SteveInFL

Hi,

I have an 04 ES330 with 130,000 miles and have always changed the oil and filter, usually at 3k miles and never over 5k miles and have taken very good care of it. About a year ago I started using Valvoline Maxlife 5W-30 in it as that's what the oil change place recommended.

A few days ago the low oil pressure light started flickering then staying on. I stopped driving it immediately. Oil level was fine, color was clear gold on the dipstick. I thought it may be electrical so to rule that out completely, I removed the pressure sending unit and hooked up a mechanical oil pressure gauge (tube type). I routed the tube and gauge and placed it under the windshield wiper on the driver's side so I could monitor it.

Started it up and pressure read 65psi ! was very happy to see that. So I took it for a test drive, drove normally and calm as usual and at about a mile the pressure started dropping, down to 25-15 psi.

Engine speed did not make the pressure increase at all. I pulled over and shut it off, waited about 8 minutes for the oil to drain back down from the top of the engine to the oil pan and started back up, read 50 psi now. Drove back to the house and it dropped low again.

After a lot of reading on here, I changed the oil filter to a new Fram and same results. Also read about the class action suit Lexus lost with some types of engines doing this but I think I'm over the 8 year limit now for any help from them (?).

I discussed all this with a very qualified professional mechanic and he said he's seen this exact problem in 2 other Lexus cars. He said (as I've also read here) that the oil return ports are too small and start getting gunked up, the oil can't return to the pan/pump quick enough.

He said there's no simple way to fix this. I asked him about flushing the block with something like seafoam and he said we could try that but he's concerned that it may dislodge stuff and clog other things up like the pump pickup, etc.

I'm considering using the thinnest oil I can to see if that helps (I'm in central Florida).

So I need opinions from some of you if you will. Such as, should I try flushing the engine ? Using thin oil like 0W20 ? Taking valve covers off and trying to clean return ports ?

Thanks for any advice,

Steve

Megafast13

Very interesting. I have yet to hear about this issue on the forums.


Sounds like Seafoam may be a good option in this situation.

tomf

The sludge problem was with the 1MZ-fe engine. You do not have that engine. I also understand the 1MZ-fe engine was eventually modified. Engines manufactured after Jun 2002 should not have the sludge problem. Based on the information you provided, I would guess that you have some other problem. I have not heard of any sludge problems with your engine.

pauloil

autorx.com may help. is the maxlife energy conserving?

SteveInFL

Thanks for the replies. I don't remember if maxlife is conserving or not, I'll have to look at the jug.

I now think my diagnosis was wrong, here's why...

The pressure drops after the engine gets to normal operating temperature, when the engine is cold pressure is high and drops off as the temperature goes up.

Since I thought the oil wasn't draining back down to the pan fast enough, I drained the 5w30 and replaced with 0w20. Same results, temp increases and oil pressure decreases. I tend to think if it wasn't draining back to the pan because of restricted ports, the hotter and thinner the oil got the better it would drain . So I just don't think that's the problem.

So, I drained the 0w20 and replaced with 20w50, cold start pressure is about 75psi. Then when the engine temp gets to normal the oil pressure stays around 40 to 50 psi and increases with engine speed. The 5w30 and 0w20 didn't increase in pressure with engine speed, just stayed low around 10 to 25psi regardless of RPM's.

But, I noticed kind of a whirring sound right when I started the engine and when the oil pressure gauge started increasing the noise got less proportionally. Kinda sounded like loose gear teeth meshing, as in an oil pump.

So, I now think that I have a worn out, failing oil pump.

I've only let the car idle to reach temp and didn't have time to take it for a test drive tonight but may first thing in the morning but I think the pressure is going to be OK. So thinking I just need to change the oil pump now.

What do you guys think about that ? Does this sound like symptoms of a failing oil pump ?

PFB

As far as I know, if your oil pressure is above 3.55 psi than it is considered normal and within Lexus specs. As the oil heats up the pressure will decrease, but it should never decrease BELOW 3.55 psi.

Phillip

SteveInFL

Thanks Phillip, the thing is though, the red low oil pressure light will keep coming on and I just don't want to take a chance with damaging or destroying the engine. And, I think 20w50 oil is just too thick even when hot to get in all the places it needs to in order to keep everything lubed properly, even at 40 to 50 psi when hot. Maybe I'm wrong (?)

And, I'm really not sure on a very hot day that it would even maintain at least 3.5psi at idle ! (with 5w30)

Looks like to have a shop I trust to replace with a new pump is about $700. Which isn't too bad I don't think. Toyota Dealer says the engine has to be removed (which I don't think so) and their cost is about $1550.

Any advice on this is appreciated !!!


BTW: It looks like you're exactly correct tomf, thanks.

PFB

Don't overlook the possibility that your oil pressure sensor or its associated wiring could be the problem.

Also true low oil pressure readings is usually caused by excessive clearance in the main bearings, not by a faulty oil pump.

Put back the 5w30 oil, attach your mechanical Gauge again, and note what the readings are.


Phillip

hypervish

The 50 weight is too thick. It's going to cause excessive wear, not to mention oil flow is going to be terrible in cold weather( which isn't a as big a concern right now).

Also, it will affect the VVT-I. It doesn't do well with thick oil.

SteveInFL

Thanks, the mechanical gauge is still connected ruling out all electrical possibilities. The 5w30 and the 0w20 were just in it and gave the same results. As long as the engine is hot, oil pressure is low, cold, it's fine. Cold: ~60psi, Hot: fluctuates ~25psi down to 10psi or so and pressure does not increase with engine speed.

20w50, Cold: ~75psi Hot: ~45psi to 50psi and does increase with engine speed.

I understand about the main bearings and clearances but this happened instantly, as soon as I heard noises what appears to be coming from the oil pump although it took me a little time to realize it. I'm certainly no expert but I have rebuilt 2 Chevy 350's and 1 Ford 4 cylinder before and put a lot of miles on them. But, I've never seen the inside of a Toyota V6 engine before.

I'm in central Florida and It's getting into the 90's, is it OK to drive it short distances and low RPM's for a little while ?