oil light flickering

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Originally Posted by justinc

DO NOT jump to conclusions until a proper gauge is connected and testing procedure performed!


JC

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I understand what you are saying Justin, but on my reading of the manual (I'm very happy to be corrected) the operating oil pressure is listed as 25-45 lb/sq in - a huge range? I could find no notation for idling oil pressure.

Obviously if you (or anyone else) can advise me on correct expected oil pressure idling and operating for a 300tdi I would appreciate it.


And thanks too Reads90 and Dave, I will check crankcase pressurisation.

G'day.

Most likely your scenario is different to mine, but here it is FYI. My 300TDI has 150,000kms on it.

Some time ago now, I had the oil light flicker on a really hot day, after a freeway hill climb I pulled over to use my phone, with the revs dropping when the air con came on. Without the air con, the revs were still high enough. The lesson here I think is that only a small drop in revs can be enough to bring on the oil light. Something to consider.

Another hot day I was sitting in traffic, air con on, and it was happening again. A few grams of weight on the accelerator was enough to stop it.

I started a thread about it and big end bearings were suggested if mileages was circa 300,000kms. At the time I was running 5W-40 oil. Since I've changed to 15W-40 and currently 15W-50 penrite. Haven't had it happen since. Far from conclusive proof, but it's worth considering too...

So to end my long post with a question, what oil are you running?

A while ago I was trying to track down an oil leak in the area of the filter housing on the 300TDI (was an o-ring eventually) but in the process changed the oil pressure sender. Not long after the oil light flickered on idle when hot, nothing else changed to create the symptom. I took the new sender off and compared it with the old one, I found that on the new sender the hole where the oil enters was much smaller than the old one. I put the old one back on as it was not the cause for the leak, just to see if it went away. No more oil light flickering. The part number was right but it was aftermarket. I'm not sure if this was the reason but it was 50K km ago and its been OK with the old sender. So if you do change the sender compare the two first so you are not at an immediate disadvantage. Simon

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Originally Posted by Reads90

Most of my experience with diesels and oil lights flickering on tick over. Which I happen to add my new 200tdi disco does too. I that it is crank case pressure

I am taking it that mine is crank case pressure. Caused by worn values, rings or something along those lines.

To check this start the engine and take of the oil filler. If is chugging like Thomas the tank engine then there your problem. The other way is when it is running take out the dipstick. If it covers you in oil then you have crank case pressure.

This will also cause oil leaks as there pressure in the engine is finding ways to get out of the engine. A defender I had a few years or so ago did this and ended up blowing oil out the rear main oil seal.
BTW all the time through this is did not blow blue smoke or show any other signs of bracketed rings or values hence why I do not look here first.

Ali

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Ali,
How can low oil pressure be the result of high crankcase pressure?
They are both symptoms of a worn engine.

Tony

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Originally Posted by TonyC

Ali,
How can low oil pressure be the result of high crankcase pressure?
They are both symptoms of a worn engine.

Tony

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Yeah seem your point but last time I had a flickering oil light was on a 2.5 N/A 90 and it turn out to be crank case pressure which ended up blowing oil out the rear main. Total engine rebuild was done


But as for the flicking oil light on my 200 TDI disco. I thought another rebuild was in order. Not that I was too worried as it is a cheap disco and has 450,000 on it. So you have to be realistic.

. But after buying a new oil pressure switch for $15 it has gone now and no oil light flickering. Still runs sweet as a nut.

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Originally Posted by TonyC

Ali,
How can low oil pressure be the result of high crankcase pressure?
They are both symptoms of a worn engine.

Tony

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it doesnt, it causes oil leaks.

a severerly restricted air filter (garbage back sucked into the airbox horn) can cause low pressure at idle as the crank case pressure is reduced by the scavanging system.