1.9dci high oil consumption. PCV valve, and oil seperator
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1.9dci high oil consumption. PCV valve, and oil seperator
Hi all,
Thought I'd make a post about the issues I've had with my Megane 1.9dci.
Got the car very cheap from my Brother who works in the trade. The car had blown its turbo, which was replaced with a brand new one.
First few days, I fell in love with it. Plenty of power,quiet,handles well, what else do I need to say. After a couple of weeks, I chucked her round a sharp right hander, and the oil warning flashed up briefly. The oil level indicator on the dash is crap, DO NOT trust anything they say. Topped it up, and carried on. A day or two later, the engine "ran away" using its own engine oil. Luckily, it was at low speed, and a stamp on the brakes to stall her, prevented it revving freely. Started it, and away it went no problem. It did this once more, before I had chance to read up on this forum about possible causes.
On opening the bonnet, I noticed oil pooling under the damper valve, so somehow oil was making it through the turbo, and into the intercooler. I suspect, that because the engine now had the correct amount of oil in it according to the dipstick, the level was higher, making this possible.
My solution:
Remove the oil seperator pot on the front of the engine. When I did, oil ran out of it. It did this because the pipe that runs from the bottom of it, back to the sump, was absolutely blocked solid. I cleaned the whole thing, and made sure the pipe that runs into the sump was clear. It's not very big, and easily becomes clogged. When it does this, oil fills the tank, which is then drawn out of the top of the oil seperator, through the PCV valve, and into the inlet system.
All cleaned and sorted, I kept my eye on things.
It seemed ok, so decided to take the car to France. Watching like a hawk, it became apparent she was still burning oil, and at a higher rate than it should (about 500ml/250 miles). I kept it topped up, and brought her home. Incidentally, the run down to Bordeaux, returned 48.1 mpg ! and I was "making progress" occasionally
I've been keeping an eye on things since, and doing a lot of reading (mainly on her...thanks all). Next suspect was the PCV valve. It's very easy to remove, and inspect, and not a problem to open up. Simply pry the top of with two flat bladed screwdrivers. Inside, should be a spring holding a diaphragm. This should be free to move, and normally should be in the open position. Mine wasn't, it was absolutely caked in crud and carbon, stuck wide open.
The valve works by allowing some of the crankcase gases into the inlet system. In normal operation, at tickover, the valve is wide open, allowing gas to flow freely. At medium power, the valve is beginning to close, and reduces this flow. At high power, the vacuum from the inlet system sucks the diaphragm down onto its seat, closing it, and stopping the gas flow. Blowing through the valve is useless as a way of testing it, it needs to have a vacuum applied to the inlet manifold side, to "suck" the valve shut. If it isn't doing this, all the hot oil vapour from the crankcase is being vacuumed into the inlet, and burnt as fuel. No wonder he oil consumption is so high !
I have just ordered one from the local Renault dealer. They could not find the part from the part number, which was strange?
It's being fitted tomorrow, and I will update you further.
Philthy
ps, mods, I have some photos that may prove useful to attach to the post if possible?
Thought I'd make a post about the issues I've had with my Megane 1.9dci.
Got the car very cheap from my Brother who works in the trade. The car had blown its turbo, which was replaced with a brand new one.
First few days, I fell in love with it. Plenty of power,quiet,handles well, what else do I need to say. After a couple of weeks, I chucked her round a sharp right hander, and the oil warning flashed up briefly. The oil level indicator on the dash is crap, DO NOT trust anything they say. Topped it up, and carried on. A day or two later, the engine "ran away" using its own engine oil. Luckily, it was at low speed, and a stamp on the brakes to stall her, prevented it revving freely. Started it, and away it went no problem. It did this once more, before I had chance to read up on this forum about possible causes.
On opening the bonnet, I noticed oil pooling under the damper valve, so somehow oil was making it through the turbo, and into the intercooler. I suspect, that because the engine now had the correct amount of oil in it according to the dipstick, the level was higher, making this possible.
My solution:
Remove the oil seperator pot on the front of the engine. When I did, oil ran out of it. It did this because the pipe that runs from the bottom of it, back to the sump, was absolutely blocked solid. I cleaned the whole thing, and made sure the pipe that runs into the sump was clear. It's not very big, and easily becomes clogged. When it does this, oil fills the tank, which is then drawn out of the top of the oil seperator, through the PCV valve, and into the inlet system.
All cleaned and sorted, I kept my eye on things.
