I really mourn the absence of a proper dipstick!
The N52 oil level system on the dash isn't useful for track work, and at some point this year it stopped working altogether. It doesn't seem to matter under what conditions I push the button, the "checking..." indicator just goes across for about 5 minutes and then stops. It never shows a reading.
I then discovered that my OBD scan tool can show the oil level in mm. So I thought that would do - I can plug-in whenever I want to take a digital dipstick reading. But how many mm equates to full? And what's the range?
So I planned to calibrate the oil level sensor by doing an oil change and taking readings every 0.5l, all the way to the 6.5l capacity. Genius! 8)
But after approx 5 litres, the oil level reading stopped increasing. Bugger. Broken sensor... that'll explain why I can't get a reading from the dash any more. Or so I thought.
Oil level sensors aren't cheap, so I found the
most recent part number and bought a used one off eBay and did another oil change. With the sump drained I removed the old sensor. Two out of the three studs sheared off with the slightest effort. Bugger. Thankfully one of the sheared studs left just enough to get a nut onto, but with only one revolution. So I added a little RTV sealant around the new sensor and attached a nut around the other sheared stud with 2-part epoxy. It's a bodge but if it leaks, it ought not to be catastrophic. A proper repair will require the sump to be removed (including front subframe/crossmember) and careful replacement of the studs.
Attached the scanner and started refilling with oil. The sensor is working, but again, no readings above 5 litres. And then I realised: the sensor is not very tall and designed to measure the level with the engine running. So with the engine stopped, the sensor is fully submerged.
Meticulously added 6.5 litres and then another 100ml so that I have an absolute max to aim for. Started the engine and watched the oil level while the water temp was at 30-40ºC. So now I have 65mm as my cold max level. I'll do a few more cold starts this week to see if it's consistent and reliable. The dash level check still isn't working. Perhaps because I can't actually drive it. Of course, the ironic thing is that the old sensor was working fine, and there was no reason to change it! But until I physically saw the sensor I did not realise that it is fully submerged with a stopped engine while filling.
I have my third race of the year this Saturday at Brands Hatch with
MSV SuperCup. The car ought to be competitive in class A but I'll be a non-point-scoring invitation entry as I didn't want to splash out on a set of the control tyres just for a taster. Either way, it will give me a chance to take a hot oil level reading on the scanner.
