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I sure could sure use some advice.

I have the 400 ci engine in my ’68 GTO and I’m having an issue with oil blowing out through the dipstick. The car was a well started basket case project when I acquired it 20+ years ago. The engine was already installed so I don’t know much about it except that it runs strong. Since then I’ve put a lot of miles on it so I kinda thought my problem was blow by from worn rings. I just pulled the plugs and they were all cocoa brown with no sign of oil. I did a compression check and I’ve got 175-180 all around.

It really only does it when I get on it hard but it has covered the passenger side of the engine compartment with oil. I first noticed the problem a little while after I took it to a local lube and tune for an oil change. Thinking they had perhaps over filled it I pulled the dipstick and found the end of it broken off. I changed the oil and installed a WIX oil filter and replacement diptick. The new dipstick read full with 6 quarts in. This morning when I started working on it I checked the oil and found the end of the new dipstick broken off.

I run a pcv valve in each valve cover rather than a vent on one side and pcv on the other but it’s always been like that and both pcv valves are working. Four or five years ago I installed a Weiand manifold and FI Tech fuel injection. When I did I had to install a smooth valley pan and it has no PCV…but it’s been fine since then.

Oil pressure runs between 20 psi – 80 psi depending on conditions but that’s normal for this engine too.

I’m racking my brain trying think what’s changed.

Any thoughts?
 

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Unknown as it could be several things, but oil blowing out the dipstick or blowing off the dipstick indicates excessive crankcase pressure - which can blow out valve cover gasket and rear main seals. You also need a breather to let airflow into the engine. Having 2 PCV valves, one on each cover, is only creating a vacuum. How does airflow enter your engine? Ditch one of the PCV valves and add a breather. This will let crankcase pressure out on higher RPM runs. Sometimes you actually need 2 depending on how high you spin the engine.

The Pontiac engine holds 5 qts in the pan and 1 in the filter for 6 quarts total. If you are putting 6 quarts in the pan and the 1 in the filter, you are over filling. This can be part of your problem - unless you have a custom pan made for more oil.

Seems to be a recent rash of broken off dipsticks. Read this recent post:

 

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You may have more than one problem. I've had a problem in the past with the valve cover bolts loosening up. Oil starts seeping out of the back of the gasket and ends up on the header. When it burns off of the header it looks like it is blowing oil out of the exhaust pipe. Try tightening up your valve cover bolts.
 

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hey guys
how about no lower dip stick elbow or the incorrect one
Im thinkin NO elbow along with incorrect pcv = crank case pressure pushes
dipstick up from the tube and the sealing is gone.. and w rpm oil creeps up the stick and tube and out ...
time for a bore scope ... down the tube and in thru the drain
peek aboo maybe
 

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hey guys
how about no lower dip stick elbow or the incorrect one
Im thinkin NO elbow along with incorrect pcv = crank case pressure pushes
dipstick up from the tube and the sealing is gone.. and w rpm oil creeps up the stick and tube and out ...
time for a bore scope ... down the tube and in thru the drain
peek aboo maybe
Is that a colonoscopy procedure for a Pontiac engine perhaps? Seems to ring a bell with me.
 

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I don't believe the bore scope is going to do you any good. You can't fix a problem with the lower dip stick tube without removing the pan. So no matter what you see with the bore scope, you can't do anything about it. I think that is a separate issue from the dip stick blowing out and leaking oil.
 

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PCV problem, you have 2, but they are likely both inadequate and you have no fresh air inlet for the crankcase.

as PJ said put a breather , a good breather on one valve cover, I use a K&N breather, has good air flow and keeps air clean. Those PCV’s may be clogged and not pulling much vac.

nice chrome & polished vale breather caps only have small holes around the bottom of the cap, not so g real. Best recommendation would be to get an ME Wagner dual flow PCV valve. On one valve cover. You dial it in with a vacumn gauge to your engine, for idle and cruise circuits.

It will pull a 1 to 3 hg vac on your crankcase 99% of the time...check out their website. I have no connection just use it and recommend it to my hot rod friends and they all rave about it.

Now listen to Mr. Taylor and bulk Judge as well you could ave a leaky valve cover gasket or something going on down in the pan. But your PCV system is definitively not right.
You will get it good luck!
 

