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 FAQ #110
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C4 1.6 HDi Oil Changing and Turbo Failure
The commonest reason for the 1.6HDi turbos to fail is due to poor maintenance, and poor oil quality.... or not being drained properly at the service. Citroen have in fact issued dealers with a specific bulletin for the changing of oil in the 1.6HDi. What they are saying is that if not drained 100%... old oil can pollute the new oil causing accelerated ageing of the new oil in the engine possibly even causing it to congeal.

Citroën wrote ...


It is necessary to follow a specific oil change procedure on all DV6 and DV6U engines so as to ensure that no used oil remains to mix with the new oil.

The following method must be used:

• The engine oil temperature must be at least 50°C :
- the engine oil temperature is considered to be at 50°C when the water temperature indicator is between 80°C and 90°C or the cooling fan has cut in
• ensure that the vehicle is level (side to side and fore and aft)
• remove the oil filter to allow the circuit to drain completely
• remove the oil filler cap and the dipstick
• remove the drain plug
• allow the oil to drain by gravity for at least 10 minutes (DO NOT USE SUCTION METHODS)
• fit a new oil filter
• refit the drain plug with a new sealing washer
• fill the engine with quantity of oil recommended for the engine
• refit the oil filler cap and the dipstick
• run the engine at idle until the oil pressure warning lamp goes out (about 1 minute)
• wait 5 minutes
• check the oil level using the dipstick: the level should be as close as possible to, but not exceeding the maximum mark (1) so as to be between (1) and (3)

For information, the lower mark (2) = Min (0%) the upper mark (1) = Max (100%) the intermediate mark (3) = ¾ litre.


If the customer does not have the oil changed at the recommended intervals, the oil will become excessively polluted and will no longer ensure the correct lubrication of the engine. One of the first consequences is inadequate lubrication of the turbocharger bearings causing a failure which is repeated after the turbocharger is replaced. Subsequent symptoms resulting from the reduced level of lubrication will be a noisy engine and then destruction of the engine.

We remind you that if the customer does not keep to the servicing intervals recommended in the Maintenance and Guarantee Guide, the customer will be responsible for the durability of the mechanical parts of the engine.
In this case, the any related repairs needed are not covered by the new vehicle warranty.


If the oil changes are not done as described above, all deposits of old oil will not be removed and will very quickly pollute the new oil, accelerating the ageing of the oil in the engine lubrication circuit (even causing the oil to congeal).

The consequences for the engine are the same as if the oil change intervals are not observed. As a result, any related repairs needed are not covered under the new vehicle warranty.


We are a Diesel Turbo Specialist workshop in South Africa.

The Citroen C4 1.6 HDi turbo has been replaced last year November because of the Turbo Wailing like a police siren.

The car came back last week with the same noise to the turbo, so I took the turbo off to inspect to find

that the Turbine blades ( hot side ) have been damaged from foreign object from the engine. The foreign object

hit it out of balance so that's why it sounds like a police siren. A Citroen specialist says it can be carbon build up in the engine that can cause this? The engine still runs smooth with no problems.

I will insert some pics to show this.

We have fitted a new turbo and the car seems to be fine, no probs.

There are big problems with poor oil change routines on 1.6HDi's causing oil clogging in cylinder head galleries, turbo supply lubrication pipes etc which is the cause for repeated turbo failure.

When replacing a failed turbo it is imperitive to replace the oil supply/return pipes. You also need to remove the sump and check the gauze on on the pump for any blockages.

Finally a good check so see if there is serious internal blockages, remove the brake vacuum pump - there's a little gauze inside that. If that has signs of blockage then you've got some serious internal clogging going on.

We've had a brand new turbo literally fail within 100 mile from the impellor seizing up and the nut which secures it on the shaft coming undone and wedging in the fan blades. This particular one was an extreme case and ended up having a new engine!

C6 Dave wrote ...

It's possible that all the carbon build up is due to poor oil quality.

The HDi's require a ' Low Saps' oil

There is an ongoing thread here on oil: - Click Here -

gmerry wrote ...

The thing to realise if using a forum such as this for information, is that just like Wikipedia, because it's posted does not necessarily make it true. For example, buying an oil just on SAE viscosity rating is a recipe for problems: the industry in Europe (ie ACEA) stopped using this other than as a marketing label years ago.

The nasty end of the lubricant blenders/marketers can use some pretty cheap base stocks, throw in some polymers and the viscosity ranges (SAE variety) will look fine on the can. Might not last very long in the engine though.

