Oil Pressure Drop

#1
Hi Everyone
I’ve recently bought a P6B which starts and runs well enough. The oil pressure reads around 35-40psi until the engine warms up when it just drops away to nothing. Engine note doesn’t change and there are no rattles or knocks. Pressure sometimes returns when revved but not always. Oil looks good and is slightly over full on dipstick. Any advice would be much appreciated.
Andy
 

clive P62

Active Member
#3
Does the oil light flicker when gauge is low ?
If it does could mean low pressure.
The electric oil pressure gauges are not super accurate.
You need to check the oil pressure with a external gauge by removing the oil light sender and connecting the gauge there.
The rover is a low pressure / high volume engine and must run 20 / 50 oil .
 

GRTV8

Well-Known Member
#4
As Clive P62 said.
.The wrong grade oil will effect the warm oil pressure. Use 20w/50-60 with zddp.
Keep us posted after youve done the above advise as I also went down the SD1 oil pump route
 
#5
If it was mine as a 'new' purchase I would start with an oil and filter change, unless you know that it was changed shorty before purchase and you knew what oil/filter were used.
 
#6
Thanks everyone. I intend to change oil next week with 20/50. I will also do a tune up, timing , carb balance, mixture etc. The oil light has not come on which makes me wonder if the problem is with sender so will clean its contacts initially. I’ll report back when I’ve done the above.
Thanks again for input
Andy
 

quattro

Well-Known Member
#7
If the oil light does come on when you turn on the ignition, but doesn't come on when the oil pressure gauge drops, it pretty much points to the pressure sender failing when it gets warm.
 

unstable load

Well-Known Member
#8
The oil pressure reads around 35-40psi until the engine warms up when it just drops away to nothing.
Does it gradually decrease or just disappear? As said, the pressure transmitter isn't a precision instrument, and as long as the light works correctly with the engine off and running, you should be fine.
 

SydneyRoverP6B

Well-Known Member
Staff member
#9
I’ve recently bought a P6B which starts and runs well enough. The oil pressure reads around 35-40psi until the engine warms up when it just drops away to nothing. Engine note doesn’t change and there are no rattles or knocks. Pressure sometimes returns when revved but not always. Oil looks good and is slightly over full on dipstick. Any advice would be much appreciated.
Andy
Hi Andy,

I have had the same problem more than once, and in each case, the oil pressure transmitter was at fault. If there was a problem, your oil warning light would come on, as pressure less than about 8 to 10psi will see it light. Genuine Smiths oil pressure transmitters are extremely hard to find and when they are hugely expensive.

Ron
 

roverp480

Active Member
#10
The only real way of checking would be to temporarily substitute a known mechanical gauge to see that the actual pressures are. That would confirm thing one way or the other for certain. Given your warning light isn't illuminating I suspect as others have said its the sender or gauge at fault
 
#11
Thanks for all the replies. Sorry I haven’t had time to do service and investigate further, hopefuls in the next week or so. I will report back then.
 
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