Oil Catch Can for 4.2 PCV system

Scavenger

Original poster
Member
Aug 2, 2013
9
Hi,

Over the past few months I have encountered what appears to be oil sprayed on the inside of the passenger side fender well area, along with a fairly good size oil puddle on the concrete under the radiator over by the front passenger side tire. Today I removed the throttle body and noticed how filthy it was. My Trailblazer is a 2002 4x4 LTZ with the 4.2 Vortec engine, and has approx. 157,000 miles on it. I understand that the PCV system is poorly engineered, and has a tendency to let blow by oil collect in the resonator. I may be wrong, but believe the oil reaches a certain level in the resonator, then is blown out around the tube/hose that is located under the front of the resonator.

Questions:

1) If I were to make or purchase a Catch Can, where would I need to splice it in...........Between where the hose is in front of/under the resonator, or spliced in between the short "L" shaped hose on the drivers side of engine.

2) Any plans for making a homemade catch can, or would it be best to purchase one that is vehicle specific......if there is such a thing.


Sorry about scrounging for information on my first post, but I really need to get going on this before my wife returns to work and needs the only spare vehicle we have...........any information would be greatly appreciated.................thanks.
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
Hi. I am running a oil catch can on my turbo i6 project and I ran it off the L shaped hose on the drivers side that connects to the intake manifold. I ran mine by taking off the L shaped and replacing it with 2 hoses to my catch can.
View attachment 30018

Appears to be working great. Make sure the hoses on intake manifold and the can are tight or youll have serious vacuum leak issues haha... Learned that the hard way.

I doubt there is a vehicle specific catch can. I just bought one from a nissan forum online when i was looking up some random info about catch cans, but I assume an eBay one would suffice as long as its decent quality
 

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Scavenger

Original poster
Member
Aug 2, 2013
9
Thank you very much for the information. I am going to look around at some local auto parts places today to see if they stock any catch cans. If they don't, I am going to fab up some quick but workable temporary can. My biggest worry is being able to find the proper sized hose that will fit on the engine connections. The inside diameter of the "L" shaped hose does not appear to be a standard size.

After I get the above squared away, I need to do some electrical repair before I can get the Trailblazer back on the road. It seems as though some resident chipmunks decided they needed more copper/plastic in their diet. They chewed the harness coming from the last of the 3 large connectors (closest to the firewall) that screws onto the PCM. They gnawed through a tan, red, black, blue, yellow, and couple of green wires. I parked the Trailblazer at the end of February because of all the problems (codes, oil spraying, ABS, Air Bag, etc.) Southern Wisconsin chipmunks must have some sort of diet deficiency upon waking in the spring. Anyway's, I hope when I disconnect the harness I can pull it up far enough to allow me to solder the wires. The wires are so small I am unsure if they make crimp on connectors that will fit them, and if so would they be weather proof ....................Thanks again.
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
Haha those damn things!!!! And sounds great keep us posted! As for the pcm wiring... I had to re rewire all of thecwires on the blue connector when I swapped in an 06 PCM and all I did was strip the ends, twist the wires together and use heat shrink to weather proof them. Running great without incidence and saved me a lot of soldering frustration haha
 

AbsoluteZero

Member
Nov 21, 2011
211
There's a vendor on the Cadillac forum that sells catch cans. His website is RevXtreme - RX Performance Products. Some of his claims has drawn negative comments. I have no personal info on his product line.
As an experiment I made a catch can using an empty 14 oz propane bottle. I've got it install on my 07 3.6l SRX. Some of these engines have a history of excessive oil consumption. Mine doesn't at 50,000+ miles. This engine family uses a similar PCV system as our 4.2l I-6, namely a fixed orifice. Some have had limited success in reducing oil consumption by drilling out the fixed orifice with a 7/64" drill. I bought a spare orifice (which on the 3.6l engine is in the valve cover and easily accessed) and am trying out the idea of the larger orifice. Since the orifice is a "calibrated" leak I was curious if engine operation would be affected.
I had an empty propane bottle and decided to make one using scrap fittings, etc. This is not a detailed plan. I used what was in the scrap box but maybe will give you some ideas:

I used a stainless scouring pad for a baffle.
Middle photo is partially assembled
Bottom shows install on the engine.
The black RTV was used to plug up some unexpected holes.
Any case this is in response of your question "has anybody make one"

As far as results. Only gone thru one oil change since the install. I drained out 8 oz in 6000 miles of mostly highway driving. After the PCM adjusted for the larger leak I can't tell a difference in engine operation. I have reinstalled the OE orifice to check the amount of oil collected thru this next oil change.
 

