It was in fact 100% plugged and took soaking in brake cleaner overnight and rinsing with water to get it clean again. However I believe the culprit to be not getting the oil changed at the recommended intervals. That will no longer be an issue though now that I have taken over the maintenance.

 

The O.C.V filter is around the right and down from the OCV itself.

You can get to the procedures on the www.hyundaitechinfo.com site, go to "SHOP", then select Elantra(XD), then 2005 (which is my year), then engine. Then go to on the left side where the navigating pane is:
- Click on G. 2.0 DOHC
- Click Engine Mechanical
- Click Cylinder Head Assembly
- Click on Components and Component Location
- scroll down on the right. That will give you the overview pics
- click on repair procedures.
- On the right pane, scroll down to step 7. #1 is remove the OCV electrical connector.
- Steps 23 and 24 for removing the OCV and OCV filter

I don't think you have to really do everything to get them out. I was able to get to mine without doing any other steps.

Under installation:

step4, step 5, step 22(12) to reinstall.

Note their are some warnings/cautions regarding the OCV stuff.

I hope by putting this in a thread that comes up pretty early with google search I can save some people pain trying to find the OCV filter and OCV.

 

So the moral of my post below for those that want the point and not the story: After cleaning out the OCV filter and cleaning the OCV, you may want to keep in mind that you have possibly upset an equilibrium that your engine oil flow had reached, and might have some residual gunk get kicked up - it might be worth checking the OCV filter a couple times after this kind of service to ensure it is staying clean. And the oil light coming on could be an indication that your OCV filter got hit with some sludge.

So the full story:

I was having issues (like described in this thread) with the CAM timing over advanced and read this about the Oil Control Valve (OCV.) That's when I posted the previous post.

I cleaned out my OCV filter, and took out and cleaned my OCV as well, checked that the OCV responded to voltage per the tech bulletin - so the OCV didn't look to me like it needed replacing - put them back together, reset my code. This was back on December 11th or so.

Code stayed cleared and car ran great - I had fixed the problem! I was pretty happy.

Until yesterday, 4 weeks later. Then all of a sudden when driving, the oil low light started to come on, then stayed on right before I got to work. I added some oil - but when checking the oil level everything looked okay. On my way home, everything was fine. About 3 miles into my drive on the highway, the oil light came on again, then the check engine light came on, and the engine got really clackety clackety.

This scared me enough that I had it towed to the nearest dealership.

They indicated that the OCV filter was full of sludge, and just as a precaution the wanted to replace the OCV also. They are wanting to charge me $400. That's reasonable I guess. But the best part was when the service advisor told me it was a hard part to get to (the OCV) so the labor was kind of high. I started arguing with him (it's probably easier to get to than almost anything on the engine - having actually done it myself) but stopped myself and I'll just try to wheel and deal when I go to pick it up today.

When my car started having this stuff go on, I wondered to myself it I had "upset the balance" in my engine when I cleaned that stuff and perhaps I should just pull and check the OCV/OCV filter again. Turns out my instincts were correct, and I could have fixed this again for almost no money. The OCV itself is only $90 on Amazon ($160 is what the dealer is charging) and dead easy to install so even if I'd decided to replace the OCV this time around I was looking at only $100.

I'm learning that for some repairs (like this), DIY can save some good money and not be too hard. But my special Murphy's law kicked in to make sure that this problem was going to cost me - one way or another

 

I have a question. 2005 Hyundai Elantra GT. The CWT Oil Control Valve. The electrical plug 2 prong that connects to the control valve. What is the wire configuration plugging it in by the colors? There is a blue wire and a white wire. I have the blue plugged in then the white. Is this correct? The outer shell was damaged and I had to plug the wires back in and tape in on. Again facing the vehicle blue left white right. Can anyone help me?