland]

Is this a new to you car?  How quickly does the oil get dark?   And how did you clean out the pan?

I would try doing a few way sooner than usual oil changes and see how it goes.  The fresh detergents in fresh oil will start working at stuff.   Like Bruce said you don't want to knock it all loose at one time.

[55 cadi]

Thank you for the info and heads up Bruce.

TJ, I have had the car a year and half, just got it driving decent.

Oil looked kinda clean when checked but that must have been just previous owner poured new in, i drove the car 2 times about 50 miles and no rocker chatter, i then did a complete oil change and saw how bad it was, cleaned out pan(Scooped out and cleaned), did what I could to oil pump filter and put back together.

Now on occasion the rockers chatter and go away after about 5 miles on a 10 mile drive 

Jason

[Bobby B]

Oil looked kinda clean when checked but that must have been just previous owner poured new in, i drove the car 2 times about 50 miles and no rocker chatter, i then did a complete oil change and saw how bad it was, cleaned out pan(Scooped out and cleaned), did what I could to oil pump filter and put back together.
Jason

Jason,
Hi. Did this all happen after you changed the oil for the first time? I wonder if the PO had some kind of "Motor-Medic" type additive in there to quiet it down to sell it.  . A lot to strange things seem to happen once you get the car home and you own it.......
                                      Bobby

[TJ Hopland]

How did other parts of the inside of the engine look?  Have you had anything apart on the top for a look?   I have seen pans get pretty nasty from sitting a lot but the rest was not too bad.

Any idea how often the car was driven in recent history?

What type and grade of oil did you use?  Bobby brings up an interesting possibility.  Maybe what was in there was not what should have been?

[Roger Zimmermann]

Did you clean also the oil filter canister? If there was sludge into the oil pan, there must be some into the oil filter canister too...

[CadillacRob]

Ive got sludge in the pan of my 50 but I just did frequent oil changes.

I did have a couple old timers tell me to run kerosene in it for a day and then change it out.  Never did it though so I cant comment.

[The Tassie Devil(le)]

We have to remember that back in the day, Service intervals were a lot shorter than these days.

2,000 to 3,000 miles was the recommended oil change period, and more often for different operation conditions.

A car that is only used for going to shopping, and church on Sundays would require oil changes at 1,000 miles or even less, as the sludge doesn't get boiled away as it doesn't get to operating temperature.

The '55 I have had 3/4 Inch of sludge in the bottom of the sump, and it was enough to completely hide the pieces of a broken piston skirt that was destroyed into little pieces by the crankshaft spinning.

Bruce.

[walt chomosh #23510]

J,
  I have some experience with 331s and their rockers WILL talk when they lack oil. The oil pump pickup tube MUST have a felt seal between it and the pump or it can and WILL suck air when the oil level gets approx. 1quart low. This results in rocker chatter and inadequate lubrication to the rod bearings. As long as the oil level is kept above the level of the pickup tube to pump connection, the motor will be quiet. A guy(or girl) can install a tee where the oil pressure switch is and be able to look at pressure with a direct reading gauge. A noisy motor is NOT a happy motor. Another point to consider is that non-detergent oil was used back in the day. The Cadillac service manual for 1955 called for removing the pan for cleaning....once a year!..walt...Tulsa,ok

[cadman56]

The oil filter system on the 331 is a by-pass system so filtration is not too good.  I have used Rislone and Marvel Mystery Oil at times.  Yes, replace the felt seal on the pick up tube and make sure the pick up itself is clean.
Good luck, Larry

[55 cadi]

Thanks for all the responses.

Bobby,
Yes  first oil change, the seller was not totally honest about the car, finding out after purchase.

T. J.,
Under valve cover parts look ok,   As far as driven before purchase he said something like 1 time a month, not much the past year.    I used 20-50 because of leak.

Roger,
I did clean filter canister also, it had sludge in it as well.

Walt,
I did not see a felt seal at pump opening, I can see the metal screen in the pump.

Jason

[TJ Hopland]

Its a good sign that the top side isn't also full of sludge.

Sounds like that seal issue on the pickup may be worth looking into.  A little air can really effect lifters so if the level is dropping past that possibly missing seal it would fit your symptoms. 

Where is the leak?  Maybe its related to low oil pressure?

I don't know that engine at all so will have to let other weigh in on if maybe 20-50 could be too thick?

[CadillacRob]

For whatever its worth i run regular  10w30 in my 1950 331

[The Tassie Devil(le)]

Using thicker oil will not stop a leak.

Just makes the pump work a bit harder.

Bruce.

[55 cadi]

I was putting in 10-30  when I changed the oil pan gaskets to stop a bad leak.

I took it to a shop after because it was still leaking but not nearly as much, it was the rear main seal that needed to be done, the shop said they needed to rebuild a lot of the lower engine to do the rear main seal, that started a discussion with them about the fact they didn't need to and I won't have that done and showed them posting here on this forum saying it didnt need to be done and they said there book says it did and they will only do the way there book says, I asked to see there book they are using and wouldn't show, so I said put it back together and I will take somewhere else, that's when they put in the 20-50 saying it might help.
I didnt think it would but they were suppose to be the experts.

So i still have a leaking rear main seal for now.
Jason

[The Tassie Devil(le)]

The later model cars with the neoprene seal, it is possible to replace the seal with the crank in situ.

With any engine that uses the "Dog-turd" rear main seal, to properly replace the rear seal, the crankshaft HAS to be removed as it is virtually impossible to remove the old one, and insert the replacement so it won't leak again.

Trying to replace the original "Dog-turd" seal, it would take less time to remove the engine, spin it over and remove the crank, correctly fit the seal, and replace everything, than to attempt to get the old one out and the new one in with the crank in place.

Plus, people forget to clean out the little sipes that are machined into the crank journal surface that facilitates the travel of the oil back into the sump.

Plus, when anyone pulls out a crank, they always check the wearing parts for wear, as they don't want to be responsible when it is all back together, for owner complaints when the disturbed bearing surfaces start to wear out.

Most engines that have leaking rear main seals will end up being rebuilt, as a worn seal is also an indication of excess bearing clearances, and the crank is allowed to move around, opening up the oil seal clearances, causing the leak.

Bruce.

[Jay Friedman]

I have to disagree with Bruce (The TD).  A rear main bearing oil seal, either rope ("Dog-turd" as he put it) or neoprene (rubber), on a 331 engine can definitely be replaced with the engine in the car.  I have done it twice: once on my '49 and another time helping a friend on his car.  It's time-consuming but definitely do-able.   

Art Gardner wrote a detailed illustrated step-by-step article describing how to do it.  If anyone (Jason?) wants a copy, please email me at jaysfriedman@yahoo.com and I'll reply with a copy.  (Sorry, but I don't know how to post it here.)