Techical Discussions => Tech- - Engine => Topic started by: Jon Brown on April 21, 2010, 01:00:21 PM

Title: Low oil pressure
Post by: Jon Brown on April 21, 2010, 01:00:21 PM
I recently took my 65' Newport Sedan for a drive up to Scottsdale, On the way there I must have been leaking a lot of oil; I stopped twice and added 2 quarts. On the way back I noticed that the oil light was flickering on; this was despite the oil level being within the correct level. The next morning I added more oil and started it up; this time oil light remained on and the engine made sounds that I think indicate that I am running it without oil, loud clicking sounds being the most prominent.  I assume this would indicate a fairly sudden loss of oil pressure. I tried running it again with a quart over with the same results and I don’t want to do any more damage to the engine.
I am certainly no mechanic. Would I be correct in the following assumptions?
1.       The oil pump has stopped working.
2.       The oil pump pickup is clogged.
My course of action is…
1.       Drop the oil pan and examine and clean the pickup.
2.       Replace the oil pump.
The obstacles appear to be a steering linkage, my exhaust pipe, and the cross member. Will I have to loosen the motor mounts and jack up the engine to get the oil pan off? Is it difficult to get to the rear main seal while down there? Is there anything I am missing in my assessment?
Title: Low oil pressure
Post by: Guests on April 21, 2010, 01:49:48 PM
It does sound like something is amiss to say the least. Is it the rear main seal that appears to be leaking or something else? I ask this because there are things on the rear of the engine behind the intake manifold that can make it look like a leaking rear main, like the oil pressure sending unit, valve cover, rear part of the intake manifold valley pan. Usually what happens with a plugging of the pickup itself it is valve stem seal umbrella pieces that get stuck in the screen (as you mentioned a possibility), but either way it can only be fixed by removing the pan. Since I assume this is a big block and not a small block, removing the pan isn't difficult at all.
Raise the car to the point you can get under it easily and block her up right under the K frame (just inside the front wheels nice and stable). Raise the hood for a couple inches extra safety clearance, pull the single bolt to each engine mount and with a board under the front bottom edge of the harmonic balancer, raise her up about four inches (a 2X4 between each motor mount and frame mount has cleared for me in the past). Drop the single bolt idler arm on the passenger side and the rest of the drag link should drop down enough to clear the pan. The starter and dust shield on the front of the tranny need to come off, so disconnect the battery. After all the bolts are out of the pan, it may require the rotation of the crank so the counter weight throws of the crank are moved so as to clear the pan, but it will come out without too much difficulty.
Now, one good thing about Mopars and the oiling system is, the lifters are the last thing to get oil and require very little in the scheme of things, so when they start rattling, less damage really occurs but it scares a person to react quicker to damage or possible damage like this. If you find little bits of hard rubber in the screen, valve stem seals will be the next order of business. Stock oil pumps are relatively inexpensive, four bolts on the ouside of the driver's side behind the power steering pump, oil filter attached, easiest to do with the engine up a few inches.
Once the pan itself is off you will be able to see exactly what is going on and best to not guess or wonder what to do before that is accomplished. Oh, and the exhaust only needs to come off if there is a connecting pipe that passes under the oil pan itself. Just use a little caution when raising the engine itself so as not to pinch the engine against the body, it will just raise the body more, so that's the limit.
Title: Low oil pressure
Post by: Herman on April 21, 2010, 02:47:23 PM
The burning oil light tells you there's "Low to No Oil Pressure", not "Low oil level".

