matts6887

Jim; what is bg moa? and isnt it a little much to have to change out that valve every 10000 miles? or is it just me?

jimsRX300

PCV valve every 10K is excessive for a normal vehicle. You should see how that think looks.

BG MOA is a engine oil supplement. Not a flush. It's what the dealer adds to each 1mz oil change. It's good stuff. I change the oil every 3-5K. It just depends on how it looks.

Now your heads? I say buy both L & R because u r already in there. SCRUB that sucker with a case of carb cleaner and REPLACE THE OIL PUMP for good measure.

Unfortunatly the 1mz engine is a giant aluminum turd pile.

Yours is a 2001? What is that... 14-15 years old? Don't spend more than you have to.

matts6887

The second rx i picked up which i have currently is a 99 300. Fortunately for me; it seems like whoever owned it previously has taken almost as good care of the vehicle as they possibly can considering the age of the vehicle. It has had no cel (YET; yet being the keyword here; knock on wood....). nothing wrong at all yet; but depending on how long i keep the vehicle; that could very well and Im guessing probably will happen at some point down the line as the cel seems to be happening to just about every older rx. As far as that oil supplement goes; when I go get my first oil change done; I will get some of this stuff before and after oil change is done dump the bottle of it in the oil fill. I only have a bit over 132,500 miles thus far. As for the oil change itself; Ive been told by both the lexus dealers here and a few other independent shops that you can wait til about every 5,000 miles to change it.

AnthonyMtz

I would just Change out the engine then you can change the timing belt and the rear spark plugs you can always ask for the seller to remove the valve cover to look for sluge I just found about 5 engines online with 70k to 95k miles for 1,200 to 1,500$ and if I'm not mistaken the have a 30 day warranty

oldusedone

Wow, this is the third time I'm attempting to post these same questions. Two previous long winded posts where victims of my dual logging in and I lost the work done.


This time I'll be short. Does the engine when manufactured have a standard oil level that triggers the low pressure light? I'm thinking there is a physics problem there for someone from the MIT side of the house. Yes, this is the least of my worries at this point but I am thinking conspiracy, maybe. A different thread where someone had a low oil pressure light go on at 2 quarts down. I was down at least three and nada.

Neither my mechanic nor I found any oil leaking on the ground even after two weeks in one spot. What should be done when someone brings a car to someone to get it checked out before purchasing? Compression test on the heads? Test for blown head gasket? In fairness, I had already bought the car when he looked at it. It was firing smooth and he drove it for 25 or more miles and did not notice oil usage. Given this experience I will never have that naive simple wide-eyed look when looking over a used car I'm thinking about buying.

Given the p0300 and p0304 would not the likely source of trouble be the #4 cylinder valves? What does the p0300 code mean anyway, random misfires was what I could determine. Buy a set of used heads, the head gasket, valves or valve covers, change the engine, or junk it? I do like the idea of getting another opinion but the mechanic at Lexus seemed completely convinced it was curtains for my motor. Would this be chasing after the rainbow?

Thanks again, I'm learning a lot this weekend.

Paul

Anthony mentioned he found engines in the $1200 to $1500 range. Could I have that link because my searches are not hitting those number even close? Thanks.

salimshah

Let me make an attempt to answer your question ..
Does the engine when manufactured have a standard oil level that triggers the low pressure light?
The level (in the contained volume) is measured by the dip-stick. level based on Volume
The oil pressure sensor checks the pressure of the oil past the oil pump (near the filter if I am not mistaken). measure in psi (sae units)

Since one can have enough volume of oil but say the oil pump breaks down, you will not get the pressure. One can have oil breakdown (shearing) a condition in which you have enough volume but the oil is so thin that it fails to develop enough pressure.

One can also have a hard block in oil passage where the pump keeps generating pressure but there is no flow of oil to the top of the engine.

So in summary answer to your question as posed is "No". The pressure and level are like apple and oranges.

Neither my mechanic nor I found any oil leaking on the ground even after two weeks in one spot.
Then the Lexus diagnosis was false. Or the lak happens when oil is being distributed by the pump.

If I am not mistaken, the choices you are dealing with are
1. Service head of your RX
2. Purchase a used head
3. Swap engine.

In all three choices you will be (most likely) service the timing belt components.

Between 1 & 2 I would vote for 1.

The unanswered questions are

1. Does your oil pressure light works.
2. Where is the oil going? Since we cant tell for sure, we will not be able to fix it. Based on this I would suggest an engine swap with some warranty on it.


Salim

jnovak01

I have one question for you Sir.
Did the Lexus service people perform a compression test on cylinders 1, 3, or 5?

Thanks

Joe

oldusedone

In answer to the last question from jnovak01, I don't know if they tested compression in 1,3, or 5 but will call on Monday to ask. Still waiting for call to test dashboard indication.


