oil smells like fuel after 500 miles.

[scuzzy]

I changed to Synethetic Castrol 10W30 recently; this fixed a few problems:

Oil leaks due to a rear main seal, I was running 5W30 dino oil and the heaver weight oil (at cold) had stopped the seal from leaking as much as it was. now I wake up to a few drops on my floor instead of a sizeable spot.

Having to change my oil every 3000 miles.

I'd hoped this switch would get me 5000 miles or more, in the old oil I always smelled fuel slightly, but this has a fairly strong smell as if there's more fuel in the oil.

Interestingly enough, I did a compression check maybe a month ago and all of the numbers turned out just fine; Cylinder 1 was a little lower than the rest (145 I believe, all the others came in at 150 on the nose) so I suspect the rings are just beginning to wear on that cylinder.


I have the PCV system hooked up just as vrg3's data sheets show EXCEPT: I do not have the plastic crossover piece that connects the front passenger side (closest to radiator) vents for both valve covers to the center engine block vent (under the manifold)

I've got all of the other hoses hooked up just as in the diagram, I'm sure that's needed for something but I didn't think it was that serious (considering that there were two sources of air to the system already)

What is the specific purpose of that hose? should I find a way to reconnect the three together? I left it disconnected before (when the engine was installed) because the plastic piece doesn't fit under my manifold, at least not when I tried last..

I did check my PCV valve, when I put my finger over the hole (with the hose disconnected and the idle running) the valve clicks and I can feel suction on my fingertips, when I take my finger off it clicks again.

The hose that connects to this valve (with the engine running) doesn't have a steady suction on it like I thought it would; not at idle or while revving the engine (granted, this isn't load on the engine) it's kind of a push/pull thing, if I've got my hand over it I can feel the puffs and suction, if I put my hand on it I can feel very light suction. I can't tell when the engine revs, it's much akin to having the oil cap loose and the cap just bouncing there in place, trying to get blown off and then pulled back down.

any thoughts, especially from vikash? I know this fuel smell in my oil isn't normal and I'm afraid it's going to damage my bearings if I don't figure it out soon enough. I did clean the PCV valve but it's been a little while ago, it functioned and rattled normally.

Additionally, the hose that connected the PCV valve to the crankcase breather thing that goes down to the oil pan was nearly clean of oil; maybe a very light residue. It's been two months so far, I figured there would be more oil residue in there. the valve itself also looks relatively clean.

As a test, I disconnected the hose that goes from the other side of this breather from the inlet side of the turbo, plugged both pieces to where the breather is just going to the PCV valve, I still felt the suction push/pull thing so the action is definitely coming from the crankcase, after a day of driving the smell of fuel is no lighter, maybe stronger by a bit but the nose isn't that precise.

Thoughts?

[douglas vincent]

Pull your injejctors and replace the 0-rings. I bet you have a slight cut in one.

[vrg3]

I don't know for sure what that extra little tee thingie is for, but I'd guess it has something to do with evening the pressure across the two heads and the crankcase.

Did you just leave them all open to the atmosphere? If you did, you're letting the oil get contaminated faster by whatever random stuff happens to be flying around the engine bay. Also, it'll inhibit the creation of a vacuum in the crankcase by the PCV system, which would explain why you don't feel suction where you should.

Also, it'll reduce the ability of the rings to seal, so you'd contaminate the oil with fuel faster.

[scuzzy]

I don't know for sure what that extra little tee thingie is for, but I'd guess it has something to do with evening the pressure across the two heads and the crankcase.

Did you just leave them all open to the atmosphere? If you did, you're letting the oil get contaminated faster by whatever random stuff happens to be flying around the engine bay. Also, it'll inhibit the creation of a vacuum in the crankcase by the PCV system, which would explain why you don't feel suction where you should.

Also, it'll reduce the ability of the rings to seal, so you'd contaminate the oil with fuel faster.

no, it's not open; if it wasn't connected to something I capped it off with RTV and the little red caps that came with the engine when it was boxed up. Been like that for two years and no problem yet.


doug: I used a light weight oil when removing and installing my injectors; the rings are fine; I've pulled them twice and on both cases the o-rings were flawless, so there's no sense in me believing that bad rings on my injectors are causing it to wash down the cylinders and contaminate my oil (it would run like shit anyway; and it doesn't)

[vrg3]

I don't really understand the whole PCV system, but I'd say you should try connecting those remaining fittings before doing further diagnosis. You can just use some 1/2" heater hose and a 1/2" barb tee to connect them; I would just try to make sure that the length of hose is about the same on each side.

[scuzzy]

I don't really understand the whole PCV system, but I'd say you should try connecting those remaining fittings before doing further diagnosis. You can just use some 1/2" heater hose and a 1/2" barb tee to connect them; I would just try to make sure that the length of hose is about the same on each side.

what i don't understand is that if those hoses/fittings have anything to do with this problem, why was the problem not showing up before the oil switch? I'm not blaming the oil, I'm just saying that's the great marker here; the change of the oil came with the smell of fuel - but it could be that the old oil just did a better job of covering the smell up.


I'll do another compression check tonight or sometime this week, to see if cylinder 1 is getting worse; I was hoping someone understood how the PCV system worked, because I sure as hell don't. the PCV valve is closed at idle, and I figured it would be open then not closed. if it's closed while on vac, and it closes when under boost (the other direction) then when is it open? at 0 vac?

[vrg3]

Oh yeah, I was gonna say but forgot -- different oils will respond differently to contamination, so it's possible the new oil is not actually getting more contaminated with fuel than the old oil. Like you say, it might just not be covering the smell up as much.

The PCV valve's operation isn't that simple. It's not an open-and-closed valve; it's a regulator. It is in fact partly open at idle. It opens more as the flow through it decreases, though. It is also a one-way valve, though, so it only allows gases to flow from the crankcase into the intake manifold and not vice versa.

Have you seen this thread? http://bbs.legacycentral.org/viewtopic.php?t=16496

[scuzzy]

oh, thought I'd update.

well I did my oil change recently; the first change was approximately last week of Feb; same for this recent change, last week of May.

So that's about three months of service and approximately 4500 miles.

Oil that came out of the pan was black as soot, or not far from it; but it flowed smooth and I didn't lose any oil - the smell also didn't get stronger. I let it drain for a good period then put two quarts back in the pan and a new oil filter.

drained the two quarts after running the engine at idle for a short period (2-3 minutes); boy it went from an almost clear color to a light brown (oxygen, foaming, etc)


important to note that the smell didn't go away, but it didn't get worse either; I suspect it's relatively normal for my car. I also capped one of the lines from the pan to the PCV valve and did find there was plenty of suction there (the cap has started to bow inwards under the suction)