PCV Valve = Knock?

[aczr2k]

This past weekend I did some maint. on my truck (02,5.3 w/88k). Changed spark plugs, came with delcos put delcos back in. Went to change pcv valve, different part numbers completely different design. Dimensionally the same but interior components different. The original one CV-2001C (factory) was replaced by CV-948C (same p/n as owners manual). The original one just has a straight through design with a 1/8 dia. hole, not the tyical plunger.

 

Now the rest of the story, I did the seafoam through the vacuum line procedure, let it set 15-20 min, drove it, smoked like heck and everything seemed fine. Now it has started knocking, cold or warm, constant idle knock. So now what did I screw up, before it only knocked when cold.

 

Any answers or ideas? I am going to change back to the old pcv valve and see what that does. Thanks a bunch guys!

[willieboy]

Are you sure the knock is from the engine and not the new PCV Valve. I bought a Autozone brand PCV valve, and the thing is noisy as heck. At first I thought it was a sticky valve till I got under the hood. I have not replaced it yet, but when I do it will be with OEM or NAPA.

[asilverblazer]

The Sea foam might have losened some carbon deposits that were not completely blown out, someone said shooting cold water from a spray bottle into the intake could losen the remaining carbon. You might could try repeating the Sea foam.

[redvett]

The PCV valve is a restricted orfice and is the replacement for the production PCV valve & all 5.3 2004 up take the new PCV. You have probably some carbon on the pistons.

[aczr2k]

I did put the old pcv back in and it still knocks. Of course that would have been too simple. So if it is carbon on the pistons do I need to do another couple of seafoam treatments? Or should I just take it in and have the GM stealer clean done? Thanks.

[redvett]

Why did you use the seafoam in the first place? Did you have a problem?

[aczr2k]

I've always had some CSK but it had been getting more frequent and lasting longer. It seemed like a lot of people have been doing the seafoam on here with good results and with 89K I didn't think it could hurt anything. Now I regret it. The funny thing is it didn't start knocking until 20-30 miles later after the seafoam. I drove it probably 6-7 miles (hard) after the treatment. Vehicle sat the rest of the day, then I went out on sat night, didn't drive sunday and drove about 200 miles on mon. Now it knocks steady, at all RPM's you can hear it. I did change plugs could I have messed up a wire in the process and could that be causing the so-called knocking sound by mis-firing. Thanks.

[100R1]

is it a KNOCKING or PINGING ?

 

Pinging, check EGR valve for clean pintle.

[100R1]

is it a KNOCKING or PINGING ?

 

Pinging, check EGR valve for clean pintle.

[redvett]

I've always had some CSK but it had been getting more frequent and lasting longer.  It seemed like a lot of people have been doing the seafoam on here with good results and with 89K I didn't think it could hurt anything.  Now I regret it.  The funny thing is it didn't start knocking until 20-30 miles later after the seafoam.  I drove it probably 6-7 miles (hard) after the treatment.  Vehicle sat the rest of the day, then I went out on sat night, didn't drive sunday and drove about 200 miles on mon.  Now it knocks steady, at all RPM's you can hear it.  I did change plugs could I have messed up a wire in the process and could that be causing the so-called knocking sound by mis-firing.   Thanks.

 

<{POST_SNAPBACK}>

 

 

 

Did you gap the plugs to specs? You i dont think can cross the plug wires they are individual for each plug.

[mcreyaufmiller]

Crossing the plugs would throw a misfire code in the computer.

[budhayes3]

Don't want to scare ya, but did you let the Seafoam in slowly? If it sucks in too fast you could get hydro-lock and bend a connecting rod which would also give you a knocking type noise. Hopefully it's just a case of a chunk of carbon that needs to work it's way out or something along those lines.

If it makes you feel any better, my engine's spotless from periodical top end cleanings, yet it's noisy as hell. At one point I was about ready to replace the rockers, lifters, the whole kit and kiboodle...so I decided to drive it until it breaks. That was about 25k ago...still hasn't broken. (and I still haven't had to shell out for all of those parts )

[aczr2k]

I thought I let in in slowly, if I would have bent a rod, it probably should have started making noise right away?

 

As far as knocking/pinging, I guess I don't really know the difference, what ever the noise is, its constant.

 

Where is the egr valve at on these engines? How would I go about cleaning it?

 

Would a bad plug or wire also cause the noise? Possibly the seafoam knocked some crap into one of the new plugs? Looking back I should have changed them after.

 

Thanks guys for the input, this noise is bothering the heck out of me

[asepgrad98]

the seafoam will make it ping the first time you drive it. Maybe try changin the oil. some of the seafoam may have gotten in the oil.

[aczr2k]

After the seafoam, I didn't change the oil, but I will change it know.