Cuppa
27th January 2018, 06:37 PM
Today it was pretty hot. We drove our car (without the Tvan) up a steep, very tight & windy hill which went for 16kms. We were in 2nd high/2wd all the way, except for dropping back to first on a couple of extra tight hairpins. For anyone who knows it it was the road in Mt Field NP, Tassie, up to Lake Dobson. 2000 to 2500rpm all the way. Coolant temp went up to 92 & EGR's were around 400.
Toward the top it became apparent that the oil pressure had dropped a little. At 2300rpm it would normally show about 59/60psi on the gauge once warmed up. It had dropped to about 52psi & at 2000rpm was at about 40psi. If I revved it harder I could still get the reading to rise to 61psi (the max it usually shows when hot) & when slowing down the minimum oil pressure remained at around 20/21psi which is normal.
We parked at the top & spend about 1.5 hours walking around the lake before returning to the car. When we did oil pressures were back to normal & remained so all the way back down the hill to the camp site.
Oil is semi synthetic Penrite HPR 15 (15w50).
This has happened once before under very similar circumstances, about 3 weeks ago ie long steep slow hill on a very hot day - except that one was bitumen & towing the Tvan.
On both occasions the smell of a hot motor has been quite noticeable when exiting the car at the top of the hill, but subsequently readings have quickly returned to normal & remained so.
Oil level is correct on the dipstick & hasn't changed.
QUESTION: I'm thinking the semi synthetic oil must 'thin out' when it gets hot, (& hoping that if so it still does he job it's intended to do). Am I right & would oil thinning out on a steep incline cause a drop in pressure reading in a TD42.
No nasty noises, no factory oil light.
Toward the top it became apparent that the oil pressure had dropped a little. At 2300rpm it would normally show about 59/60psi on the gauge once warmed up. It had dropped to about 52psi & at 2000rpm was at about 40psi. If I revved it harder I could still get the reading to rise to 61psi (the max it usually shows when hot) & when slowing down the minimum oil pressure remained at around 20/21psi which is normal.
We parked at the top & spend about 1.5 hours walking around the lake before returning to the car. When we did oil pressures were back to normal & remained so all the way back down the hill to the camp site.
Oil is semi synthetic Penrite HPR 15 (15w50).
This has happened once before under very similar circumstances, about 3 weeks ago ie long steep slow hill on a very hot day - except that one was bitumen & towing the Tvan.
On both occasions the smell of a hot motor has been quite noticeable when exiting the car at the top of the hill, but subsequently readings have quickly returned to normal & remained so.
Oil level is correct on the dipstick & hasn't changed.
QUESTION: I'm thinking the semi synthetic oil must 'thin out' when it gets hot, (& hoping that if so it still does he job it's intended to do). Am I right & would oil thinning out on a steep incline cause a drop in pressure reading in a TD42.
No nasty noises, no factory oil light.