Oil pressure

[Gertie]

Gertie's engine has been idle for about 1 year & I recently drove about 40 KM at approx 100 KPH. When I left the M7 the oil light came on at idle (don't have the oil pressure gauge fitted yet). This problem occurred in the past after long runs at similar speed so during the resto period I exchanged the oil pressure sensing switch for a new one.

I called into the Castrol office (West Guildford) & was advised to change to Castrol Edge Sport 25w 50 & was assured this would keep the oil light off.

A mechanic friend of mine suggested that the higher oil pressure developed from the heavier oil may cause the rear oil seal (original type) to blow out.

Has anyone had experience with this problem?

[mcl1959]

It could be the pressure relief spring in the oil pump - these are prone to losing tension in the grey engine and cause a lowering of the oil pressure.  They should always be replaced when doing a reco on an engine.

Ken

[Gertie]

Thanks Ken, that could be the problem. I suppose it requires engine removal to rectify?
Do you see any problem using the heavier oil in the meantime?

[gp]

It can be quite normal for the light to come on at idle (what's your idle speed?). As long as it goes out whne engine is above idle I wouldn't be too concerned.

Cheers,

Graham

[Gertie]

Thanks Graham. It has been happening for a long time but only when the oil gets hot after a continuous run at 90 KPH +. After changing the sender it no longer flickers but has a steady glow until fast idle.
I bought the oil that castrol suggested & will change it tomorrow. Next time the donk comes out I will change the pressure relief spring.

The idle speed is just enough to keep the gen light off & feels about right. I will check the idle rpm anyway.

[gp]

I think some of the O/P senders you buy now are more suited to Red motors which tend to have a little more O/P at idle than greys  . This could be where the problem is. As I said earlier, I wouldn't be too concerned about it.

I guess this means Gertie is back on the road? Good to hear.

Cheers,

Graham

[Al]

Why don,t you take Gertie to your mechanic or to a workshop and get them to do oil pressure test, within about 10mins you should know if it is low oil pressure or the switch ? Simple!!!!!        Cheers Al

[Geoff_K]

It takes about 40km at 100kph (constant) to get oil temp up to water temp.
In my new reconditioned grey motor at 90kph, oil temp is water temp -(ve) 10degC, at 110kph, oil temp is water temp +(ve) 10degC. (during the running in period the oil really got hot -110degC when running at 80-90kph, so I would varied speed to keep it low - remember the owners manual said keep it below 50mph!)
Around town, stop start etc, oil temp never gets over 60decC (still deemed cold by Castrol Technical Dept). 
Thus MOST engines, for nearly all their lives in the city, NEVER properly warm up the oil. 
Therefore this is deemed EXTREME use, and the oil should be changed more frequently.
It is also probably the reason why you see so many cars expire about 60-100 km's along the expressway: their oil was really water, and when it gets to about 100 degC, it boils off, and bingo, bearings pickup etc and the rest is history!
On the other hand, warn motors will run for years, with the oil light on at idle (when oil is hot), especially if you have the idle down low (generator light just glowing).
Geoff_K

[Gertie]

Thanks for that info Geoff. We have been in Qld for a couple of months & I have not been on the forum.
I still haven't changed to the higher viscosity oil as yet. Appears to be unnecessary. Will be back home before Motorfest.
Regards
Geoff