C5 X7 1.6 HDi Low Oil Pressure - To flush or not

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carlsberg101
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C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by carlsberg101 »

Sorry if this has been covered before, I did try to search and got some useful information but not specifically on flushing.

So I've got the good old low oil pressure warning and it is sounding a bit rattly up top so I figure it is a genuine thing.

I've only done about 3 or 4k miles since I changed the oil and cleaned the oil pick-up etc. etc. as part of a turbo rebuild so before I drop the sump and clean it all again I though I'd try to run an engine flush through first.

I've not flushed before and I'm reading conflicting advice so what do folks here think?

PS I'm beginning to realise why this car is on it's 3rd turbo!

411514
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by 411514 »

carlsberg101 wrote:
30 Oct 2020, 16:36
So I've got the good old low oil pressure warning and it is sounding a bit rattly up top so I figure it is a genuine thing.
I'd be a bit concerned about that - as far as I know low-oil pressure light is not known to be a liar. Combined with the rattle, that sounds like the oil pump is shot. That's going to damage the engine.

I wouldn't bother flushing, it's just a waste of oil when the existing oil is so new. But it sounds like you have bigger problems than dirty oil anyway.

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myglaren
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by myglaren »

Could be the sensor - I had a duff one some years ago. Hope it is as anything else is likely to be expensive.

lexi
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by lexi »

I would be trying to get an oil pressure gauge on it at sensor and maybe turbo. A new oil pump could be fitted before any other damage is done. Did you do the whole shebang with injector tube seals etc. If your oil pressure is good with a new oil change, then deteriorates fast, then you are making sludge, to give low oil pressure or your oil pump is worn. You obviously used the proper oil.

RichardW
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by RichardW »

If it rattles at start, and there is a light rattle at idle the pick up strainer is blocked. Drop the sump and rip the strainer out. As long as there is no strainer in the turbo oil feed banjo it will be fine. Ours ran to low oil pressure twice approx 7k after I replaced the turbo, the second time I removed the strainer and it did another 40k like that without trouble before I chopped it in.

carlsberg101
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by carlsberg101 »

Thanks guys. If it ever stops raining that's given me plenty of things to investigate.

One thing I didn't mention previously which I probably should have is the low oil pressure warning is only intermittent at the moment. It happened first time last weekend, it just came on for a few seconds at start up then went away and only came on again for a few seconds after driving for about 20 miles when I came to a stop at a roundabout. I checked the oil level which was fine and wondered if it was a faulty sensor. It was not until yesterday when it came on again but kept coming on repeatedly, but again only for a few seconds each time and only when the revs dropped when I was pulling up to a junction etc. As soon as I brought the revs up slightly it would clear the fault. This is what got to thinking maybe sludge in the oil ports or maybe that was just wishful thinking and it is the oil pump on the way out.

In answer to some of the questions. I used the correct grade of oil if not the most expensive. I was only planning on keeping it in for 6 months and then doing another oil change as I've still got a nagging doubt about this car.

The previous turbo replacement was only 12 months before I bought it and they seemed to do a thorough job, the oil pick up and oil feed banjo looked quite new and clean. I just replaced the core and inspected and cleaned all the other components. I suspect that turbo failed because I found a stray oil feed pipe washer inside the turbo which looked like it had bounced around in the exhaust inlet for a while before it jammed and destroyed the exhaust turbine, snapped the shaft and took out the compressor. So possibly a clumsy mechanic dropped it in the exhaust inlet when he was putting the new turbo in????

carlsberg101
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by carlsberg101 »

Quick Update.

I used the STP engine flush then changed the oil and filter. I have been driving it for a couple of weeks now and albeit low mileage (fingers crossed touch wood) the low oil pressure warning has not come back. Also the engine seems to be a bit quieter, or at least as quiet as a diesel can be.

I will probably repeat the process again in a month or so just to make sure any sludge is flushed out but I'm hoping it will behave itself for a little while. :roll:

admiral51
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by admiral51 »

Hi carlsberg101
Not sure where in Dorset you are but if need a Lexia session if you do not have one i am in Poole

carlsberg101
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Re: C5 X7 1.6 HDi Low Oil Pressure - To flush or not

Post by carlsberg101 »

admiral51 wrote:
16 Nov 2020, 18:21
Hi carlsberg101
Not sure where in Dorset you are but if need a Lexia session if you do not have one i am in Poole
Thanks mate. I have got it but still not too proficient but I am slowly learning.