I have a 2010 GS350/AWD (V-6, 3.5 liter) with 180k miles and probably 50/50 split of highway/in-town on those miles. Change engine oil (Valvoline 5w-30 Synthetic Blend) between 4-5k miles and also a new OEM oil filter each time. I bought car 5 years ago with 100k m iles. At the beginning of my ownership, I was using full synthetic engine oil and going 8-10k between changes before deciding that was too long of an interval.

Until approx 30k ago (so, at approx 140-150k miles on car) I would have to only sometimes add oil between oil changes, if at all, and typically not even 1/2 qt. total between changes. Now, it seems like I am adding up to 2 quarts (half a quart here-n-there) between changes (again, every 4-5k miles).

Sometimes, there is a very SIGNIFICANT blast of blue smoke (can last for a couple of seconds) right when I start it. I would guess this to happen approx 10-20% of the time. This occurs most often in the morning after it sits all night but there has been a few times it did this after only a fairly short time of sitting too. Btw, there are no oil spots or leaks that we can see.

The first spark plug change I did (120k miles?) the plugs were quite "worn" but they didn really have any sludge, clusters, etc, on them. When I checked tham again (when I started noticing car smoking more often at approx 150-160k miles) the plugs had a ton of built up sludge, carbon, etc. and had "worn" (electrode) much worse than I thought I would find. I also had to replace a faulty spark plug coil during this time.

My gas mileage has pretty much been the same throughout all of this...pretty much 24-26 mpg all day long with my 50/50 driving and will even creep up to the high 20's mpg if its an all highway tank of gas.

A local and very reputable repair shop (great familiarity with Lexus) mentioned a service bulletin and said they thought it was most likely piston rings and that it could cost as much as $10k to repair (which I wont be doing). The shop did not perform any kind of compression test, etc. nor did they have a chance to see the car smoke. This determination was based on our converation, their experience, and the research of a Lexus service bulletins referencing this issue on 3rd generation GS's.

I was hoping that my problem was something in the cylinder heads/valves to hopefully have a lesser repair cost and thus justify keeping keep the car. From reading many threads on here and some minor research.... it almost seems like it could be valve seals, seats, etc.(?). Maybe I am way off (I'm not a mechanic) but it seems plausible that it could be oil dripping down through a partially open valve (from worn seals, guides, etc,) and "pooling" in the combustion chamber. Maybe that would explain why the smoke is inconsistant (frequency) as maybe it is only one or a few valves having issues? Am I way off on this logic? I've also read that more frquent oil changes could help as its possible the piston rings are not working as designed and that use of a cleaning agent (Seafoam, etc.) and much more frequent oil changes may help to clean the rings and possibly open up the ringsorifices, etc.?

From reading other threads in GS forum....it seems like oil consumption is a very typical problem with these cars. It seems like a lot to me though(?).

Should I get rid of this car? Should I have certain specific tests performed to confirm if its valves or rings? Should I just keep driving it and add oil as needed since I like the car so much?

All views welcome. Thanks.

 

Its more likely due to you running your oil at 5,000 miles or more. Start changing your oil at every 3,000 miles, you also need to unclog your pistons oil control rings as more likely there all gummed up. Before your next oil change, buy BG moa and epr. Run this cleaner before the oil change and add the additive to the new oil.

If you do not see an improvement! You can try pouring seafoam directly on top of the pistons, through the spark plug holes and letting that sit over night, and then crank the engine over without the plugs to remove the seafoam. If that doesnt cure it, then time to remove the pistons and buy new rings/gaskets etc.

Majority of oil issues with the 3GS are from allowing oil changes past 3,000 miles. If you read the fine print for lexus suggesting 5k miles you will see it is under certain driving conditions.

 

Thanks for the info. I will be trying your recommendations before deciding what else to do, for sure.

BG MOA/EPR: typically bought at Walmart or auto parts stores? How much should I add as a cleaner (or, just follow recommendations on product?)? Do I use all of the EPR at once when adding to new oil change?

