Oil coming from dipstick tube

**schoolboy** · 10-29-2009, 07:17 AM

I have oil coming out of my dipstick, about a .5 qt every 50 miles. I do not see any oil coming out at idle or even fast idle. After I drive down the road oil has come out of it (I put a tube to a bottle to catch the oil).
I have had this problem for awhile apparently. Initially I thought the "leak" was coming from the valve cover. The engine "leaked" out a qt about every 2-3 hundred miles. It suddenly got worse. It is not over filled (5 qts). I blow down into the dipstick tube and I can hear the air bubbling in the oil, which I think is normal. I have 2 PVC valves. One on the valve cover going to the air cleaner and one on the intake which goes to the base of the carburetor. Both seem to be ok (not stuck). Any ideas what may be causing this? 73 Buick Electra, 455 Engine seems to run ok. Engine in good mechanical condition.
Rick T

**bobc455** · 10-29-2009, 09:21 AM

Unless you have a LOT of blowby, or your PCVs are blocked, I don't know how that would happen...

-BC

**suntreemcanic** · 10-29-2009, 12:34 PM

You say you can blow air down your dip stick tube and hear air bubbles. That indicates that your dip stick tube is extending into your oil. The dip stick should extend into the oil but not the tube. I believe the oil is being pumped into the tube from presures in your crank case created from the actions of your pistons going up and down or slight blow-by from the rings. Does anyone else agree with this?

**Spud** · 10-29-2009, 02:02 PM

Should not have two PCV valves. The one in the valve cover should be a hose with a filter in the air cleaner, that is the way I always had them. ?

**WildKitty** · 10-29-2009, 03:13 PM

1. I agree the tube should not be IN the oil - try using 4.5 qts of oil and check the oil pressure

2. I agree there should only be ONE PCV valves. the hose from the second valve cover should go directly into the air cleaner.

3. is the PCV valve in the correct "up/down" position? if it is horizontal, or upside down, it will not relieve the back pressure.

my 445 uses 4.5 qts oil, dunno about the 455 yet, still tinkering with it
Butch
64 Wildcat
64 LeSabre
455 rebuild

**bobc455** · 10-30-2009, 05:09 AM

Having an extra PCV can't hurt his problem. It might not be right, but it won't cause his issue.

I run two PCVs too - one in the intake, one in a valvecover.

-BC

**Bob** · 10-30-2009, 07:55 AM

i wonder if the dual pcv is an attempt to solve the dipstick oil problem.

A while back I put together a 455 and during the bench run it ate the dipstick!

The cam had been broken in, and it was during a high rev. On investigation it had the wrong dipstick tube in it. It needed a longer one to keep the dipstick secure as it passed the crank area.

As mentioned by suntreemcanic the problem could lie right there. I am not sure he is right with the tube should not extend into the oil. I can't quite remember, but the engine was using the finer dipstick and the fix was a longer tube to stabilize it past the crank.

During this experience, it was not noticed that there was any oil coming from the dipstick tube, but I could see where if it was too short, the splashing of the crank could force small amounts of oil up it.

**schoolboy** · 10-30-2009, 10:25 AM

The two PVC valves was an attempt to get the engine crankcase ventilation system back to stock form. When I bought the vehicle the stock emissons components were missing or not hooked up. I believed that the valve cover had a PVC valve in it so I just recently put one in. The interesting thing as I was thinking about the oil problem is that after installing the 2nd PVC valve is when the engine started using more oil. I am in the process of removing the second PVC valve and test driving it.
The problem I am having is the previous owner, come to find out, was not very competent. The engine was rebuilt by him, but I am only assuming at this point that he has used the right dipstick, oil pan, and the other original parts. I have nothing to compare the engine parts with.
The fact is that when I put 5 quarts of oil in with a 1/2 size oil filter, the dipstick reads a little above full. When full and I blow down into the dipstick tube I can hear the air bubbling through the oil.
Another thought I had in seponse to someone using two PVC valves is that my filler cap is sealed with a rubber gasket. It is not a breather. I think if it was not sealed it would be ok to use a 2nd PVC valve, but with the filler cap sealed there could be a pressure build up. The crankcase needs to breath freely and with the two PVC valves, which only let air out, the block is sealed.
Thanks for the comments. I'll let you know if the oil consumption goes down once I remove the 2nd PVC valve.
Rick T

**bobc455** · 10-30-2009, 03:26 PM

If the PCV in the intake does not have some sort of splash protection underneath (i.e. a valley-pan style intake manifold), it can suck a lot of oil and burn it.

-BC