Dipsticks and Sumps

Manual   Auto

Manual:

The three dipsticks and tubes:
  • Top - two different types:
    • 3 main-bearing: 1B1735, 18G/GA, sliding dust seal, no stop.
    • 5 main-bearing: 12H74, 18GB to GF, sliding dust seal, no stop.
    Tube 1B1063 for both types screws in. The sticks rest on the sump bottom to give the correct oil quantity, seal pushed down to the top of the tube.
  • Middle: Cranked stick 12H2694, 18GG to GK and early 18V581/582/583, 584/585 and 672/673. These have a stop-seal which acts as a seal on engines with positive crankcase ventilation, where the crankcase is under vacuum all the time the engine is running.
  • Bottom: Straight stick 12H3963, later 18V. These also have a stop-seal.
  • The middle and bottom sticks are said to be interchangeable, but the tubes are significantly different lengths to suit the block: (image from British Automotive)

    The stop on the middle and late sticks also acts as a seal for both dust and the vacuum created by the PCV systems. These were first introduced while the early stick was still being used, but if the sliding seal is pushed down to the top of the tube it would have the same effect. I've wondered if the stick resting on thre sump floor could rattle, and eventually wear a hole through. But if the seal were slid down an inch or so before the stick was replaced, then the stick pushed down to the sump floor so lifting the seal to the correct position, when released the resilience of the seal may well lift the stick just clear of the sump, as well as ensuring a seal.

    The reason for the different length tubes becomes clear in these pictures from Edouard Prioul - 18GB left with the entry hole for the tube in the block much higher than later blocks on the right. The tops of the two tubes are at the same height:

    Early sumps had the plug forwards of the right rear corner, the dipstick rests on a raised portion of the sump (arrowed):

    Here on the 18G/GA 12H395: (NTG Services)

    After that the sump plug was on a cut-away corner (top right here, see below for the arrow):

    The above shows a 'shelf' under the dipstick, but that is not apparent from the outside of the later sump 12H3541:

    The part with the sump plug is cut away to access the torque converter bolts for the automatic gearbox via a hole in the engine back-plate, without removing the sump:

    The auto was available as an option with Mk 2 cars but this style of sump may not have been available from the beginning as published information varies on what sump was used when. The Parts Catalogue only lists 12H395 for 3-bearing and 12H3541 for 5-bearing, Moss Europe lists 12H1976 for 18GB (5-bearing Mk1) to 18V797 (Dec 74 i.e. almost a year into rubber bumpers), and British Automotive states 12H1426 for 18GF, GH and GK i.e. Mk2 before the 18V, but I've not been able to find any detail on either of these. Clausager says a changed sump for the 18V797 "may have been introduced on North American engines from the start of the 18V836/837 series" which dates to September 74 i.e. the start of rubber bumpers. Oil capacity does not help as driver's handbook give the change from the high volume to the lower with the 18V i.e. the 581 in August 71.

    The bolt pattern on the 3-bearing sump is different to that of the two (interchangeable) 5-bearing sumps - the 3-bearing has an extra bolt along the left-hand side which moves the front left-hand one (lower left in these images) round the corner a little way: (Chris at Octarine Services)

    And what is the purpose of the vertical 'tube' (arrowed) in the lower right-hand corner of the 5-bearing sump, with matching hole in the 3-bearing gasket? There is a matching hole in the block right by one of the sump screws, overflow from the relief valve?

    Auto:

    The Auto dipstick and tube are long, the latter has a pronounced 'S' shape:

    It appears to have a retaining nut that screws onto an adapter in the gearbox, similar to the oil-cooler hoses:

    Showing the position of the dipstick in the sump: (Rover P5 Club)