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oil and exhaust leak


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Car has been sitting for a while, and when I started it up, there was smoke in the engine bay.  It smelled of oil too.  Underneath, I found loose bolts into and out of the catalytic converter, and while tightening them up, I found possible culprits to the smoke.  I am completely missing a stud on the exhaust manifold, and also have a loose nut, both on #1 cyl.  I also noticed an amount of oil clinging around, and seemed to be associated with the forward blanking plug.  It's sticking out of the block by a few millimeters, so I thought maybe it has worked loose, but I see other pictures where that looks about right, so I'm not 100% sure if that's the origin.  The cam cover seems clean and dry, so I don't think it's leaking down.  Possibly something at the front of the head?  I'm having a hard time with the hex size on the blanking plug.  Anyone know?  I've tried 4mm, too small, 5mm too big.  I don't have a 4.5 - is that the one I need?  I hijacked a picture from Travis and drew on it to show the location.

As for the manifold stud, I was able to verify that it hadn't sheared off, so I'll just contact JAE for replacement.  Do you think the leaky oil helped it work loose?  I did notice that the lock tabs were not bent up as they should be.  I never really noticed before, but I'll remedy that.  DPO  :thumbdown:

exhaust side questions.jpg

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The blanking plugs seal the oil gallery. Im not sure that tightening it will make any difference as they are supposed to be inserted with Permabond A134 IIRC, to make the seal complete. Im not sure if there is anything to be gained otherwise? Just my thoughts. By the way it is a 1/8 the BSP dowel, not sure on the hex size.

Same applies to the exhaust manifold studs using Permabond A025.

Caught between a rock and a hard place in a catch 22 situation, So its 6 of one and half a dozen of the other. Your damned if you do, but your damned if you don't so shut your cock!!!!!!!!!!!

Lotus Espirt Turbo S3    

Lotus Esprit S4 

Lotus Elise S2 Sport 130

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I was planning to remove the blanking plug and reinstall with new sealant to see if that would help.  I wonder how much oil might come out behind it?  Can't be too much up there after the engine not turning for months, can there?

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Russ,

Having worked on quite a few 910 engines, I have never seen a blanking plug leak although it's certainly possible. I have seen a persistent small leak in that area at the corner where the cam tower meets the cylinder head just above that blanking plug. There is an oil feed roll-pin and o-ring at that area which I think causes the problem. Pulling the cam tower and re-sealing it correctly with a new o-ring will probably be the ultimate solution...

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1995 S4s

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13 hours ago, Russ91SE said:

 Can't be too much up there after the engine not turning for months, can there?

HehHeh, let us know the answer to that question when you remove the plug. :P

 

Pools of oil are always retained in the cam carriers after shutdown especially in the exhaust carriers. :)

 

 

 

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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Yeah, thanks for the vote of confidence, Atwell.  I just feel lucky I don't have leaking gas tanks again!  :unworthy:

 

Jim, I've cleaned the area around there as much as I can, so maybe if it starts a fresh mess I can figure where it came from.  The blanking plug just had the biggest drop of oil, so that along with it sticking out attracted my attention as the culprit.  I had assumed it was supposed to be more flush.  If it doesn't show any new signs of leakage, then I probably won't disturb it.  Your suggestion sounds more legit, but that looks like a bit of a job to get the cam tower off.

 

 

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Update from the past weekend.  I didn't see any fresh leak around the blanking plug.  In case anyone else wonders, it's a 4.5mm hex bit.  I got one and gave it a wiggle, but it didn't want to move, so I left it alone.  The cam cover is clean, but the cam tower to head area may be the culprit as mentioned above.  I also read a thread over on Lotus Talk about others who had manifold studs work loose.  Someone else mentioned the area behind the stud threads is pretty thin and could become compromised allowing leakage.  Seems like a long shot, but could that assist the stud to work loose?  The stud has been replaced with appropriate threadlocker and nut tightened to spec.  I'll run it a bit and see if any new oil shows up.  At least I feel comfortable that the exhaust manifold, cat, and muffler are secure again.

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Just to chime in with my experience - it's probably the cam tower to head. When I start up my SE for the season after a winter it always smokes for a couple of minutes as the oil burns off the manifold. Scared the bejesus out of me the first time, but now it's just par for the course. Really gotta get that sorted one day.

But after the initial burn off I never see smoke during regular use.

Do you have oil pooling around the spark plug wells? If you do, there's your culprit. I wouldn't lose any sleep over it. 

 

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Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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Thanks for posting your experiences, Vanya.  I started my Esprit up recently after a 4 month break, and saw the same oil smoke symptoms.  Cleaned everywhere and couldn't see anything obvious, but suspected the lower cam cover, even though it had had a new seal early last year.  No oil in spark plug holes (had seen this before).  As you say, it went away and I haven't seen any obvious oil collecting, so hoping it's as you say.  Will keep an eye on it, but doesn't seem as if it's going to be a real problem.

Cheers,

Trevor

 

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Thanks for chiming in, Vanya and Trevor.  The spark plug wells are, and always have been, clean and dry.  I cleaned as much residue as I could from the manifold and lower block, then ran the engine for a bit until the smoking stopped.  I hope, as you say, that running the car more will reduce or eliminate the smoke in the future.  It was sitting far too long without running last year.  Now moving to the next jobs, bleeding the clutch and checking the brakes...

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  • 6 months later...

I'm having similar problems - oil leak from the exhaust cam housing, progressively getting worse. A couple of months ago I took the cam cover off the housing and tested the tightness of the bolts holding the cam housing onto the cylinder head - used my torque wrench set to the right number. All but three of them were OK - did not move - but three of them just turned freely - evidently stripped. So that's probably the cause of my leak. I will need to install helicoils. Anyone else come across this problem before? Looks to me like the engine has got to come out for that job...

Steve

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  • Gold FFM

Very, very common.  And you can do the job insitu, although access to a couple on the exhaust side is quite tight.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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2 hours ago, Sparky said:

Very, very common.  And you can do the job insitu, although access to a couple on the exhaust side is quite tight.

Thanks for that - did you have any tips or photos of how its done?

Steve

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  • Gold FFM

Depends on your level of expertise!  The job involves cambelt removal.  If you've tried to tighten the bolts then you already know how to get the towers off.  Do you have a workshop manual?  Even if you have, you'd do well to bone up using forum search.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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Just to add a bit for anybody looking for possible culprits to that spring "oil burn off".

 

The o-rings in the back of the cam tower get baked by turbo heat and often fail.  Oil from there drip quite nicely onto the back part of the exhaust manifold.  An easy and cheap fix worth looking into if you have the issue.

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  • 3 weeks later...

Quick related question to the original post.

I'm missing an exhaust stud/nut from my 88 Stevens N/A that has seemingly shaken itself out thread still fine..

Is it an M10 that I can get anywhere or will I need a genuine stud - I've seen this part listed on SJS  

A912E2529F

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I'm going to work on the basis it is a M10 stud, but buy from SJS as although you end up spending £5 it's still a small amount to be sure of the right part.

On the subject of exhausts,

While the rear discs are off and car up in the air with access, has anyone used exhaust heat wrap on their manifold or even just the exhaust section on the near side that generates a lot of heat near the brakes?

It seems a cheap purchase but I wonder if it would affect the tone, or prove to be a moisture trap and prematurely age the exhaust? 

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