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blazinlow89

Member
Jan 25, 2012
2,088
I have thought about doing something similar to this

Catch Can Install

I ran this on my 4.3 S10 Blazer and it would be about half full every 5000 miles. Something like 6-8 ounces. Seemed to help with some of the issues I had with the TBI system.

Maybe when I have some extra cash I might attempt to make another.
 

Scavenger

Original poster
Member
Aug 2, 2013
9
Thanks to all the information I received I was able to toss together a very temporary catch can. I do not have a way (or the knowledge) to attach any photos, so I will give a brief description.

1) I stole the small (expired and dead) fire extinguisher from my skid loader.

2) Removed the discharge head and emptied the powder.

3) Removed the steel tube from the head.

4) Placed extinguisher cylinder in band saw and cut off the flat bottom along with several inches of cylinder.

5) Plasma cut a round plate of 1/4" flat stock. This replaces the old bottom which was too thin to tap for fittings.

6) Use ironworker to punch a 1" diameter slug from 1/4" flat stock. This was drilled and tapped for a pet cock valve for draining.

7) Drill and tap 2 holes in plate from item #5 for 90 degree barbed fittings.

8) Cut steel discharge tube to length. Tube is soldered to a sintered metal flange...not too conducive to welding so.....I JB welded flange/tube
to underside of item #5 lined up with one of the tapped holes.

9) MIG welded #6 to old top....which is now the new bottom.

10) Welded plate #5 to old bottom which is now the new top.....I only hope the JB weld handled the heat.....Nothing rattling so maybe ok.

Project is idle for now.........need to figure out where, and how to mount this sub ghetto fabrication.........more later, thanks again.
 

gmcman

Member
Dec 12, 2011
4,656
After Conekilr's catch can install, it gave me the thought as well for doing one. What about taking the big hose under the intake resonator and route it to a can, then back into the intake tube? I think this would possibly catch the most oil.

I want to keep the intake resonator in place but install a straight tube from the IAT sensor to the TB, but leave a port for vacuum to pull the PCV system. :undecided:
 

AbsoluteZero

Member
Nov 21, 2011
211
gmcman said:
After Conekilr's catch can install, it gave me the thought as well for doing one. What about taking the big hose under the intake resonator and route it to a can, then back into the intake tube? I think this would possibly catch the most oil.

I want to keep the intake resonator in place but install a straight tube from the IAT sensor to the TB, but leave a port for vacuum to pull the PCV system. :undecided:

The way I understand the crankcase vent system works is the tube under the intake resonator supplies filtered air to the crankcase. A vacuum source supplied thru the intake manifold causes a flow thru the crankcase, thru an orifice in the head gasket and into the manifold. I'm probably not understanding your idea but wouldn't think there would be much advantage to have the catch can in a filtered air supply. Maybe a flow schematic would be helpful. In any case I like experimentation. That's why I installed a catch can on the SRX.... plus got to use up some of my accumulated scrap!
 

Zx2ner88

Member
Jan 2, 2013
51
I used to run a water seperator for a shop air system on my Escort. About $20 at any hardware store. I would recomend you get the biggest one you can find, as they can fill up pretty quickly
 

gmcman

Member
Dec 12, 2011
4,656
AbsoluteZero said:
The way I understand the crankcase vent system works is the tube under the intake resonator supplies filtered air to the crankcase. A vacuum source supplied thru the intake manifold causes a flow thru the crankcase, thru an orifice in the head gasket and into the manifold. I'm probably not understanding your idea but wouldn't think there would be much advantage to have the catch can in a filtered air supply. Maybe a flow schematic would be helpful. In any case I like experimentation. That's why I installed a catch can on the SRX.... plus got to use up some of my accumulated scrap!


