Toyota 1MZ-FE PCV Valve

[kschachn]

I have a '99 Sienna with 199,000 miles on it. Due to the reputation of this engine, I've been using synthetic oil since new (now GC 0W-30) and I also change out the PCV valve every other oil change - every 9000 to 10,000 miles. Well, the last two times now that valve has been clogged up solid. Gee, do I have to replace it every oil change now? What makes it clog up so fast?

I just replaced the valve cover gaskets and the inside looked great. No sludge and no varnish to speak of. So I'm pretty sure the engine is OK but that clogged PCV valve is new.

Edit: I should clarify "clogged up solid". What I mean is that the valve doesn't rattle, not that the hole in the bottom of the valve is clogged.

 

[c3po]

Do you use this car for short trips, that is one cause, always make sure the car gets up to operating temp before shutting the car off.

Have you checked your thermostat, running too cool may cause this.

I would also check your PCV hoses to make sure they are clear.

 

[ChiTDI]

Could be the beginning of the sludge situation. I'd keep at the Pcv and the hose, watch your OCI and maybe modify that if the conditions don't improve.
I'm watching the exact thing with my Avalon.
Are you burning any oil at all?

 

[c3po]

Is this the car with the small oil return holes in the cylinder heads.

 

[kschachn]

The thermostat is new-ish (~15,000 miles) and is Toyota OEM. The van is and always has been used for a mix of short trip and long trip, I'd say about 20% short. Anyway, I'll try and check out the hose. It's very hard to get to but if I remove the cowl maybe I can replace it.

I have to back up the truck on my earlier statement. I was going on memory with the every-other oil change. Looking at my Excel spreadsheet, apparently I missed it the last time so this is actually the third oil change. It was 14,802 miles since the last PCV which I suppose is better than the my first thought, but still pretty bad.

And yes, it does have a reputation of small return holes in the head.

Oh, and I have done an oil analysis on this engine before but not recently. It shears down quite rapidly and the TBN is pretty low after 5-6K miles. That's why I try and not go over 5,000.

 

[c3po]

It sounds like your PCV hose is original, start with the simple stuff 1st, of course that PCV hose on your car does not sound like it is easy to get too.

Since you live in Milwaukee, I would try to limit the short trip driving in the winter time up there.

 

[gofastman]

Is there actualy vacumn at the pcv hose when the engine is running? also do you have the plastic or metal valve?
I have noticed the plastic valves arnt as loud when shaken compaired to other engines valves, are you sure its actualy cloged? try moving the valve with a nail or toothpic, or blow into it if you are brave :0

 

[ChiTDI]

Originally Posted By: c3po
Is this the car with the small oil return holes in the cylinder heads.


I think it is.

 

[ChiTDI]

ksh - you can check the hose by removing it from the PCV and feel the vacuum pull. Pain in the neck to remove completely.

 

[PT1]

I run PP in all my Toyotas...ditch the GC...IMO as it won't help that engine at all...PP has a high calcium add pack that will keep it clean. Oh yeah, don't throw out the old PCV valves just soak them in some TB cleaner to clean them.

 

[c3po]

I would hold onto the old PCV Valve, but doesn't the spring inside the PCV Valve eventually get weak over time.

 

[ChiTDI]

Yes, and OEM are $5 here: http://www.trdparts4u.com/

 

[Donald]

I would consider a clean & rinse with Auto-Rx or if that is too much of a hassle then the maint does of Auto-Rx. The vehicle may have too much blow by past the rings and Auto-Rx will clean crud around the rings.

Most people can go 30K - 50K miles before changing the PCV.