TOPIC: Modification of the PCV System

Thanks guys,

It's good to know it's nothing to worry about. I'm not too concerned with it after all, the engine is running fabulously. However, I did find a little trick that helps with the coloring of oil, or at least with my car. I discovered most of the most moisture was being pull in through the dipstick slot. The dipstick doesn't seal well. So, I just put a rubber vacuum cap over the dipstick slot and 20 miles later, the oil looks better.

Thanks Tracy for all the catch-can info, I know it works, I've used it when I was using 2 valve-cover vents. In other words, I have the breather and the pcv inlets on the crankcase, I rerouted the pcv hose to the main-intake (before throttle-body) and only had the catch-on that one simply because the hose-size was convenient.. and this was before I truly understood the pcv and crankcase ventilation system...

Now I just have the breather doing all the venting. The PCV inlet has a stock pcv valve on it, but the pcv-hose is not connected to anything. (Normally, as OEM-setup, it connects to the intake-manifold which is now plugged). I don't have any concern about inspectors checking hose placements here in VA, so haven't needed to do the JB qwik on it.

Anyway, just thought I'd share capping off the dipstick inlet because it really seemed to make a difference. There's plenty of holes under the hood to secure the dipstick for when I need to check the oil. Just a thought...

Cheers and thanks for the feedback all,

Wes

Ron, I haven't had the creamy stuff on the oil filler cap, but just creaminess on the dipstick like so:



However, on a hunch I wondered if the moisture could be getting in thru the dipstick inlet (crankcase vacuum leak) because it didn't feel like the dipstick actually sealed the inlet completely. I capped it with a rubber vacuum cap and secured the dipstick in one of the many holes under the hood and the oil seemed to improve only 20 miles later to this:



This was just 2 days ago and haven't really had a chance to take another snapshot, but will do so ASAP. It's very rainy here in VA and today we had our first snow; I've kept the dipstick-slot-inlet capped and will report back w/ another photo to add or subtract any substantiation to this 'hunch'...

Wes,
Glad you found the reason for the creamy dip stick.
I also had a vac leak years ago and racked my brain looking for it.
Wasn't until I did a smoke test and found a large amount of smoke being
discharged thru the dip stick that solved the mystery.
Strange thing was that the mechanic who first did the smoke test told
me that was normal for smoke to be escaping thru the stick.
Had to politely ignore the ignorance and address that issue.
After I capped with a silicone hose and a golf tee did I see my vacuum leak
ECU code clear. Shows that mechanics are like doctors.
They dont know it all and their mistakes can cost their clients dearly.

Hey guys,

Wanted to share my experiences with the PCV mod. I have a 2008 Lexus ES 350 with the reliable Toyota 3.5 L V6 with the groove and PCV mod. While the pcv mod has worked fine in the warmer months, I have had problems with the line clogging up when it gets cold. In my case it requires weekly cleaning to keep free flow.

One night when it dropped below 0, I came to a stop light off the highway and smelled strong crankcase fumes coming into the cabin. I checked the breather line and it was clogged with frozen gunk at the top where it plugs into the 90 degree fitting into the intake boot. The PCV valve opened up to allow the crankcase to vent to atmosphere. Luckily this didn't cause any damage and I caught it quickly. I found that blocking the radiator grill partially has prevented this from happening again by containing more heat in the engine bay. Something to be aware of for those of us up in the freezing cold north.

The build-up of water vapor is a natural by-product of better combustion, coupled with worn cylinders. You should add some Snake Oil and that will reduce.

But it's not polluting your oil. It's just that steam rises, and blends with the oil coating your upper engine surfaces...

An uncomfortable side-effect, to be sure, but not worthy of alarm, I can assure you.

Ron

2 other things that help to prevent clogs from happening: use bigger diameter hoses, and use the accelerator aggressively on occasion to make what’s flowing through them really move (higher pressures/volumes...)

Yes, my V6 has already been snake oiled. Doesn't burn a drop of oil and it runs so smooth it's incredible. The breather hose on that engine is already 5/8ths diameter, which should be plenty. I have experimented with running an additional 5/8th's hose off of the other valve cover, however it was even more of a pain to maintain in the winter due to another hose and fitting clogging up. Keep it simple stupid.

I also just did the modification on my Lexus LS400 with the 1UZ-FE V8 engine. The first time I just capped the PCV port on the intake and called it good. But shortly after that my lower oil pan developed a leak, which I don't think was a coincidence. So I added another hose off of the other valve cover in addition to the stock breather hose and plumbed it into the intake before the throttle body for extra ventilation. It's been working great and it looks like I picked up 1-2 MPG. Also noticed a little more power.

Trevor Haining wrote: Yes, my V6 has already been snake oiled. Doesn't burn a drop of oil and it runs so smooth it's incredible. The breather hose on that engine is already 5/8ths diameter, which should be plenty. I have experimented with running an additional 5/8th's hose off of the other valve cover, however it was even more of a pain to maintain in the winter due to another hose and fitting clogging up. Keep it simple stupid.

An additional note for this engine: My current full synthetic oil, which was the first to receive the snake oil, has almost 9000 miles on it and it looks almost like new oil. The engine also has the groove.

What does the owner's manual say about oil change intervals? I wouldn't go past 10000 miles if I were you, regardless of what the marketing on the container says.
oil with 9000 miles that still looks like new is a sign that you've got a clean running engine. (and a good filter) - Snake oil and the groove are no doubt the main contributors to that.

I know this thread is a few years old but im new to the forum. Just a question about pcv modification. I've rerouted mine by T into the breather and capping off the intake manifold for the old line. Being that this is a closed system I would like the thoughts of putting one of those breather filters, about $15 on amazon, on the the breather port on top of the valve cover. Then in between the pcv and where it enters into the old breather port ahead of the TB putting a Air oil separator. If my theory is correct this would still allow air to travel through the system but keep the crap out of the intake. 2 suctions from the T into one seems counter intuitive, but I'm no engineer. My appologies if this has already been covered.

Hey, Mike.

While I have seen a bunch of guys get all crazy with the Cheez-Whiz, the crankcase vents perfectly well through the breather hose.

And one thing very few have considered is the modifications that can be seen from outside the engine stand a high likliehood of generating a FAIL from any future emissions inspections, causing additional trouble and expense should it ever need one in the future.

As for me, I want it to LOOK stock. Not ACT stock, to be sure!

But that's what we're all about in Gadgetman Land: Making things better with as LITTLE W-U-R-K as possible!!!

Hey Ron,
Didnt' think about the stock look. So much information on this forum to digest. I guess thats what this forum is for. When something popped into my head, I had to propose it to get some thoughts. Looking forward to reading more and trying out some of the tricks, that have come across the gadgetman land.