I wonder under full load and acceleration, if the oil flow bypass value is open and therefore no oil is filtered?

 

The reason for the extra quart in the ISF, as an oil cooler. AFAIK, the one in the LC is much smaller than the ISF which is smaller then the one in the RCF and GSF.

Lou

 

This is an old question but I would like to address it.

The answer is an absolute no.

The oil bypass valve is a relief valve (works to regulate pressure) that diverts the oil flow back to the sump, never does unfiltered oil allowed to the friction surfaces.

Why regulate pressure? The oil pump is pumping oil to different locations in the engine and it is based on an original oil flow path.

The engineers design the pump capacity based on 1) flow and 2) pressure to ensure proper flow to locations near and far.

The flow is affected by the pressure at the discharge of the pump and they don't want that pressure to change too much, because it can create problems. So, they regulate it to ensure consistency.

You may ask, what circumstances result in the pressure change, well engine temps are one reason.

There are other reasons (such as oil filter clogging over time) but I will stick to this one.

The pressure at the oil pump discharge changes with the oil temperature because it changes the density of the fluid.

That's my 25 cents answer.

 

The best bet is doing an used oil analysis and see for yourself. It's pretty cheap. For instance, in the 4.3 V8 10k OCI's even with an oversized filter was leading to a bit of sludge. Now this is in higher mileage engines than you guys have but still. Not desirable even if the oil is still good. 7500 - 8500 I found to be the ideal mileage. Your engines has a lot more oil too. Anyway, check out the link. It's pretty cool stuff to know exactly what's going on.

https://www.blackstone-labs.com

 

Lol wow, where have you been? Didn't you get rid of your LS?

 

This happened to me on the way back to Ohio while in Fort Worth. I valeted the car at a hotel and when they started it up to bring it to me in the am, I received the low oil warning on the Lexus smartphone app. I had the oil changed a few days before in Beverly Hills and I was in a hurry and didn't check their work. So a quick check of the dipstick showed the oil a little low. I stopped at an auto parts store in Texas and picked up a qt of Mobil One and toped it off. I think it is two things: 1.) The oil level sensor is probably at the top of the oil pan and parking on an incline in some orientation caused it to throw the alert. 2.) The tech that did the oil change probably didn't re-check / fill after the filter got filled up during initial startup. Since then, Ive never had the issue. Im guessing this is your issue as well. Mine has 25K miles now and it doesn't leak or consume any detectible amount of engine oil. Im guessing you just got a somewhat hap hazard oil change. I know its a little old school, but I think Its still a good idea to check your engine oil every couple of fill ups.

 

Nope. I only have 2k on the clock so still on initial factory fill. But like ive said a few times in earlier posts, I push my car really hard and it's still breaking in (not getting into an argument now about the ideal break in style, easing in vs pounding the hell out of it. ha!)

 

Understood. If you aren't parking on extreme inclines, I would just keep an eye on the dipstick every couple of fill ups. I would make sure it has oil all the way up to the top of the full mark on the stick. Oil isn't just for lubrication, its also very instrumental in the cooling process. So a larger volume of oil will technically cool better than a low volume. But having said that, the 5.0 V8 in the LC is only making about 94 hp per Liter, so its not running on the ragged edge of pressures and heat, like a supercharged or turbocharged car would be. This is why I expect mine to go 10 Years / 250,000+ miles without any major service issues. Like most any Lexus or Toyota is known to do.

 

So I just experienced the same thing - in regards to the vehicle notifying me that the oil level was low. Car has been broken in (2018 LC500), and has about 11,700 miles. Went through 2 oil changes before I switched to Mobil 1 Full Synthetic. Though what happened today, seems to coincide with prior warnings. I was oiling up my garage doors, and left the vehicle outside running on idle for about 15 - 20 minutes under 96 F temperatures. When I was done, I pulled the car inside and saw the warning. I checked the dipstick, and in fact it was low - so filled her up with 1 quart and verified the dipstick again (halfway now). Took her for a short drive, and no issues, except for some smoking out of the engine - I presume it must have been some of the oil I spilled while topping her off....

 

^^^^I did my second oil change back in January, the first was dealer complementary, I put in nine quarts, waited a bit, and checked with the dipstick, it was low. I put in another half quart, still low, topped it off with the rest of the tenth quart and now full. For checking between oil changes, I can check at the Lexus owners site:





Lou

 

I'm amazed at the low mileage so many of you have on your 2018 LC's! Are you purposely trying to keep the mileage low? I have multiple cars, but I guess I drive a lot more than the average bear, because my LC has more than 25K miles on it and I bought it new in February 2018.

 

Drive the wheels off it, remember it's a Lexus. They drive the same at 150k as they do at 20k.

 

So you're averaging a bit over 10K per year. Certainly, not excessive. My average so far is a bit over 5K. I'm retired and am holed up due to Covid-19. I am also widowed with 2 dogs, so don't get out much. My daily for around town is my truck. But, when I sold my ISF after 11 years, it had a bit over 50K miles

Lou

 

Understood. If the LC was my only vehicle, it would have a lot more miles on it than that. I drive now mainly to get away from being cooped up in the house due to the virus. But I do split that drive time with the other cars.