Oil pressure guage hits 0 under load! HELP!!
Discussion
Had a great hoon to Euro Disney to watch daughter dance in show. On the way back, I spied an Aston (modern) coming up the outside lane fairly sharpish. You know where this is going don't you, you've been there yourself! Long story short and all that; after some time at "high speed" I dropped my eyes to dial height and realised that the oil pressure gauge read 0. Several expletives later and a very confused wife wanting to know what the problem was I lifted my foot off the throttle and slowed down dramatically only to find that the oil pressure regained itself to a, slightly below, normal state at 30 psi. What the...???? I stopped when appropriate and checked for knocks or even slight taps (none), oil level (fine), oil leaks (none). Perplexed and not inconiderably worried for the state of my relatively new acquisition, I pootled home at 60 - 80mph maintaining 15 - 30 psi for the remaining 300 odd miles home.
Has anyone experienced this before? Is it a sender unit failure? Thing is that the pressure gauge now plummets under load but at steady speed the pressure is between 15 and 30 psi where I have, for the last two months been getting 40 psi all the time. I am still getting 30 psi on tickover.
Any views or comfort available would be welcomed.
Off to Austecs on saturday!
Has anyone experienced this before? Is it a sender unit failure? Thing is that the pressure gauge now plummets under load but at steady speed the pressure is between 15 and 30 psi where I have, for the last two months been getting 40 psi all the time. I am still getting 30 psi on tickover.
Any views or comfort available would be welcomed.
Off to Austecs on saturday!
I think the Chim has a STOP light which is lit for low oil pressure and works from a separate pressure switch - hopefully someone will confirm this. If the gauge reads zero, but the stop light doesn't come on then it's most likely a dodgy connection, sender or gauge fault. If both oil warnings come on then it seems more likely that there is actually a pressure problem. Since you don't mention any other symptoms - stop light, engine issues etc - it sounds as though the pressure is ok and the fault lies in the electrics.
Alex
Alex
Had a similar experience on mine around a year ago with roughly the same figures.
When you accelerated hard the gauge went into a negative reading. I checked the spade connector to the sender first just in case, but in the end I changed the sender and all went back to normal.
As your off to Austec it may be worth your while asking them to quickly put a capillary on to give you the true oil pressure as a reference.
When you accelerated hard the gauge went into a negative reading. I checked the spade connector to the sender first just in case, but in the end I changed the sender and all went back to normal.
As your off to Austec it may be worth your while asking them to quickly put a capillary on to give you the true oil pressure as a reference.
Recheck the oil level.
Low oil pressure can be a clue that the oil level is low. (The oil spends less time in the sump so it gets hotter and thinner.)
Oil surge under acceleration or cornering can also be a clue that the oil level is low.
The next thing I suggest you do is ensure that the no charge warning light and low oil pressure warning light both work. (The reason for checking both is that they are sometimes confused and you may think you have checked one but actually been looking at the other.) Assuming they do work and tha the warning light hasn't been coming on, I'd stand down from red alert on the oil pressure front and start suspecting a gauge fault. The senders can go intermittant, and the wiring loom and connector at the sender also tend to suffer and can become unreliable.
However, until you've corrected the problem I'd take the warnings from the gauge at face value and back off any time the gauge said there was an oil pressure problem, just in case it's telling the truth.
Low oil pressure can be a clue that the oil level is low. (The oil spends less time in the sump so it gets hotter and thinner.)
Oil surge under acceleration or cornering can also be a clue that the oil level is low.
The next thing I suggest you do is ensure that the no charge warning light and low oil pressure warning light both work. (The reason for checking both is that they are sometimes confused and you may think you have checked one but actually been looking at the other.) Assuming they do work and tha the warning light hasn't been coming on, I'd stand down from red alert on the oil pressure front and start suspecting a gauge fault. The senders can go intermittant, and the wiring loom and connector at the sender also tend to suffer and can become unreliable.