Title: Low oil pressure
Post by: Snotty on April 21, 2010, 03:51:03 PM
Oiol pumps will go out.  I would replace that first before dropping the pan.  It's relatively easy being on the front of your motor block.
Title: Low oil pressure
Post by: Steve on April 21, 2010, 04:27:24 PM
The only thing that concerns me is what happened to the bottom end as a result.
But I agree with Snotty, put an oil pump in it first.  Much easier than what Ed described, But that would be next
If that brings up the oil pressure, it will take a while for the lifters to quiet down.  Fill the oil filter and pump with some oil before installing.
I strongly urge you get a mechanical oil gaube and T it into the oil light.  Or there is aanother plug on the opposite side from the sending unit.  Put the gauge in there.  You need to see what the oil pressure looks like now.
Title: Low oil pressure
Post by: Jon Brown on April 21, 2010, 06:17:18 PM

Wow, thanks for the responses!  I am going to do valve cover gaskets as they
appear to have been leaking heavily.  A
couple of questions…

Is the oil pump as simple as it appears? Just
unbolt and replace? I had read something about cleanliness; should I hit the
area with my pressure washer or something? Is there any reason to get a high volume oil pump as opposed to a standard one?

Where can I find more information on installing
a mechanical oil pressure gauge? Is there a specific one that is suitable? Where
is the oil pressure sender on the 383?
Thestengun2010-04-21 23:27:36
Title: Low oil pressure
Post by: Steve on April 21, 2010, 07:19:52 PM
By all means wash the area down.  If nothing else your hands will be happy.
Yes it is as easy as it looks.  I think it's 5 bolts and it will slip out.  There is an o-ring on the shaft body (You'll see what I mean) you may have to persuade the old pump out.
Lube the O-Ring on the new pump before installing it and try not to knick it when installing.  As I said above, but a little oil in the pump and some in the filter before installing.
The oil sending unit is in the back of the engine.  Its down behind the intake manifold just before the transmission bell housing.  Clean it up when you identify it to be sure it's not leaking too.  Adjacent to it on the other side of the high point in the back, about the same distance from top center, there is a small plug.  You can put your guage in there.
Doesn't matter what gauge you put in, I suggest a mechanical one.  That's the one with the tubing.  You can get one in Wal-Mart or an auto parts store.  They are all about as accurate.  Well enough to know if you have oil pressure or not.
When you have successfully installed all this, change the oil, but I strongly suggest you start running 6 quarts instead of 5.  This will ensure the pick up screen will be covered all the time.  New pumps usually send more oil up into the engine.  This will stop the light from popping on, especially on hills and abrupt stops.
When you have the pump out, and before you change the oil, you could send some compressed air (If available)rts to blow out any gunk possibly stuck in the screen.  When you drail the oil, hopefully some of that will come out, if there is any.  This is only a bandaid, sometimes it works forever, and sometimes it goes right back to being clogged.  I have only scene one clogged screen in my lifetime, and allot of that was the engine parts stuck in the screen.
Let us know what you see for oil pressure.  Start running 20/50 weight oil too.
Title: Low oil pressure
Post by: Guests on April 21, 2010, 07:54:06 PM
And to add to what Steve said, a high volume oil pump is best, but the four bolts require a little extra length of 3/8ths inch longer than the original ones. There should actually be between 6 and 8 threads extra when the bolt is put through the oil pump bolt holes to be safe (it is a little more than a quarter inch taller/wider whatever). The oil ring thing, yes, oil it up, and the last thing is the drive connection, which is a hex, and since the distributor and pump gear is in the engine, when pushing the oil pump on, twist it as you push and it will pop right on.

As far as the mechanical or electric oil pressure gage goes, if mechanical, get a pressure line to connect the gage to the engine (oh, the plug in the block is a cap screw and can be fun to remove, the oil sending unit, it you T it, should be 1/8th inch pipe, but match it up if you T it, and use teflon tape to keep it from leaking). I have seen several of these gages melt the plastic hoses and it will burn your leg, cause a fire, basically ruin your day and engine in quick order, so I went to a hydraulic hose company and had a pressure hose with the proper ends to prevent any chance of failure (70-80psi through a 1500psi line is pretty safe in my book, cost about $25-30 depending on length). These days, all electric baby. One wire to the sending unit, no leaks, no mess, mount it anywhere with long enough wire.

