Anodising is a layer of insulating Al2O3 , sapphire. If its done properly heavily it really doesnt conduct electricity until you crack or sand/scrape it off..
The problem is that the sender is air cooled in that location so it reads a bit lower than other places. But the 90C (cover plate) to 100C (e.g. dipstick) is about right at 55mph. Its the relative change that is important. As you go over 55mph it gets hotter then the cooling plateaus out at 65-70 mph (4000 rpm the T1 fan basically stops moving more air as the RPM climbs, T4 fan better) and the temperatures really start to climb. I used to drive at 65+mph / 122C .. why I ended with an oil cooler. Which I dont really need on my JK Preservation Parts engine as it runs a lot cooler at the same speed. EMPI heads... On a hot day I see 107C while going as fast as possible up hills and 65-70 on the flat along the M4. Its the cylinder head temperatures that really need watching, these climb really fast on hills, and that leads to cracked heads. My sensors are screwed in the m10x1 tapped bosses in these EMPI heads. I have seen 130-150C on hills and even more with heat soak stationary at Membury Services..
Agreed, but the circa 10µm thick layer is usually broken through by the bolt heads and sender threads. It would be better to not anodise, or powder coat it at all.
Breaking though sender threads is ok.. but current path has still got to get back out the plate and into the fixing bolts due to the rubber o ring bolts using a hole that's not threaded.. if the anodising is a problem that is.. Sent from my SM-G930F using Tapatalk
I have one if these, seems to work well, gives you a good indication big you're pushing too hard on a hot day.
With the sender only screwed in finger tight and no washer yet, the resistance is negligible i.e. close enough to continuity that I won't fret about it
It's a really cheap one that I bought about 30 years ago and still going strong I'd love a Fluke, but can't really justify the cost when the cheapo one just keeps going
Its not really the absolute value, its value is that you learn 'normal' temperature. Then it is things like if the oil level drops, the engine temperature will tend to go up at the same speed and ambient temperature - e.g. on my old leaky engines, a 5 degree rise was enough to make me check at the next stop for oil loss, and top up again from min to max on the dipstick.
