View Full Version : Oil catch can filling up too fast

07-05-2008, 01:12 PM
Okay so i was driving down the interstate the other night and i romped on it a little bit because i drive my car like an old lady. so i hit like 5k rpm in 5th and i slow down. i look behind me and i see smoke pouring out then it stops. The next day i pop my hood and my catch can was FULL (its a 480cc can) i'm talking oil was going into my intake plumbing and into my turbo. i put in a quart of oil the day before that because it said i was a quart low so i obliged. obviously it was too much and my oil wasn't settled.

So i have oil everywhere, its in my intercooler piping because it blew off a shitload all over my hood etc... i drain the catch can, i drove the car i never really got into boost and it filled up again like 3/4 of the way and i drain it again, fills up again half way afterwards.

so i'm wondering... is it possible that i have so much extra oil in my piping that its going through my intake manifold and back into the engine and the PCV is shitting it right back out? i checked my oil yesterday because i changed it. my oil level is perfect but my catch can filled back up like halfway again. i'm just confused because i can't figure this out. sorry if i confused anybody i'm sure i probably said some things backwards.

i dunno if my setup has anything to do with it but its basically a stock redtop sr20det w/ s14 t28 and some other things. thanks.

07-06-2008, 12:15 AM
blow by is sneaking past your rings. The PCV valve will allow oil to flow into a vac source, which hopefully your can is connected to.

Also IMO sometimes the catch can causes excessive blowby from causing an added restriction on the system.

The PCV system is almost a lose lose design. Ive been fighting with it for years, wtih plenty of catch can setups. I found my PCV valve would sludge up wtih a catch can installed and the flow was reduced quite a bit.

Do you ahve a vented valve cover?

07-06-2008, 01:05 AM
i get a lot of oil in my catch can too man, but only when i am romping on it at the track. it seems that when the oil gets hot (110*C) is starts to fill up the catch can little by little. during normal everyday driving it doesnt happen though. my theory is that the oil is thinning out at such a high temperature and is flowing out the T in the valve cover straight into the catch can. many people have said that it may be blow-by but i havent had the time to go and get a compression test done yet. i would recommend not running the hose back to the intake though, under boost conditions that hose is seeing a lot of suction and it seems to actually pull the oil out of the valve cover, into the can, and into the intake system. i had the same thing happen to me and i had to take off my whole intercooler setup and clean it out. since then i havent had that hose connected and the catch can seems to fill up a lot slower. some people i have talked to here said that they have had a compression test done and it was perfectly fine, yet their catch cans also fill up crazy fast. some cars around here have this problem and some dont. what kind of oil are you running? i am using Royal Purple 10w40, but i have also heard that RP thins out much easier than other oils. i am thinking about switiching to Mobil1 15w50 because my friend runs that and his shit doesnt have the same symptoms. i am also waiting on some fittings for my oil cooler so i can get that installed. i am hoping that having that will drop the oil temps and keep it from thinning out enough to fly out of the valve cover.

07-06-2008, 02:51 AM
I think i may reroute my line from my intake to see if the problem goes away because i dont really think its my rings because my car runs fantastic other than this oil problem, pulls hard everytime i want it to. where could i run my line that goes to the intake though??? i have line "A" going from the valve cover to the catch can and i have line "B" going from the can to the intake plumbing. i think i may compression test just incase. I'm using Mobil 1 15w50 btw. I dont see why this happened all of a sudden though because i have been running the same setup for a while and now i'm having issues.

As for the valve cover being vented. No its not the only openings are the pcv and the line that goes to the back of the valve cover from the intake manifold, where could i vent it? how? thanks guys

07-06-2008, 03:56 AM
i have line "B" as you describe it, just running to air. plug the hole on the intake pipe with a cap or something, thats what i did. i am in the same boat as you though, the car runs strong as fuck and seems to have no issues except for this oil problem. im gonna try and get it compression tested this week.

07-06-2008, 02:17 PM
I am going to do that to see if anything changes, let me know what goes on with your setup. thanks.

ant s13
07-06-2008, 04:17 PM
i'm having the same problem, was told seals in turbo are going bad.

07-06-2008, 04:50 PM
i'm having the same problem, was told seals in turbo are going bad.

doubt it bro. my seals in my last turbo went bad and it was having this problem. changed out bad T25 for a BB T28 and the same shit still happens.

07-06-2008, 10:36 PM
I had to empty my catch can out again today. I dont understand how it can still make power and pull hard like nothing is wrong. when you gear brake from a high rpm like in 4th gear for instance and lets say like 5k or 6k rpm for example. your car smokes pretty bad? that is what mine is doing, only in the high rpm when its making alot of blow by. I really hope its not rings because i dont have another vehicle to drive if i put this thing on some downtime!!

07-07-2008, 01:35 AM
if your car is smoking then it is very possible that your turbo seals are fucked. that still doesnt explain the catch can problem though

07-07-2008, 08:59 AM
Mine did that with a 10w 30 so I switch to a 15w 40 and it has stopped all together. It seems tho that is not your case. I would do a leak down test and see how your rings are that will tell you something.

I'm getting a 15% drop over my #2 cylinder so I know my motor is coming out soon. :)

07-23-2008, 12:55 AM
ok well here is the update i promised. i switched my oil to Mobil1 15w-50 and added in the oil cooler. temps are quite a bit lower at the track and now the catch can collects a lot less oil. it still collects oil but not at a super fast rate like my old setup.

i went from being able to do about 3~4 laps and having the oil get too hot, to about 20 laps before the oil gets to a higher temperature. unfortunately at the temperature the oil is reaching the shit is still coming out of the valve cover and collecting in the catch can. i have ordered a 5.2" puller fan that i will be attaching to the back of the oil cooler core and hopefully that will keep my oil at a low enough temp to solve this problem or at least hinder it greatly.

i also did a compression test and everything seemed to check out good so i dont think the car has blow-by. here is what i was getting:

cylinder 4 (front-most cylinder): 135
cylinder 3: ~132
cylinder 2: ~132
cylinder 1: ~135