Good one on blowing air through the pickup location for a quick, pump works fine, check.
Title: Low oil pressure
Post by: Snotty on April 22, 2010, 08:35:06 AM
Whoa, I must disagree about putting in 6 quarts.  I will always remember my Dad's words, who was a motor mechanic, "Too much oil can be as bad as too little.  Only put it what the system was built for."   I'm sure Steve will defend what he suggested, but I would give you a thumb's down on that suggestion.

I like Steve's suggestion about using the second port on the bark of your block.  That way you can use a mechanical guage, but still have your dummy light too!  Most mechanical guage kits come with plastic hose.  While it's very easy to use, I would suggest using copper of the same diameter.  It won't leak or melt if you happen to get an engine fire.
Title: Low oil pressure
Post by: Steve on April 22, 2010, 08:52:00 AM
That maybe so.  I probably have almost as many years as Pappy does.  In the case of a big block mopar, I take the exception.  I put thousands of miles on a BB with no ileffects, not even leaking valve cover gaskets.  if something was going to leak, it was going to leak regardless.
further, that is NOT enough to cause foaming.  too much oil lays up in the engine way too long
Title: Low oil pressure
Post by: Stewart Van Petten on April 22, 2010, 01:56:28 PM
I know that some of my engines that have high volume oil pumps would fill the valve covers with oil. The pump moved so much oil I had to add a larger oil pan because it would suck the oil sump dry if you stood on the throttle for more than 5 seconds. Once I added the oil larger pan I also put shorter valve covers back on the engine. I had to pound out the valve covers to gain some room for the aftermarket rockers also. It worked well after those mods.
Title: Low oil pressure
Post by: Leaburn Patey on April 22, 2010, 02:16:40 PM
Big block oil sending units tend to leak oil on the back of the block and down around the bell housing fooling you to think it is a rear main seal.When they leak badly,they do not hold pressure and cause the oi light to flicker.
I agree that the oil pump be swapped out first.
As Steve says,add an oil pressure guage.
I would recommend swapping out the old sender as well.
Make sure you shampoo everything to confirm any oil leaks afterwards.
Title: Low oil pressure
Post by: Jon Brown on May 02, 2010, 05:06:56 PM

I finished the oil pump today; it was more difficult than I expected. I had to take the thing apart to get enough clearance to take it off. I installed a high volume oil pump in it's place. It looks like something had contaminated the shaft of the old pump; it was worn down in the center and the gears appear to have seized up. The engine again appears to be running normally; I have not installed an oil pressure gauge yet so all I can tell is that the oil light clicked off. Thanks for all the help! That saved me from dropping the pan first!
Thestengun2010-05-02 22:08:44
Title: Low oil pressure
Post by: Steve on May 02, 2010, 05:36:42 PM
In a case like that, it's better to disconnect the right motor mount and rais the motor a few inches
Title: Low oil pressure
Post by: Jon Brown on May 02, 2010, 08:04:33 PM

That is exactly what I was thinking about halfway into it. Well; it is all a learning experience. 
Title: Low oil pressure
Post by: Steve on May 03, 2010, 07:29:12 AM
I go back to what I said about adding an extra quart.  Since you have a high volume pump in there now, even more the reason.  The oil light will pop on when you make turns, go up steep hills and make abrupt stops.
Are you talking about the hex inside the pump being worn?  If so, you better get another distributor gear shaft.  Chances are the shaft spun in the pump.  That's not good.  It's just a matter of time.
The gear will be pretty easy to change.  Just put the new one in the same way the old onw cae out and retime
Title: Low oil pressure
Post by: Jon Brown on May 03, 2010, 09:24:15 AM
I am talking about the outside of the shaft that sits on the hex shaft. The hex shaft itself was fine. The gears in the pump would not turn freely because of this.
Title: Low oil pressure
Post by: Steve on May 03, 2010, 09:42:22 AM
OK  then you are good to go
Just add that extra quart as I suggested