Any ideas on the source of this oil leak?

[soldave]

I got under the car yesterday and noticed that there was a pretty significant amount of engine oil covering the underside of the mission and up along the front of it. I looked

I noticed that the turbo feed line where it went into the turbo (a HX-40) had a little wetness around it. Maybe as oil pressure increases the oil was coming out and getting blown a little back by the radiator fans, causing it to make the driver's side (left hand side as you look at the car from the front) of the engine, shifter fork bushings, top of the mission etc at the front wet. So I tightened the feed line bolt a little more. Started the car and idled it for 5 minutes and there was no visible sign of any leak.

Jump forward 60 miles and we get to tonight. I look at the car again to make sure it's all sorted and the bottom of the mission is once again covered in engine oil. All the places I'd cleaned before were wet once again, although the oil feed into the turbo looked ok. I'm not losing a substantial amount of oil but it's got me more than worried.

Especially considering I've been having a lack of boost spool (boost curve has changed shape and is coming in over 500rpm slower compared to 2 months ago). I initially put it down to an increase in ambient temperature of around 8-9C (causing similar increases in intake temps) as well as one or both wastegate springs weakening. I'm now getting scared that the oil leak might be connected to either the loss of power and/or the turbo. No shaft play in the turbo, the wheel is spinning freely and I'm getting no smoke coming out of the exhaust.

Got to clean it up on Friday and try to do more leak sourcing this weekend, but at the moment I have no idea. Does anyone have any clues of things it could be? For the record, the engine is a forged build with about 6,000km on it, and a relative compression test using a PicoScope Oscilloscope gave each cylinder a 99-100% clean bill of health. That doesn't mean the headgasket couldn't be leaking outside of the cylinder though.

 

[Focused1]

Do you have a crank vent filter installed?

 

[soldave]

Yup, 2 big custom lines going into a custom catch can/swirl pot setup.

Here are a few not very good pics:

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[Focused1]

That's a lot of oil for 60 miles. Those pics don't show the edge of the oil leak which would help with locating the source. If you can get access to a UV lamp then clean it up well and add some oil dye. Check it for dye leaks at idle and then as often as possible after driving. What is the blue hose in those pics?

 

[soldave]

It's the line going from one of my wastegates to the boost controller.

No, it's a HX-40 being fed from the oil filter housing. The feed hole from the head has been fitted with a teflon-taped hole & copper washer.

 

[Archer Fabrications]

are you feeding the HX40 from the head for some reason? there seemed to be alot of oil on that coupler. id check that, and also your valve cover gasket. the HX40 should be fed from the OFH if it isnt already.

 

[soldave]

As stated above, it's from the oil filter housing (auto-merge messing me up a little). The valve cover has also been removed, cleaned, and RTV applied to it before reinstalling to try and seal everything. The half moon piece has also been removed, cleaned up and new RTV applied onto it.

 

[Archer Fabrications]

As stated above, it's from the oil filter housing (auto-merge messing me up a little). The valve cover has also been removed, cleaned, and RTV applied to it before reinstalling to try and seal everything. The half moon piece has also been removed, cleaned up and new RTV applied onto it.

why did you put RTV on the valve cover gasket? i install all mine dry and they never ever leak. RTV the half moon only. i hope you arent reusing a previous gasket?

Edit: i hope you ARE even using a gasket...

 

[soldave]

Well the previous gasket had only done 5,000km and wasn't leaking. I RTV'd to confirm a seal onto the head (especially near the camshaft corners, which seems to be recommended), and there's no oil coming down from there.

 

[Archer Fabrications]

the milage isnt really what determines it should be replaced.. it depends on how many times its been clamped and i dont usually like it to be clamped more then twice. more pix would be appreciated of the valve cover area by the CAS

 

[soldave]

I'll take a picture later but that area is dry as a bone. The oil is on the front part of the block, below the head.

 

[Archer Fabrications]

I'll take a picture later but that area is dry as a bone. The oil is on the front part of the block, below the head.

then take a pic of the front of the block, just be more inclusive in the pix.

 

[soldave]

OK. Won't be too clear up under the exhaust manifold but I'll take one.

 

[soldave]

Coolant system checked out ok and the oil in the drivetrain is Royal Purple so I know from the smell it's not that.

One interesting thing though - I just got back from a leisurely night drive (nothing too quick and hardly ever in much boost). As soon as I parked up I popped the hood and shone my flashlight in there. As I did I noticed a little something that looked like smoke/steam (hard to say with a flashlight). It was coming from the front of my turbo blanket, which is right next to the oil feed line into the turbo. Continued to steam/smoke for a while but I couldn't get a definite fix on where from. Am wondering once again if the oil feed line is leaking. Will have to pull it tomorrow and take a good look at it. I would love to teflon tape it to seal it, but know that's not a good idea with the next thing in the system being the turbo bearing.

I really wish it would be this leaking, as in theory it should be a relatively simple fix.

Oh, and sorry for the lack of extra pics so far. Been hella busy recently.

 

[Focused1]

Without seeing more pics yet I will take a stab at it: Maybe it's coming from the grommet around the clutch fork and/or the gear selector. My gear selector constatly leak but not enought to worry about. In your pics the clutch forkl grommet is deformed and there is a gap on the left. You may have oil or trans fluid in the bellhousing exscaping from there and being blown onto the outside trans casing.

 

[FIBA M - EC17PSE]

Have you got any oil coming throught your gearbox from your flywheel? That could he the rear crank seal and ive seen it a few rare times. Or your pushing oil around the intercoolee pipes and its being pushed out with boost pressure? Just a few things to check just to make sure

 

[WES_393]

You would be amazed how small of a leak can make a mess like that, especially when coming from an area such as the turbo where oil is hot and pressurized. Just recently I spaced on the copper crush washers for all 4 drain bolts and completely soaked the trans, transfer case, etc in just over 100 miles. However, since you have some smoke coming from the turbo blanket as well as the trans being soaked, I would be equally suspicious about leaks at the feed line. If the turbo feed is in fact leaking at a fitting (and it's not -AN), I personally don't see a problem with Teflon thread sealer as long as it's done right. At least as a temporary fix until you find a new line and search for other leaks. Hell, it's better than risking an oil fire...

One other option that I rarely see done now days is the UV oil dye and a handheld black light. Hit the engine with some degreaser, pour the dye into the oil, start the car (preferably in low-light), and shine the black light around the engine bay watching for any glowing neon colors. You'll find most of your oil leaks within seconds of starting the engine. It's also completely safe to leave in the oil until the next oil change. Not sure about the parts stores over in Japan, but here in the US you can find it anywhere that sells oil and filters. Just an option to consider.

 

[kidmet]

Check the oil filter. Is it screwed in all the way? Also, the bolt that it screws into is notorious for being loose.

 

[bryanwheat]

Check the oil filter. Is it screwed in all the way? Also, the bolt that it screws into is notorious for being loose.

That is on the bottom of the other side of the engine. Kind of hard for oil to get up on top the transmission from the oil filter.

 

[jimbob_843]

Maybe a blown turbo seal? Causing oil to gather in the intake and blown out with the blowoff valve? Idk if that is even possible. Probably not need better pics

 

[Focused1]

Did you ever figure this one out?