I have asked this question to several people and seem to get different answers everytime.

There seems to be a 1mm or less thick film of black oil in the intercooler.

Shiv said this is ok and is normal.
Someone else said that this is bad and means I'm burning oil.

1. Should there be any oil at all in the intercooler?
2. If so, how much is too much?
3. What are somethings I should look for in my set up to see if the oil routing and circulation is ok?

What turbo setup do you have? I'm supposing a Minnam Stg. II (Vishnu) kit. Depending on how old it is, it is normal for it to blow some oil past the seals on the turbo, but it usually happens when the turbo is getting worn out and is almost in need of a rebuild.

Ideally, you shouldn't have any oil in there. Realistically, as long as you aren't putting a quart in a week to keep it topped off, it's not too bad.

Worn out!? Rebuild?! I just got it! Man if this is true, I'm gonna be pissed off.

If Shiv says it is normal, THEN IT MUST BE.

Actually, JC Sports told me the same thing when I noticed that about my intercooler a while back.

Larry

It is normal and it is ok up to a point. Your valve breather and PCV valve hoses are usually routed back into the intake piping. Then the oil goes throught the turbo, then IC then gets burned. The problem is, that some of that oil builds up inside the intake piping, compressor and finally intercooler. So it builds up and builds up, attracks dust and dirt and finally you have a clogged IC. Not good at all. IC efficiency goes down.

What I recomend doing is getting an oil catch can/breather valve to avoid sending the oil into the intake.

Or, clean intake piping and IC regularly. Take it off, fill it with gasoline, shake it around, drain it, repeat it and ait it out. This way your IC will be nice and clean. http://www.i-club.com/ubb-files/smilies/wink.gif

Not having seen the oil in the intercooler, I cannot be sure of the situation. But I do know that almost everyone gets alarmed with they look in the inside of their intercooler for the firt time. Loopback-- I don't know exactly what turbo your running (new, used, or rebuilt) but I do know that your IC came off an EJ20 and probably has many miles on it. And if it was never cleaned, it's likely that a lot of that oil was in there before it ever went into your car. My suggestion is to remove the IC, clean it thoroughly, install it again, drive around for a week and inspect it. If you're not sure, bring it over to me and I'll check it out. If there's too much oil, I'd suggest notifying the folks that installed and built your turbo kit. I'm sure they'll take care of it. No reason to get upset yet.

Shiv

The oil is from "blow by" and happens on all WRXs (AFAIK).

As "Imprezer" said, the way to reduce it is to use a breather - I am looking to get one.

I'm looking at this one: http://www.avoturbo.com/scans/subaru_wrx/slide9.jpg

If anyone knows of other suppliers, I would be interested as well.

Thanks

Gavin

In factory form, all oil fumes circulate in a closed-circuit setup due to emissions requirements. It is normal to find the intercooler (core and Y-pipe) contaminated with oil as a result of the factory setup. First of all, understand where the oil comes from and the effect of it in the intake.

In the EJ20 engine, there are essentially two hoses that "blows" oil from the engine, crankcase and rocker covers (left and right). The crankcase has a vent with a hose running to the Positive Crankcase Ventilation (PCV) valve, located under the throttle body. During idling, oil fume is sucked into the inlet manifold through the PCV (PCV shuts off on boost). The other source of oil is from the rocker covers. Both the left and right are T- to the turbo inlet pipe. On boost, oil fumes that's blown from the crankcase/rocker get sucked by the turbo and blown into the intercooler.

It is said that oil fumes tend to lower the octane of fuel so therefore the PCV valve is often bunged up to stop any oil from getting into the intake. In a turbocharged engine, it is normal to experience "blow by" where oil is forced past the pistons rings due to high cylindrical pressures. The higher the boost, the higher the pressure, the higher the incidence of blow-bys. To provide relief, the crankcase and rocker hoses can be vented to either an external air/oil separator or oil catch tank (difference being an air/oil separator has internal baffles to separate the mixture and has a separate vent to return the "filtered" air, while a catch tank is nothing but an empty tank). While plumbing the EJ20 engine can be slightly daunting for the DIYer, it is by no means difficult once you understand where the hoses go to ... now, I've come to conclude that different tuners tend to plumb their hoses differently but the method I used (and it works beautifully) is as per JUN's way when S. Koyama did the JUN 2.2L Stroker WRX wagon in Brunei. It has been two years since I had my Can-less setup and the throttle body/intercooler is very clean.

