text: Oil pump - replace or not? - Engine/Ancilliaries - The Lotus Forums #ForTheOwners
  June 18, 2011 in Engine/Ancilliaries
  Engine is now out and almost clean enough to dismantle.
  I'm intending to replace crank shells and seals, and basically rebuild the bottom end. Also replacing the clutch and the exhaust manifold, and belt service too. oh and both oil coolers!
  Now the manual says to check the working faces of the rotor, pump body and annulus for signs of wear, scoring or scuffing.
  Surely this wear must be measurable??
  Do I just replace the pump as a matter of course?
  I wondered the same as much of my engine is in bits. Advice I have is that they rarely give trouble and you only need to replace if there are signs of scoring, scratches etc. Its an item that can be replaced fairly easily without dismantlingthe engine so if your one looks ok I would leave. You dont mention the water pump - make sure you replace that or use a kit (Lotusbits) as a matter of course. I struggled to remove the water pump bearing and got my local engineering firm to do the work for less that £50.
  If finances are limited, preference should go to the water pump, based purely on access. It's unlikely that there would be issues with an oil pump, but as said above you can get to it with the engine in, the water pump is a @#$%*&^ to get to so do that with the engine out.
  Its a no brainer not to do the water pump. Access was dreadful even with the top end of my engine removed. The repair kit is only around £40 from Lotusbits and you can do it yourself if you fancy putting bits in the oven and others in the freezer. My missus would blown her top if I tried that so thought it best to get an engineering firm to do it. You will however need to buy the liguid gasket as well if your is not fitted with one. Again Lotusbits supplied this to me.
  Leakage is not the only reason to replace. The impellor bearing can fail etc so do it now and forget it .
  Glyn, do you mean replace the water pump (around £200, don't know $ cost) or replace the bearing, seal and impeller (around £70, again don't know $cost) as the latter is advisable, the former seeem a waste of finances.
  Ok guy, I get the message! I did replace the bearing and seal on my previous s4s, and yes it was a cow in situ. I still have the press which I bought to do the job! I'll add the parts to the list
  Cheers for making me see sense
  Probably don't need to replace the oil pump rotor and annulus, but you should clean the passages.
  There is a little bleed hole that helps the pump prime. If you don't clean that out, it could be a real problem to prime the pump later.
  This little bleed hole ... is it shown anywhere on the parts list or service manual - page number or reference?
  Sounds critical....
  I just looked on my picasa site, and apparently i didn't take a photo of it, but it is a tiny pin hole in the oil pump using that allows the air to escape so the rotor can draw oil after the system has been empty.