I have a 97 Toy Avalon (with the notorious 1MZ-FE) and I notice that the PCV valve gets clogged more than once a year. Every time I take it out, there is sludgy grit around the outside of it. I assume the PCV is getting clogged with sludge. I change my oil every 3000 to 3500 miles with conventional, but am going to switch to synthetic very soon. Do you think that the PCV valve clogging this often is normal? I know that the PCV valve is clogged because when I shake it, it does not move freedly AND the valve cover gaskets start to weep oil, a sign that there is pressure build up in the engine.
PCV Valve Clogs Very Often
- Thread starter parimento1
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Awareness of the problem is the first step to managing it. I am not familiar with the specific problem, so this is generic advice. I would see what happens to a gummed up PCV if you soaked it in a solvent instead of tossing it. Assuming it freed up , I would rotate the PCVs every oil change or so.
Is the engine creating a lot of blow by? Consider rigging a catch can. The whole thrust with a 12 yr old car is to keep it going as cheaply as possible for as long as possible.
Is the engine creating a lot of blow by? Consider rigging a catch can. The whole thrust with a 12 yr old car is to keep it going as cheaply as possible for as long as possible.
I bought my Sienna used two years ago and have run it on synthetic with 3500 to 4000 mile changes, which equates to three times per year for me. I've also heard that for these particular engines you should buy OEM pcv valves from the dealer.
This appears to be an increasing issue w/ some engines.
My '05 Silverado w/ 91 K miles (5.3 engine) just began consuming oil like crazy (2 quarts in 4000 miles) where it had used little or none between OCI.
Dealer knew about it right away. Said PCV is plugged up.
It turns out that GM has issued a TSB with a new 2nd design valecover that has larger/ changed PCV passages internal to the valve cover. They replaced both valve covers and problem is gone. Weird.
My '05 Silverado w/ 91 K miles (5.3 engine) just began consuming oil like crazy (2 quarts in 4000 miles) where it had used little or none between OCI.
Dealer knew about it right away. Said PCV is plugged up.
It turns out that GM has issued a TSB with a new 2nd design valecover that has larger/ changed PCV passages internal to the valve cover. They replaced both valve covers and problem is gone. Weird.
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AND the valve cover gaskets start to weep oil, a sign that there is pressure build up in the engine.
Assure that the other end of the system is also free flowing. I couldn't find an image of a 1997 engine bay, but make sure the fresh air vent to above the throttle body is also free flowing. By the looks of the images I can find for the engine, this is a relatively honking hose. If your PCV is clogging, your throttle body should be soaked with oil. I would think this would adequately vent any blow-by production. That is, I wouldn't expect over pressurization of the crankcase.
AND the valve cover gaskets start to weep oil, a sign that there is pressure build up in the engine.
Assure that the other end of the system is also free flowing. I couldn't find an image of a 1997 engine bay, but make sure the fresh air vent to above the throttle body is also free flowing. By the looks of the images I can find for the engine, this is a relatively honking hose. If your PCV is clogging, your throttle body should be soaked with oil. I would think this would adequately vent any blow-by production. That is, I wouldn't expect over pressurization of the crankcase.
Perhaps the EGR valve is not functioning correctly? Worn piston rings?
Some PCV systems are better than others.
You are keeping it functioning, which is great.
Why so much? A lot of heat or blowby [rings/bores] combine to get a lot of PCV sauce.
Normally, PCV systems don't need this much attention at all.
I am a big fan of using a PCV catch can, so any weird gunk is mostly stopped from getting in your manifold, valves, and combustion chamber.
You are keeping it functioning, which is great.
Why so much? A lot of heat or blowby [rings/bores] combine to get a lot of PCV sauce.
Normally, PCV systems don't need this much attention at all.
I am a big fan of using a PCV catch can, so any weird gunk is mostly stopped from getting in your manifold, valves, and combustion chamber.
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