Intercooler Drain Plug?

This may be old news, but it's news to me. Anyway, while changing the oil on my 1998 (A3) Jetta TDI Saturday, I noticed that there was a lot of accumulated oily crud on the panel underneath my intercooler. I removed the panel and inspected it.

I found that this rubber piece:



wasn't properly seated into this hole:



(Here's what it looks like properly seated:


)

I haven't dumped kerosene down into my intercooler to test it out, but based on the fact that the oily goo seemed to be originating from there I'm inclined to believe it's some sort of drain plug. This would be a much simpler way to drain cleaning solutions from the intercooler post cleaning than cracking the seal of the intercooler hose (the one with the blue writing on it in the pictures above) with a screwdriver (like Tongsli and I did back in July with messy results).

My intercooler's not due for a cleaning for a while, but maybe someone can check this out and report back.

[ January 01, 2002: Message edited by: Beowulf ]</p>

Ok, ok,

Why must we always bring up my messy work? Hmmm?LOL!!

Stephen, that's an interesting thought. Is it possible to find a place on the OEM intercooler and drill and tapp a NPT hole and place a 1/2" plug with a washer? I'd think that you'd just need the lowest spot, and a nice thick piece of metal to do the drilling? What do you think?

Lito

An idea I had was to drill an extremely small hole in the intercooler at the lowest point. This way the intercooler is self purging. But now the other issue is the oil mess that can buildup on the belly pan. I have no concerns about the hole affecting performance since it would be so small.

Or you could reroute the CCV or make a homemade CCV filter like the Racor unit...

DB

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by tongsli:
Ok, ok,

Why must we always bring up my messy work? Hmmm?LOL!!

Stephen, that's an interesting thought. Is it possible to find a place on the OEM intercooler and drill and tapp a NPT hole and place a 1/2" plug with a washer? I'd think that you'd just need the lowest spot, and a nice thick piece of metal to do the drilling? What do you think?

Lito<hr></blockquote>

Sorry, Lito. You have been taking it pretty hard lately. I made a fair mess myself.

Anyway, do the A4 intercoolers not have this hole and plug setup? I wonder if other A3s do. I swear it looks for all the world like a drain plug.

The idea of a home made drain plug system would have to be better than the "crack a hose" method where kerosene runs all down your arm.

i've never had any oil leak out of my 02 TDI but recently saw a couple of spots on the driveway.

Based where the drips were I immediately knew they were coming from the intercooler.

Sure enough, upon inspection there is oil oozing out of the lower connection point (I see a short tube section connecting the actual intercooler and the snorkel looking tube that runs back to the turbo). Anyway, I recall having loosened this connection several months back and now think that it wasn't seated all the way, and thus, oil is leaking from there.

My main concern is: how much oil is in there?? Could it get sucked into the intake manifold and cause a hydrolock situation?

I'm not in the mood to remove everything to get to the intercooler for removal and am wondering if anyone has had success with putting a self-tapping screw in for periodic draining/maintenance?

Thanks for any insight~~

You can keep the intercooler clean with your right foot. Get the boost up on a regular basis to increase airflow though the intercooler to slowly burn the oil. This also keeps the boost pressure up on the sealing ring on the turbo shaft, helping to keep that oil in the turbo and out of the intake track.

yea, it will never get full up, because of the air flow, it will just sip it now and then lol

Drivbiwire said:

An idea I had was to drill an extremely small hole in the intercooler at the lowest point. This way the intercooler is self purging. But now the other issue is the oil mess that can buildup on the belly pan. I have no concerns about the hole affecting performance since it would be so small.

Or you could reroute the CCV or make a homemade CCV filter like the Racor unit...

DB

Click to expand...

It would be a small leak, routing it to the crankcase would mean the dirt not removed by the air filter will now be in the oil. Best bet would be a small trap and vent the leaking air to the CCV.

I drilled and tapped a 6/32 screw in all three of the turbos at the lowest intercooler point. A small oring seals the screw. Remove and give the car a bit of boost and all the oil comes out. I would not keep the hole open as the system is very sensitive to leaks and you might have a strange whistle.

I would only do the 1/2 MPT if you frequently go visiting with a bore scope

so is there a consensus that accumulated oil in the intercooler will NOT get sucked into the intake and cause a hydrolock catastrophe?

ReferenceDesign said:

I would not keep the hole open as the system is very sensitive to leaks and you might have a strange whistle.

Click to expand...

This could be an alternative to those stick-on things HERE.

madrean said:

so is there a consensus that accumulated oil in the intercooler will NOT get sucked into the intake and cause a hydrolock catastrophe?

Click to expand...

The velocity through the IC is rather low. Most of the oil ends up there, further cleaning the air . The oil getting past the IC will slowly creep up to the intake manifold where it will seep into the engine.

Now if the turbo grenades and the entire crankcase dumps into the IC, it might make it to the engine before the bearings starve.

ok-- i've got it now and don't feel as worried about a surge of oil making it into the intake manifold..

I wish it were easier to just pop off one of the connections and move it out of the way to drain it.

thanks for all the input

I have a niece who babied her NB too much. She lives in Phoenix, so it was really strange when I saw that she was idling her car to warm it up before heading off to work. She said that it would surge* if it was cold. That was about the time that a new TB was due, so I checked, and sure enough there was at least 200 ml of printer's ink in the intercooler. I drained it of course.

After the TB was changed, engine warmed up, we went for a spirited drive. The first flooring of the go-pedal generated a huge cloud of smoke easily visible, even though it was midnight.

The car quit surging after that. So did the clouds of soot.

*Surging - rpms running from idle up to about 1200 and then back down to about 800 before recovering, but doing the cycle many times by itself.

well, all i can say is trust me, i don't baby it. i regularly put the pedal to the medal, er plastic and redline through the bottom 3 gears.

where i think my problem lies it that when i put in some pp520s about 40k mi ago, i didn't have the ecu remapped/programmed. i used my VAG-COM to check the timing and it seems to be ok, and disabled the EGR and tweaked the IQ. nonetheless, i have a persistent plumage even with barely moderate acceleration.

if the fuel mixture is too rich could this be causing a buildup that is leaking back into the intercooler?

is reprogramming absolutely essential? seems like my mileage has never been the same since i put in the nozzles, even when i've tried not "using" the extra power..

since giving up on getting my mpg back up, i just have fun with the increased performance. so once again, i don't think my problem is from a lack of spirited driving..