Is250 Oil Mystery

[james250]

I'm hoping someone can shed some light on this. I have a 2006 IS250 Auto which is now on 160k Miles. Past few oil changes i've done myself. Previously I used Castrol Magnatec 5W30. After that service, car felt quite responsive and good, but few hundred miles later it started becoming less responsive and worse than before the service. On slow moving traffic on third gear specially it would judder. Also, the oil levels were really falling, I checked it after 1,400miles and it was already towards the bottom.

So, every so often I would top-up to keep it on level. Until i got fed up and 6k miles later decided to do another oil change and try another oil. Just over a month ago, I did another oil change, this time with Mobil 1 ESP 5W30. I've driven almost 2,600miles with the Mobil 1 oil. After doing the oil change with 6.3L, i check the level and it was just above the halfway mark. Now after 2.6k miles the level is still above the minimum mark. Not half way and closer to min. About quarter way between min and medium. The judder has disappeared and car now feels better and responsive.

Just wondering if anyone can shed some light as to why the Castrol Magnatec behaved like this and levels were dropping?

Thanks

[ChumpusRex]

Could be related to deposits on the piston rings. If the rings get sludged up then you can get major oil consumption because they don't seal the combustion chamber; this can also give poor performance and rough running.

An oil flush or change to an oil with better sludge resistance can free up the rings and give better sealing.

I've found that the IS250 engine is quite fussy about oil, and it will tend to consume mineral and semi-synthetic oils, whereas a decentish synthetic tends not to be consumed.

I just use the cheap TripleQX 5W30 C2 synthetic from Euro car parts whenever it is on sale. You could probably go cheaper and use the "GM engines" A3 version, as it still meets the relevant specifications (but may not be quite as catalyst friendly, and given the special catalyst design, getting an aftermarket replacement welded in is unlikely to be an option).

[is200 Newbie]

I use the 5/30 Magnatec oil and have experienced level drops but nothing to the extend you have described

I expect the cars to use the oil in its normal operation - I had an Astra a few years back and had a hell of a time with it using more oil than petrol (bit of an exaggeration) - it was using approx. one litre per month and this was proved on an oil consumption test that Vauxhall undertook. I was eventually told this was normal as it was within the engines tollerances (I knew it was total Boll*%s what they were telling me but I took the complaint as far as I could ...... It was a low mileage 2.0 sri, needless to say after about 7 months of persevering with it the engine sounded like a bag of nuts - so not to be out done I managed to part ex it back to an unknowing Vauxhall sales rep for my first Lexus ..... KARMA

I am due to do an oil change on my 250 soon and I have a Europarts close by so I will give the oil Mark uses a go. I ALWAYS run through the engine with the Wynns engine flush before changing the oil. On a couple of occasions I have ran it through twice. The oil tends to stay cleaner longer.

[james250]

I also get my oil from EuroCarParts and timing the purchasing when they have the coupons is essential. I used a 50% coupon code to buy the Mobil 1 ESP 5W30. I was initially considering doing a engine flush, but all the members over on the american club lexus highly advise against it. They claim that flushing engine with these cleaners will cause the engines days to be numbered. Sounded a bit scary to me so I avoided :)

I read that the Mobil oils have their own cleaning properties. Not sure how true this is, but I get the feeling maybe this is what has helped? 2.6k miles on and the oil still looks quite clean. (not as clean as new, but not dirty). With the magnatec, the oil went dirty within the first 1k miles.

[North west beast]

I've heard bad reports on that magnatec , it's crap

[Gramera flash]

I would say never cut corners with engine oil, and always buy a good quality product.

[is200 Newbie]

For the past 7 years I have always used an engine flush and on two oil changes a year, I have had no issues at all - it does make a difference to the colour of the oil after the oil change, it seems to stay cleaner longer. There must be differences of opinions in doing this as there are different driving styles that would effect what type of oil to use in the car.

I will definitely try another make of oil as you cant make a judgement while just using the one type. If Lexus recommend the 5/30 grade then what mileage does that cover the car up to - is it a bit too thin for high mileage cars hence the discolouration of the oil? Is it being burnt and hence the discolouration? - maybe a thicker grade 10/30 would be a better match for cars with high miles as afterall the engine hasn't just rolled off the production line.

