Engine oil Temperature

[Anglefire]

After my run out yesterday, I checked the temperature around the engine with my IR temperature probe.

Specifically around the sump and bottom of the engine.

I know oil has to be hotter than the water in the engine so that any moisture gets driven out - but what temperature should it be? 

I was reading over 100'C (107-110) at the sump in places - though the bottom of the sump was slightly lower than 100 - the top hose was around 85'C 

I discounted the temperature on the exhaust manifold side at nearly 150 on account its proximity!

This was after a 15-20 mile run at upto 70mph on a dual carriage way but the last 5miles was between 30 and 40 due to the speed limit, so I assume would have cooled down slightly?

[Sparky_Spit]

About 90 to 110 is a reasonable figure to aim at. Including any measuring errors, I would say that yours is fine.

[Clive]

Those oil temps shouldn't bother a decent oil. If you start getting 130-140 a proper synthetic oil would be a better bet, or a cooler. (oil stats are usually set at 85 degrees, but I know ford specialists say use a 95 degree type, I think oil likes to be at about 100 degrees or so)

[Anglefire]

Thanks. 100’c is reasonable I would say too. Wasn’t sure if 110 was a bit hot. Especially as sump temp should be lower anyway as it has been cooled a bit? Though the only cooling it gets is air across the sump and from the block/water. 

 

[JohnD]

Air cooling across a standard sump is insignificant,  just not enough surface area for the mass of oil.      That surface might be a bit cooler in use, but in the time you need to get out and get your IR sensor working, the oil heat will have soaked through the thin steel to the surface, so a real measure of oil temp.    Finned sumps have been used, but an actual oil cooler vastly increases the surface area, oil-air, or oil-water.    Your reading was fine.

John