UDel

i have been using Mobil 1 5W 30 High Mileage Synthetic for my GS. I had a valve seal leak mostly in the winter, I put in some Motor Oil Saver and tightened the bolts, hope it stops most or all of it. When it comes time for my next oil change I want to do a engine flush with Lubro Moly Engine Flush and add Certec and may go with a higher end synthetic to see if I notice any difference.

What experiences have others had with some newer/top line synthetics out there for the GS or other Lexus vehicles? Most of these higher end synthetics seem to be made for German cars. Which ones are full Group IV Ester synthetic?

I have read Mobil 1 5W 30 is not really a "full synthetic" with looser US standards and is a Group 3, the only Group IV Ester full on synthetic from Mobil 1 I read is their OW 40 European formula which is actually no more expensive then 5W 30 at Wal Mart but is OW 40 okay to use in a GS430 when it recommends 5W 30? What about 0W 30? I am afraid it may leek a little more out of the seals if the MOSaver did not work with the thinner cold oil.

I may try Lubro Moly Synthetic oil, saw it in in 5W 40 and 5W 30, any experiences?
German Castrol Syntec full synthetic is Group V but I have only seen in OW 30 instead of the recommended 5W 30 for the GS.
Amsoil is hard to find and pricey but highly rated, not sure which one is Group IV.
Redline is highly rated but pricey, I assume it is a Group IV
Motul is pricey but gets good reviews, most likely a Group IV
Penzoil Platinum is getting good reviews, I believe it is a Group IV.
Heard mixed reviews on Royal Purple, some bad experiences.

I mainly want to see how my engine runs with something a little higher end then Mobil 1 5W 30 especially after I do a flush. If I notice no real difference I will just go back to Mobil 1 5W 30.

re-rx7

iTrader: (1)

Penn PLat.

RamAirRckt

Amsoil, easy to get, Amsoil.com. I use Signature Series 0W20.

Avoid the German oils that are 0W40 they are not ILSAC GF5 and 0W40 is waaay to thick for the 1UZ/3UZ-FE. Specs on the 1UZ-FE are super tight, far tighter than the UR engines even.

I did some bearing clearance study on the UZ vs UR and amazing how tight the UZ's are. And the UZ's were spec'd 5W30, and the UR's were 0W20....

burny

Castrol gold jug with the titanium.

MattyG

I've heard good things about German Castrol but it's hard to find in Canada. Some of it's being made elsewhere.

I put in Amsoil 5w30 and an Amsoil filter late last year, and I'm really pleased with it.

Smoother starts in cold and it has even quieted down a noisy lifter, which I wasn't expecting it to do. Car runs great on it.

In my mother's Suzuki 2.7 V6 I put in Mobil 1, it's been pretty good too but I find it's slightly leaking from the valve covers - which wasn't happening before. Mind you, two different vehicles and designs.

ntwrkguy1

My '03 GS430 is now at the 176,000 mile mark, and has only had dino oil. I've been wanting to try synthetic in it, but I've heard a few stories about "new leaks". I currently have zero oil leaks, and don't know whether I want to take the chance that synthetic oil might do just that.

MattyG -- was this the first time you used synthetic in your Lexus?

RamAirRckt

My GS and RX have been running Amsoil for a while (SSO 0W20), no oil leaks. Runs great, even down to -15F this winter.

MattyG

Yes I think it's the first time the car might have seen synthetic oil. I'm not the first owner but I do know the previous owner was a cheapo and he didn't spend any money on this car. I too was worried about leaks developing, but not a drop under the car or having to add at all.

UDel

If you go to a synthetic you might want to try a product for the seals/gasket like Lubro Moly Motor Oil Saver or ATP-205.

UDel

Sounds like Amsoil is the more popular choice from reading responses which is what I might try or German Castrol.

No experiences with Lubro Moly oils, Redline, or Motul Synthetics with a GS or other Lexus/vehicle?

RamAirRckt

IIRC (somewhat dated info, as the companies change oil formulation over the years) is Redline is/was a Ester base stock and Ester only base (compared to DiEster) makes for a much harsher oil. As to what all that means I don't know. I suspect it is the detergent properties of the synthetic oils.

I personally would lean towards the DiEster oils.

MattyG

Very good point. It's a question of what you want to pay for vs what you get. If you do your research than you zero in on which oils meet the highest standards.

But on any used car or high mileage car, just put in what is reasonably priced synthetic or what the oil change place will do for a good price.

If you're racing Porsches on the track yeah that's different. But it's more important to just change the oil/filter according to season/use and certainly go synthetic in cold climates.

RamAirRckt

I wouldn't use Redline in an older engine, more likely to get leaks than a diester base stock synthetic like Amsoil.

With the court decision on what is/isn't a "synthetic", it isn't so easy to know what a real PAO oil or just a Group

http://www.opieoils.co.uk/pdfs/Bewar...-labelling.pdf

Mobil 1 isn't a full synthetic despite the name. Most oils aren't truly synthetic, they might have some synthetic properties, and some additives that are synthetic, but not 100% synthetic.

MattyG

Yeah I won't say I'm totally disappointed with Mobil 1 vs Amsoil, but I would say just based on personal experience - it seems like a reasonably priced oil change with Amsoil, and you won't go wrong.

If I had the facilities to just dispose of used oil and do my own oil changes, then I would find the best/cheapest synthetic and change more often. The key being change that filter and oil frequently.

Our cars have a great motor - it's all aluminum and highly machined to tight tolerances, so showing it some love with fluids is not that expensive.

I don't know of too many 4.3's that haul around a two ton vehicle effortlessly and reliably at just about any mileage. (edited to add a note about the reliability of the 1uz/3uz motors)

I sometimes wish Lexus had just put on old school 4.3 V8 designator badges on it and called this car an Aristo. I couldn't care less that I'm driving a Lexus. Toyota is just fine with me.

RamAirRckt

Looking at the prices of Amsoil vs Mobil 1, and knowing Amsoil is truly synthetic and Mobil 1 isn't. The vote for me goes Amsoil.