High oil temp despite correct oil level (or is it) - K16

[thompster]

82 degree stat and rock steady water temperature at all times.  On motorway runs however, my oil temperature can be anything from 100C to 120C measured from the sender in the Apollo tank.

I gather windage is the usual cause so today after a long run and high temps I checked the oil level:  With engine running the oil is about halfway up the hatched section.  Does that rule out too high an oil level and if so should I investigate further or just fit a cooler?

[SM25T]

That seems hot. Half way up with engine hot and running is not full. Have you got the right grade oil. Maybe replace the (known to be problematic) temperature sender. Not too expensive from Redline Components.

[revilla]

My VVC 160 used to get the oil very hot on long motorway runs, similar temperatures to what you are reporting, water temperature also rock steady. In the end I fitted a small (10-Row Mocal I think) oil cooler and an 80° thermostatic sandwich plate take-off. Never seen it above 90° since and even that takes some doing, even on a day like today.

[revilla]

My VVC 160 used to get the oil very hot on long motorway runs, similar temperatures to what you are reporting, water temperature also rock steady. In the end I fitted a small (10-Row Mocal I think) oil cooler and an 80° thermostatic sandwich plate take-off. Never seen it above 90° since and even that takes some doing, even on a day like today.

[thompster]

Thanks both for your answers which got me thinking - and experimenting.

My water rail temperature sender is the newer button/right angle style and my Apollo sender is the older spade connector type, both connected via toggle switch to the same Caterham branded gauge.  Time for the saucepan of boiling water:

It appears that the resistance of my new style sender is double that of the old style one!

	OLD	New
23C	900 ohm	2000 ohm
52C	288 ohm	600 ohm
100C	76 ohm	145 ohm

 

Without knowing what impedance results in what gauge reading I'm not sure exactly what the gauge will show but I can guess at the answer - my oil isn't reaching 120C at all.  Time for a new sender.

And just to thicken the plot, while reading up I found quite a few posts where people report the exact same high temps in their apollos.  That's got me wondering whether the Apollo kit was shipped with the wrong sender at some point....

[revilla]

That is interesting. Certainly something calibrated wrongly there!

[aerobod - near CYYC]

Both the oil and water temp senders I have are close in resistance to your "new" one. I have verified they are accurate within about 5 degrees with an infrared thermometer. They seem to be closest to the standard Bosch NTC sender resistance curve, such as found here: Bosch NTC Temp Sender Datasheet

[p.mole1]

Thats interesting, I fitted an oil temperature sender into the filter housing and there was a bewildering array of senders. I  fitted the switch to use the water temperature gauge.

The first one did not match my water temperature sensor so I tried another from Rimmerbros, just pot luck as there were numerous types. The resistance match was spot on. My oil temperature seems to match the water temperature within a few degrees even on the motorway. I measure my oil level without the engine running and have at the maximum but use an accusump so I may not have windage issues. I'll see what happens on a track day.