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somethins bustin 2 of his dipsticks... sure sounds like the dipsticks end up in the wrong position...
with the second one reading correct after oil change is wierd if the elbow isnt installed tho...
I would think for 35.00 you could peek down the dipsticktube ...to make sure elbow was there
my buddy just bought one and it seemed small enuf to go down the tube we looked in the cylinders of his
56 lincoln to check out the rust and looked thru the drain pug of his 68 400 to see the timing gear plastic
all over the bottom of the pan ,,, Im sure if we looked around we could have seen the widage tray and dipstick and elbow ...
Im gettin one ,,,, it has an adjustable led ... takes pictures ,, and movies
the stuff thats available is mind boggling .... plugs right into his cellphone 3' 6' 10'cables ... zooms in too
seemed like a time saver idea to me ........ so many uses ,,,,

it seems to be 2 different issues tho ,,, pcv vacuum having no intake breather and chopped dipsticks
 

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Agree with all of you on this,but judge has a point about the scope saves on wrenching chores and it works good tracing wires under the dash
 

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Discussion Starter #10
Thanks for the suggestions. For lack of a better idea I think I’ll find a breather that will fit the grommet in the valve cover and ditch one of the PCV valves. I know it’s not normal to have two but that’s how it was when I got the car and it’s worked fine for over 20 years and 70K plus miles. Something changed recently and I’d sure like to know what.

I first thought I had a valve cover leak but because the oil was all over the place I wasn’t sure where it was coming from. I added die and used a UV light to see. It’s all from the dipstick.

The broken dipstick issue may be an unrelated coincidence. it’s an AC car so the dipstick is longer and a little tricky to get in and out. When the first one broke I thought either the lube and tune place was too rough or maybe the 52 year old dipstick was just past its life expectancy. I really don’t want to pull the pan to check on the lower tube. BTW, you can pull the pan with the engine in the car. I installed a one piece pan gasket years ago by disconnecting the mounts and lifting the engine a bit. A PITA but doable. I need to think on it but I may do as suggested and use the short stick while the engine is running and the long one to check the oil when the engine is not running.

The endoscope a good idea and just a nifty little gadget.

Again, thanks to all for taking the time to respond. All good suggestions but none explain what changed and that’s what worries me. I just keep thinking I’m missing something.
 

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2 PCV’s are ok if you have a breather, the crankcase needs fresh air.....and it needs that blowby crud and condensation removed....fresh air in and bad crud out....
 

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Just wanted to give an update. I had a suitable valve cover vent laying around so I installed it on one side and my problem went away. I may look into the tunable PCV later but for now I'm a happy camper. I should have known better but again the two PCV set up has been there for years and worked fine. I was so focused on the broken dipstick and finding out what changed that I missed the obvious and easy solution.

Thanks for giving me a new perspective.

Still wondering about the dipstick. I plan to pick up an endoscope. I looked at them a little bit yesterday but didn't buy one. The smallest camera I saw was 8.5mm and I want to see if I can find one that's smaller.
 

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We’re they both hooked to manifold vac?..one wasn’t run up to the air cleaner was it?...

PCV are Mostly closed with Vac at idle....once vac goes away,...like when throttle opens, the spring in PCV opens the valve and lets blowby crankcase fumes enter the intake...

there are different configurations but they all depend on vacumn.

If you had one PCV hooked to direct manifold vac, and another hooked to the air cleaner,
The one with the direct manifold vac would be closed at idle correctly...

but the one hooked to the air cleaner would see no vac from the manifold at idle and therefore be open by spring pressure essentially being a fresh air intake....

You asked how could it have worked, well this is one way it would have, not very good, but still had fresh air in and crud out.
 

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Discussion Starter #14
We’re they both hooked to manifold vac?..one wasn’t run up to the air cleaner was it?...

PCV are Mostly closed with Vac at idle....once vac goes away,...like when throttle opens, the spring in PCV opens the valve and lets blowby crankcase fumes enter the intake...

there are different configurations but they all depend on vacumn.

If you had one PCV hooked to direct manifold vac, and another hooked to the air cleaner,
The one with the direct manifold vac would be closed at idle correctly...

but the one hooked to the air cleaner would see no vac from the manifold at idle and therefore be open by spring pressure essentially being a fresh air intake....

You asked how could it have worked, well this is one way it would have, not very good, but still had fresh air in and crud out.
I don't recall how they were connected before I installed the fuel injection but from then until the other day they were connected to a Tee so they saw the same amount of vacuum from the manifold. How it worked and why it stopped working suddenly will remain a mystery. I've been asking myself why I left it that way even though I knew better and I suppose it was just because it was working so I didn't see the need to "fix" it. Lesson learned...the hard way of course because that's the way I roll. 🙂
 

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Don’t be so hard on yourself!.....at least the way you roll..is to keep rolling!

you have the right attitude with these old cars, you have to deal with the things that come up.....that is part of the enjoyment.....!

every mechanical thing needs service and or will eventually malfunction, from wear, age abuse or just for no specific reason!

check out that ME Wagner website they have a ton of solid info there and for the price of that valve you can really help your engine run better, stronger, cleaner, more efficient...and you can do the work yourself in short order, a great return on investment!
 

