Granville Hypalube 5W-40 oil analysis Renault Clio Mk1 1.2 8,815miles

This is a repost of the Granville oil post on Bobistheoilguy forum. 9 years has passed since that post, and my English has improved, I tried to edit it on bitog to clarify and let other people understand it more but the edit button was not available. So I am going to repost it here.

My reason for oil analysis is because I want to find out when I should change my oil, I want to know how long I could push fully synthetic oil in a car.

The car: 1996 Renault Clio Mark1 1171cc E7F engine Naturally Aspirated Throttle body single injection 60hp, 4 speed manual, weighs less than 900kg.

The oil: At odo 132,000mi, this oil was put into the engine. The oil was Granville Hypalube Fully synthetic 5W-40 engine oil. Oil company replied that they use Group III base. UK does have Castrol Edge, or Mobil 1 selling here, but for this oil, it's half the price of those, that's why I chose to use it. (Castrol 40pounds 4L, Granville 19pounds 5L)

Car usage: Used extensively as a pizza delivery vehicle. 80% of the 8,815 oil mileage was used as city stop&go traffic with no more than 4 miles trip 1 way. So with each delivery, the car would have travelled less than 8 miles. Engine will also experience a lot of turn on & offs. At 4000 mi oil mileage a Track day was done. Under normal usage (apart from the track day), I baby it 80% of the time, even on the 200mi trip to the trackday, i don't drive more than 60mph on the motorway. Car can achieve at least 47.04mpg (us) 5L/100km on motorway and at least 31.64mpg (us) on pizza delivery duty.

Sampling method: When the oil has 4,297 miles, a sample was taken through the dipstick hole and sent to the lab. The oil was not drained out from the sump, and the car continued to use this oil.

When the oil has 8,815 miles (car odo 140,815mi), a final sample was taken through the dipstick hole again and sent to the lab. No Make up oil was ever added during the entire time.

My comments: Ah. My very first car with sentimental value. Took me to all sorts of places and pizza delivery vehicle, and my first ever track day. It has no power steering, no aircon and a 4 speed manual transmission. I even installed Spax coils and shocks which improved handling a lot, can even keep up with BMWs in turns. The car has a minor vacuum leak but since it only stalls in idle during very hot weather, I decided not to fix it. That explains the silicon in the oil, You can see the strange number of Iron dropping in the 2nd report. Silicon means dirt/sand, didn’t increase that much. Viscosity of the oil, at first sampling appeared to be already in the 30 range (70.9 cSt). In the second sampling it thickened up a bit, pulling it in the edge of 40 range (76.6 cSt). A typical 40 has a viscosity range of 77-80 cst. Fuel was not tested in both samples. But TBN was tested in the 2nd sample and it showed 2.2, which means the additives neutralizing the acids had mostly depleted. I’d say given the miles I put on this oil, the unfixed vacuum leak, the track day (sustained full throttle, revving the hell out of it), this oil was decent enough for my usage and due to TBN at 2.2 at 8815 miles, it was the right time to be changed. If I was using this oil again in this same car with the same usage pattern, i would change it at 6000 miles for peace of mind, it should have plenty of additives left as a safety net. In my opinion, I would also recommend using this oil in today’s modern Direct Injection engine (Year 2019) with an oil interval of 6000 miles.