PCV Line Clogged (How to clean?)

[NocalFJ60]

I checked my PCV valve and it is working then took off hose above PCV and not much vacuum at all while idling.

Then disconnected it right at hard line just before it goes into intake manifold and vacuum seems weak.

What is the proper way to clean it out? Wondering if something is in hard line before intake mainfold.

 

[jwest]

I use carb cleaner to free up a good pcv valve. It should work for the manifold hard line if you think it's clogged. Just a shot of it to dissolve the blockage. You don't want to hose it in there since you're probably going to do it with the motor off.

 

[NocalFJ60]

I shot some carb cleaner straight in the hard line and it still seems restricted. It is going to the intake manifold so it should have the same pressure as the brake booster line? I am measuring like 20 on my vaccum guage at the brake booster line.

 

[jwest]

I don't think there's any restrictor in the pcv line in the intake manifold.

In fact the pcv valve itself is supposed to do that job. So yes, afaik, the pcv line HG's on the intake side "plugged" , that is, without the valve connected to the crankcase, should be the same as brake booster vacuum. Again, afaik.

 

[NocalFJ60]

Yeah it is barely anything at the hard line off the manifold. I guess I got a lot of crud in the hard line. I was thinking maybe I could push it into the intake and let it burn up but maybe I will try and pull a vaccum from the top of the tube and suck whatever is in there out.

I might just disconnect the brake booster line and put it on the hard line and try to suck the crud the other way.

 

[NocalFJ60]

Does anyone know if I can open up the intake manifold right where the PCV line goes into it? There are a couple of bolts. If I opened it up I might be able to clean it out from the other side.

 

[jwest]

Btw, if you measured vacuum with the PCV valve inline, it should measure much lower.

I see what your talking about.
Someone else might advise you differently, but I'd rather see you try everything else first,
only because I don't want to see you stuck with a rusty broken stud.

But, if the studs and nuts are clean and you've had good luck in other areas where those small studs are, like at the EGR pipe, then it might be ok for you to try it. Soak 'em real well with PB or penetrating oil first.

I also see that you might need to remove the egr valve since it shares that same intake as PCV. Studs, rather than bolts, are used used at the intake, and there might not be enough room to clear the sleeve out of the EGR valve without removing it. I'm not 100% about this but I'm just telling you what I see you might be up against. I don't remember how far the sleeve goes into the EGR valve. You probably should replace that gasket at the intake too.

I also see that spraying carb cleaner in it while idling might work. Seafoam through the PCV line will certainly work better than through the brake booster line anyway. With the engine off, the stuff might just go into the EGR side. The obstruction could also be in the hard line.

You won't get it to turn into the manifold, but have you tried using some stiff wire in the hard line to see at least how far it will go? Maybe that'll loosen it up. Mechanics wire comes to mind.

 

[jwest]

Pics I found on the web.

 

[NocalFJ60]

Wow.. Thanks for the nice pictures. That is just what I was looking for.

It seems to be something big in the hard line right at the bottom where it meets with the EGR valve.
I drove up to a shop today and borrowed their compressed air with a small end and slid it down and tried to blow it out with no luck.I took off another line for the intake for the air to go while I shot air into the mainfold. I can not feel any suction at the top of the hardline. Before I tear into the manifold I am going to go get a long hose and fill it with carb cleaner and tie it up and let it soak all night in there. I tired to change my EGR valve before and it is a pain to get the big nut off to take it out.

If I could get it to loosen up alittle, I will start running seafoam into it to clean it out until I get good suction.

I am running now with the PCV valve out. I figure it can't hurt anything just pollute more. I am not driving it that much anyhow now.

 

[NocalFJ60]

I was able to pull the end of the intake manifold off and here is what is looks like. It is carbon that had cooked and hardened. There would have been no way to clean this out unless I pulled it. I just need to pick up a new gasket and clean the line real good.

 

[jwest]

That's plugged solid.
You can barely see the outline of the pcv opening in the plate.
Makes you wonder how the pressure was getting out.

Nice, now your crankcase can breath again!
Oil will stay cleaner and less pressure on your gaskets.

 

[jwest]

I'm guessing the manifold side is just as bad?

Now that I'm seeing this, I really don't like the design of this setup.
Hot EGR flows just above the PCV port, compounding an already hot manifold.
Then oily crankcase gasses come through the PCV port and get cooked, leaving behind carbon which continues to build up until you have total occlusion.

Good thread.

 

[NocalFJ60]

I'm guessing the manifold side is just as bad?

Now that I'm seeing this, I really don't like the design of this setup.
Hot EGR flows just above the PCV port, compounding an already hot manifold.
Then oily crankcase gasses come through the PCV port and get cooked, leaving behind carbon which continues to build up until you have total occlusion.

Good thread.

The manifold side had a thin buildup just to the inner wall of the manifold. I guess that is why the pipe is exteneded on the EGR hole on the manifold so they don't exit at the same plane.

After seeing this, I think the best place to seafoam your engine is the PCV line. It cleans the lines and ggets to all cylinders equally unlike the brake booster line. It also bypasses your carb which probably does not need cleaned as much.

I am wondering how long it was like this. This probably contributed to my worn rings. The air was going up out the usual inlet at the back of the valve cover. That is where the oil and carbon bits in my air cleaner housing where coming from.

 

[jwest]

Yea, ditto ditto on the seafoaming through the pcv line.
Every once in a while seafoaming through the carb would be good, but going through pcv makes it alot easier, does a better job and hopefully keeps the line cleaner. Plus, there's no need to remove the air cleaner.

I see that the EGR tube extends the exhaust.
But since they both share the same plate, my hunch is that the heat from the EGR inlet is heating PCV more than it would otherwise. Again, that's my hunch.

Nice info. Kevin.