engine oil level warning light

[nuggs77]

hi guys

the lexus 400h display came on after 30 seconds saying engine oil level low. Ive had the engine oil and filter changed but no different also the oil pressure switch still know different.

what else could I check any help would be really appreciated  

[NemesisUK]

You changed the oil and filter but has the level been re-checked? Does the RX have a dipstick, or maybe just the tube?

[Herbie]

Have a look at the replies you got in the other thread when you first asked this question:

 

 

[nuggs77]

sorry just check so oil pump might be on the way out 

[nuggs77]

This AISIN Engine Oil Pump fits your 2006-2008 Lexus RX400h 3.3L V6 is this what im looking for

[Herbie]

3 minutes ago, nuggs77 said:

sorry just check so oil pump might be on the way out 

Well I'm no mechanic, but logically I would think so.

The engine can't be burning oil or you'd have to keep topping it up.

There can't be any oil leaks or you'd have to keep topping it up.

The 'Low Oil Pressure' warning light is on, but as long as your dipstick is showing the correct amount of oil in there (it is, isn't it?) then it can't be lack of oil causing low pressure.

If you've swapped the oil pressure switch for a known good one, then logically, the only other thing that's left is the thing that creates the oil pressure in the first place, ie, the oil pump.

But again, I'm no mechanic so take my input as you will.

[nuggs77]

thanks for your help looks like a bigger job than I can do on my drive i'll have to take it to the garage. oil level is were it should be just below the max level.

 

[Herbie]

 

32 minutes ago, nuggs77 said:

thanks for your help looks like a bigger job than I can do on my drive i'll have to take it to the garage. oil level is were it should be just below the max level.

Just looked at the workshop manual and it is indeed a very big job. You have to remove all sorts of stuff.

In fact, Step No. 1 says "Remove engine and transaxle assembly"

In the screenshot below, Step No 1 has the words "Click Here" underneath it. When you do click on it, another window opens with more than 110 steps, just to remove the engine/transaxle assembly alone - then there's another 36 steps to get to the oil pump!

These cars are complicated and I can't see it being as simple as the oil pressure switch clicking in and turning the warning light on. It's more likely that the switch will send a signal to an ECU for it to do something, so it could be a faulty ECU or a strange signal level turning the warning light on in error, when there really isn't a problem at all. Given that, I think first step would be to get an oil pressure gauge attached to see what the actual pressure really is and compare to what it should be, before thinking of changing the oil pump.

Good luck!
 

[Lager shandy]

Whoa there tiger all this talk of doom and glooom the first thing you need to do is take it to your local trusted garage and have the oil pressure checked against the recommended pressures and remember factor in age here .if your getting low oil level then I presume it has a level indicator some were .

[Lager shandy]

Sorry herbie just read all your essay herbie explained it correctly 

[Delphius1]

I'm not sure if it's the same on the RX400, but on my RX300 the oil level warning and oil pressure warning are two entirely different warnings, supplied by two different sensors.

The oil pressure switch measures the oil pressure in the oil gallery after the oil pump and lights the red oil can if the pressure is low on my RX. The light is red for a reason: the engine shouldn't be run with low oil pressure.

The oil level is measured by a float switch in the sump. The oil level warning light is an amber oil can on my RX300. ON the RX400 I assume the warning is in the information display. Being amber (or the information display) it means the warning is not as critical as oil pressure. You can check the level using the dipstick and if the level is okay, then get the sensor changed.

Regarding the Original Posters comments, they've got an oil level warning, but changed the parts that sense oil pressure. They changed the oil pressure switch and the oil filter, but not the oil level switch, which is completely different. No wonder the fault is still there.

The oil level float switch in the bottom of the block needs changing.

 

 

[Herbie]

There doesn't appear to be any mention of an oil level float in the sump, as you can see from the 'On car inspection' instructions in the workshop manual - only thing for measuring oil is the dipstick as far as I can tell:

EDIT:

Well there you go, every day is a school day as the saying goes. I had a look at the workshop manual for the meter/gauge system - lo and behold, that does indeed give instructions for inspection of the low oil level warning display - Step No. 5 below:

Just got to nip out but when I get back I'll find the procedure for replacing the float and post it up for you.

WEll done Mark for pointing that out.

[Delphius1]

Herbie,

It just seemed obvious when the OP was posting about oil level, especially as it was an info screen message rather than a big red warning light!

I've tracked down the sensor for the RX300/RX330, I'm guessing the RX400 should be similar or the same: https://www.lexuspartsnow.com/parts/lexus-sensor-engine-oil-level~89491-33030.html

It would be worth checking the sensor is (a) connected and (b) faulty before shelling out for a new one. They don't seem particularly cheap for what they are!

 

[Herbie]

You're right Mark, it does seem obvious and I think it was my fault in latching onto the word "pressure" in the OP's opening line and diverting the conversation:

Quote

the lexus 400h display came on after 30 seconds saying engine oil level low. Ive had the engine oil and filter changed but no different also the oil pressure switch

I really must learn to read things properly first before replying 

[Herbie]

Hmm, curioser and curiouser as Alice would say.

I've scoured the workshop manual but absolutely no mention whatsoever of an oil level switch other than how to inspect it (as in Step 5 of that last picture above).

No mention of where it's located or how to get to it, no mention of electrical resistances or anything. The only clue as to its location was found in the following illustration from 7zap.