Starving for oil?

lexus
gs400

#1

Hey guys. My 2000 Lexus GS 400 (4.0L V8) has been worrying me lately. It has 226,000 miles and still runs great. My concern is that on occasion when I go to crank the car after it has been sitting for a day or two- usually over the weekend, the engine sounds really rough when starting. Almost like a lower end clank noise. I am not a mechanic, but to me it sounds like the lower end of the engine is starving for oil.
It does burn oil (smoke at cold start up)so I try to ensure it always has enough oil. This morning it made that same clanking noise. I check the oil level and it was right at the minimum level. I went ahead and added a quart and after cranking it back up the sound went away.

Can any of you more experienced guys get me started on the right direction to fix this? I don’t want to put too much money in the car because it is not worth much as is, but I do want it to last me at least another year. Besides this issue- the engine is always chugging along like normal and very quiet.

Thank you in advance!
Frankie


#2

Run it until it blows!

That answer is a bit harsh but with 226K on the engine, it is pretty likely what you are experiencing is excessive oil clearance in the bearings for both rods and crankshaft main bearings. Add a worn oil pump to that and you will get a rattle upon startup until oil pressure builds up. To replace them at this point would be very expensive. Basically a new engine or a rebuilt one.

That said, keep a sharp eye on oil level. Check it as every gas fill-up. Carry a couple of quarts with you. Use the thickest oil Lexus recommends for this car. If they recommend 5w30 OR 10w30, choose the 10w30. You should get some more life from the car - impossible to say how much - but save your dollars, this one’s one the way out.


#3

I was afraid of that. I will say that no warning lights have ever illuminated on the dash, so hopefully the pressure has never dropped too low. I don’t mind putting a little money into it to ensure it runs a little longer, but I have no idea on how to replace the oil pump on this engine. I am researching the procedure to see if it is not too complicated.

I have been running 0w 20 Mobile 1 synthetic in the engine. That has probably been some of the cause of the problem. I read online that low weights will help reduce dry starts. (everyone knows everything online is true!) I will start running a thicker oil.


#4

OK, just do as Mustangman advised. Change the oil now and don’t waste your money on synthetic at this point.


#5

Yes, synthetic oil WILL help dry starts IF the clearances are small enough to hold the oil in place. Yours are not anymore.

As for the oil pump… Just replacing it with another likely will have very little difference in the problem. In the old days, we would install a high-volume (bigger) oil pump. Not higher pressure, higher volume. That would help the excess clearance problem for a while longer. I doubt you can get such a pump for your Lexus.


#6

I’d be very curious how your oil pressure is doing. Any way you could have that checked? Your mechanic could temporarily install a gauge in the engine compartment to see what happens.

Does the oil pressure or engine warning light stay on until the noise stops?

That initial exhaust smoke may be due to leaking valve seals, which has nothing to do with this. I had that with my ES300 at about 120k.

How many miles between adding a quart?

What oil is specified for it?


#7

A little hope for you. Toyota engines “on the way out” often take a ridiculous amount of time to die. My MR2’s engine has been showing signs of being on the way out for 10 years now. I’m intentionally waiting for the stupid thing to die so I have an excuse to put something more powerful in there. At this rate I’ll be dead before it is.


#8

@texases
I am always pressed for time, but will try to see about doing a manual gauge to obtain an actual pressure reading.
I have never seen the oil pressure or CEL turn on for this issue.
I also agree that I probably have leaky valve seals. I can live with the smoke puff in the mornings and afternoons. :slight_smile:
I am not great at keeping track of data such as miles between adding oil, but I would have to estimate around 500-750 miles per quart.
Factory specs call for 5W 30 weight oil.


#9

Yep. I am a big fan of Toyota. When this car kicks the bucket I am going to look for another similar vehicle, with a lot less miles of course!


#10

If it calls for 5w-30 you may see a significant improvement just by switching to that.


#11

I can imagine that running engine on the oil with lower weight can lead to higher wear rates as oil film is thinner and it is less oil to keep bearings protected, especially at startup.

I would not only switch to the grade recommended by Toyota/Lexus (which I believe is 5w30 / 10w30 for this engine), but to find the thickest oil of the same grade, based on real specs.

For example:
http://content.valvoline.com/pdf/synpower.pdf

Notice that viscosity of 10w30 is higher at 40 Celsius to compare to 5w30 one, while on 100 Celsius they are almost the same, slightly less for 10w30 as manufacturer likely uses less thickener additive at thicker base oil stock. Less thickener leads to less viscosity loss over time, which translates to less wear and smoother operation.

In your particular case you want as thick as possible at cold, so 10w30 is what you need.

You can get similar specs for most other reputable oil manufacturers, for example here is one for Mobile 1: https://www.exxonmobil.com/Passenger-Vehicle-Lube/Mobil-Super-Synthetic/pds-us

BTW, on spec Mobile 1 looks to be thicker, but by my subjective observations, it drops viscosity faster than Valvoline, so it is my favorite.


#12

just what you need

If motor is spec’d for 5-30 than 0-30 is perfect.
Quick flow when cold and proper flow when hot


#13

You mention that this problem only happens after the car sits for a few days. It might help to switch to an oil filter with a better drainback valve.

I had this problem with a 2003 Chrysler and the lifters were clattering on cold startup even overnight. It happened with Fran and Mopar oil filters and I read a post on a Mopar forum that said someone had cured that by switching to a Motorcraft filter because they had a better anti-drainback valve.
I am NOT saying Motorcraft is the best filter, just that it worked for me. I am sure that there are many other filters that would have done the same thing, I just don’t know which ones they are.


#14

If you see black smoke out the tailpipe on start-up, but not after the car warms up, you could have leaky valve stem seals. That could cause the engine to run poorly at initial start up as well. Valve stem seals can often be replaced for a reasonable price if the top of the engine allows replacement without removing the cylinder head. Often the case of a 2 L 4 banger, but on a 4L V8, might not be so easy.


#15

Was this engine one of the Toyota engines that were susceptible to sludging? IIRC the problem could mean oil passages got clogged with the residue of overheated oil. I don’t know what if anything was done to fix the problem, but it could be as easy as taking off the valve cover and cleaning out passages with something like industrial strength pipe cleaners.

IIRC, prevention was to change the oil more frequently than Toyota had originally recommended.


#16

I went ahead and changed the oil to Mobile1 10w30 high mileage. I am using an extended performance Mobile1 filter good for 1 year or 20k miles so I left the same one installed.


#17

The engine in this car is well known to be bullet proof. I also owned a Toyota Avalon with the 3.0L V6. That was one of the engines prone to sludge.


#18

I am using Mobile1 Extended Performance filter. I am not certain as to its drain back valve. I will research this further.


#19

I sure hope you’re not planning to leave the filter and/or the oil in place for 20K . . . ?!


#20

Use the correct Toyota oil filter…Some oil filter brands have less than perfect anti-drain-back valves which can delay oil pressure reaching the bearings. What weight oil are you using?