No announcement yet.

DIY Oil Change for a Classic Impreza

This topic is closed.
This is a sticky topic.
  • Filter
  • Time
  • Show
Clear All
new posts

  • DIY Oil Change for a Classic Impreza

    In depth (as in it goes on forever ) guide to a DIY Oil Change for a Classic Impreza courtesy of a thread on Surrey Scoobies site.

    To those who know the score this isn't intended as an egg sucking exercise but hopefully it will help some of the new guys out. You read an awful lot about dry cranking and I sure it puts some people off, I'd hate to think that the process is skipped due to fear of the unknown, potentially contributing to or directly causing a premature end to an engine.

    The term dry cranking simply describes trying to start up the engine with the crank sensor disconnected. The engine will turn over on the starter motor only (as the crank sensor has been unplugged the engine will not fire). The whole point is to distribute the oil and establish a decent pressure before firing the engine.

    You will need: -

    5 litres (4.5 will be used) of your chosen oil.
    A new Subaru manufactured oil filter
    A new Subaru sump washer
    17mm socket for the sump plug
    Flat surface to stand the car on.

    1. Warm the engine (to ease the draining process).

    2. Pre-fill the new filter with fresh oil. Fill to the very top and keep topping up (it will take 15 minutes or so to fully absorb the oil).

    3. Remove the oil filler cap (to allow the oil to drain easily)

    4. Remove the under tray.

    5. Drain all of the old oil from sump (be careful it will be warm/hot and gushes out so be ready and have a suitable sized (depth & width) container for the oil to drain into). It will take a few minutes to run dry.

    6. Remove old filter (you should be able to do this by hand, if not use an oil filter wrench or alternatively stab with a screwdriver for leverage if necessary).

    7. Wipe the filter seating & apply a small amount of oil to the face of the new oil seal on the new oil filter and then fit the pre-filled filter (Step 2). Make sure the thread is not crossed and do not over tighten as this can lead to leaks. ¾ to a turn after it begins to feel tight is about right.

    8. Wipe the sump plug seating and apply a new washer to sump plug and tighten.

    9. Fill the engine with oil to halfway between the two holes on the dipstick (you should allow 5-10 minutes for the oil to settle to get an accurate reading).

    10. Refit the oil filler cap.

    11. Disconnect (unplug) the crank sensor to stop the engine firing (this prevents both spark and fuel injection to the engine) Location: -

    or (preferably) remove the spark plugs - removal of the spark plugs is generally accepted as the preferred option as it prevents compression meaning that the load on the bearings during the dry cranking process is relieved until oil pressure has been re-established (after dry cranking). It's a bit of a chore. That said it is good to check your plugs every now and than as it can give a heads up of other potential problems.

    So.You do not have to remove the plugs, disconnecting the crank sensor is sufficient but if you are going to remove the plugs you should disconnect the crank sensor too.

    12. Dry crank the engine until the oil pressure light extinguishes (some cars lights don't always extinguish but as long as you crank for the recommended time there should be no issues). This could take 30-80 seconds, don't worry if it takes a little longer. Crank in short bursts to save the battery (wait a few seconds between each crank). You cannot over crank. This action primes the system establishing oil distribution until it meets resistance, creating pressure.

    13. Refit spark plugs (only if removed obviously)

    14. Refit (plug back in) the crank sensor

    15. Start the engine and leave to idle for a minute or two so the oil pressure can stabilise before driving.

    16. Check sump plug and filter seal for adequate tightness/leaks

    17. Go for a short and slow drive until the engine is at full operating temperature then switch off.

    18. Top up the oil to the upper hole on the dipstick but do not overfill. The highest notch on the dipstick is the fully hot/overfill mark. The oil level shouldn't be any higher than the second hole even when hot.

    19. Check sump plug and filter seal for adequate tightness/leaks one again.

    20. Refit the under tray

    Disclaimer: follow at your own risk! I can't guarantee that this guide will stop your engine going pop but a badly carried out oil change can certainly increase the chances. If in any doubt as to your mechanical aptitude - Get professional help!!!

    This thread is for reference only & is locked so no replies thank you.