engine drinking and blowing oil!!

Budfreak · #1 03-22-2005, 11:00 PM

my 92 ls-l has been filling it's intake with oil lately and leaking it from the valve covers. I believe my secondary catalytic converter is clogged but i'm having a hard time findind a hi-po replacement.would the cat cause the oil problem?? someone help with any info. please. also i was planning on removing the front cats and just having the hi flow secondary with no resonator(it's already removed) and either a magnaflow or flowmaster muffler. does anyone know how well this works??

Hohopirates · #2 03-22-2005, 11:55 PM

Hey I just read a post about someone who had oil their intake as well, they thought it had something to do with head I believe. It's labeled OT MR2 problem....hope it helps.

Steve

#3 03-23-2005, 01:54 AM

Quote:

Originally Posted by budfreak1

my 92 ls-l has been filling it's intake with oil lately and leaking it from the valve covers. I believe my secondary catalytic converter is clogged but i'm having a hard time findind a hi-po replacement.would the cat cause the oil problem?? someone help with any info. please. also i was planning on removing the front cats and just having the hi flow secondary with no resonator(it's already removed) and either a magnaflow or flowmaster muffler. does anyone know how well this works??

Ya know, my SVX does that as well. It didn't do it for a long time, and then all of a sudden, oil started appearing in the intake tract. I'm not sure of the cause, but I can give you a description for my situation.

I used to leak a poop-load of oil out the front engine seals. So I replaced the front crank seal, and the cam seals behind the cam pulleys. I had to get back under the timing belt cover, and noticed that the other two cam seals were leaking. They weren't before, and out-of-site out-of-mind, so I forgot them. I changed them out as well, and at the same time also changed the PCV valve.

Not long after all this, I noticed that my oil dipstick started popping up. It stopped after a while, and then came back. I checked all the breather hoses (the ones that go into the intake tract), and none of them were clogged. However, there was a small puddle of oil in the intake.

So my hypothesis is that my engine is choosing to blow oil out of whatever passageway that it can. Why? I don't know. I do know that if I change that O-ring on the dipstick, sure it might stay down, but then where is the oil going to go? More of it will probably go into the intake tract, or I will blow out my rear main seal. And no one wants that.

Harvey, where are you when we need you?!

So, yes, you are not alone in this, and I would like to find the answer just as much as you would. I haven't found a damn thing about it on this site, though. No one appears to have had this problem before.

Bobb · #4 03-23-2005, 02:24 AM

Hi everyone, You might take a look at your SVX's PCV valve. They are supposed to be replaced on a regular basis, but most people don't bother. Take care, BOBB

dcarrb · #5 03-23-2005, 06:03 AM

Quote:

Originally Posted by Bobb

Hi everyone, You might take a look at your SVX's PCV valve. They are supposed to be replaced on a regular basis, but most people don't bother. Take care, BOBB

Here's one joining the ranks of those who've reported that a new PCV valve cured dipstick pop-up (I did NOT replace the O-ring) and substantially diminished overall oil seepage. I keep an old towel beneath my car in the garage, and there are difinitely fewer drips present.

As to oil in the intake: No, the catalytic converter would have nothing to do with this. I'd guess it's being sucked through the valvetrain breathers... that's the only route for oil to find its way into the intake. (Isn't it?)

dcb

SilverSpear · #6 03-23-2005, 07:53 AM

definitely it is a head problem, something to do with the guide valve joints....

Beav · #7 03-23-2005, 10:25 AM

99% of the time it is going to be ths PCV valve. It sits upside-down in the intake and is easily clogged. I'd recommend replacing it the first time around and then cleaning it every six to twelve months - definitely easier than replacing gaskets and seals every year. The gaskets and seals are probably due for repalcement (age & heat) but a clogged PCV system will hasten future leaks.

Excess oil in the exhaust can eventually, over time, cause cats to overheat and melt, resulting in clogging. I wouldn't jump on that bandwagon without experiencing a pretty good performance loss, and even at that I would be checking everything else first.

#8 03-23-2005, 10:35 AM

[QUOTE=Beav]99% of the time it is going to be ths PCV valve. It sits upside-down in the intake and is easily clogged.QUOTE]

Yep, see it all the time in the shop. Oil in the intake is a sure sign of PCV failure. You should be happy, it's a cheap fix

Dave

Earthworm · #9 03-23-2005, 11:48 AM

Yeah the PCV is supposed to vent the pressure in the crankcase but why is there pressure in the case to begin with?

