Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: polilara on 24 February 2020, 13:14:02

Title: AR-25 Sump Bolts, Risk of Snap...
Post by: polilara on 24 February 2020, 13:14:02
So, time to change gear box oil, 280 000 km behind and still original oils in there. Everything works very well with this gear box but I just changed new radiator which had in built oil cooler for gearbox so thought I have to add a bit. The guy which I visited proposed that he would like to change the oil & filter as that work should be carried out after each 100 000 km. Agreed to meet him tomorrow morning but he warned me that there is a risk that the sump bolts (after having been there 20 years) can snap which really means a bigger job than expected. Is there a risk of that with AR-25?
Title: Re: AR-25 Sump Bolts, Risk of Snap...
Post by: Marks DTM Calib on 24 February 2020, 13:44:33
Never snapped any myself, they are only circa 8-10Nm from memory so far from tight.

Not over tightening on refit is key!
Title: Re: AR-25 Sump Bolts, Risk of Snap...
Post by: polilara on 24 February 2020, 15:09:43
Never snapped any myself, they are only circa 8-10Nm from memory so far from tight.

Not over tightening on refit is key!

Hope they did not over tight in year 2000...
Title: Re: AR-25 Sump Bolts, Risk of Snap...
Post by: Shackeng on 24 February 2020, 18:16:47
Very strange comment. Does he know what he is doing? I suspect he is thinking of a different gearbox.  :-\
Title: Re: AR-25 Sump Bolts, Risk of Snap...
Post by: LC0112G on 24 February 2020, 19:05:19
I've had engine sump pan bolts shear off, both on removal and re-insertion. I think it's because the tops of the threads are exposed to the elements (they're not in blind holes), and the steel bolts corrode into the aluminium engine bits (or vice verca). If you overstress the bolt on removal the little sh1ts shear off on re-insertion.

From memory the Gearbox sump bolts are in blind holes, so that shouldn't be an issue.
Title: Re: AR-25 Sump Bolts, Risk of Snap...
Post by: polilara on 25 February 2020, 15:51:59
Changed now, all ok, all bolts opened easily. What was interesting is that the old oil has excellent outlook, it was still transparent after 280 000 km. There was a magnet in the bottom which had a thin layer of metall. He proposed that we could change the oil again within next 12 months to get out the rest (dirt?).
Title: Re: AR-25 Sump Bolts, Risk of Snap...
Post by: STEMO on 25 February 2020, 16:14:18
Changed now, all ok, all bolts opened easily. What was interesting is that the old oil has excellent outlook, it was still transparent after 280 000 km. There was a magnet in the bottom which had a thin layer of metall. He proposed that we could change the oil again within next 12 months to get out the rest (dirt?).
Doesn't sound to me like there is any reason to do it again.