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Post by djm16 on Feb 28, 2019 11:36:31 GMT
It starts off good when cold, and gradually drops over about 30 mins as the engine warms up. What is very strange is that if you turn the engine off for only a few seconds and restart, the oil pressure goes back up again, almost to the cold value. This effect is absolutely repeatable every time!
OK, this is not a Rover engine. It is a 2.2 litre turbo diesel, by Shibaura / Perkins and is resident in a CAT 226B skid steer. It is relevant to Rover in that I am borrowing it from my neighbour in order to clear a pad for a new shed to put the Rovers in.
So far, I have drained the oil, flushed out the oil pan and inspected it for cleanliness with a fibre-optic camera. The oil pan cannot be removed without lifting the engine, or I would have done it.
I have replaced the oil pump, which was shagged and incorrectly mounted in the first place, with three of the commnunicating passages obscured.
I have replaced the oil pressure relief valve. I have even diasassembled the old relief valve and polished the piston and bore to be certain it could not be sticking open.
Despite all these things, and despite the oil pressure now being improved at cold start up and hot idle, the oil pressure as monitored on a capillary gauge and on a mechanics gauge still goes through this hysteresis when hot. I have searched the internet in vain for anyone else who might have experienced this.
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Post by Brendan69 on Feb 28, 2019 19:53:34 GMT
If she runs and drives ok then I would not worry about it.
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Post by enigmas on Feb 28, 2019 23:40:55 GMT
It starts off good when cold, and gradually drops over about 30 mins as the engine warms up. What is very strange is that if you turn the engine off for only a few seconds and restart, the oil pressure goes back up again, almost to the cold value. This effect is absolutely repeatable every time! OK, this is not a Rover engine. It is a 2.2 litre turbo diesel, by Shibaura / Perkins and is resident in a CAT 226B skid steer. It is relevant to Rover in that I am borrowing it from my neighbour in order to clear a pad for a new shed to put the Rovers in. So far, I have drained the oil, flushed out the oil pan and inspected it for cleanliness with a fibre-optic camera. The oil pan cannot be removed without lifting the engine, or I would have done it. I have replaced the oil pump, which was shagged and incorrectly mounted in the first place, with three of the commnunicating passages obscured. I have replaced the oil pressure relief valve. I have even diasassembled the old relief valve and polished the piston and bore to be certain it could not be sticking open. Despite all these things, and despite the oil pressure now being improved at cold start up and hot idle, the oil pressure as monitored on a capillary gauge and on a mechanics gauge still goes through this hysteresis when hot. I have searched the internet in vain for anyone else who might have experienced this. Ok so it's not a V8. As you haven't had the sump off you can't thoroughly clean the pan or oil pump pickup screen. This could be a sludge related issue (due to turbulence when the pump is drawing oil(?) I had something similar with the V8 in my Rover but the issue was noisy hydraulic tappets on startup...for a period of time. I intially put it down to age related parts. Some time later I carried out a mild engine refurbish...new brass welsh plugs, timing chain set, water pump, etc. I also removed the sump and cleaned out 20 years of accumulated sludge although I always changed the (quality) oil every 6 months. What I found was that paint inside the pan had lifted and stuck to the mesh of the oil pump strainer. This reduced initial 'cold' oil flow (although the pressure appeared excellent. Tappets quietened after warm up. Since cleaning the pan and oil strainer...no more tappet noise on startup! * Another possible issue is that you have a dodgy oil filter...try a different brand as weird as this may sound.
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Post by djm16 on Mar 1, 2019 22:44:32 GMT
Thanks for the reply. Sludge was high on my list too. While it is true that I could not get up close to the oil pickup screen, the bottom of the oil pan was shiny metal as viewed on a fibreoptic scope.
It does occur to me that the oil pump pickup tube is sucking air. The tube was replaced under warranty 10y ago by CAT (who deny to me doing any such thing) as this was a known problem (one of many with these engines), but it is just possible it is fractured again, even though it only has 1600 hours on it.
Lifting up the engine is probably more than I am prepared to do to an expensive machine for free that does not belong to me, and the owner is talking about just selling it. But I don't like mysteries.
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Post by Phil Nottingham on Mar 6, 2019 22:57:22 GMT
All the above but has the oil filter head a bypass valve which should only open when the filter is blocked. The spring can weaken or some crud is lodged on the ball seating. I had this with our 3 Litre - the pressure just dropped once the oil slightly warmed up and was OK again on restarting only shortly after
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Post by djm16 on Mar 6, 2019 23:24:44 GMT
That seems like an excellent suggestions. I will look into it and report back.
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