Page 1 of 1

Low oil pressure 12-HT

Posted: Tue Jun 12, 2007 12:26 pm
by TimMQ
Hi

ive recently noticed in my hj61 that the oil pressure drops on idle.

Before now it has always sat around the 1/2 - 3/4 mark, under load, at idle etc.

It still sits at 1/2 - 3/4 mark when driving, but when idling drops right down to the 1/4 mark.

Ive read the manual, but i was hoping someone may have experienced the same thing and could point me in the right direction.(and tell me i dont have to remove the timing case :cry: )

Also, would this have caused any damage?

Cheers
Tim

Posted: Tue Jun 12, 2007 3:29 pm
by beavis
first up i wouldnt trust the original gauge, try a mechanical after market, like autometer, vdo, etc. If you still getting good pressure at half throttle but low at idle i would lean to faulty guage, having said that the readings your getting sound ok but the readings you had before seen a little high for idle

Posted: Tue Jun 12, 2007 10:50 pm
by TimMQ
Thanks the the reply mate.

I suppose first and foremost i should know where the guage should be sitting at idle and underway. Could someone tell me?

cheers
Tim

Posted: Wed Jun 13, 2007 7:03 am
by carts
Oil pressure should be significantly lower at idle.

On the factory guage, idle oil pressure should be somewhere between the bottom of the guage and 1/3. Under throttle, anywhere between 1/3 and 3/4 is the norm. If you have the original owners handbook, it explains this in there.

It is not abnormal to see high oil pressure at idle when the motor is stone cold. But as it warms up, you will notice oil pressure will drop at idle.

If you are worried, get a mechanical guage as others have suggested, or take it to your mechanic and get them to test the oil pressure for you. If the guage is functioning correctly at the moment, it sounds normal to me!

Have you recently done an oil change? a thicker oil, say 20/60 will give the higher oil pressure readings, whereas a 15/40 oil will give normal readings, as you are getting.

Posted: Wed Jun 13, 2007 3:45 pm
by pootrollin
Never trust a standard guage. My son and his mates all have turbo 80s. They have all fitted mechanical guages because it is scary when the oil pressure guage shows low pressure when it actual has around 30 psi at idle.

12HT oil pressure

Posted: Wed Jun 13, 2007 6:13 pm
by Dents LN65
The 2H & 12HT have an inherrant problem with the oil pressure relief valve wearing and getting stuck, to fix this problem you can buy a new piston for the valve which is longer than th genuine item. Available at Sunshine state spare parts (07) 32166333