However, until you've corrected the problem I'd take the warnings from the gauge at face value and back off any time the gauge said there was an oil pressure problem, just in case it's telling the truth.
Crazycraig said:
Had a similar experience on mine around a year ago with roughly the same figures.
Me too. I was flat out down Bruntingthorpe's main straight, glanced down; 0 psi. Eeek! Slowed down & it came back. Drove home *very* carefully. The sender was knackered.I've been umming and ahhing about getting a "wet" gauge ever since.
Thanks guys. There is some good advice there. As a mechanical numpty (self-confessed but not proud of it!) Austecs are by far the best people to check her out. They have done some great work so far and am sure this will be the same. At least I shall be able to ask the right questions! I shall let you all know how it works out. Thanks again.
Oh how I wish that the problem hadn't occurred, it is not often one gets the chance (outside Le mans hooning) to have a blast with an Aston on foreign roads. Natch!
Oh how I wish that the problem hadn't occurred, it is not often one gets the chance (outside Le mans hooning) to have a blast with an Aston on foreign roads. Natch!
Johnniem said:
Thanks guys. There is some good advice there. As a mechanical numpty (self-confessed but not proud of it!) Austecs are by far the best people to check her out. They have done some great work so far and am sure this will be the same. At least I shall be able to ask the right questions! I shall let you all know how it works out. Thanks again.
Oh how I wish that the problem hadn't occurred, it is not often one gets the chance (outside Le mans hooning) to have a blast with an Aston on foreign roads. Natch!
I had issues with mine showing zero or negetive oil pressure under acceleration.Oh how I wish that the problem hadn't occurred, it is not often one gets the chance (outside Le mans hooning) to have a blast with an Aston on foreign roads. Natch!
Before you do anything i would check 2 things.
1 Double check your oil level and 2. Check the spade connector to your Oil pressure sender. Mine was already at full stretch and had the wire had popped off the connector. I had already bought a new sender and so i now have a spare because i assumed and didn't do the simple check.
Fire99 said:
Johnniem said:
Thanks guys. There is some good advice there. As a mechanical numpty (self-confessed but not proud of it!) Austecs are by far the best people to check her out. They have done some great work so far and am sure this will be the same. At least I shall be able to ask the right questions! I shall let you all know how it works out. Thanks again.
Oh how I wish that the problem hadn't occurred, it is not often one gets the chance (outside Le mans hooning) to have a blast with an Aston on foreign roads. Natch!
I had issues with mine showing zero or negetive oil pressure under acceleration.Oh how I wish that the problem hadn't occurred, it is not often one gets the chance (outside Le mans hooning) to have a blast with an Aston on foreign roads. Natch!
Before you do anything i would check 2 things.
1 Double check your oil level and 2. Check the spade connector to your Oil pressure sender. Mine was already at full stretch and had the wire had popped off the connector. I had already bought a new sender and so i now have a spare because i assumed and didn't do the simple check.
Mine does this every winter. The first time I had the sender replaced the next year it happened I looked at the connetor and just cleaned it up with some wet and dry paper it gets covered in c*ap under there. I'll put a fiver on it just needing a clean up. I bet if you go to a stealer you will come away with a new sender.
Thanks Dave, I shall do this tonight and report back later. As it happens I did stick 1.5 litres of oil in last night which gave me a better general oil pressure across all speeds but she still plummets under load so must assume it is the senders spade connection or the sender is knackered.
I've posted this before, but my oil pressure fluctuated as you describe. It turned out to be bits of silicon sump gasket caught up in the oil pick-up pipe. The more the pump sucked (i.e.under acceleration), the more the silicon blocked the strainer. Its not a massive job, a couple of hours should see you okay.
I have also come across pick up pipes where the 2 bolts holding them to the block have come loose, which in turn allows oil to leak past the joint.
kim
I have also come across pick up pipes where the 2 bolts holding them to the block have come loose, which in turn allows oil to leak past the joint.
kim
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