Oil Pressure!!!
Discussion
In my excitement to go out in my S (V8) this evening I did not check my oil! Big mistake 
after a quick blast down the motorway the oil pressure suddenly dropped to almost zero at tick-over 
as I approached a roundabout and my revs dropped - I pulled over quickly (I could not pull-over immediately due to other traffic). I assumed it was due to a lowish oil level, and the oil getting thinner as it got hotter -I waited a while (to cool down), checked oil, topped up and carried on my way home very gently - above 2000rpm the oil pressure was fairly normal, but at tickover dropped to almost zero.
Have I killed my S??
From the bible, I think that I could have air in the oil pump, but would think that this would mean no oil pressure when above tickover?
Has this happened to anybody else?............help
after a quick blast down the motorway the oil pressure suddenly dropped to almost zero at tick-over as I approached a roundabout and my revs dropped - I pulled over quickly (I could not pull-over immediately due to other traffic). I assumed it was due to a lowish oil level, and the oil getting thinner as it got hotter -I waited a while (to cool down), checked oil, topped up and carried on my way home very gently - above 2000rpm the oil pressure was fairly normal, but at tickover dropped to almost zero. Have I killed my S??
From the bible, I think that I could have air in the oil pump, but would think that this would mean no oil pressure when above tickover?
Has this happened to anybody else?............help
Was the oil level extremely low? Oil pressure that low at 2000 rpm doesn't sound healthy, and the low oil level / hot oil theory doesn't really account for this much pressure loss.
Edited to add: it might only be a stuck oil pressure relief valve or broken spring, so needn't necessarily indicate a severely worn engine. But it might do.
>> Edited by GreenV8S on Monday 25th April 22:30
Harry - No oil warning light at any time. Would worn bearings be excessively noisy?
GreenV8S - Oil level was approx half way between min & max on the dipstick. Oil pressure todate has been between 25-40psi (from gauge) at normal running speed, and approx 15-20psi at tickover which I believe is ok (inspected by RI).
Has only covered 59k with FSH?
I very briefly started him up (after 2 hours sitting) to see whether a cool off had helped? The oil gauge stayed just above zero, and with a very gentle blip of the throttle to take the revs above tick-over, the needle seemed to jolt upto a more normal pressure (as above), until the revs are reduced to tick-over when it drops to just above zero??
I agree that a low-loader to a garage (Austec?) is the way forward
Larry
GreenV8S - Oil level was approx half way between min & max on the dipstick. Oil pressure todate has been between 25-40psi (from gauge) at normal running speed, and approx 15-20psi at tickover which I believe is ok (inspected by RI).
Has only covered 59k with FSH?
I very briefly started him up (after 2 hours sitting) to see whether a cool off had helped? The oil gauge stayed just above zero, and with a very gentle blip of the throttle to take the revs above tick-over, the needle seemed to jolt upto a more normal pressure (as above), until the revs are reduced to tick-over when it drops to just above zero??
I agree that a low-loader to a garage (Austec?) is the way forward
Larry
That sounds less alarming then. I wonder whether the problem may simply be with the oil pressure sender. It's your engine at risk, but if I was in your situation I would feel comfortable driving it gently to somewhere for a check over as long as the indicated oil pressure was always above a couple of psi, and it went up to 15+ psi at 1500 rpm. It's not at all uncommon for tired old engines to lose virtually all oil pressure at tickover and there's no harm as long as oil still is being supplied (although at minimal pressure) and as long as the oil pressure picks up at normal revs.
. I'm sure Paul at Austec will sort it out one way or the other in short order. From what you say though it could be minor sender/relief spring, as the dip stick reading stated is nothing to worry about IMHO. I have a 2.9 V6 that has the same problem, however I have had the problem for 6 months and as there is no knocking from the big ends, nor any other untoward sounds and the oil is clean and steady between max/min then I have concluded that it is likely to be a problem with the sender. 
S3 Rich said:
I have spoken to a couple of tiv specialists, & they all say the oil pressure senders are as prone to failing as much as a TP.
Yes mine had been replaced on the old car for a similar problem, I think that I have seen postings saying that the V8's do run lower oil pressure than the V6's though.
From your post about oil level, it appears to me that you were only about a litre off max level, I wouldn't have thought that disasterous.
Cheers for the responses
I have booked the 'S' into Austec for a 12,000 mile service and to sort out this little hiccup!!
I assume if it is the pressure sender, then the gauge would only be mis-reading, and it would not harm it to drive to Austec?
The pressure relief valve sounds a bit more dodgy? I assume if it is stuck open then, the pressure will be reduced.........would it harm it to drive to Austec?
Ta
Larry
P.S. I think it's about 40 miles
>> Edited by larryb on Tuesday 26th April 22:14
I have booked the 'S' into Austec for a 12,000 mile service and to sort out this little hiccup!!
I assume if it is the pressure sender, then the gauge would only be mis-reading, and it would not harm it to drive to Austec?
The pressure relief valve sounds a bit more dodgy? I assume if it is stuck open then, the pressure will be reduced.........would it harm it to drive to Austec?
Ta
Larry
P.S. I think it's about 40 miles
>> Edited by larryb on Tuesday 26th April 22:14
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