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Discussion Starter · #1 ·
A month or so ago the turbo failed. Had lots of smoke from the exhaust and oil all over the engine bay.
Removed the turbo and found lots of play ion the shaft, so bought another turbo (used) which seemed in good condition and fitted it. Removed intercooler, turbo oil return pipe, cam cover, PCV valve and gave them a thorough clean.
As soon as I started driving the car again I noticed a pool of oil appeared under the front when it was parked, and the cambelt end of the engine soaked in oil.
Inspection showed the oil was leaking from around the cam, so I replaced the cam oil seal, timing belt and tensioner and alternator drive belt.
Then when I drove the car again oil was leaking from the joint between turbo and oil return pipe.
Yesterday I fixed this problem and drove for about a mile, and left the dipstick sticking up a bit to hopefully allow any excess pressure to escape without blowing another seal or gasket.This didnt help though as when I parked up it had an even worse oil leak. I havent dismantled anything to inspect it yet, but initial examination suggests its now coning from the bottom of the turbo oil return pipe where it goes down into the sump.
Last night I removed the glowplugs and poured a capful of ATF into each cylinder hoping to free up any stuck rings.
I think Ive made a mistake there as I refitted the glow plugs.
It might "hydraulic" if I try to start it ? I think I will take the plugs out again and wind it over on the starter for a bit, to push out any ATF which hasnt seeped down the sides of the pistons.
In summary Im not sure if I have a crankcase pressure problem or Ive missed something along the way and am barking up the wrong tree.
Any tips on how to come to a definite diagnosis please ?
All suggestions welcome. Im very close to giving up on it altogether.

Thanks in advance.
 

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It might "hydraulic" if I try to start it ? I think I will take the plugs out again and wind it over on the starter for a bit, to push out any ATF which hasnt seeped down the sides of the pistons.
This...deffo spin any engine over to blow out excess if you have added fluid into the pots.

Your oil problem....... oil level being too high is a common cause of oil leaks.
PCV valve stuck closed is a second.
 

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Discussion Starter · #3 ·
Oil level is slightly below Max on the dipstick.
I have taken the PCV valve apart twice, cleaned it out thoroughly and checked the diaphragm and spring ,which both seem ok.
When I put it back together I held a finger over one hole while blowing and sucking down the other. I could hear the spring moving in and out, so assumed its doing what it should.
Im leaning towards worn / stuck rings, but cant be sure it isnt something Ive missed or done wrong.
Im not that familiar with these engines.
Is there any method of establishing how much crankcase pressure there is, and how much there should be ?
 

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Discussion Starter · #4 ·
Oil level is slightly below Max on the dipstick.
I have taken the PCV valve apart twice, cleaned it out thoroughly and checked the diaphragm and spring ,which both seem ok.
When I put it back together I held a finger over one hole while blowing and sucking down the other. I could hear the spring moving in and out, so assumed its doing what it should.
Im leaning towards worn / stuck rings, but cant be sure it isnt something Ive missed or done wrong.
Im not that familiar with these engines.
Is there any method of establishing how much crankcase pressure there is, and how much there should be ?
Thanks for the tips and info by the way.
 

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IT's identifying the underlying reason.
Some of that would be where the leaks are occuring.
Cam seal is unpressurised so leaks would suggest crankcase pressure or overfilling.... or simply worn out and is a coincidence.... or your turbo fail caused low oil so some seals ran dry and could be you are chasing those.

Turbo feed is a pressurised system so crankcase pressure unlikely to affect.
System relief valve not operating properly could be an issue.
But AFAIK, the return pipe is simply that, an open return to the sump.
I would be removing pipe and ensuring no blockage... a turbo fail could have stuffed burnt gunge down the pipe?
Or it could be a failed seal?
If that seems all good, getting a pressure gauge into the system... can be teed into the oil pressure sensor port.

As for the pressure in the sump?
Should not be high but that is as far as I would go, dunno a value.
On older engines the filler cap was simply an open cap with a mesh filter..... common way to check for ring issues was to leave it off and run the engine.... you would soon see fumes if combustion gasses were getting into the sump.
Plus don't forget yours is a diesel, they rely on compression so ring problems are likely to give starting or running issues.
 

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Discussion Starter · #6 ·
I should have mentioned, I have removed the turbo oil return pipe to check it was clear, and it was fine.
Turbo blew about 4 miles from home, and when I got home the oil level was still above MIN on the dipstick, so shouldnt have caused any damage.
Im sure your correct. Return pipe is just an open return back to the sump.
It seems that each time I make sure a leak is properly fixed, the oil finds the next weakest place to find a way out.
Im actually surprised it hasnt blown a crank seal..................yet !
When running it runs fine apart from revs surging at tickover, which had been a problem before any of the current problems appeared.
I will take the glowplugs out, wind it over, then put them back and fire it up and see if anything has changed.
Then either report back or get a box of Swan Vestas from the village shop.
Thanks again for the advice Dancingdad.
 

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Discussion Starter · #7 ·
Been for a drive again. A lot of blue smoke from the exhaust initially to burn off the remains of the ATF presumably, and it then ran ok.
When I got back the oil leak seemed less than it had been, so its just possible that the underlying cause has been cured and I now just need to fix the leak.
Wont know until I try, but if the weather holds I might get back on it this afternoon.
I hope this will be the last time I have to take the cat off and put it back. Im getting really tired of that now.
 

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Discussion Starter · #8 ·
Im not there yet, but thought I would update on progress.
Removed the cat again and confirmed oil is now leaking from the bottom of the oil return pipe.
I removed the pipe and found the reason is that it has a small crack at the bottom, no doubt caused by me when I was struggling to remove it the first time I took everything apart.
Now need to source a pipe which is easier said than done by the look of it.
Part number is 8200-714 637, and the only ones on ebay at the moment are used ones from abroad which are around the £80 mark !
Cant imagine what Renault charge for a new one.
Looks to me like the kind of thing that should be less than a tenner, but then I am old.
Might look into the possibility of getting it brazed, as its too thin to weld.
Once thats sorted, fingers crossed and hope it will be oil tight again.
 

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Can you post a picture of said part
 

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Discussion Starter · #10 ·
There are quite a few which appear similar for various k9k installations, but this is the one I need.
 

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So the crack is on the outside then,
Clean it and cover with Araldite if its only the return
ALLOW the araldite full curing time, before refitting,

Repaired the megane over 4 years ago with araldite, and still good now
 

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Discussion Starter · #12 ·
Great idea. Will give it a try, thanks. The crack is on the flange where it fits into the block, but doubt that will make any difference. Hopefully Araldite will do the trick.
 
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