Seafoam: are you talking approx like a tablespoon of Seafoam in each cylinder? or, it really doeasnt matter (I think its an oil additive anyway, correct?)?

The repair shop quoted me a rough price of $10k for the ring replacement. This seems extraoordinarily high to me. If it were rings, wouldn't I have more of a continous, steady blue smoke situation while driving and not only when I start vehicle? Would a compression test or something help to determine? I'm not sure what type of test can determine whether it's rings or valves?

A mechanic friend and myself stilll wonder about the issue being in the valve guides/seals since blue smoke is happening more so when starting vehicle as opposed to a steady, constant smoke occurance. Any thoughts on this?

Thanks again for you input. I appreciate it.

 

BG products usually are not sold to retail consumers, but you can find them on amazon and on ebay. If the BG doesnt cure it, then tackle it from the top of the pistons through the sparkplug holes. Grab a funnel and pour as much as possible, the more the better. If you see the fluid level rapidly drop, know that cylinder is the problem.

What happens is theres small holes inside the pistons that flow into the oil control rings. Those oil rings control the amount of oil needed to lubricate the cylinder walls. When you leave your oil for long periods of mileage/5k miles or more the engine collects deposits, you will get staining at first and slowly it builds on in small holes. My theory, the problem isnt the oil breaking down, but that the oil filter will get over worked. Once those small holes in the oil control ring get filed with gunk, it compresses the spring. Once that happens it passes more oil to the compression rings, and those will eventually get clogged. When the compression rings get clogged then you will lose your compression.

With chemicals you want to see if you can melt that gunk and free up the rings.

 

Heres a video explanation

Heres how to pour the seafoam.... I just wouldnt crank the engine over with seafoam and sparkplugs. After letting it sit over night, crank the engine without the plugs and this will allow the chemicals to shoot out, then install the plugs. Doing it his way you will have a big chance of hydro locking the engine and thats bad.

 

Wow, thanks for all the info. I think the first thing Im going to do is try these additives and cleaners you recommend along with a couple of low mileage oil changes and see what happens.

ibidu1, thanks for suggestions.

I'll post resulsts later, after some of these treatments.

 

How do I crank the engine?

 

Rotate the engine by hand(on the crank bolt).

 

Any update?

 

How do you know which way to rotate?

 

if your going to be piston soaking you should use berrymans b-12 chemtool, it’s much more effective than seafoam and has had quite a bit of success if you have not seen the oil burning experiments by DIY Dave on YouTube with his I think 2000 corolla with the 2zz 4 banger, I’ve had 0 luck with running either seafoam or b-12 through the crank case and from what I understand it’s just not concentrated enough to clear out the carbon from the oil control rings, it’s some extremely hard carbon and really to have the best chance is gonna need soaked.

also from it having blue smoke on start up that makes me suspect possible valve stems seals have been worn out due to too long oil change intervals, since overnight the oil will seep down and when you start it it’ll get blue smoke, but I’d start with piston soak since it cost essentially chump change

 

Clockwise always when turning an engine.

 

I am concerned about the oil consumption of my vehicle, as it has reached 96,000 miles and seems to be using oil excessively. I recently had to add 1 and 1/2 quarts of oil at 2,100 miles, which is higher than expected. The car was initially owned by my sister, and I am unsure about its maintenance history. I will monitor the situation closely to see how things progress. It's worth mentioning that I acquired the car at 2,500 miles, after which it was passed to my mom, then to my sister, and now it's back in my possession.

 

Drain one quart of oil then add back in a quart of ATF. The detergents in ATF can help unclog gummed up rings, if that is the cause. If after treatment oil consumption is still an issue, give 5W-40 synthetic such as Mobil 1 a try.

 

Hello, I'm facing similar issues with my gs350 (2008), please tell me where you able to fix it?

I don't have oil leaks. I did a 695km trip. after i arrived i noticed my oil didn't gauge anymore

I use a synthetic oil


Please anyone with possible answers should help me