Got stuck in traffic on my way home from work today and didn't notice the oil light until the engine started making horrible noise.

Did the only thing i could think of which was to pull onto the side strip and get on the gas hoping to get oil pressure back.
That actually worked!

Pressure went back up to ~80 under load and ~30 at idle for the rest of the drive home but i'm afraid i might have done some permanent damage.

By the time i noticed the engine noise and the pressure being at zero i was probably already running completely dry.


Now the real question is, how the heck did that happen?

I checked the oil after i got home and it's still all in there. All 16 quarts of it.
Could there be a blockage somewhere? Stuck piston? Clogged filter?

That sucks. I would cut open the oil filter and look for gold.

Yes, I agree. Cut the filter open.

What would starve the pressure pump?

Charlie

Ouch

That does suck !! Hope there's not any major damage

The oil filter canister should have a spring for oil bypass if it gets clogged so that probably isn't it. . The oil filter base assembly has a pressure bypass also. . Scavenge pump and pressure pump are always turning so oil should be returning to the oil tank always . . . the bypass valve on the side of the engine case is the over pressure bypass valve that bleeds off excess pressure right out of the oil pump . . there is another over pressure on the bottom of the sump which is the end of the oil supply galley. . . either of those could bleed off some pressure but i wouldn't expect a total loss that returns when you reved the motor. . that is puzzling. .
I would pull the sump cover off and see if the wire screen is plugged at the oil inlet tube.

If after the event you had 30 psi at an idle I wouldn't think you damaged bearings? What was the idle pressure before the event?

Same as after, about ~30 at idle and ~80 under load ...


PS: Also should mention, the noise went away once the oil pressure came back up, but it sure was a loud mechanical noise like a bad bearing or a valve hitting a piston

3.6L right?
Hydraulic lifters? Hydraulic cam guides? What do you think the noise was?

Doh, yes, could it be that the lifters ran out of oil???

This may be stupid, but was the engine about to die because of some sort of idling issue? Hence the noise and green light on. Maybe some shaking?

Nope, the engine was running ok through all of it, no shaking. Oil pressure was at dead 0 though ...

From my wondrous experience with my 3.0L I learned a lot. I couldn't get oil out of the case fast enough and the extra 3-4 quarts in the engine sump really slowed the motor a lot. I could feel the loss of power. There also was evidence near the breather on top of the case for this. It doesn't sound like this was you problem and it didn't leak out. My thoughts would be why a full tank of oil wasn't making it to/through the pump, or how am I bleeding ALL the pressure.

Hope this is helpful.

Well that explains it, i was running everything upside down!

youve had a good run on that 3.6...time for case through bollt o rings rod bearings bolts, rod bearings, rings, valve job..min,,good catch , 90% sure you have at least one or two thin rod bearing...the way of the 3.6,,If it not leaking ouut the #8 or partingline..

I vote for dissecting the Oil filter.

Car sitting a while Andy?

Sludge into an oil passage and rev cleared the sludge?

Andy if you were running everything upside down I would think the pressure on your head would have been unbearable!

What 911 did the motor come out of? If 964 based I thought those are solid lifters.

'95 993, last of the true air cooled ...

Park it, finish up the house projects.

Well, i just did some reading and apparently it's pretty common for the lifters to gunk up and collapse.

What damage have those motors seen. So what is the solution? Teardown? A couple of oil changes?

Well, that’s good news; I think. Weird. Anyway, glad it fixed itself. You don’t need a rebuild on top of a remodel.

You're just guessing until you start examining stuff. The first step is to open up the oil filter and see if there is any metal trapped in it.

--DD

But that was sort of the point of this thread, i want people to guess so i can cover more possibilities.

There are many people on here that know a lot more about /6 engines than i do ...

See post #2. It can be a lot of things but the oil filter will tell you a lot with very little effort. If you see gold, you will know to pull the engine for a rebuild. No other search needed. If the oil looks clean, then step 2.

Lifters are at the end of the supply chain, so it's likely what you heard. Sounds like tapping an unsharpened pencil on a desk.
Doesn't explain the pressure loss though. Since it recovered I'd check for sludge buildup somewhere.
Cutting the filter open is still a good idea. It will answer the bigger questions.

I agree on the lifters. I would investigate the filter. It might have been the feed hose restricted. Scary stuff!!!

No smoke out of the tailpipe means your rings are still good..

I don't know if these engines are prone to sludge, but most people change engine oil on collector / hobby cars way before it's due. I don't put that many miles on my car each year, so it doesn't get away from me. Hopefully it's an easy fix. I'd cut the filter open and take a look first because it's the easiest thing to do.

Maybe send the oil out for analysis. That’s not too expensive

Paul Sayeh had a couple collapsed lifters when he first got his 3.6 from LA Dismantlers. And we all know how that turned out...

I got one of these to cut open the oil filters on my Cessna 150 but I also use it for my car. I cut it open, slide a strong, slim magnet between the folds of the filter. I then cut out the filter paper, unfold it, take it out in the sun and check for shiny bits. If you want to borrow mine, I'll ship it up to you. http://www.aircraftspruce.com/catalog/topa...p?clickkey=4975

You can also send a sample to these guys. I know, this is airplane stuff but it's still an air cooled boxer style horizontally opposed engine. I have airplane oil checked every oil change every 25 hours. I know that sounds like over-kill but if my engine has trouble, I can't pull over and stop on the side of the road. http://www.aircraftspruce.com/catalog/eppa...lickkey=3058045

Andy my concern is that the lifters don't have much to do with oil pressure as the pressure is measured prior to that point..

Do you have braided stainless oil lines? If so I'd recommend checking all the oil lines. I've seen those things internally collapse closed, and the outside of the hose looked perfect.

OK, 'nother thought....is there a pinhole leak in your cooler such that when the thermostat kicked the oil pressure dropped out for a bit?

I think this is really good advice. Having had a similar experience there's a risk of chasing anything and everything without getting to ground truth.

Getting a lab to let you know what's in the oil is also a really good idea I think.

My fingers and toes are crossed for you that that the filter is clean.

I know the two aren't related, there is/was obviously also a blockage somewhere ...

The only braided line is the shot hose from the tank to the hardline going to the engine.

No leaks anywhere that i could find, the oil is still all in there, the dipstick shows just about middle between the high and low marks.

Since we're guessing:

A piece of paper towel got into the tank and wound up across the pickup. It finally dislodged and things are back to normal for now. The loss of pressure caused the hydraulic lifters to hammer the valve tips, caused the piston skirts to scuff the cylinder walls, and put a lot of wear on your bearings.

Of course, if you drained the oil and checked the filter, you could get some idea of what is actually going on, but until then we can keep speculating and telling you it's all doom and gloom....

--DD

Funny you should say that, i am missing a shop towel that was tucked away in the engine bay ...

When did you change the oil last Sir-Andy? Sorry that happened...whatever the cause. I have an engine shipping Monday from an oil related failure = feel your pain!

Cracker

Right before McMark moved his shop. The car hasn't been driven much since though.

Yeah, it only won the WCR AX. Maybe the flogging followed by non use has stacked up a toll?

I worry about this with mine. It's been sitting lately. They need to be driven regularly and filtered as much.

Question: Can sludge be flushed with chemical additives and such? I know there are a ton of products on the shelves that make claims. But, they must sacrifice good oiling in the process if they are dissolving that crap. Sigh. I hope this doesn't mean a tear down.

There should be like a dialysis machine that you could hook up to and flush every oil passage clean while offline. Heh.

Any updates?

I've been avoiding the car, i haven't touched it since ...

Sorry man. I totally get it.