It seemed ok, so decided to take the car to France. Watching like a hawk, it became apparent she was still burning oil, and at a higher rate than it should (about 500ml/250 miles). I kept it topped up, and brought her home. Incidentally, the run down to Bordeaux, returned 48.1 mpg ! and I was "making progress" occasionally
I've been keeping an eye on things since, and doing a lot of reading (mainly on her...thanks all). Next suspect was the PCV valve. It's very easy to remove, and inspect, and not a problem to open up. Simply pry the top of with two flat bladed screwdrivers. Inside, should be a spring holding a diaphragm. This should be free to move, and normally should be in the open position. Mine wasn't, it was absolutely caked in crud and carbon, stuck wide open.
The valve works by allowing some of the crankcase gases into the inlet system. In normal operation, at tickover, the valve is wide open, allowing gas to flow freely. At medium power, the valve is beginning to close, and reduces this flow. At high power, the vacuum from the inlet system sucks the diaphragm down onto its seat, closing it, and stopping the gas flow. Blowing through the valve is useless as a way of testing it, it needs to have a vacuum applied to the inlet manifold side, to "suck" the valve shut. If it isn't doing this, all the hot oil vapour from the crankcase is being vacuumed into the inlet, and burnt as fuel. No wonder he oil consumption is so high !
I have just ordered one from the local Renault dealer. They could not find the part from the part number, which was strange?
It's being fitted tomorrow, and I will update you further.
Philthy
ps, mods, I have some photos that may prove useful to attach to the post if possible?
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- Passed Theory
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Some more info in case it proves useful:
The car is a Megane senic 1.9 dci with the 120bhp engine (turbo diesel). I don't know if it has the "fap" thing?
The car is a Megane senic 1.9 dci with the 120bhp engine (turbo diesel). I don't know if it has the "fap" thing?
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Hi
To attach the photos you will have to upload them to a site like photobucket and then use the image tags to place in your post
To attach the photos you will have to upload them to a site like photobucket and then use the image tags to place in your post
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- Passed Theory
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Thanks Freelander.
Well, the stage is set. Replaced the valve, topped up the oil to exactly the top mark, now I've got to get some miles done and see if it's made a difference?
Some pics that may help others?
The PCV valve with the top prised off, showing the diaphragm completely stuck to the top:
The PCV valve part number 3911171919 (not recognised by Renault)? The part number that is on the label of the new part is: 8200576778
The Renault parts exploded diagram showing the valve (component 10):
Well, the stage is set. Replaced the valve, topped up the oil to exactly the top mark, now I've got to get some miles done and see if it's made a difference?
Some pics that may help others?
The PCV valve with the top prised off, showing the diaphragm completely stuck to the top:
The PCV valve part number 3911171919 (not recognised by Renault)? The part number that is on the label of the new part is: 8200576778
The Renault parts exploded diagram showing the valve (component 10):
Last edited by Philthy on Sat Aug 22, 2015 7:33 am, edited 1 time in total.
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Your photo are not showing ,have you used the correct image tags
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- Passed Theory
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Is it ok now, I realised that, and edited the source?
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Phil,
Did you notice any improvement?
My 2004 1.9dci (117k) has been using oil excessively for over 2 years! It was extremely bad at one point. Cleaning the oil return bottle and pipework made a huge difference (as you have done) and similar to yours (250ml every 500 miles). I suspect the seals on the recon turbo fitted at 80k are allowing oil into the inlet system as I do need to clean the intercooler every 6 months or so. The car isn't worth and otherwise runs ok so I've lived with the oil consumption.
I've also found the internal oil level reading can't be trusted. The daft dipstick attached to filler cap doesn't help either.
Did you notice any improvement?
My 2004 1.9dci (117k) has been using oil excessively for over 2 years! It was extremely bad at one point. Cleaning the oil return bottle and pipework made a huge difference (as you have done) and similar to yours (250ml every 500 miles). I suspect the seals on the recon turbo fitted at 80k are allowing oil into the inlet system as I do need to clean the intercooler every 6 months or so. The car isn't worth and otherwise runs ok so I've lived with the oil consumption.
I've also found the internal oil level reading can't be trusted. The daft dipstick attached to filler cap doesn't help either.
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Forgot to ask - how much was the PCV valve? The code you gave appears to include the pipework too and comes in around £65 on a Google search.... ouch!
Re: 1.9dci high oil consumption. PCV valve, and oil seperator
let me tell you I story...
I bought my 1 owner serviced same place every 3000 mile car to 25k and the oil was beautifully clean for the first 1000 miles I had it...
At about 2000 miles I noticed the turbo sounding louder and when I blipped the throttle it behaved in a manner that left the gear box with a slight rattle due to engine revs falling away in a peculiar manner...
By 3000 miles it was worse and I dipped the oil and rubbed it between my fingers and had not felt anything like it... it felt sticky rather than slippy so I changed it immediately and the engine behaved perfectly on blipping the throttle and the turbo was much quitter and over the following days became almost inaudible...
