The Honda has responded well to a dose of TLC. On Friday, I changed the thermostat, and this has fixed the gearbox. Brilliant! But how?
It turns out that the Honda’s electronic brain will not allow the torque converter to lock-up if the engine is not at full operating temperature. The lock-up feature is a major improvement to the world of automatic transmissions, and effectively bypasses the automatic bit by locking the engine to the road wheels, just like a manual transmission does. Without the lock up, the transmission relies on the torque converter, which in simple terms, is like a fluid turbine. The engine spins the fluid, which acts on the stator of the gearbox to create forward movement. This means you don’t need a clutch, because if you stop, the spinning fluid can’t overpower the brakes.
Anyway, with the torque converter locked up, engine speed is reduced (by around 250rpm) and, because transmission and engine are now physically linked together, it improves efficiency. The torque converter loses efficiency because all that spinning motion generates heat. Heat demonstrates the lack of efficiency, and indicates why automatics usually have a transmission cooler…
Changing the thermostat was pretty easy. There’s a drain tap on the radiator to drain the coolant, and just two 10mm bolts holding the ‘stat in place. Not that accessing them is all that easy – ratchet spanners proved ideal.
This all means that I wafted along the M54 on Saturday in a rather more relaxing manner than my run up the M5 after collection the car. The new thermostat, of course, also means quicker engine warming first thing, and that it maintains that temperature on the move. All this means better efficiency and hopefully, better mpg. Sadly, this hasn’t yet been borne out by the figures – the second tank of fuel seems to have returned 28mpg rather than the 32 of the first. That did include rather a lot of motorway driving at or around the speed limit, whereas the first tank involved some of that, but also rather more 60mph limit single-carriageway.
The trek along the M54 was the start of a 600-mile trip that saw me end up in Kent, then driving all the way back to Wales. The news is generally good. I’ve now covered 1000 miles in the S-MX in total and I still like it a lot. I’ve improved the bed situation with a self-inflating mattress, and while it’s still a bit uneven, I managed two nights of pretty good kip in it.
I do need to improve the headlamps though. They’re a bit dim at night. I’m hoping the newly-arrived Autoglym headlamp restoration kit can help here (see next update, probably). I do also still need to sort the alignment out and fit some new tyres. It makes embarrassing squeals on some surfaces, and just does not feel planted.
It must be said though, I still like it a lot. It may corner with all the grace of Boris Johnson in a thong, but unlike BoJo, I just want to spend time with it. Could this be the start of Good Times?