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aside of the pcv issue ....
tonite I put together a 68 ac dipstick and windage tray assembly
kindof ... for a visual ,,, maybe you already get the idea/picture ..
the 68 ac dipsticks were very tender to start with ,,and MOODY ,
they had perforated dipsticks that like to often bend at the hole,,,
you can see all the snaking the dip stick needs to do ,,, in 69 the upper tube goes to
the valve cover bolt ,,, not the back of the ac compressor like 67 68,,, 70 it moved again
but the 69 n up had a smoother curve for the stick....
now it looks very possible "IF" the lower elbow thru the windage tray is missing,,,,
that the dip stick COULD hit the hole and read fairly correct,,, also if it missed and
deflects it could get wacked by the crank ....
IF your parts are all 68 still ,,,, oil pan windage tray etc they should look like this set up

Scott
its worth a peek thru the drain plug next oil change it will be easy tooo see ...

if a 70 n up pan was used ,,,, well ... we will save that for another day
 

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Discussion Starter #17
aside of the pcv issue ....
tonite I put together a 68 ac dipstick and windage tray assembly
kindof ... for a visual ,,, maybe you already get the idea/picture ..
the 68 ac dipsticks were very tender to start with ,,and MOODY ,
they had perforated dipsticks that like to often bend at the hole,,,
you can see all the snaking the dip stick needs to do ,,, in 69 the upper tube goes to
the valve cover bolt ,,, not the back of the ac compressor like 67 68,,, 70 it moved again
but the 69 n up had a smoother curve for the stick....
now it looks very possible "IF" the lower elbow thru the windage tray is missing,,,,
that the dip stick COULD hit the hole and read fairly correct,,, also if it missed and
deflects it could get wacked by the crank ....
IF your parts are all 68 still ,,,, oil pan windage tray etc they should look like this set up

Scott
its worth a peek thru the drain plug next oil change it will be easy tooo see ...

if a 70 n up pan was used ,,,, well ... we will save that for another day
Thanks for the pictures. Very enlightening. I have an AC car but I removed the AC long ago and haven't gotten around to reinstalling it. I was considering installing the shorter non AC dipstick until I do. I see from your pictures that if that lower tube is missing the shorter stick isn't going to help much. I ordered an endscope; when it arrives I'll check it out.
 

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I sure could sure use some advice.

I have the 400 ci engine in my ’68 GTO and I’m having an issue with oil blowing out through the dipstick. The car was a well started basket case project when I acquired it 20+ years ago. The engine was already installed so I don’t know much about it except that it runs strong. Since then I’ve put a lot of miles on it so I kinda thought my problem was blow by from worn rings. I just pulled the plugs and they were all cocoa brown with no sign of oil. I did a compression check and I’ve got 175-180 all around.

It really only does it when I get on it hard but it has covered the passenger side of the engine compartment with oil. I first noticed the problem a little while after I took it to a local lube and tune for an oil change. Thinking they had perhaps over filled it I pulled the dipstick and found the end of it broken off. I changed the oil and installed a WIX oil filter and replacement diptick. The new dipstick read full with 6 quarts in. This morning when I started working on it I checked the oil and found the end of the new dipstick broken off.

I run a pcv valve in each valve cover rather than a vent on one side and pcv on the other but it’s always been like that and both pcv valves are working. Four or five years ago I installed a Weiand manifold and FI Tech fuel injection. When I did I had to install a smooth valley pan and it has no PCV…but it’s been fine since then.

Oil pressure runs between 20 psi – 80 psi depending on conditions but that’s normal for this engine too.

I’m racking my brain trying think what’s changed.

Any thoughts?
 

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I sure could sure use some advice.

I have the 400 ci engine in my ’68 GTO and I’m having an issue with oil blowing out through the dipstick. The car was a well started basket case project when I acquired it 20+ years ago. The engine was already installed so I don’t know much about it except that it runs strong. Since then I’ve put a lot of miles on it so I kinda thought my problem was blow by from worn rings. I just pulled the plugs and they were all cocoa brown with no sign of oil. I did a compression check and I’ve got 175-180 all around.

It really only does it when I get on it hard but it has covered the passenger side of the engine compartment with oil. I first noticed the problem a little while after I took it to a local lube and tune for an oil change. Thinking they had perhaps over filled it I pulled the dipstick and found the end of it broken off. I changed the oil and installed a WIX oil filter and replacement diptick. The new dipstick read full with 6 quarts in. This morning when I started working on it I checked the oil and found the end of the new dipstick broken off.

I run a pcv valve in each valve cover rather than a vent on one side and pcv on the other but it’s always been like that and both pcv valves are working. Four or five years ago I installed a Weiand manifold and FI Tech fuel injection. When I did I had to install a smooth valley pan and it has no PCV…but it’s been fine since then.

Oil pressure runs between 20 psi – 80 psi depending on conditions but that’s normal for this engine too.

I’m racking my brain trying think what’s changed.

Any thoughts?
Take a look at the valley pan grommet which the PCV valve fits into. If it is worn or not correctly pushed into the grommet you can get oil blow by. I know because I had that problem . Replace the
grommet and all is well. OPGI has replacements. Also Edelbrock has great looking and performing valve cover vents.
 
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