Oil leaks

[p38js]

I had a bad oil leak coming from my drivers side valve cover so removed valve cover and resealed with new cork gasket from NAPA. Not a good idea still leaked removed and sealed with ultra gray rtv still leaked. Removed and sealed with right stuff still leaked. The leak appears to be coming from the same spot each time and that would be from the 3rd cylinder back on the drivers side. Put a new valve cover on and sealed with the ultra gray rtv. Leak still coming from the same spot. Has anybody ever seen the oil dip stick tube leak from the top and blow oil out? My next step is to place a bag over the dip stick to see if in fact this is were the leak is coming from.

[Hubert]

Crankcase should be under slight vacuum. Take off the oil fill cap and see if it draws or blows. You can take a piece of saran wrap and loosly put it over the fill opening (with extra loosely piled at opening) and rubber band it in place. Be very careful its a big piece and secure it good could easily suck it in. The Fan will blow it around too. Might want to crank up and hold it after too. Again big piece hold well. It should pull the wrap inward after just a bit.

Might have a bad tuna can (brain loss the crank case decompression regulator thingy thats incouraging leak) but would probably leak other places too.

The dip stick has an oring where its inserted into the pan if the oil is on bottom only and not from top.

[p38js]

I put a new can on about 500 miles ago.

[p38js]

today I got a chance to work on my oil leak again, Installed a new "O" ring on the dip stick tube and placed a bag over the dip stick itself drove truck for about 25 miles bottom of dip stick dry valve cover dry back was filled with oil. Any suggestion on the next step

[94Suburban]

was looking for help on diagnosing mine when I came across your post apparently with the same problem. about 5 days ago i noticed excessive oil coming from the same area , #3 valve cover, which is also by the dipstick. I pulled a load of wood home 2 days ago and had to put a whole gallon in to make it home.

I believe its called 'blow by' one or more cylinders pressurizing the crank case and pushing oil out any easy access, like the dipstick tube.

there is a simple test you can do by sliding a piece of 3/8 clear tubing over the dipstick tube (dipstick removed) running that tube into a bucket of water ( on the ground or any lower place as not to allow water into the crankcase). with the throttle about 2k the water should draw up the tube 1-2". You should NOT see the water being pushed into the bucket and/ or blowing bubbles, which is what I saw. I replaced my CDR valve (tuna can as Hubert stated) today. Same bubbles. I will have to investigate further tomorrow. Perhaps a compression test.

Seems to idle and drive as good as it has other than leaking a quart an hour , out, under and up the barn doors.

hope this helps

[p38js]

I'm going to do that test today, Since I put a new CDR can on about 500 miles ago after some reading it sounds like the screen in the valve cover could be blocked. That fix would be easy for my run of luck LOL

[p38js]

performed the water test here are the results
1st run: had good vacuum 1to2 inches of water and bubbles devolped at 2500 rpm
2cd run: removed the screens from the passenger side valve cover same
results as the fisrt run.
3rd run: removed cdr valve no vacuum or bubbles all the way to red line.

Is this telling me I have a bad cdr valve or craked piston broken ring??:(:(:(

[94Suburban]

Am i correct to understand that she was pulling water up the tube (1-2" ) then as you were gradually still inc throttle to 2500, bubbles developed then?

And if that was the case when did the water start to recede back down the tube, to eventually start blowing. How much oil are you blowing out?

before Church this morning I found my CDR not to be sealing correctly at the point that it enteres the hard line to the turo inlet. I corrected this and it passed this tube test. It was actually sucking the water up a good 12-16" and no bubbles. cleaned it up and drove to Church and back to test today and so far no more oil blowing.

Perhaps someone more versed in this problem will offer some insight, but it sounds like a compression test is the next step for you.

[p38js]

It was pulling water up 1-2 inches and at 2500rpm it would push all the water out of the tube and start to bubble.

It is using about 1-2 qts in about 50 miles

I guess that I will have to get the proper tools to perform a compression test.

[94Suburban]

i will be doing a couple of comparison tube tests tomorrow since I have two Suburbans. It seems I'm pulling alot more vacuum than I should, even though i'm not leaking any oil presently.

i read somewhere on the diesel page of someone making an adapter from an old glow plug to do a compression test. I know when I did my head gasket this past dec I had a hard time finding a tester with the proper adapter, without ordering it. I got some fittings at Lowes today so I can convert my old gas comp tester. I have a higher reading gage somewhere. Its about time I find out how the condition of my rings also

[p38js]

I still do not understand why when I run the engine without the CDR valve I get no blowby or vacuum? I have taken the CDR off and blew thru in both directions and it is open. I have not checked to see if the lines to the air intake are blocked.

[94Suburban]

changed the oil in the '94 since I was getting some excessive blow by the last week. Went to check the air filter and it was pushed or sucked toward the engine about and 1" or so. Enough to distort and warrant a new filter. It did not appear to be all that dirty. Another interesting note since I change the air filter at each oil change.

I know the CDR valve will almost install backward. Back when I did the head gasket. I reinstalled it flat slide port into the cover(wrong way). It didn't seem quite right, good thing I had a Chinese blue print sitting in the drive. I'm not sure of the condition this would cause.

its my understanding that you should only see the signs of blow by when the piston rings or cylinder are in bad enough shape that it will overcome the vacuum allowed by the CDR valve.

even with all the oil I had been blowing, at idle I could not see any evidence of blow by. Only when I was running under load was it leaking.

[p38js]

Problem solved I hate to admit to it but I induced the problem with my so called cold air box created by me. Removed this and went back to the stock version and all is well again.