2012 Vauxhall Corsa 1.2petrol A12XER oil pump
Discussion
I recently diagnosed a failed oil pump on my daughter's 2012 Vauxhall Corsa 1.2petrol, i believe this is the A12XER engine but it could be a different engine code. Today I finally got the front cover removed (the oil pump is in the front cover) and confirmed the oil pump has broken up.
The oil pump is driven directly from the crankshaft, the front end of the crank goes through the centre of the oil pump. The drive area of the oil pump is hex shaped and I was expecting the drive on the crank to also be hex shaped, so I was surprised to see the drive on the crank is round with 2 flat areas. This drive on the crank doesn't seem to be damaged or worn to this shape, it seems it is supposed to be that shape... This brings me to my first question - Is this how it is supposed to be or has someone had it apart in the past and fitted the wrong front cover or oil pump to this engine? I expect the answer will be that it is supposed to be like this, perhaps the oil pump rotates off centre on the crank or the the 'round peg with 2 flats is supposed to fit into the hex hole', but it's a question I'd rather ask than make assumptions.
The front cover doesn't seem to have suffered damage with the broken oil pump, so to keep costs down I am considering replacing just the pump (fitting a new pump into the old front cover) but I did see a weep of oil from the front crank seal that is built into the front cover... So if I'm just going to replace the oil pump and not the full cover (which would come with a new pump built in) I will at least want to fit a new crank oil seal to the front cover. Having had a quick look at parts suppliers on the internet I could buy a complete cover including new pump and new crank oil seal for around £120 or just an oil pump for around £60. If I buy the full cover I don't have to mess about fitting the new oil pump or front oil seal to it because it will come complete with those parts fitted. My question here is what parts to trust from what suppliers? In the old days I/we would have gone to a Vauxhall parts department and bought genuine parts, these days internet car part buys can be a lottery with many firms making knock-off components but listing than as OEM quality. There's the usual cost versus benefit considerations and I don't think my daughter will think it worth replacing the timing chain and chain tensioners, she's on a limited mileage insurance policy anyway and I think she and I would trust those parts to last as long as she intends to keep the car, but on the other hand I don't want to be stripping the engine again in 6 months because I fitted a knock-off poor quality oil pump.
I'll likely replace the water pump because I think there may have been a little water mark below it where it might have leaked very slightly in the past. Since I've noticed the potential water pump problem I think the little money she wants to spend on repairs would be better spent on a water pump than timing chain and tenisioners even though the water pump is only driven by the fan belt (so couldn't cause a timing problem if it failed). Question here is much the same as the last question, where to buy a decent replacement?
Edit to add the outer ring of the oil pump that doesn't look broken actually is broken, a piece around 1cm broke out of it but I placed it back in the position it snapped out of before taking the pic when I was checking to make sure all the broken pieces were accounted for (and were not pushed up into an oil gallery etc).
The oil pump is driven directly from the crankshaft, the front end of the crank goes through the centre of the oil pump. The drive area of the oil pump is hex shaped and I was expecting the drive on the crank to also be hex shaped, so I was surprised to see the drive on the crank is round with 2 flat areas. This drive on the crank doesn't seem to be damaged or worn to this shape, it seems it is supposed to be that shape... This brings me to my first question - Is this how it is supposed to be or has someone had it apart in the past and fitted the wrong front cover or oil pump to this engine? I expect the answer will be that it is supposed to be like this, perhaps the oil pump rotates off centre on the crank or the the 'round peg with 2 flats is supposed to fit into the hex hole', but it's a question I'd rather ask than make assumptions.
The front cover doesn't seem to have suffered damage with the broken oil pump, so to keep costs down I am considering replacing just the pump (fitting a new pump into the old front cover) but I did see a weep of oil from the front crank seal that is built into the front cover... So if I'm just going to replace the oil pump and not the full cover (which would come with a new pump built in) I will at least want to fit a new crank oil seal to the front cover. Having had a quick look at parts suppliers on the internet I could buy a complete cover including new pump and new crank oil seal for around £120 or just an oil pump for around £60. If I buy the full cover I don't have to mess about fitting the new oil pump or front oil seal to it because it will come complete with those parts fitted. My question here is what parts to trust from what suppliers? In the old days I/we would have gone to a Vauxhall parts department and bought genuine parts, these days internet car part buys can be a lottery with many firms making knock-off components but listing than as OEM quality. There's the usual cost versus benefit considerations and I don't think my daughter will think it worth replacing the timing chain and chain tensioners, she's on a limited mileage insurance policy anyway and I think she and I would trust those parts to last as long as she intends to keep the car, but on the other hand I don't want to be stripping the engine again in 6 months because I fitted a knock-off poor quality oil pump.
I'll likely replace the water pump because I think there may have been a little water mark below it where it might have leaked very slightly in the past. Since I've noticed the potential water pump problem I think the little money she wants to spend on repairs would be better spent on a water pump than timing chain and tenisioners even though the water pump is only driven by the fan belt (so couldn't cause a timing problem if it failed). Question here is much the same as the last question, where to buy a decent replacement?
Edit to add the outer ring of the oil pump that doesn't look broken actually is broken, a piece around 1cm broke out of it but I placed it back in the position it snapped out of before taking the pic when I was checking to make sure all the broken pieces were accounted for (and were not pushed up into an oil gallery etc).
Edited by SimonYorkshire on Thursday 12th February 19:21
The oil pump is driven by the outside of the crank pulley hub, you'll see it's hexagonal to match the pump rotor. The flats on the nose of the crank register to the inside of the pulley hub.
These engines are known for cam chain wear; having got this far, you'd be foolish not to renew chain, guides and tensioner at this stage, sprockets too if they are worn. Obviously renew the water pump and drive belt, then you'll never have to delve into that end again, there's nothing worse than doing the same job twice. Oil and filter change too of course.
Oh, and you will probably get oil leaks at the bottom corners of the timing cover, unless you remove and refit the sump last, having cleaned the oil pick-up strainer.
I'd also renew the cam cover gasket whilst it's off, they shrink and harden over time.
These engines are known for cam chain wear; having got this far, you'd be foolish not to renew chain, guides and tensioner at this stage, sprockets too if they are worn. Obviously renew the water pump and drive belt, then you'll never have to delve into that end again, there's nothing worse than doing the same job twice. Oil and filter change too of course.
Oh, and you will probably get oil leaks at the bottom corners of the timing cover, unless you remove and refit the sump last, having cleaned the oil pick-up strainer.
I'd also renew the cam cover gasket whilst it's off, they shrink and harden over time.
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