1997 xk8 low oil pressure on cold start up
Discussion
My xk8 has been garaged all winter, 2 weeks ago I kicked it back into life, started first time , no problems
Been using it for a couple of weeks, 30-40 mile trips a couple of times
Started it on Wednesday and the oil pressure gauge read low andt he light came on, 5 seconds later the gauge goes to normal and the light goes out
No problems for the rest of the day
Then tonight exactly the same thing.
The car has an engine from a 2001 car fitted by a local mechanic 3 years ago engine sourced by me, it's never missed a beat
I did a search but nothing came up, it starts from cold on the button, fires as soon as you turn the key
It's a bit worrying
Been using it for a couple of weeks, 30-40 mile trips a couple of times
Started it on Wednesday and the oil pressure gauge read low andt he light came on, 5 seconds later the gauge goes to normal and the light goes out
No problems for the rest of the day
Then tonight exactly the same thing.
The car has an engine from a 2001 car fitted by a local mechanic 3 years ago engine sourced by me, it's never missed a beat
I did a search but nothing came up, it starts from cold on the button, fires as soon as you turn the key
It's a bit worrying
You don't say how many miles the engine has done or when the oil was last changed but 5 seconds is maybe a bit long for oil pressure to come up from a cold start. Both V8's I've owned have been a little lazy building enough pressure to put the warning light out when left standing for a few weeks so it may be you don't actually have a problem or could be just the pressure sender switch getting slow to respond, posibly because it's got sticky and contaminated with crud from dirty oil.
All you can realisticaly do is change the oil and filter - I'd fill with a proper full synthetic 5W-30 or 40 - and see if this makes any improvement. Changing the pressure sender swich might help but if not there's not much else you can do apart from live with it.
If you're still concerened you can have the oil pressure checked on a master gauge, that'll be a usefull indication of the engine's general health.
All you can realisticaly do is change the oil and filter - I'd fill with a proper full synthetic 5W-30 or 40 - and see if this makes any improvement. Changing the pressure sender swich might help but if not there's not much else you can do apart from live with it.
If you're still concerened you can have the oil pressure checked on a master gauge, that'll be a usefull indication of the engine's general health.
Edited by Jaguar steve on Saturday 5th May 07:05
Now something really odd is happening
I posted a couple of months ago about the low oil pressure when cold now it's the opposite
When cold its fine , when it's hot the oil pressure drops off the gauge so the light comes on
Raise the revs and it's fine again, I changed the oil and filter yesterday but it made no difference
The funny thing is on tickover it got hot enough to kick the electric fans in after about 15 mins but the gauge showed ok all the time
Next step is a new switch but it's worrying when it dives off the end in traffic
No funny noises though
I posted a couple of months ago about the low oil pressure when cold now it's the opposite
When cold its fine , when it's hot the oil pressure drops off the gauge so the light comes on
Raise the revs and it's fine again, I changed the oil and filter yesterday but it made no difference
The funny thing is on tickover it got hot enough to kick the electric fans in after about 15 mins but the gauge showed ok all the time
Next step is a new switch but it's worrying when it dives off the end in traffic
No funny noises though
wack said:
Now something really odd is happening
I posted a couple of months ago about the low oil pressure when cold now it's the opposite
When cold its fine , when it's hot the oil pressure drops off the gauge so the light comes on
Raise the revs and it's fine again, I changed the oil and filter yesterday but it made no difference
The funny thing is on tickover it got hot enough to kick the electric fans in after about 15 mins but the gauge showed ok all the time
Next step is a new switch but it's worrying when it dives off the end in traffic
No funny noises though
I used to have a 1990 xj40 which seemed to struggle to get decent oil pressure when it was hot and at tickover.I posted a couple of months ago about the low oil pressure when cold now it's the opposite
When cold its fine , when it's hot the oil pressure drops off the gauge so the light comes on
Raise the revs and it's fine again, I changed the oil and filter yesterday but it made no difference
The funny thing is on tickover it got hot enough to kick the electric fans in after about 15 mins but the gauge showed ok all the time
Next step is a new switch but it's worrying when it dives off the end in traffic
No funny noises though
If it's any consolation I had the car 10 years and just learned to ignore it.
Could be the sender unit-I've had a few cars where the oil pressure sender unit has failed & the red light has come on. My old 1995 V12 Daimler did this, as did a number of BMW's I've owned. The engines made no strange noises & with the BMW engines idling & the oil filler cap briefly removed, the oil was clearly being thrown around the cam lobes as it rotated.
Sender units had failed & replacing them always cured the problem...
Try replacing the sender unit-if this doesn't work then the next thing is to get the oil pressure properly checked with an accurate gauge. Sometimes the oil pump internal pressure relief valve can stick & bleed off oil pressure, but the only way to find out is to have the oil pressure properly checked at a garage etc.
Sender units had failed & replacing them always cured the problem...
Try replacing the sender unit-if this doesn't work then the next thing is to get the oil pressure properly checked with an accurate gauge. Sometimes the oil pump internal pressure relief valve can stick & bleed off oil pressure, but the only way to find out is to have the oil pressure properly checked at a garage etc.
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