A specific question about the old "dipstick popping out" issue

[Huskymaniac]

So I noticed one day that the dipstick was out. I pushed back in and drove the car a few times and it didn't pop out. After a couple of weeks, it was out again. I noticed it when I went to work on the hood squeak.

I know the two issues are the rubber o-ring and the PCV valve. I know that a new o-ring usually solves the problem. My concern is what if it is the PCV valve? Getting a better seal on that dipstick would only cause the pressures to rise and there might not be any other immediate symptoms of a stuck PCV valve. Assuming that were the case, what damage could be done by not replacing a bad PCV because either one doesn't know about it or one saw a symptom but fixed that symptom another way and assumed the PCV valve was OK?

Normally I would just replace the o-ring and not worry too much about it but I have another symptom that might point to the PCV valve in an indirect way. When the weather got cold my idle would bounce immediately after starting the car. It would jump up to a normal RPM first. Then it would drop very low and nearly stall. Then it would bounce back to the normal cold RPM again. Then it would drop again but not as low. This repeats and the "undershoot" is less each time until the car finally settles on the normal RPM for a cold idle. It takes all of about 5 seconds for this to happen.

From what I have read, it sounds like this could be due to a stuck AACV and the AACV could be stuck due to oil being pushed out which in turn could be due to the stuck PCV valve. However, this bouncy idle seems to be getting better with time since I replaced the O2 sensor. Sometimes it doesn't bounce at all. Maybe the AACV is OK and the bouncy idle was due to the O2 sensor. And the underside of the car looks pretty dry right now. I get zero drips of oil on the driveway. So maybe the PCV isn't stuck after all.

But the bottom line is, what damage can be done by a stuck PCV valve?

[Cam]

If the pressures in the crank case are high enough you could potentially start leaking from your cam, crank, valve cover and/or rear main seals.

[Coan]

I've had the same issue with the dipstick popping out and replaced the o-ring to get it to stop. I also planned to replace the PCV valve at the same time, but after 3 failed attempts I still haven't been able to get it out. I'm going to try once more with a different tool before I take the manifold off and do it the hard way. But yeah, the pressure has to go somewhere, it's best if it goes where it was designed to go.

I've also had the same issue with the idle during start-up. I've never looked into because I usually forget about it by the time I get back home lol.

[Huskymaniac]

Originally Posted by Coan

I've had the same issue with the dipstick popping out and replaced the o-ring to get it to stop. I also planned to replace the PCV valve at the same time, but after 3 failed attempts I still haven't been able to get it out. I'm going to try once more with a different tool before I take the manifold off and do it the hard way. But yeah, the pressure has to go somewhere, it's best if it goes where it was designed to go.

I've also had the same issue with the idle during start-up. I've never looked into because I usually forget about it by the time I get back home lol.

Yeah, the cold idle is a weird one. It was doing it consistently so I was convinced that I was going to have to remove and clean the AACV at some point. It didn't stop immediately after replacing the O2 sensor but now, suddenly, it occasionally will start in the morning with no bouncing. Someone had mentioned that the computer may just be taking its time settling on correct air/fuel mixtures.

[NikFu S.]

Originally Posted by Huskymaniac

Someone had mentioned that the computer may just be taking its time settling on correct air/fuel mixtures.

On this note it could be temperature related.

All summer long I had the dipstick popping out, but as winter rolled in that has stopped and now I have vicious bouncy idle which kicks in right after I pull out of my garage.

I have had PVC issues in the past, but there is something else causing the fouling of the valve. I know Harvey explained it to us once but damned if I can remember.

[Huskymaniac]

Originally Posted by NikFu S.

On this note it could be temperature related.

All summer long I had the dipstick popping out, but as winter rolled in that has stopped and now I have vicious bouncy idle which kicks in right after I pull out of my garage.

I have had PVC issues in the past, but there is something else causing the fouling of the valve. I know Harvey explained it to us once but damned if I can remember.

It doesn't happen when you start it but when you pull out of the garage? If that is the case, I would suspect IACV which, from my understanding, is what takes over when the engine warms up versus when the car has just been started and is still very cold.