That makes perfect sense I'm not sure why I thought it traveled the opposite direction
 

Heavyblaze

Member
Dec 5, 2011
9
Scavenger I think you better look at the transmission lines they run on the passenger side and connect to the bottom of the radiator. The transmission lines rust out on some of the GMT360. Thats what happened to my one line I had to replace the line.:smile:
 

Scavenger

Original poster
Member
Aug 2, 2013
9
Heavyblaze ,

I appreciate the heads up.............been there......done that. It is definitely Mobil 1 being sprayed in the passenger side forward fender well area, and leaving puddles on the cement. Last fall when it developed the oil problem I accidently stumbled across a lower leaking tranny line. The connector clip had rusted away on the short line at the end opposite of the radiator connection. It was at that time I found out they changed the design of the lines, and ended up having to buy both pieces. When I found the bad transmission line connection I thought all was going to be well, and I had solved the leaking/spraying oil mystery. Evidently all common sense flew out the window while I was gloating over my new found detective skills, and I did not hear, or didn't want to hear that little bell between my ears going off saying "hey double dumb, the transmission fluid was full, please explain the fair amount of engine oil loss". A day or two after replacing the tranny line, I was at a stop light and experienced that burning oil smell again. When I got home I found oil dripping from the front passenger side, and the fender well area was oiled again. During this latest rash of repairs I did find that the hose that connects to the front connector on the resonator was loose fitting, and wonder it enough pressure can build up in the resonator to blow the oil out at the loose connection....Hmmmmm........Thanks.
 

AbsoluteZero

Member
Nov 21, 2011
211
Scavenger, oil in the pass. fender area.... that's nearest the oil filter. Wonder if something is leaking there? ... oil filter or gasket or oil pressure sensor?
 

Scavenger

Original poster
Member
Aug 2, 2013
9
AbsoluteZero ,

When all of the oil mess started, it was about 3 weeks after I had changed the oil. Thinking I may not have sufficiently tightened the filter, I crawled under and gave the filter an extra nudge. At that time I did not notice any oil on or around the filter. Then..........a day or two later when coming home from work I experienced that burnt oil smell. That next day I installed a new filter thinking the seal may have been bad. I have never had a problem with any Wix/Napa filters before, and apparently still have not...........the oil leaked again that same day, and still no oil around the filter.

The most perplexing thing about this leak is that it will not always leak...........I can go several days without a problem before it has a relapse. The one thing I have noticed is that when it does start leaking, it takes about 5-10 minutes of driving time, it will leak enough to get things coated with motor oil, smoke for a few minutes, then stop leaking and smoking. I can then drive it to hell and back the rest of the trip and it will not act up again until it has been shut off for several hours, but it could occur several days later. I assume the smoking part comes into play from the oil getting on the exhaust manifold.

As far as the oil pressure sensor being suspect........sorry, I forgot to mention that I had changed the sensor. Even though it has an "O" ring on it for sealing purposes, I put some Loctite white sealer paste on the threads of the new one before I installed it.........Thank you for your efforts in helping me solve this mystery.
 

Scavenger

Original poster
Member
Aug 2, 2013
9
In the above post I forgot to ask a question. I am pondering the addition of a sight tube on "cobble can". This way I can better monitor any major accumulations if the thing even gets any oil at all...........In a way I am hoping it does so I can hopefully solve the mystery. I know I asked the question about which hose to splice the catch can between (the hose from the resonator, or the "L" shaped hose on the drivers side). Could someone tell me which hose would be best suited for the catch can. I am sure the person who answered my question suggested the best choice, but having gray matter atrophy makes it hard to comprehend at times......ha ha. In fact, the new periodic table shows my brain as being denser than lead.

