Not sure if the mountings price is not high ...





Sorry, mistakenly deleted pictures on O2 sensor, before cleaning and after cleaning externally.
Internal can not clean, so mechanic recommend replacement, IDK.
He bought Perodua sensor (same Denso sensor but different electrical fitting) as it is cheaper than 'Toyota' sensor, but used back my old fitting.

Below are the 2 oil seals,

Yes, fuel consumption increases from 11.5-12.5 km/L to 9.9 km/L despite similar tyre pressure of 44 psi.
Computer reads old (wave oscillations) readings between 0.1 and 0.6 in Volts(?).
After sensor replacement, back to specification of between 0.1 and 0.9 , again pictures wrongly deleted.

Edit:WKC, will find you a Shell Helix HX7 5W30 virgin oil analysis.
You used SL or SN ?

This post has been edited by zeng: Aug 27 2021, 10:00 PM

The HX7 was the free engine oil provided by the dealer under free maintenance programme, don't know which rating was given, but assume is SN.

Where did you get this VOA data? Did you do it or from oil-club.ru?

From the russian oil club, sir .

Here it comes ....
Virgin Oil Analysis of Shell Helix HX7 5W30 SN MB229.3 :

Hope it helps .

This post has been edited by zeng: Oct 3 2019, 11:57 PM

noack 6%??? and TBN of 10, pretty insane

Testing ada salah kah?

Or am i reading it wrongly?

To be honest, I was taken aback too when first came across this voa results.

From my readings around, VOA testings in Germany/Russia is more sophisticated then that in NA like Blackstone etc.

I don't doubt the 'ball park' figures in this test, though Labs do make mistake occassionally and there is always a margin of error in any lab testing, hence the requirements of periodic calibration of lab equipments.

I'd used HX7 10W40 before but not its 5W30 siblings, and I must concede this Helix HX7 5W30 SN is a quality engine oil in relative terms to other 5W30's .

Shell's GTL basestock is well known to hv very low NOACK figure, not surprising in this respect at all. just that i didn't expect they use GTL base in a lower tier SS oil.

This post has been edited by speedy3210: Oct 4 2019, 04:10 PM

noack of 6 is very damn good for a semi synthetic product, the baseline for SN if not mistaken is about 12-13%, so this is insanely good with a 100% margin from baseline!. Even many top tier fully synthetic can't reach that low of noack value at that viscosity range, only a handful that i know of, namely mobil1 esp (5.6%) and ravenol dxg (6%). Others like the venerable amsoil signature synthetic is 7.8% for 5w30. Even these top tier fully synthetic are around of 7-8%, some surprisingly at the higher end of 9%.

On the other hand, pennzoil platinum ultra and helix ultra ect c2/c3 (also using shell's GTL), is 9%+ noack, why leh?

Agree with you on the use of GTL base oils in this HX7 5W30.
IMHO, technically it is a fully synthetic oil but somehow marketed as semisyn.
It's really a good bargain for buyers.

This Noack 6.0% can't be a semi synthetic oil , IMO.
I believe it is a full synthetic oils.
It would be wise to sapu these fully synthetics paying for semi synthetic price.
Alas, I have already a huge stash of fully synthetics in stock awaiting to be used .

This post has been edited by zeng: Oct 4 2019, 10:33 PM

the only way is do another voa on it

Well,SL version of Helix HX7 5W30 has a VOA Noack of 7.4 % ; whilst
Shell Helix HX8 5W30 SN MB229.3 has a VOA Noack of 6.6 % .

There is no doubt on my part on the base oils quality of these three Shell oils here.

maybe Shell has perfected the GTL processes to a degree that its yield is so high that they can just pass it off as semi-syn, and play around the additive level as differentiation with fully-syn.

then again, as per those voa sheets in oilclub.ru, hx7 has (almost) identical additive level as SHU, making these 2 almost indistinguishable to the consumers apart from the appearance of the containers.

Shell Formula 5W30 is sometimes called Conventional, and other times called Full synthetic, granted its VI of about 160 or so.

However, the 2011 PQIA voa sample shows a very high Noack of 14.9 % and also generally much higher content of Sulphur at 3471 ppm .



It's said to be composed of Shell Very High VI (VHVI) base oil, of which I am a bit doubtful of its quality in relation to other name brand's (say, Mobil 1) or Shell GTL base oil quality .

So, be cautious with Shell oils though .

But with VOA's or UOA's(Refer to post#1) and blotter spot test performance, I feel assured about the base oil quality of the 3 Shell oils mentioned above.

This post has been edited by zeng: Oct 6 2019, 09:26 PM

Dear @zeng
Would you be willing to review this 48hr blotter spot ? Thanks in advance.



Car make: Nissan AD Resort 1.6L Manual (Carburetor)
Odometer: 307030 km
EO in use: Mannol Diesel Extra 10w40 API CH-4/SL
EO mileage: 9771 km
Traffic conditions: 95% stop-go in town

Hi Chemistry ,
There is absence of darkened or black perimeter ring or rim surrounding the centre/deposit zone , indicating absence of or negligible amounts of insolubles or semi-solubles ,or coagulation of contaminants and pollutants within the oil eco system , that has been properly and successfully dispersed away from metal contacting surfaces as represented by the transparent and light-coloured centre zone area and its absence of opaquecity .

Taking Russian site formula for Coefficient of Dispersancy CD = 1 - ( d*d/D*D ) , where
d = outer diameter of 'gray perimeter ring,per se' inclusive of centre zone and/or part of diffussion zone , 45 mm in your picture ; and
D = outer diameter of diffussion zone (just within translucent ,fuel zone if any), being 95 mm here ,
Your CD is 0.77 which is well above the arbitrarily set oil change limit of 0.3 .

IMHO, this 9771 km used CH4/SL Mannol oil is good to carry on in service , if you so wish or comfortable .

Yes, you have some fuel dilution problem which I feel is academic and of no issue in the oil's continuing service ,yet .

Note:95% stop-go in town is classified by OEM as severe service implying oil change intervals is to be halved . However , in the absence of UOA, your blotter spot indicates the oil condition and its detergency/dispersancy capabilities is in good shape , IMO .

This post has been edited by zeng: Oct 24 2019, 11:56 AM

Thank you so much for your detailed evaluation.
I shall extend oil change for another 1month or two.

An 'ugly' 15600 km blotter spot from Russia ,
do you think it is good to go on ??