[daveoxide]

I have always been having this problem, but am just now addressing it since I am getting all of my minor leaks fixed.

Almost every time I get aggressive with the car, romping on the gas, cornering hard and such, I get a light oil spatter around the top of my dipstick tube. The dip stick isn't coming out of the tube, but there is a light oil spray right around there on the heater hose, and then back onto the manifold and spark plug wires on the passenger side. I also noticed a new leak today down at the base of the dip stick tube. It seems like it is leaking from where the tube goes into the front timing cover. It was leaking from there with the engine off, I was watching it drip. It only dripped about 10 drops or so, then it stopped, took it 2 minutes or so after I shut it down to stop dripping.

So what is going on? The spray out of the top of the tube, is something weird causing this? The engine is running well, the pcv is new, and most everything else seems to be in good working order.

One thing I do notice too is that my oil gets dirty quickly. The motor was rebuilt about 30,000 miles ago, and every time after an oil change, at about 1000-1500 miles, it is black again. I have tried flushing it, like change the oil, run it for 500 miles, and change it again, but it still gets dirty quickly.

So, any ideas for solutions to my problems (regarding the mustang, I am a whole different story...)?

 

[woodywrkng]

Does your PCV hook into a nice big fitting, such as the one on a stock carb spacer? For awhile I had a PCV meant for a Taurus I think, since it had a nice 90 degree bend in it, but don't think it flowed as much as it shoulda. After cleaning up my PCV setup and converting it to a closed system (intake air from inside air cleaner) I noticed the oil stayed cleaner longer. However, I've heard in years past that oil is supposed to turn black, since it's trapping crud, but I'd rather it stayed clean.

 

[Art]

Most likely, your rings are not sealing, causing more crankcase pressure than the vent and PCV valve can release. Oil that gets dirty quickly is a result of combustion gasses and carbon going into the crankcase.

 

[66coupe289]

The seal at the bottom of the dipstick tube should be an easy fix by pulling it out cleaning it up and buttering the bottom with some RTV silicone.

As far as oil coming out of the dipstick tube, it sounds like your block is becoming pressurized beyond what the PVC can handle. Do you have a breather cap on the other valve cover? If not, try installing one.

I am wondering if you may have some excessive blow by going on which is causing the pressure and contaminating your oil at the same time.

This sounds like something that someone here will know exactly what is going on.

Good Luck.

 

[bosscars]

The condition that you describe usually indicates excessive crankcase pressure caused by worn compression/oil rings. A good compression/leak down test should confirm this. You state that the engine was rebuilt 30k miles ago. Do you know if the block was bored to the next oversize with the correct oversize pistons and rings? Typically, a "rebuilder" will just deglaze the cylinder surfaces and reinstall the old pistons with new rings which is usually good for 10 to 15k before the blowby situation starts up again. Are you getting any smoke from the valve covers with the PCV unhooked?? I would go back and research the "rebuild" and see what exactly was done during the rebuild. If the block was not overbored on a high mileage block, chances are good the rings are no longer sealing meaning the engine needs to be reopened and done properly....

randy

 

[daveoxide]

I did the rebuild myself, so I know what was done (I hope, assuming I don't have dual personalities /forums/images/icons/smile.gif). Anyway, the block was bored .027" over, then honed the last .003" and new pistons and rings were installed.

 

[daveoxide]

I don't have a breather, and I don't have the means of putting one on either. I have those stock aluminum valve covers, and they only have the filler tube and pcv connection on one, and on the other it is closed.

 

[daveoxide]

I am going to go do a compression check right now, and I will post the results soon.

 

[Axnjxn]

What kind of compression are you running? Higher compression ratios will force more blowby into the crankcase.

Also, are your valve cover gaskets leaking/weeping? What type of cap do you have on that filler tube? I totally agree with the others that it sounds like excessive crankcase pressure, the question is why.

 

[daveoxide]

The valve cover gaskets are new rubber ones, and they are not leaking (those darn cork ones were awful). The oil filler cap is one of those ones like on a taurus or tbird or something newer like that. It is black plastic with yellow "Oil Fill" writing on it.

 

[Axnjxn]

So, what I'm hearing, you have nowhere for that extra crank pressure to vent. Those oil caps will completely seal off the filler neck. So the only place for crank pressure to vent is the PCV. But this is limited to a certain volume.

What will eventually happen, your gaskets will begin to weep as the pressure forces crankcase gases out. That's why the cork ones leaked. BTW, I hate cork gaskets too.

The only other open port on the engine is the dipstick tube, which is where the oil is getting sprayed out. How you are managing to NOT push the stick out of the tube, I have no idea.

Bottom line, you need to provide another place for the crankcase pressure to vent, prefferably on that other valve cover. You know what that means...get the Dewalt out. The three simplest solutions I see, are 1) a KNN type breather element on that other valve cover, keeping your current oil cap 2) replacing your Taurus style cap with a breather cap (not the same as a KNN element, the KNN ones aren't meant to come on and off that much), 3) install another pcv valve on the other valve cover.

Why you are getting that much crank pressure, I don't know. I suspect that either your rings are worn, like the others suggested, or that you have high compression pistons and low CC heads, in which case you need to deal with the extra pressure rather than try to prevent it. Oil consumption and a leak down/compression test will ultimately tell you what the case is.

 

[70Coupe]

Just to throw out another idea, I once had a similar situation that turned out to be a hairline crack in the underside of an intake manifold. Showed up after I had it baked.