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How to prevent injector seal failure and turbo failure on 1.6HDi engines.

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Wed Feb 05 2014, 07:50am
Member No: #15026
Joined: Aug 12 2010
Location: Bedfordshire
I have been researching this as it seemed to be a common issue and injector seals are not a part that should ever fail in a diesel engine. After reading lots of posts from both HDi and Ford 1.6TDCi owners, I have found the very simple solution to preventing huge repair bills.

Every 1.6HDi owner should tighten the injector retaining bolts.

The problem is the injector retaining bolts are very cheap metal and stretch over time with the heating and cooling of the engine. This then leaves much less than the required torque on the bolts and injector seal leak starts. Citroen now use a different bolt to prevent this problem and I have been told there is a technical bulletin to dealers to check the torque of these bolts at service time. When injector seals start leaking, there is no evidence. No loss of power, no rough running etc. The engine just slowly contaminates the oil with soot, which blocks filters and starves the turbo of oil causing turbo failure.


Tools Required: 6mm and 7mm Allen keys.

1. Remove the plastic engine cover so the injectors are exposed.

2. use the 6mm allen key to undo the two bolts securing the wiring loom across the top of the engine so it can be moved out of the way to get at the rear four injector retaining bolts.

3. Use the 7mm allen key to re tighten each of the bolts (two per injector). You need to crack off each bolt gently, just enough so that it moves, then tighten.

They should not be overly tight. There is a torque specification of 4NM + 65 deg turn.

I just did mine by feel but used a small crescent wrench on the allen key as I needed a bit more leverage than I could get on the short end of an allen key. Six were very similar torque so I just turned them 1/4 turn tighter. Two (on injectors 2 and three) were quite a bit looser so I tightened them to a similar torque as the others.

My engine is now noticeably smoother, with less vibration after doing this and I can drive happily knowing that I am not likely to have a major repair bill on the horizon.
7 User said Thank You to JohnC4GP for this Post :
 Dave_Retired. (05 Feb 2014 : 12:33) , Storman (01 Jun 2014 : 02:12) , Ballistic (26 Aug 2014 : 08:44) , brum1steam (03 Aug 2015 : 03:30) , Willswheels (29 Mar 2016 : 16:27) , Jc4130 (20 Jul 2018 : 05:02) , c4gpharold (27 Dec 2018 : 08:05)
Wed Feb 05 2014, 08:16am

Member No: #82
Joined: Jan 22 2007
Location: Hoylake
Cheers! Good maintenance advice.
Wed Feb 05 2014, 09:04am
Member No: #28268
Joined: Nov 22 2012
Location: north wales
I can see where you are coming from and see the point. I also think it is not a bad idea to tighten the bolts slightly further after a couple of thousand miles with the problems the HDI engines have.
though the 1/4 turn extra (90 degrees) sounds a lot to me after a torque of 4NM plus 65 degrees.
Sat Mar 29 2014, 02:13pm
Member No: #11964
Joined: Jan 05 2010
Location: Glasgow
how tight is overly tight. All mine where loose to the point I could tighten with my hand (no 3 chuffing). I done them all with an allen key then used a spanner to give me a little more purchase.

BTW thanks for the info.

Sun Jun 01 2014, 02:20am
Member No: #35762
Joined: Jun 01 2014
Location: Mornington
Thanks for the post on this problem checked today 3 injectors just over hand tight, tightened engine now running noticeably smoother.5 door 08 80000klms.
Thu Jul 31 2014, 02:23am
Member No: #21107
Joined: Jul 31 2011
Location: Ruislip, Middlesex
This is good advice, and does explain - given I had injector seal failure at the beginning of the year - why my turbo failed yesterday
Mon Aug 25 2014, 12:45pm
Member No: #37059
Joined: Aug 23 2014
Location: North Wales
Something I've not been able to get my head around yet is how does leaking injector seals introduce the carbon into the oil? I would've thought you would just get 'chuffing' and some fuel/air mix escaping around the seal to the outside atmosphere but I can't see how the carbon deposits build up in the oil as a result? I know I'm being thick but even after googling it I can't find an explanation as to how it happens so if anyone can enlighten me that'd be great
Mon Aug 25 2014, 01:13pm

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
If the seal is leaking and fuel gets pushed out to the cylinder head top on the compression stroke, the same cr*p can get sucked back in on the down stoke would be the obvious answer plus the unburnt fuel gets added to the sump oil diluting it's lubricating effect.
Mon Aug 25 2014, 01:15pm
Member No: #11964
Joined: Jan 05 2010
Location: Glasgow
Could be something to to with the fuel/air burn mixture. The gasses escaping gets into the oil and contaminates it. Or it could cause the mixture to burn hotter.

Don't know if the above is true, but seems to me to be the only explanation.

Sun Sep 28 2014, 05:44am
Member No: #27768
Joined: Oct 13 2012
Location: Hove
I've had exhaust fumes in the cabin for weeks now but not seen any evidence of a leaking injector until today. I'll have to give this a go when I get home.
Mon Sep 29 2014, 01:19pm
Member No: #27768
Joined: Oct 13 2012
Location: Hove
Got home this evening & was surprised how loose the clamps were on cylinders 2 & 3

Anyway tightened now so fingers crossed.
Tue Mar 17 2015, 02:57pm
Member No: #12402
Joined: Feb 08 2010
Location: Chester
Are these steps relevant for an '09 2.0hdi? I've removed the engine cover but the injectors are tucked away right at the back of the engine - I can't even get a proper look at them let alone get any tools in there.

There doesn't appear to be a wiring loom either, just individual connections running to each injector. I guess I need to disconnect these to get at the bolts - do they just pull off or is there a knack? I don't want to start blindly pullling at things that I dont have a good view of!

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