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Discussion Starter #1 (Edited)
I've been noticing a build up of what appears to be oil blow-by (I'm sure there's a proper technical term for this) on the front of the plenum (which I suppose is technically the rear) and I'm wondering if I should be concerned about the amount and/or the location.

Here are a couple photo's; sorry about the low quality, cell phone camera.

its a '98 V8 with 23K miles which I purchased June this year.
 

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I would clean the area really well so you can see exactly where it's coming from before you can determine how critical it is to fix.

I have the same year with similar miles, so I'll be following this thread.
 

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Discussion Starter #3
I would clean the area really well so you can see exactly where it's coming from before you can determine how critical it is to fix.

I have the same year with similar miles, so I'll be following this thread.
Thanks; I will degrease and keep a watch on it.

I take it you don't have the same sort of oil residue?
 

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No, mine engine is very clean. But I only got it a week ago today, so maybe it was cleaned off before I got it.
 

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Discussion Starter #5
Maybe a busted EGR pipe; heard they tend to be a bit fragile.
 

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take the IAC hose, then check pipe below going to the turbo (the pipe in the drawing with the silicone hose) - suspecting a blowby oil coming from the intake....meaning oil zipping out from the piston ring. You should see good amount of oil in the plenum. If not,you are ok. (need a flashlight). Hard to take the silicone hose to see the plenum, you can only poke to that IAC pipe.

I rebuilt my engine with the same problem.
 

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Discussion Starter #7 (Edited)
Are you saying "peek" inside the plenum aperture connected to the IAC hose? and I should NOT see any evidence of oil residue?

after following up on your suggestion, maybe a compression check is in order?

no additional images at the moment; but, the same sort of residue is evident on the top right (pax) side of gear box; left side is clear.
so, I'm assuming the oil is blowing both upwards and downwards from the right side near (wish I knew more about engines) the plenum?
 

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Yes-- peek not poke.. sorry my bad.
If you see evidence of oil chances are coming from the top intake plenum.

Just to be sure,
take the passenger rear tire, you will be able to see & access the intake plenum that goes to the turbo compressor. If you can push the silicone hose away to check if the oil is going down to the turbo compressor.
Have you seen any blue smokes in the exhaust?
Try driving the car, ask someone to follow you.. see if there is a blue smokes while you are driving and shifting.

Sometimes it is hard to pinpoint if its the ring by doing a compression check. The oil in the wall will raise the compression...but it's not bad to take the compression...might as well.
 

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Discussion Starter #9 (Edited)
all good advice; I'll follow up on it to my best ability

which is not so much; I'm a computer engineer and not very experienced at this.

I understand about the compression test not being foolproof; your rationale makes sense and I should first look for more evidence... i.e. follow the trail of blowby then perhaps do the test.

the engine is finally getting cool enough to be able to get close enough to see. There's a bunch of 'stuff' in there; I see what appears to be a blue-silicone hose which might be the IAC hose; but nothing like the drawing, its all curved around and in fact, appears to be tad crimped; the drawing is probably more of a block-functional diagram; not necessarily what you're going to see. I think I'll have to remove a bunch of components to be able to get a view inside the plenum via the IAC port.

tks for input
 

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I'm a computer engineer and not very experienced at this.

Hmmmm, i'm a cisco (CCIE) guy too...voice & data routing-switching...good luck, i hope it's nothing.
 

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#1 sign an Esprit has worn or damaged rings/pistons is blow by. It will show up as oil in your airboxes, not the back of the motor, and smoking out the exhaust. If your airboxes have no oil, I wouldnt worry about a compression test.

A bad turbo will fill the inside of your charge pipes and plennun with oil but that will show up as smoke in the exhaust but no oil in the airboxes.

I suspect your passenger's side turbo oil feed line is leaking. It's a braided steel line bolted to the head to the top of the turbo. You can see it here in the oil diagram in this thread. Oil passageways? - Page 2 - Engine/Ancilliaries - The Lotus Forums - Page 2

Report back what you find.
 

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Isn't it easy to check for blow by from taking off the oil filler cap and seeing if a good breeze is coming out of there?
 

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Discussion Starter #13 (Edited)
#1 sign an Esprit has worn or damaged rings/pistons is blow by. It will show up as oil in your airboxes, not the back of the motor, and smoking out the exhaust.

I recently replaced the stock filters with K&N and happened to notice how clean the originals were. Old and dry looking they were.
I'll need to enlist a worthy observer to do the smoke test. I wiped the inside of both exhaust pipes with a white paper towel and could be my imagination, but the right side may have been darker... Of course can't get a second opinion because they're both clean at the moment.



A bad turbo will fill the inside of your charge pipes and plennun with oil...

That's going to take some serious digging to reveal...
Maybe...


I suspect your passenger's side turbo oil feed line is leaking. It's a braided steel line bolted to the head to the top of the turbo.

I saw the lines you're describing; my first hunch was oil line; glad my hunch was correct.

I'm just going to have to follow the breadcrumbs and see if there's a pattern to the source.

Actually, I have an appt with a local guy next tues for him to pull the stock cats and rear ballast (muffler) and swap in 200 cells and straight center pipes and valence. He's not a Lotus shop, but has a reputation as a smart guy so I'll show him what I've found and let him weigh in on it.




Report back what you find

Absolutely



Thanks
 

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Discussion Starter #14 (Edited)
Isn't it easy to check for blow by from taking off the oil filler cap and seeing if a good breeze is coming out of there?
Funny guy; you'll have to forgive me for being too concerned about my baby to ROFL or LMFAO
 

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Funny guy; you'll have to forgive me for being too concerned about my baby to ROFL or LMFAO
WTH are you talking about?

If your rings are worn, and you are getting "blow by" past the rings. That blow by will pump air into your crankcase and you will see that air come back out the oil filler cap since your crankcase is now over pressured with air.

What in the world did you think I was talking about that made you think your baby was being attacked?
 

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Discussion Starter #17
Overdue Update

MAP Sensor
Removed the sensor; there is what appears to be an OEM sealing rubber; orange multi-level, accordion looking thing... you can see it was partially split; pretty sure it came "out" that way.

The wall of the port was fairly clean; some grudge in the bottom (seat); I wiped it out with a qtip and also ran the other end of the qtip down inside the port to try to wipe a sample from inside (never have seen the inside) and could not reach anything solid. Did not loose the Tip of the Q; that was good. I would say it was not too bad; but, never have looked at this before.

Oh, and the gaskets between the layers (plenum/manifold/etc) are fitted and seem OK; looking at the outside edges only.
 

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Discussion Starter #18
I did manage to inspect the turbo coupling hoses and I would say right away, I'm having some leakage from the right side turbo on the compression side. The hose clamp had a few turns left in the adjustment screws and I tightened them down, both turbos.
 

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Discussion Starter #19
The intake passage of the IAC looks very clean, I even crimped a paper towel wad on a "claw", inserted it into the aperture, swirled it around and it came out with a yellow orange sport or two. No blackness, smudge whatsoever.

I'm sort of scratching my head over this at the moment. I'm thinking nothing is out of sorts with the turbo. I'll keep digging

I also ran a dewalt remote camera inside the port. Looks ok
 

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Discussion Starter #20 (Edited)
Apologies for the hugeness of that image. Now that I'm looking at it "close up" so to speak, there is "blackness" there; but, it seems baked on? The paper swab did not pick anything up...
 

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