I can only assume the garage that serviced it regular every 3000 miles once a year, were using the wrong oil and for it to affect engine and turbo I would suggest it was poor quality mineral oil that was used..
No lasting damage....
But I would encourage anyone to watch out for these clues when buying and have to confess despite being skilled enough to strip an old vw petrol block from a scrap sirocco car and use it to replace a damaged one in an old 1.5 diesel golf rabbit - I got caught out and didn't ask about the obvious too regular oil changes as I never envisaged a garage stupid enough to stick mineral oil in a diesel....
would certainly gunk the oil ways up given time or servicing as per Renault intervals...
I bought my 1 owner serviced same place every 3000 mile car to 25k and the oil was beautifully clean for the first 1000 miles I had it...
At about 2000 miles I noticed the turbo sounding louder and when I blipped the throttle it behaved in a manner that left the gear box with a slight rattle due to engine revs falling away in a peculiar manner...
By 3000 miles it was worse and I dipped the oil and rubbed it between my fingers and had not felt anything like it... it felt sticky rather than slippy so I changed it immediately and the engine behaved perfectly on blipping the throttle and the turbo was much quitter and over the following days became almost inaudible...
I can only assume the garage that serviced it regular every 3000 miles once a year, were using the wrong oil and for it to affect engine and turbo I would suggest it was poor quality mineral oil that was used..
No lasting damage....
But I would encourage anyone to watch out for these clues when buying and have to confess despite being skilled enough to strip an old vw petrol block from a scrap sirocco car and use it to replace a damaged one in an old 1.5 diesel golf rabbit - I got caught out and didn't ask about the obvious too regular oil changes as I never envisaged a garage stupid enough to stick mineral oil in a diesel....
would certainly gunk the oil ways up given time or servicing as per Renault intervals...
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Hi guys. Early days, so can't tell the difference yet, I'll keep you posted. I have been keeping an eye on the engine to see if any pipes have blown off, or any other signs of crankcase pressure. Thankfully, there aren't. The part had to come with the pipes, and was £76! That's steep for what is a very simple valve. The pipe that goes down the back of the engine is a pain to get to, so I didn't replace that pipe. I'll do it when I get it on the ramp, and can get the belly pan off.
Fingers crossed.
Fingers crossed.
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
A thought has occurred to me. Given how easy it is to access this valve, it could probably be tested using a vacuum cleaner attached to the inlet side? It has to be a vacuum to draw the valve down to its seat.
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Found this in one of the .pdf's linked from this site:
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
Having seen that this valve has a much smaller breather hole in the image above, I decided to have another look at the old one. Sure enough, it's there. It was completely blocked, and covered with gunk. I had to scrape away the crap to find it.
You can see it in this photo:
If this hole is blocked, as well as the diaphragm, it will cause a lot of crankcase pressure! I would suggest that anybody who has crankcase pressure problems, and oil being blown out of the engine, checks this valve. I wouldn't be surprised if it is very common?
I've done 100 miles since I changed the valve, and when I checked earlier, it doesn't appear to have burnt a drop of oil? It's hard to tell for certain yet, as these dipsticks are useless, but it's looking promising?
I'll update you when I've done some more mileage.
You can see it in this photo:
If this hole is blocked, as well as the diaphragm, it will cause a lot of crankcase pressure! I would suggest that anybody who has crankcase pressure problems, and oil being blown out of the engine, checks this valve. I wouldn't be surprised if it is very common?
I've done 100 miles since I changed the valve, and when I checked earlier, it doesn't appear to have burnt a drop of oil? It's hard to tell for certain yet, as these dipsticks are useless, but it's looking promising?
I'll update you when I've done some more mileage.
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Re: 1.9dci high oil consumption. PCV valve, and oil seperator
An update:
The new PCV valve has made a difference. I've done nearly 500 miles since I changed it, and it doesn't appear to have used much oil. It is hard to tell with the useless dipsticks that they are fitted with, but does still appear to be burning some.
One of the things that I've noticed during the course of my fault finding, is that there is still oil vapour coming out of the pipe from oil seperator to PCV valve, so I'm going to fit an oil catch can with return to sump, and get the oil back where it's supposed to be.
I'll keep you posted.
The new PCV valve has made a difference. I've done nearly 500 miles since I changed it, and it doesn't appear to have used much oil. It is hard to tell with the useless dipsticks that they are fitted with, but does still appear to be burning some.
One of the things that I've noticed during the course of my fault finding, is that there is still oil vapour coming out of the pipe from oil seperator to PCV valve, so I'm going to fit an oil catch can with return to sump, and get the oil back where it's supposed to be.
I'll keep you posted.
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