Anyways, my reason for wanting to know which tube to hook the can up to is because I have no idea about how much pressure is developed in these hoses, and need to make the sight tube out of sufficient strength materials. If I had to guess I would assume low pressure since none of the original tubes even have clamps on them..........but, I have been wrong before.......thanks.
 

AbsoluteZero

Member
Nov 21, 2011
211
The only hose likely to have oil vapors is the one going to the intake manifold. Cone's post show a pix of the intake manifold confirming this. With that said IF the pcv orifice in the head was plugged internal pressure in the engine could force flow out the tube in the valve cover. The one with the hose to the intake resonator. When this happens on the SRX 3.6L V-6 it will leave oil deposited in the intake tube where it connects to the throttle body. BUT I don't see how this could get from there to your fender area.
Out of curiosity have you looked in the air filter box for oil residue?
 

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Scavenger

Original poster
Member
Aug 2, 2013
9
AbsoluteZero ,

Thank you very much for the detailed photo. With my obvious comprehension disability "a picture is worth a MILLION words. Would you happen to know if the ports where the "L" shaped hose connects were to be plugged, would it hurt anything to shoot a little compressed air in them to alleviate any possible blockage...........thanks again.
 

AbsoluteZero

Member
Nov 21, 2011
211
Scavenger said:
AbsoluteZero ,

Thank you very much for the detailed photo. With my obvious comprehension disability "a picture is worth a MILLION words. Would you happen to know if the ports where the "L" shaped hose connects were to be plugged, would it hurt anything to shoot a little compressed air in them to alleviate any possible blockage...........thanks again.
I would think the pcv orifice in the head gasket would be the most likely blockage source. I don't know the diameter in the I6 engine but it's only 3mm in the 3.6L engine. But I don't think you'd do damage with blowing out the tube in question..... another approach you might consider if you are near an oil change interval..... try back flushing some solvent like Seafoam thru the tube. This can end up in the crankcase if the orifice is not restricted.
I'd think if there was a blockage this would allow crankcase pressure to be relieved thru the valve cover outlet and you'd see evidence of oil residue somewhere in the air intake system. It's strange this started after an oil change. Have you thought about using UV dye in the oil to trace a leak? or I've read using foot powder to find a leak.
Any case hope you getter fixed!
 

SBUBandit

Member
Dec 5, 2011
597
Just curious, but has anyone who has installed a catch can kept track of how quickly the oil is being caught, or run it long enough to see how much of a difference it makes in the TB getty nastied up?
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
SBUBandit said:
Just curious, but has anyone who has installed a catch can kept track of how quickly the oil is being caught, or run it long enough to see how much of a difference it makes in the TB getty nastied up?

hey I caught about 4 ounces in the 3 months my turbo build was running! kept the throttle body fairly clean compared to before surprisingly
 

seanpooh

Member
Jan 24, 2012
461
SBUBandit said:
Just curious, but has anyone who has installed a catch can kept track of how quickly the oil is being caught, or run it long enough to see how much of a difference it makes in the TB getty nastied up?

I can't believe I missed this thread. I installed a BMW Oil Catch Can built by Burger Tuning.

ConeKilrAutoX was the member I asked about direction of the flow of nasty oil since he already had one installed.

I actually left that stock L shaped vacuum hose still attached to the bottom of the intake manifold with the stock clamp. There I attached a 3/4" PVC quick connect (plastic snap in style) to the L shape to a 1/2" clear hose to the catch can. Then from the catch can I routed another 1/2" clear hose to the top opening on the intake manifold. I clamped everything together.

For about the 8K miles I have had it installed, throttle body isn't the slightest dirty at all. I thought it needed cleaning when I did my headers but nope. The catch can is doing it's job. I get oil, yellow stuff and water in my catch can. More water than oil some days (I used to check everyday, now every week or so) because of the atmosphere I guess.

It really gives me a piece of mind knowing that all the blow-by crap isn't getting into the intake and gumming up the valves along with everything else. But you have to remember it's not 100% efficient.

