This is a very important topic if you want to get the best benefits when using auto-rx. I keep reading posts about people having oil leaks and then blaming auto-rx for not fixing the leak.
I tell people to check there PCV Valve and also the PCV Hose, and many people report back that it is fine. But there is another item that needs to be checked, and if this is not cleared up it will not matter if the PCV Valve and PCV Hose are clear.
One of our members was working on a car with a bad oil consumption problem, he eventually pulled off the valve cover or maybe there were 2 valve covers. On the valve covers there are baffles where the PCV Valve or breather hose sits, if these are clogged you will have problems. I am not telling you to remove them, but they must be clear to vent the gasses or vapor through the PCV Valve.
If you have too much pressure from these vapors that are not allowed to escape they will find there way and cause a leak in the :
1) Valve Cover Gasket 2) Oil Pan Gasket 3) Rear Main Seal 4) Timing Cover Gasket
I had a problem on my small block chevy when I put on some nice Edelbrock Valve Covers, the baffles were basically a piece of steel, I took the valve cover off and noticed that the PCV Valve only had about a centimeter of air clearance between the baffle and PCV Valve. I just went ahead and took these baffles off, would not recommend that on todays cars, I did this on a 1983 Chevrolet Small Block Chevy.
I have a little bit of oil wetness on the outside of the PCV Valve grommet, but I will trade this for oil leaking out the rear main seal or oil pan.
Others may chime in, but the baffles in the valve covers are very complex in that it is easy for junk to get in there and eventually get hard or gooey and not let the engine vapors escape into the PCV Valve and then up to the intake tract to get reburned.
Auto-rx can only work on leaky seals if the PCV system is working properly.
I believe this is a must read for anyone that is posting about leaky seals, and we need to refer people to this post if they are still having oil leaks while using auto-rx.
Any comments are appreciated just in case I may have missed something.
I wanted too add a few more things here. If you need to buy a new PCV Valve make sure you get one that is the same one that came on your car, no generic cheap brands. An examole being if you have a Ford product use a Motorcraft PCV Valve, not some cheap Fram or Purolator PCV Valve.
The old school trick of shaking a PCV Valve and hearing it rattle does not mean it is good, if it has a spring it can weaken over time. I would recommend replacing the PCV Valve at 30,000 miles or if you really care about your car, once a year.
I have seen people put on cheap non oem PCV Valves and then having problems.
I wanted too let people know that if you have a seal leak it may also be a good idea to check your Harmonic Balancer or as others may call it a Torsional Dampr. These are usually made out of rubber and if they show signs of cracking they can go bad. I replaced my Dampner on my El Camino that was made out of rubber and had some cracks in it, the engine ran smoother after I put a better balancer on there. My thinking is that when the balancer starts to go bad you can have some movement in the crankshaft which could lead to having some oil leak out of the seals.
I would maybe try some carburetor cleaner or maybe Brakleen. I know you cannot do this on your car, but I have a small block chevy that has aftermarket Edelbrock Valve Covers, I took them off and noticed my baffles were only a centimeter away from the PCV Valve and breather, so I just took them off, no more leaks, no more puffs of smoke.
Does your breather have a tube that goes to your throttle body, under hard acceleration you could have oil mist traveling through the tube into your throttle body, you may want to cap that tube off and run a K&N Breather, I have seen some LS! guys do this.
If you have some carbon in your manifold or runners, GM makes a product called GM Top Engine Cleaner, you can start the engine and run it through your PCV Valve line going to your intake manifold. If you have any concerns about what I have written please PM me.
Rattling tells you nothing. I've removed "rattling PCV valves" from two vehicles that caused problems. Both valves were the original OEM valves which hadn't been changed previously. Both vehicles had over 100,000 miles. In one vehicle after the valve was replaced 90% of the oil leaks went away immediatly. In the other vehicle the oil consumption dropped from a quart every 1,700 mile to a quart every 3,000 miles. Both engines had sludge as a result of a warn out PCV valve.
is there a recommended change interval for a pcv? or is it safe to say that if the pcv is sitll "rattling" its still good to go?
I would say if you were very anal than once a year, otherwise then I would say to change it every 30,000 miles. Turbo Jim is right in that if the PCV Valve still rattles it means nothing.
Using auto-rx means you will probably have less blowby which could prolong the life of the PCV Valve, just remember a malfunctioning PCV Valve can lead to many problems, its a cheap part so replace it often and you will save yourself some money and headaches.
