My VHPD was rebuilt in the early summer and whilst this was being done, I took the opportunity to get various bits replaced (e.g. oil and water pumps; clutch; cam pulleys; cam belt). I also had the air-con compressor and some pipework removed and an Eliseparts remote thermostat fitted.
All was fine until one day last week when the car became a little difficult to start from cold (it’s usually excellent) and the radiator fan came on when I got home (this doesn’t usually happen). The fan also came on as I started the car the next morning, which clearly shouldn’t happen when the engine is cold. The fan hasn’t come on since, but I’m not quite convinced that the cold starting is back to normal.
The other weird thing I’ve noticed is that, when warm, the coolant temperature has started to cycle from the low 80s to the high 80s and back again with a period of about 30 seconds. This cycling is quite regular. At first I thought that maybe there was a problem with the brown temperature sender, but I don’t think that this would cause the temperature to cycle.
Sounds a funny one - if the fan came on 1st thing in the morning, i.e., with a totally cold engine that that can only be the brown sender/electrical fault.
The blue sender serves the Stack so that’s completely different! Could be a problem with both?
Has me confused. The fan coming on with a cold engine has only happened once, but it coincided with the car almost failing to start and the obvious answer was that the brown temp sender was telling the ecu that the engine was hot when it wasn’t. I don’t think that it would cause the periodic tempererature variation that I’m seeing though.
Engine coolant temperature sensor (can’t remember which colour blue or brown).
The one pointing down over the exhaust manifold. Mine was cycling the same, so replaced and temp on STACK is as steady as a rock. The sensor tends to get cooked sitting above the hot manifold.
Cheers for the explanation… I was asking Bryn if he maybe had an airlock, not questioning why you said Airlock… IYSWIM… Unfortunately I made my comment before reading the whole thread and it was then a coincidence that your post was just before mine… no harm done