Thanks to Salim for going over those real world oil pressure issues. My wife tells me I don't live in the real world so let me rephrase my question. Let's pretend a brand new Lexus AWD engine came off the assembly line everything working perfectly with new premium 5W30 oil in the crackcase filled to the top dot. The engine is in a lab setting where the engineers can remove oil without affecting the oil pressure. Is there any way to say where the oil level would be on the dip stick at the time the oil pressure light illuminated? Would this information be part of the service manual? We are ignoring the breaking in period and assuming the engine is fully broken in working without mechanical issues.

Correction: This is a 2002 not 2001, according to carfax it was purchased January 2002 and so probably built in 2001.

salimshah

These specifications are listed: (skipping the unrelated ones like viscosity etc)
Volume of engine oil.
Oil pressure range when engine is running.

Unfortunately I have not come across the combination you want. I think I understand your question but am helpless to get it for you.

I do understand that you want a specific information which I dont know. Lets see if some one replies. We have kicked it around a few times to get visibility.

We have another option .. if you want to go that way...

Lets assume that the answer to your question is a number between 1 and 2 qts. What would this number enable you? Does it help you make any confirmed diagnosis? In all cases, I would top up the oil and run the engine. Put the engine through its paces and hear for metal on metal wear sound of permanent damage. One can drop the pan and look for filings and even cut open the oil filter. If none then not worry about it.

Salim

oldusedone

Salim,

I like your new idea to look for metal fragments in the oil pan. That might give me some evidence to go on to help me make my decision. This will require coordination with my son and the shop he is able to locate nearby his current location. Since he only recently learned how to check the oil, this job would be next to impossible for him to manage without guidance. Almost as bad a me trying to change this engine on my own.

You are also right about the question what does knowing the oil level that triggers the dashboard light really matter at this point? Maybe curiosity did kill the cat, but I'm still curious why there would be a failure indication without criterion to assess what the failure means. The pursuit of perfection? No, the pursuit of ambiguity, if in fact, that is the Lexus motto. My uneducated sense is that running an engine with 2 quarts of oil would be bad and something to avoid at all costs. Still waiting for the call home to look at the dashboard lights.

Paul

A 2010 RX350 with 32k miles had a low oil pressure around 1.5 quarts. https://www.clublexus.com/forums/rx-...l-mystery.html
I think I'm on to a major cover up here!

oldusedone

Don't see the oil pressure in this photo. Had my son apply the parking brake and open the door then turn the key to on, as the manual says to do oil light still missing, as is the headlight adjust one too.

Still find it amazing Lexus does not have a low oil level gauge on the RX300. There is one on the ES300 but not this one. The manual says to check the oil every time you fill up the tank. Sure, all the ladies, lazy guys, and college kids will do that. The lack of a gauge makes buying a used RX300 a risky gamble. We ran on 2 quarts for three hundred miles, but the pressure was good, must happen more than we care to consider. Unless you can unequivocally say the oil was monitored religiously I would stay away from this as a used purchase. What I have learned this week is to make sure every dash light works before purchasing anything used. That means learn the secret method to make the lights go on and know what lights you should have.

Do other cars only have a oil pressure gauge as does the rx300? Since I'm new to the car world I have no clue what is out there on the dashboards of cars of this century.
From the manual in reference to the oil pressure gauge:

The light may come on when the oil level is extremely low. It
is not designed to indicate low oil level, and the oil level must
be checked using the oil level dipstick.

I wonder what they mean by "extremely low"?

salimshah

One needs to pay attention to the warning lights on every start.

Salim

Nelexus88

The oil pressure warning light is located just to the left of the battery light. It should be on during the lamp test but since it is not, the bulb could be burned out, the sensor could be defective or there could be a wiring problem.

The link you provided to the 2010 RX 350 oil problem never had a follow up by the original poster confirming the problem or the solution. As some of the other posters suggested, it may have been a measurement error.

Some older cars (Lexus included) did have oil level indicators, but very few new cars have them. I expect that is due to instrument failures causing too many false readings and the fact that very few modern cars use any oil between changes.

The amount (level) of oil required to provide adequate pressure depends on several factors. It needs to cover the oil pickup tube in the bottom of the oil pan or the pump will draw air instead of oil and loose pressure. If the car is sitting still on level ground, the pickup tube may be covered but if you are driving around corners or on hills it will become uncovered with the same amount of oil.

oldusedone

Checked with Lexus service about the compression in the other cylinders. Those were not checked but the service manger assured me with a 20psi in #4 along with the oil in the manifolds, the engine needed to be replaced or fixed, and neither of those options would be worth it on a car this age he felt. We may attempt to drop a used engine in it but still up in the air on that.

The moral of the story is know your gauges and lights. Had I taken the time to discover there was a missing low oil pressure indicator I'm quite confident I would have walked away from the car. Not something I will take for granted again, ah hind sight it's such a wonderful thing.

salimshah

Did the dealer put forward any theory as to how oil got in the intake manifold?

Salim