There is a good presentation on Southern Lubricants website by Total explaining the thinking behind ACEA service fill specifications for PSA FAP equipped diesels like our 2.7HDis

- Click Here -

In the Lube Library under Total open the presentation named Low Saps details

Look at the photo of the fouled EGR valve when using a normal non " low SAPS" oil.

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FAQ Posted by Phil
Info Created: 04 May 2009
Last Updated: 03 February 2014
Herongate 09 Jun 2010 : 08:39

This happened to my last C4, for exactly these reasons, at 110k miles. Absolutely essential that the oil sludge is drained properly.

I now have another C4 after sadly writing off the first one in a shunt, my only ever biggish bang, category C.

Arvid 19 Jun 2010 : 03:21

Here in Norway the workshops are using something called "engine flush". This is some special liquid designed to clean out oil sludge. When this is done, engine is ready for the new oil.

abiec 07 Sep 2011 : 06:26

I had a no turbo boost on my c4 1.6hdi. Took it into the citroen dealer and said that no errors where found. I took my car to a friend of mine that specializes on turbo's. He stripped the turbo with the waste gate. The waste gate was clogged with carbon. He cleaned it up, put everything back together and all is back to normal. in fact my cars performance and feul economy is much better that before. I am getting 20km/l in town which for me is very very good.

C6 Dave 15 Feb 2012 : 12:10

Please post any help requests in the forums, not in 'Comments'

wiki 24 Jan 2013 : 12:25

Turbo failure associated with blocked oil feed on diesels are NOT caused by oil change issues. They are caused by leaking injector seals. These allow hot gas into the cam box and this carbonised the oil. These hard particles will block the turbo oil feed filter and the main sump strainer. A quick check for an impending problem can be done by removing the brake servo pump and checking its oil strainer. Any bits of carbon and you have a problem.

Often the injectors come loose over time and the problem can be cured by just tightening the bolts. Ford (same engine) recommend checking these bolts at certain intervals. Citroen don't!

If you don't cure the cause, your new turbo won't last long.

gmerry 25 Jan 2013 : 07:10

Good practice as part of the oil change procedure is to examine the oil filter surface (cut out a section and then unfold) for any metallic or carbon particles.


lister45 28 Feb 2013 : 02:16

Thank you Wiki I have just replaced my turbo and all oil lines, unblocked my sump pick up that was completely blocked. It has been fine but noisy, just tightened the injector bolts and now the motor is much quieter as it used be. So looks like I was heading towards another issue so I am so glad I read your post re loose injectors. none of these things were diagnosed by any mechanic so thankyou!!!!

rc84 20 Sep 2013 : 02:31


Could I ask how to check the guaze on the pump as referred to in the OP, is is the oil-pickup/strainer, or is there another gauze actually in the pump ? :

"When replacing a failed turbo it is imperitive to replace the oil supply/return pipes. You also need to remove the sump and check the gauze on on the pump for any blockages. "


paulmonks 25 Feb 2014 : 08:01

This happened to my C4 1.6 HDI.... 06 plate with 104k miles on the clock.

Bought it from a trader, less than 3 weeks later had a loss of boost and engine management light on. Diagnosed the following morning by "my" mechainc.... fault code was EGR Valve...... took it back to dealer and thier mechanic confirmed error code reading, took EGR valve off, cleaned it up, socked it over night and put it back on and hey presto...... Nothing happened.

Further inspection was that the turbo had failed completely and blown it's self to bits.

Now for the fun part, the traders mechanic's (who I will say are a good, honest bunch of boys) confirmed to me that they had previously worked on the car as it came to them a few week before with a failed turbo and were instructed to simply "replace the internals"..... thus not solving the underlying issue.

So.... they agreed to put a recon turbo on the car, new oil feed pipe (GMF Motor factors and LDS Motor factors would not give a warrenty on the turbo unless the oil feed pipe was bought).

This did still not solve the problem....... as the turbo had sucked oil out of the engine and thrown it into the intercooler.... So..... You guessed it..... They had to replace the intercooler as well.

I worked it out that parts alone would have been over £450 never mind the labour......

I think myself lucky that I bought the car and it went bang so quickly as I would be cursing if this was 6 months later down the line.

From now on i'm going to give the car the same treatment as I used to give my nissan 300zx twin turbo..... oil change and engine flush every 5-6k Miles..... Hopfully this will stop the turbo from failing ever again.

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