Flushing crankcase

[RECHRGD]

A couple of years ago I replaced the rear main seal on the 440.  When replacing the pan and windage tray I may have been a little generous in my application of the "Rite Stuff" sealant.  I've experienced oil pressure drops at higher rpms and short bursts.  Not always, but sometimes.  Tried a lot of things, thought it was fixed, but it still raises its ugly head from time to time.  I've changed oil and filters a couple of times also.  Anyway, today I drained the oil and thought that I would check the bottom of the pan with a bore scope to see if any sealant residue was on the bottom of the pan.  The pickup is too close to the opening to allow for any kind of useful view.  I really don't want to pull the pan if I don't have to.  Is there anything that I can pour in there to try flush out any possible contaminates?

[cdr]

the only way to get the silicon off the pick up is to drop the pan. 

[BSB67]

I really doubt the sealant has anything to do with your oil pressure function.

What kind of gauge, and have you verified the condition with a second, mechanical gauge?

[RECHRGD]

the only way to get the silicon off the pick up is to drop the pan.  

I was afraid you'd say that.  But if it's stuck to the pick up I would have a constant low pressure condition.

I really doubt the sealant has anything to do with your oil pressure function.

What kind of gauge, and have you verified the condition with a second, mechanical gauge?

I did check it with a mechanical gauge.  But only at my shop, not on the road where this can happen....

[c00nhunterjoe]

How big is your pan? Define "high rpm". Are you possibly sucking the stock pan dry?

[RECHRGD]

How big is your pan? Define "high rpm". Are you possibly sucking the stock pan dry?

It's a six quart hemi pan.  Never had any problems like this before.  It usually happens after hard acceleration through a couple of gears, let's say 5,800 rpm.  More often than not, there's no problem......

[c00nhunterjoe]

Do you have a windage tray? Can you duplicate the concern in park? If this happens after a 3 gear pull, then hold it at 5k for the duration of whatever your 3 gear pull takes and look for the drop. I would still lean towards either aeration or an exposed pickup at this point.

[RECHRGD]

I forgot to mention that this has happened after long periods at highway speed, say 3,500 rpm, but rarely.  The car does have a windage tray.  I've tried different pumps, different gauges, and different weight oil.  I never sucked the five quart pan dry before I upgraded, so doubt that that's a factor.  Being that this may or may not happen under identical circumstances just leads me back to silicone residue resting at the bottom of the tank that is too large to pass through the pickup strainer.  It does seem though, that with every oil change the frequency of this occurring has lessened.  That said, I may just put on a new filter and fill her up with new oil and go cruising.  You know what they say; doing the same thing over and over and expecting different results is a sure sign of insanity.

[c00nhunterjoe]

Sustaiined high rpm oil pressure loss still sounds like starvation or aeration to me.

[RECHRGD]

Sustaiined high rpm oil pressure loss still sounds like starvation or aeration to me.

I changed the oil and filter.  20/50 Valvoline RacIng and K&N 3001 filter.  At idle it stays at 45lbs..  at a sustained 3,500rpm (no load) it stays at 60lbs..  I'll take it to the storage area in a few days and give it a test drive then.  Wish me luck......

[BSB67]

My money, arbitrary oil fluctuation with an electric gauge is an electrical issue.   Would not do anything until you install a good mechanical gauge and confirm the problem.

Also, if the pressure drop is confirmed to be real, how much does it drop?  It might not be an issue worth worrying about.

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little time.

[cdr]

My money, arbitrary oil fluctuation with an electric gauge is an electrical issue.   Would not do anything until you install a good mechanical gauge and confirm the problem.

Also, if the pressure drop is confirmed to be real, how much does it drop?  It might not be an issue worth worrying about.

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little time.

I agree ^^^^  & if that all checks good ,I would then check the oil pump shaft bushing for wear just to rule that out. I had one go bad & cause pump damage & oil pressure fluctuation .

[RECHRGD]

My money, arbitrary oil fluctuation with an electric gauge is an electrical issue.   Would not do anything until you install a good mechanical gauge and confirm the problem.

Also, if the pressure drop is confirmed to be real, how much does it drop?  It might not be an issue worth worrying about.

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little

Thanks for your input. I have tried different sending units and, as said, verified their accuracy via a mechanical gauge, albeit not in a driving situation.  The first time I remember this happening was in route to a car show approximately 100 miles from here.  The speed limit was 75mph and I had been "playing" with a friends new Challenger along the way.  So there were some short bursts into 100 plus range.  As we reached the off ramp leading to the show I noticed the low oil pressure (I believe a little under 20 pounds) along with an increase of valve train noise.  I pulled over and let it idle for a bit and the pressure returned, but still about ten pounds less than normal.  After a few hours, I left the show early and drove back at normal highway speed.  The pressure was OK, but never returned to its normal 60 or so pounds.  It stayed around 40+ for the whole trip.  That's when I started trying different pumps, sending units and so on.  As of now it seems happy with the Melling high volume pump.  Everything is good, except for the occasional pressure drop (not as low as the first occurrence) after a higher rpm romp.  That's what has lead me to the conclusion that there must be something in the bottom of the pan that gets sucked up onto the pickup screen at higher rpms.  I have probably changed the oil and filter three times since this began (other than now) and believe that the occurrences have lessened each time.  Although that may just be wishful thinking.  I know I should just pull the pan as Charlie suggested, but I'm old and getting lazier by the year.....

[RECHRGD]

My money, arbitrary oil fluctuation with an electric gauge is an electrical issue.   Would not do anything until you install a good mechanical gauge and confirm the problem.

Also, if the pressure drop is confirmed to be real, how much does it drop?  It might not be an issue worth worrying about.

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little time.