p.s. I have seen what happened to my friend's STi ver 3 two weeks before his engine blew (no air/oil plumbing). His stock intercooler had unusual amount of oil. Seems Apparently he was running 1.3 bar boost every day, pistons suffered from excessive blow-by resulting in alarmingly high oil comsumption and a dodgy engine metal gasket job resulted in coolant getting inside the cylinders and jammed the pistons from serious overheating !!

Gavin, before you get all too excited about shopping for an an oil/air separator or catch tank, I have once fitted the lovely Cusco catch tank to my '98 WRX wagon. It was a painstaking chore deciding where to fit the tank in the rather space-starved engine compartment ... eventually after running for two weeks and seeing that the little can isnt much good, I chucked it in favour of an "open" system whereby the crankcase hose would vent-to-air and the rocker hoses connected to a K&N crankcase (ironic term) filter. The crankcase hose doesnt require a filter as it is blowing all the time. The rocker hoses, on the other hang, sucks filtered air from the air filter (in a factory setup) but blows on boost. Hence is is necessary to stick a filter here.

Lastly, I have taken pictures of my engine compartment with illustration on how to DIY an oil/air/catch tank plumbing using some 6mm (could be 8mm, have to measure them again) hoses, clamps and a K&N filter (tank optional). I am more than happy to share these pics with anyone who wants them.

Jan Shim
janshim@brunet.bn

Thanks everyone for your answers!
Well I just cleaned my intercooler and I'll be taking a look next week as shiv recommends. And it seems that a certain amount of oil is normal.

I installed the K&N breathers on the crank case and on the valve cover of my SVX turbo. This has worked well. The only thing is I smell tar once and a while when driving hard. No big deal. Its worth it to keep that crap out of your turbo.

My JC Sports turbo kit comes wth and air/oil seperator, or "vacuum chamber" - only a small amount of oil gets into my turbo inlet. I am told when I run water injection, this oil will keep my MAP sensor from rusting...

It also keeps emissions down, which is why I run 2 cats with my turbo kit.

Larry

Great post, Jan. I would love to see the photos and instructions.

Oh yeah, one other thing that didn't get mentioned is the BOV ... I don't know what the setup is on your car Rick, but on WRX's it vents back into the intake, sucking whatever is behind the throttle body with it.

Oh yeah, totally forgotten about the BOV. I have been running a Sard Racing BOV since day one 3 years ago and it hasnt given up yet unlike the Apexi Twin Chamber unit that so often fails over here.

The factory BOV is again another component that circulates back into the intake to complete the "closed circuit" environment. Called an "air by-pass valve" the factory BOV "actuated by the vacuum created by a sudden closure of the throttle valve, allows suction air to by-pass the turbocharger and pass directly upstream, thus lowering the pressure in the air passage" ['98 Workshop manual]

There are many controversies surrounding the use of externally venting BOVs in conjunction with the factory ECU. One of such arguments is that by NOT venting back to the intake, air goes unmetered and therefore sends the ECU to pump more fuel off throttle and many argue that this momentary "rich" condition shortens the life of the O² sensor. I'd like to think that the good side of running a ex. venting unit is to have all the crap blown out of it, perhaps dirtying the engine compartment a little bit http://www.i-club.com/ubb-files/smilies/wink.gif.

Photos have been emailed. Apologies for not having a website to host 'em pics.

Jan

Last thursday I installed a Cusco Catch Can...When I pulled the IC it was clean. But the Throttle body was dirty and the hard lines that cross in front of the IC had oil collected in them.

I Connected the PCV valve vent, and the Valve cover vent with a brass 3 prong Tee, to a single line to the Can, then one line back to the intake. I capped the the second inlet on the intake left over from the Valve cover vent. Took about an hour.

Ken
Ken