Possibly blow-by due to worn rings?

dcarrb · #10 03-23-2005, 12:23 PM

Quote:

Originally Posted by Earthworm

Yeah the PCV is supposed to vent the pressure in the crankcase but why is there pressure in the case to begin with?

Possibly blow-by due to worn rings?

This won't be a technically-astute answer by any means, but I remember pre-PCV valve cars simply had a breather which allowed crankcase gasses to vent into the atmosphere. (I drove a '62 Chevy with failing rings, and smoke would absolutely billow from the breather pipe at a traffic light.) The purpose of Positive Crankcase Ventilation plumbing is to suck these fumes into the intake for burning, thus reducing overall emissions. So if the PCV valve is gunked-up, there's no proper outlet for these fumes. Pressure gradually builds (there's some degree of blow-by even with good rings, I'd say), oil gets sucked through the cam-cover breathers and oozes past seals.

dcb

Edit: My '68 Mustang, which was the first model year to have a PCV valve, I believe, had a conventional "breather" cap on one valve cover, and the PCV valve literally popped into a large rubber grommet in the opposite one. Super-easy to replace, unlike some cars we know. A rubber hose ran from the PCV valve to the air filter housing.

oab_au · #11 03-23-2005, 03:32 PM

I can't add much more to what Beav and others have said. The dipstick blowing up is a sign that the crankcase is building pressure, due to the venting system becoming blocked.

The Pcv valve is the main fault, also the cam cover breather pipes, where they enter the air box. One pipe from each cam cover enter the air box on each side. This passage passes through the bottom of the box to be vented into the air pipe, through a small elbow pipe on the RHS of the air box. The small passages in this section of the box may become blocked.

There is also a small pipe in the same area, that runs from the air pipe down to the PCV valve, to feed air to the valve. If the valve is blocked, oil can be blowen up this pipe, into the air box and throttle body area.

So it is a case of, if you have oil leaking out of every where and the dipstick pops up, replace the PCV valve and check the breather hoses and passages in the air box.

Harvey.

Budfreak · #12 03-23-2005, 04:50 PM

you guys are awesome!! i didn't even remember to say anything about the dipstick popping up but yes, it does that to. so i guess next week i'll replace the pcv and see what happens.the oil is entering the intake mostly from the line going to the pcv, so it sounds logical to me. the cats definitely need replaced cause they are clogged badly! sounds like crap too. i'm probally gonna chop the front two off and replace the secondary with a hi-flow.the resonator is already off. thanx!!!!!

CigarJohnny · #13 03-23-2005, 06:05 PM

Cool thread, and very timely as well.

I am not leaking oil but I have noticed a large cloud of oil smoke when I fire up the car that clears up in a few minutes. I figured it was the valve guide seals allowing standing oil in the valve covers to seep into the combustion chamber while it sat between runs. Now the fact that my dipstick won't stay down had me fearing that I had major compression leaking and an engine with all new seals that was pretty much shot internally.

Now I am praying that it is nothing more than a bad PCV valve that needs replacing. Need to replace that as soon as I can and hope for the best!

Johnny

Beav · #14 03-23-2005, 09:40 PM

.....and they think it's an easy job to change the PCV valve on an SVX.... muhahahahaha. It isn't too bad if you're prepared. Do a search before making any plans.

Beav · #15 03-23-2005, 09:50 PM

Quote:

Originally Posted by dcarrb

Edit: My '68 Mustang, which was the first model year to have a PCV valve, I believe, had a conventional "breather" cap on one valve cover, and the PCV valve literally popped into a large rubber grommet in the opposite one. Super-easy to replace, unlike some cars we know. A rubber hose ran from the PCV valve to the air filter housing.

'64 (or '62 - '63) was first year the Fed req'd PCV. "68 was first year for emissions - usually in the form of air into exhaust injection (read:air pump.)
Prior to PCV the was just a wire mesh inside of a steel can attached to the engine block to separate oil from the crankcase fumes. The problem was after the mesh, which was only marginally effective, the vapors were sent out a small tube to drip on the roadway.

Now with port fuel injection, intake manifolds are 'cold' and the oil in the crankcase vapor condenses in the manifold. That is where the bit of oil on top of your engine block is most likely coming from - the collected oil in the manifold makes its way out the IRIS shaft and blows back, usually to the left rear. It isn't much -hopefully- but it is noticeable if you're one trying to keep a clean engine.