I agree ^^^^  & if that all checks good ,I would then check the oil pump shaft bushing for wear just to rule that out. I had one go bad & cause pump damage & oil pressure fluctuation .

Thanks Charlie!  When I was changing out pumps everything appeared fine.  Although I may not have known what to be lookin for.....

[RECHRGD]

OK, after a little glitch with the ignition system, the car is up and running great.  I took it to a pretty secluded hwy around here and played with it a little.  I took it up to 100mph and the pressure raised from 50lbs. To 70lbs.  It dropped back down 55-60lbs. At cruising speed.  I then went several miles at around 70mph and the pressure remained steady.  Finally I kicked in the GV overdrive and took it up to around 125mph and held it there for around ten seconds.  The pressure peaked at 70lbs. again.  It seems all is well.  I hope it stays that way!

[BSB67]

My money, arbitrary oil fluctuation with an electric gauge is an electrical issue.   Would not do anything until you install a good mechanical gauge and confirm the problem.

Also, if the pressure drop is confirmed to be real, how much does it drop?  It might not be an issue worth worrying about.

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little

I have tried different sending units and, as said, verified their accuracy via a mechanical gauge, albeit not in a driving situation.  

Of course there are considerably more "electrical" aspects than just simply the sending unit.

Honestly, if you've been chasing this thing for some time, and it is bothering you, just put a mechanical gauge in it and be done with that part. You have not fixed or found anything so far, so it will come back, and installing a mech gauge is really the only logical next step, and when it does come back, you will have definitively answered if it is the gauge.

[RECHRGD]

 

My money, arbitrary oil fluctuation with an electric gauge is an electrical issue.   Would not do anything until you install a good mechanical gauge and confirm the problem.

Also, if the pressure drop is confirmed to be real, how much does it drop?  It might not be an issue worth worrying about.

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little

I have tried different sending units and, as said, verified their accuracy via a mechanical gauge, albeit not in a driving situation. 

Of course there are considerably more "electrical" aspects than just simply the sending unit.

Honestly, if you've been chasing this thing for some time, and it is bothering you, just put a mechanical gauge in it and be done with that part. You have not fixed or found anything so far, so it will come back, and installing a mech gauge is really the only logical next step, and when it does come back, you will have definitively answered if it is the gauge.

I get what you're saying, but the thought of running a pressurized oil line to the interior of the car just spooks the hell out of me....

[BSB67]

It shouldn't

[c00nhunterjoe]

You are worried about an oil line inside the car more then a 10,000+ engine that may have oil pressure problems? If the plastic or copper line bothers you, run a braided line.

[RECHRGD]

You are worried about an oil line inside the car more then a 10,000+ engine that may have oil pressure problems? If the plastic or copper line bothers you, run a braided line.

I realize that a mechanical gauge is the only 100% full proof way of knowing what the oil pressure is.  As stated earlier, I used one to verify that my electric sending unit was accurate.  Also, as stated earlier, when the gauge read low initially, the valve train noise increased significantly.  As the pressure rose at idle, the valve train noise went away.  That indicates, to me anyway, that the electric sending unit, gauge and electronic IVR were functioning as intended.  If the gauge reads low and the engine starts making noise, the pressure is low.  If I watch the gauge go up and the engine noise subsides, the pressure is increasing.  In both cases the gauge was reading properly.  Misguided as I may be, I have good reason to believe that I'm getting reasonably accurate readings.  If I didn't, I would certainly follow the well intended advice and plumb in a mechanical gauge to the interior.

[BSB67]

 I've experienced oil pressure drops at higher rpms.........

...... If the gauge reads low and the engine starts making noise, the pressure is low.

So, you are driving along at 3000 rpm, the oil pressure is fine, then it drops suddenly for no apparent reason and you hear the valve train banging away while you're driving along at 3000 rpm?

[RECHRGD]

 I've experienced oil pressure drops at higher rpms.........

...... If the gauge reads low and the engine starts making noise, the pressure is low.

So, you are driving along at 3000 rpm, the oil pressure is fine, then it drops suddenly for no apparent reason and you hear the valve train banging away while you're driving along at 3000 rpm?

No, I pulled over at the bottom of the off ramp after noticing the pressure had dropped.  Then the noise was apparent.  After letting it idle for a few minutes it gained some pressure and the noise subsided.

[BSB67]

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little time.

[RECHRGD]

If you run the car hard for an extended period of time in hot weather you will probably see a 10 to 15 psi pressure loss when you slow down and especially at idle.  It will usually come back after a little time.

I read that and agree.  However, if you've read my different scenarios that are precursors to the pressure dropping, you know that extended highway driving is only one of them.  To be clear; when the pressure dropped on the highway to the point of hearing the valve train, I had just been playing with a new challenger next to me and had been at 100+ speeds.  Yes, the pressure dropped while at highway speed.  I did not hear the engine noise most likely because of the wind, road noise and my old man hearing loss.  The noise was easily heard when I pulled over.  The pressure had fallen from 60+ to around 20, certainly more than 10 or 15lbs..  I've had the car for over twenty years and the current engine configuration for over ten.  I know what is normal and what is not.  Anyway, this thread just seems to be going in circles at this point.  I'll let you know if something new arises......

[c00nhunterjoe]

Not trying to sound like an ass, but i dont know how else to put it- nothing new is happening because you havnt done anything. Im not trying to sound rude, but yku have said you had good oil pressure, you lost it, engine was knocking, oil pressure came up but never back to where it was. Ok, that tells me you did damage. But you refuse to pull the pan and check the screen that you feel is plugged up or pull a main and rod cap to look for damage, so what do you want us to tell you? Again, not trying to be a dick, but i dont know how else to put it or what to tell you to do.