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LOW OIL PRESSURE AFTER TENSIONER FAILURE

Engine, gearbox, exhaust and other drivetrain issues

Post Wed Dec 13, 2017 9:34 pm
robrac Regular
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RCZ 1.6 THP 2010 INTERMITTENT FAULT LOW OIL PRESSURE WARNING.

As a newcomer to the forum I thought I would introduce myself and let you know about something I discovered about the 1.6 THP motor.
I am a retired engineer and build F1 and F2 Sidecars. Over the years I have built hundreds of engines and problem solved for several motor dealers and teams. I have multi diagnostics including pp2000 and am based at Oswestry Shropshire.

I have been working on a Peugeot RCZ 1.6THP that came in with a variety of issues.
Codes relating to Low oil pressure …Engine Repair Needed ...STOP
This was an intermittent code, that appeared after harsh driving or cold starts!!.
A misfire was present intermittently and there were no horrendous clangs and bangs.
Codes showed all 4 cylinders inconsistent. ?? VVT out of range :crazy: because of low pressure could fit??

Striped the motor cover to see the top chain tensioner had failed. Part of the rail including one part of the inner aluminium arm was missing.
Removed the sump and deep inside the pump inlet shroud were several flat pieces of plastic. In the oil pan was the chewed up alloy arm. The oil drive chain was slack but not excessively slack. Bear in mind this is a smoking gun as the motor had thrown a low oil pressure warning.
NOW THIS IS THE INTERESTING BIT.
I connected an oil pressure gauge, connected a hydraulic rig to it and noted that the pressure was steady. I left it to settle.
I pinched the chain together to check the actual run out when I saw the pressure drop on the gauge. Now to me that was impossible so I investigated further.
Pinch the chain together hard and again the pressure dropped again, and a hiss followed by oil drops falling. Stop pinching, oil pressure steady.
The alloy piece of debris had teeth marks on it. EUREKA!!!!!!
It had failed and had fallen into the area of the lower oil pump drive chain sprocket and gone between the chain and the actual sprocket teeth.
This had locked the oil pump drive for a split second and that in turn put incredible force through the oil pump body and had FRACTURED THE OIL PUMP cast body at its rear mounting bolt. Without removing the oil pump, it was almost invisible.
Pinch the chain together (simulating a load on the chain) and the pump rear lifted about a zillionth of a millimetre from its mounting point, allowing the oil under pressure to escape….. The amount the pressure dropped was 50% on the gauge, not nice if you are putting the motor under serious load to have your oil pressure drop.
So, in view of the shock the train took, I have replaced the oil pump, all sprockets and bolts, all chains, all tensioners and guides.
Now this is an interesting point, if another owner found the debris in the oil pump pick up, they might assume they had found the cause of a low pressure code, happy to rebuild it all back up again.
That appears not to be the case. Any low oil pressure warning, no matter how intermittent should be investigated carefully IF THERE HAS BEEN A TENSIONER FAILURE.


neilgsxr69 User avatar

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Great post robrac :clap: how many Peugeot technicians would have found that out?
Nice one :thumbup:
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DKZ5745 User avatar

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:text-goodpost:

Something that you would imagine would be checked as standard, but I’d have a side bet that often it’s just the tensioner kit that’s fitted, without any further investigation.

At least now, after reading your post, it’s information that can be passed on to any dealership/mechanic dealing with any failure of this type.
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Thumbs up!
Mechanics who understand the whole engineering aspect of an engine are rare nowadays :greetings-wavingblue:

The failure you describe here drove my mechanic to replace the chain and tensioner prematurely due to very high loads on my engine. Tensioner was already leaking and the chain made loud noises during the warm up phase.
RCZ R in red. driven daily. and driven hard.
Dyno results here: http://www.peugeotrczforum.co.uk/viewtopic.php?f=20&t=10118


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