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RCZ 1.6 THP 2010 INTERMITTENT FAULT LOW OIL PRESSURE WARNING.

This is going to be relevant for all 1.6 THP based motors.

I am a retired engineer specialising in race F1 and F2 sidecar and car engines. I have have been working on a Peugeot RCZ 1.6THP that came in with a variety of issues. PP2000.

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. Could this be because of low pressure?? that could fit??

I 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 running to check integrity.

I pinched the pump drive 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!!!!!!

That alloy piece that failed 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 to the naked eye and was almost missed.
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 past the mating surfaces….. The amount the pressure dropped was approximately 50% on the gauge, not enough to do instant damage, but not very 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.

If it has happened once.....................
 

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Very interesting.
I think it quite likely than someone without a mechanical engineering background could easily miss this. Even a competent mechanic could miss this one, especially considering they might be working under pressure to get the job done on time.

Roger.
 

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the chains on the thp are prone stretching, throwing up vvt codes and noisy valves.
well done, first iv heard of taking the oil pump out.
 
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