Lx470 Engine Oil Pressure

[Capt Pete]

I recently pruchased a 2006 LX470 that has 12,000 miles. Beautiful SUV that looks like new and appears to have had a very good life before me. But I do have one concern.

The oil pressure guage is divided into 5 dashes, with a "L" at the lowest dash and a "H" at the highest dash. For this description I will refer to the lowest dash as "1" and the highest as "5". My engine operates at the 2 position and when started first thing in the morning almost gets to the 3 position. At hot idle through cruising at 65 MPH the needle remains between 2 and maybe a 2.75 position. Since there are no numeric markings on the dashes I do not know the PSI translation, but an oil pressure guage reading less than half scale at 2000 RPM sounds low to me.

Thus my question as to what readings are other owners seeing? I am running the Lexus 5W-30 oil with a Lexus filter, having had the oil changed about 1000 miles ago. Your help in sorting this concern out would be most appreciated.

Pete

[G M E]

Capt Pete,

My engine operates between 2 - 4 positions.

GME.

I recently pruchased a 2006 LX470 that has 12,000 miles. Beautiful SUV that looks like new and appears to have had a very good life before me. But I do have one concern.

The oil pressure guage is divided into 5 dashes, with a "L" at the lowest dash and a "H" at the highest dash. For this description I will refer to the lowest dash as "1" and the highest as "5". My engine operates at the 2 position and when started first thing in the morning almost gets to the 3 position. At hot idle through cruising at 65 MPH the needle remains between 2 and maybe a 2.75 position. Since there are no numeric markings on the dashes I do not know the PSI translation, but an oil pressure guage reading less than half scale at 2000 RPM sounds low to me.

Thus my question as to what readings are other owners seeing? I am running the Lexus 5W-30 oil with a Lexus filter, having had the oil changed about 1000 miles ago. Your help in sorting this concern out would be most appreciated.

Pete

[LXPearl]

The gauge is a real one. At idle the oil pressure is lower than at highway speed. I had an F150 where the oil gauge always read the same when on... turns out it was a fake - essentially an idiot light with an artificial readout that looked like a gauge.

[Capt Pete]

Agree that the oil pressure gauge is a real one, but about as useful as the F150 version, as it has no values associated with the marks on the gauge face. My thought is if Lexus is going to use such a gauge, they would scale it so normal running would be in the center of the scale. The way it is now the gauge reads on the low side of the scale so oil pressure must be on the low side???? Do not know how it compares to other engines of the same vintage, thus my question. For the price of these vehicles you would think Lexus could include an informative gauge.

My general opinion on this subject is that any manufacturer who uses non informative oil pressure gauges does so to cover for significant tolerance variance in their product, resulting in significant variations in the oil pressure from one engine to the next. Somehow, I expected more from Lexus.

Still am very interested in what other owners are seeing as the hot idle and 60 MPH hot cruising indication on their gauge. Thanks

Pete

[dakarl2003]

Agree that the oil pressure gauge is a real one, but about as useful as the F150 version, as it has no values associated with the marks on the gauge face. My thought is if Lexus is going to use such a gauge, they would scale it so normal running would be in the center of the scale. The way it is now the gauge reads on the low side of the scale so oil pressure must be on the low side???? Do not know how it compares to other engines of the same vintage, thus my question. For the price of these vehicles you would think Lexus could include an informative gauge.

My general opinion on this subject is that any manufacturer who uses non informative oil pressure gauges does so to cover for significant tolerance variance in their product, resulting in significant variations in the oil pressure from one engine to the next. Somehow, I expected more from Lexus.

Still am very interested in what other owners are seeing as the hot idle and 60 MPH hot cruising indication on their gauge. Thanks

Pete

[Texasoil]

Settle down folks. Ya'll trying to brain surgery on a gnat with a backhoe. There are a great many things that will conspire to cause an electric gauge like that on the LX-470 oil pressure be unrepeatable and a poor indicator of reality.

First there is the pressure sensing element , that converts the actual oil pressure into a resistance that varies with pressure. Then there are the electrical connections to that precise?? sensor. Then ther eis the actual voltage applied across that precise? sensor to produce a current flow (milliamps). Then there are the connections in the wiring harness and finally those to the indicator unit. The indicator may be either an electromagnet type or thermo-electric type. Thermo-electric ones show more steady readings (which some people prefer). Electro-magnet ones, like the meter in a VOM, are quick acting. Either type can be inaccurate or poorly calibrated. Or the sensor may not meet the calibration requirements.

MECHANICAL oil pressure gauges run a tiny copper tube from the engine oil gallery to the back of the indicator, which is a bourdon tube ( a curved flattened tube that straightens out as pressure is applied) which is geared to the indicator. They also may be inaccurate.

For example, in the MBZ V-8's , normal cruising RPM oil pressure is 75 psig, limited by an oil pressure relief valve that sprays on the cam chains. Idle speed of 600 rpms, hot, with 10 W 30 may indicate 15 psi or less. Increasing speed to 1500 rpms should show a pressure increase to 30-40 psi, while 2500 rpm should 'peg' the gauge (5 Bar-75 psi) BMW 6 cylinder engines may have hot idling oil pressure of less than 5 psig when in good condition.

Using the electrical oil pressure gauge as a 'normal reference' is OK, but it is not accurate or precise enough for anything else. If you really want to know the 'real' oil pressure, buy and install a Good mechanical oil pressure gauge (+/- $100 + labor) .

For what it is worth, MBZ scientists determined that incidences of low oil pressure caused engine damage were so few that it was costing many times more to have even an oil pressure warning light--so they discontinued in on their 'C' class---the first car they ever designed to a price target. Customers were shocked, and demanded a warning light. Feedback was lack of the warning light communicated extreme cost cutting and 'cheapness'.

Don't sweat it.