Installed new oil filter housing, coolant hoses, oil pressure gauge switch, and valve cover gaskets. Now the oil pressure is running much lower than before. So what’s the normal range? With engine warm, I’m idling at about as low 10. Upon acceleration, 45-50, cruising at 30. Is this normal? Before these fixes, she would never go below 30 even at idle.
Oil Pressure 1998
- Thread starter Nefyn
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- idle oil pressure
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how are you reading the oil pressure?
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- #3
Sorry, just looking at the oil pressure gauge on the dash
it would be a good idea to get a proper mechanical gauge that fits inplace of the oil pressure sensor and comfirm OR install the old oil pressure sensor and see if any change in behavior
you also mentioned replacement of oil filter housing - was it a used or new part?
you also mentioned replacement of oil filter housing - was it a used or new part?
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- #5
It was new. So my question is…what is normal idle pressure reading? I thought that 10 was dangerously low even at idle.
So the oil pressure gauge in the dash has no numbers on it, only hash marks. Where are you getting these numbers from?
In any case, the dash gauge and sender are notoriously inaccurate. If you need to know real numbers, then a mechanical gauge is required.
1998? Dash pressure guage. Are you driving a 100 series cruiser with a V8 engine?
You are posting your question in the 80 series section. No pressure guage with numerical values on 80 series. And it is not uncommon to have low pressure at idle on the 1FZ straight 6 engine.
You are posting your question in the 80 series section. No pressure guage with numerical values on 80 series. And it is not uncommon to have low pressure at idle on the 1FZ straight 6 engine.
10 psi is not bad but not good either
usually 1fz idles at 15-30 psi oil pressure
usually 1fz idles at 15-30 psi oil pressure
This is from the '96 FSM for the 1FZ engine
Yep, not really sure why folks have such concern over Oil Pressure (at idle).
Basically...if the engine isn't knocking, you're OK.
Not to mention Oil 'pressure' is about 3rd on the list of importance. Oil 'Volume' and Oil 'Condition' being your key concerns.
Even the FSM suggests Toyota isn't too worried about Oil Pressure either, given the rather generous range of acceptable pressures.
Yeah but I don't understand why - because any toyota or other engine i've seen that runs on around 5 psi at idle is a broken one, it can't keep up at mid to high revs and the engine dies. Toyotas usually idle at min 15 psi when warm and go upto 65-70 psi during the normal course of driving depending on engine rpms - thats a healthy pressure.
Yep, not really sure why folks have such concern over Oil Pressure (at idle).
Basically...if the engine isn't knocking, you're OK.
Not to mention Oil 'pressure' is about 3rd on the list of importance. Oil 'Volume' and Oil 'Condition' being your key concerns.
Even the FSM suggests Toyota isn't too worried about Oil Pressure either, given the rather generous range of acceptable pressure
I've seen mine idle as low as 7 psi at idle, but typically is 12-15 psi (hot). That is using a digital gauge and good quality sensor. My engine (all original except for head gasket) has 330K miles on it. Oil pressure will vary with temperature and viscosity. Pressure and 'volume' are somewhat inter-related, but 'pressure' is easier to 'gauge' and understand by the consumer. Good/Sufficient Oil Pressure speaks to a free and constant flow of oil through the system BUT also to 'clearances' (I.E. Crank and Rod Bearings).
The general rule of thumb for 'sufficient' oil pressure (not espoused by Toyota, but for most engines in general) is 10 psi of pressure per 1,000 rpm.
Using that criteria... the 1FZ-FE at idle (650 rpm) is not far off at 5 psi. Mine is normally double that (at least). But Toyota's engineers (no doubt smarter than me) are satisfied with as little as 4 psi and provided they have also engineered the pump to be relatively high VOLUME, I would take no issue with that. The Oil 'routing' of an engine is also of prime importance along with additional features such as oil squirters.
What you cite above is pretty much what I see with mine. Still.....we should separate what might be ideal from that which is sufficient (per Toyota). Then we must consider all the conditions and places the 1FZ-FE is called to operate under. The guy in the Outback of Australia with 115°F temps, straight 30 weight oil at the end of its useful life...is probably lucky to see 4-7 psi. But the fella in Minot, ND running multi-weight in -25°F will likely see 18-25 psi at idle (if he can keep the engine running at all).
There are 'variables' that Toyota had to consider when printing the FSM while not unduly alarming vehicle owners. In fact, they took that a step further when they purposely created a big 'dead spot' in the coolant temperature gauge, as an example.