I will stick to the 5/30 but will change the brand. I have also had the VVTI rattle on startup and its an indication, I think, that the oil needs changing - its happened twice now - both times before an oil change and after an oil flush and oil change it has disappeared. Again, id this Magnatec too thin that its draining from the VVTI chamber. The rattle happens on a friends Mazda 6 and he is running Magnatec so I might get him to change brand to see what the difference is...

[james250]

I am now coming up to 3k miles with this Mobil 1 ESP 5W30. Colour of the oil is still quite clean compared to the condition the Magnatec was in after around this many miles. The level is also very good. It's between min and medium.

[is200 Newbie]

Hi James

Keep us updated .....

[ChumpusRex]

There's nothing terribly wrong with using an engine flush, provided that the engine is reasonably clean and has been well maintained.

The issue with a flush in a dirty engine is that it can dislodge lumps of crud from large passageways, which then get forced into smaller passageways, blocking them and starving the bearings of oil.

As it is, the IS250 engine is not one that tends to sludge up, provided that it has been maintained correctly and reasonable quality oils have been used. So, a flush would be of somewhat lower risk, but also lower benefit.

I'm also not really a fan of oil additives in general. However, I recently took my car to a different garage (closer to work, so convenient) for a service and I've no idea what oil they put in it, but afterwards the VVTi was rattling like never before. It was literally 5 seconds on every single start, hot or cold, on the new oil, and had never been that bad before, even on dead oil. Hoping for a cheaper option than changing the oil for my favoured cheap synthetic stuff, I poured a can of BG MOA into the engine - total silence since.

I've no idea what the MOA did - maybe it just increased the viscosity a bit, maybe it did something else. I don't know. However, I wouldn't have expected a garage to put a 0W20 oil in so I don't see why it should have been so much worse than my usual 5W30.

[james250]

An update, now at 3k miles since I changed the oil. It's now on the minimum mark. When i changed the oil with the recommended 6.3L, the level started at about half way mark. So it took 3K to get from half way to low mark. I thought I would try and figure out how much oil in Litres is from min to max. I topped up 0.5L (500ml) with the same oil then started car and drove around, then after car sat overnight, i checked it and the level is exactly on the middle point. So this makes me believe there is probably about 1L (+/- few ml's) between the min and max mark. Now that I have the car on the middle mark, I have noted the mileage of the car and will monitor how many miles it takes before it goes back to min mark.

Does anyone know how much oil burning is acceptable?

[is200 Newbie]

The level between Min and Max on the stick IS 1 litre.

The figures I had for oil consumption from Vauxhall against an Astra I had was 1 litre per 1000 miles - I was told that this was due to the tight tolerances of the engine and in order for them to meet the emissions targets.

Don't know if they were fobbing me off but it seems a lot for the car to use under normal circumstances

How did the oil look when you topped it up at 3k miles?.

[james250]

1L per 1k miles? that sounds a bit like a joke lol. I would be worried if I was burning that much. When i topped up the oil, it looked much cleaner than it looked around this time with the previous magnatec oil. I've definitely confirmed that from min to middle is 0.5L so that means min to max is most definitely 1L. So i've burned about 0.5L IN 3K miles. But to be sure, I now have exactly 0.5L topped up taking the level to middle, I will monitor exactly how many miles I get before it reaches minimum again.

[ChumpusRex]

1L per 1k miles? that sounds a bit like a joke lol.

That's pretty standard for a 1.6 litre engine.

In the IS250 service manual, lexus state 1 litre per 600 miles is the maximum.

[james250]

Update - I topped up 0.5L when the oil level got to minimum mark. This took it to the middle mark. I made a note of the mileage so that I can check at what mileage it goes to minimum. So it's now on minimum again and i've covered 1,860miles.

[toffee_pie]

engine flushes......

I have been told these are not good and remove natural lubricants (to put it bluntly) on the engine components, basically they are not really necessary.

what engine flush are you on about as you also get the engine treatment stuff, i use the wynns stuff for that, i have not used an engine flush.

[aly-g]

ah to flush or not to flush that is the question, flushing oil is only oil with probably more detergents than normal to clean carbon deposits from the engine, I really cant see flushing oil doing damage to an engine......

Allan

[toffee_pie]

I dont think modern engines really need engine flushes, but maybe thats just me.

give them good quality oil and thats all they need.