The only bad thing using the clear braided tubing is:
1) the tubes turn yellow and you can see all the nasty stuff on both sides.
2) when the engine gets hot and especially when you drive on a long road trip, the tubing will collapse. My fix was to put clamps every 4-6" apart and at the bends to keep the shape of the tube.

I'll post up pics for you guys later.
 

SBUBandit

Member
Dec 5, 2011
597
seanpooh said:
I can't believe I missed this thread. I installed a BMW Oil Catch Can built by Burger Tuning.

ConeKilrAutoX was the member I asked about direction of the flow of nasty oil since he already had one installed.

I actually left that stock L shaped vacuum hose still attached to the bottom of the intake manifold with the stock clamp. There I attached a 3/4" PVC quick connect (plastic snap in style) to the L shape to a 1/2" clear hose to the catch can. Then from the catch can I routed another 1/2" clear hose to the top opening on the intake manifold. I clamped everything together.

For about the 8K miles I have had it installed, throttle body isn't the slightest dirty at all. I thought it needed cleaning when I did my headers but nope. The catch can is doing it's job. I get oil, yellow stuff and water in my catch can. More water than oil some days (I used to check everyday, now every week or so) because of the atmosphere I guess.

It really gives me a piece of mind knowing that all the blow-by crap isn't getting into the intake and gumming up the valves along with everything else. But you have to remember it's not 100% efficient.

The only bad thing using the clear braided tubing is:
1) the tubes turn yellow and you can see all the nasty stuff on both sides.
2) when the engine gets hot and especially when you drive on a long road trip, the tubing will collapse. My fix was to put clamps every 4-6" apart and at the bends to keep the shape of the tube.

I'll post up pics for you guys later.

Good point about the clear tubing yellowing and softening/collapsing. This silicone hose is pretty cheap and might solve that issue and look better in the process. Of course they also have red and blue, if that floats your boat

1 2" Verocious 1 Ply Silicone Heater Hose for Radiator Coolant Black Sold by Ft | eBay
 

palitoiii

Member
Dec 5, 2011
77
Hey AbsoluteZero or anyone that knows. Ive wanted to put a catch can on my 4.2 have it on my long list of things that i want to do to the TB. So where is the correct place to put it. On the driver-side or the passenger-side of the engine? Or should there be 2 of them installed?
:crazy:
 

AbsoluteZero

Member
Nov 21, 2011
211
palitoiii said:
Hey AbsoluteZero or anyone that knows. Ive wanted to put a catch can on my 4.2 have it on my long list of things that i want to do to the TB. So where is the correct place to put it. On the driver-side or the passenger-side of the engine? Or should there be 2 of them installed?
:crazy:
See post #19 in this thread. As to where you mount the can..... it's where you have room but for it to do it's intended function, I believe in the line shown in post #19 is the only option for our 4.2l engine.
 

palitoiii

Member
Dec 5, 2011
77
Well guys i went and purchased the PCM of NC Catch Can. Looks GREAT! They sell 3 Universal brackets and i used one of them and fit nicely connected to our engine. I had to slightly modify the SS engine cover again to fit. Reason i put it was to get less oil gook in the air intake and stuck to the throttle body. So better idle and no bogging down in summer when the AC is on. Contact Kelly at sales@pcmofnc.com.

image1_zpssms58rya.jpg
 

palitoiii

Member
Dec 5, 2011
77
Well guys since oct of 2016 to now I opened the catch can up to clean and see how much oil it has gotten in. Well it's been plenty. I washed engine today and looked and was amazed how much oil goes threw here that really ends up on throttle body. Not no more with catch can.
 

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Capote

Supporting Donor
Member
Jul 14, 2014
24,227
Atlanta, GA
Well guys since oct of 2016 to now I opened the catch can up to clean and see how much oil it has gotten in. Well it's been plenty. I washed engine today and looked and was amazed how much oil goes threw here that really ends up on throttle body. Not no more with catch can.
I've thought about putting a catch can on mine, but I've just been sticking with a breather filter on the crankcase vent. Works just fine, throttle body has been clean for a long time.
 

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