All good on the car front.
A couple of weeks ago it was treated to an engine oil and filter change - the oil was well black and in need of a change...
This time I decided to go for 5 litres of fully synth Castrol Magnatec 5w-40 and a Bosch filter. I know not everyone here likes Castrol but I have always been partial to it. In the month or so before the change I had noticed there was sometimes a light "tapping" coming from the engine for up to 10-20 seconds or so after a cold start, not from the top end either....
That has completely gone with the oil and filter change.
(I'm guessing the oil pressure was a bit slow to rise from cold - it certainly wasn't low on oil)
Last weekend I got around to changing the air intake temperature sensor - I previously mentioned it had two tabs broken causing it to fall out of place, seen here beside the new one:
With two of the tabs broken it was falling down on an angle causing the sensing tip not to protrude nearly as far into the air stream as it should, and also causing an air leak past the o-ring.
I had speculated that this might be contributing to intermittent low power as the air intake temperature reading has quite a big effect on the injection time, so an inaccurate reading could adversely affect the mixture. I was noticing that after I'd been driving for a while (or on a very hot day) and the engine bay had heated up fully that power and performance started to sag quite significantly, and that it ran markedly better first thing in cold weather.
I only half expected it to make a difference but it did!
No more sagging power when it heats up. My theory is that the sensor was reading too hot when the engine bay was warmed up - any air drawn in past the leaking o-ring would be hot engine bay air (which can be very hot, exceeding 50 degrees) flowing right past the sensor tip, and also if the tip of the sensor had fallen most of the way down inside the tube its mounted in so that it's not properly in the air stream, it's going to tend to read the temperature of the plastic housing rather than the air flow itself - and that plastic housing also gets pretty hot.
Hotter air is less dense so the injection pulse is reduced when the air intake temperature reading increases, all other things being equal - but if the reading is falsely high compared to the actual air temperature going into the manifold (remember the sensor only measures the air flowing into the ICV bypass not the main throttle plate) then you will end up with a mixture that is too lean when the engine bay gets hot. Certainly fits the symptoms anyway.
As I have been wondering for a while whether the engine was performing as it should be (and it wasn't before I changed this air temperature sensor) after changing the sensor and noticing that it was performing a lot better I decided to be naughty and time the 0-60 time with a rather neat iPhone app called Dynolicious (David will know the one I mean
) and on a safe stretch of road which unfortunately has a slight rise towards the middle I measured 9.01 seconds. Depending on what figures you believe it should be 8.6 or 8.2 seconds for the V6 auto so I'm quite happy with that considering I was going slightly uphill, did nothing more scientific than plant my foot in sport mode, and the car is 17 years old!
Not only does it seem to be performing nicely now, the strange and annoying induction "whine" that has been there at around 2800rpm ever since I've had the car seems to be gone at last.
(I think David remembers hearing this noise ?)
Clearly there was an air leak past the o-ring - I notice that the new one looks slightly bigger in diameter, as well as the unbroken clips holding it in position better, so it won't be leaking now. There was also a leak past the edge of the air filter when I first got the car - when I fixed that last year with a new filter the whine got a lot quieter (it was really
bad before that) but it never went away - now it has gone completely.
So if you're ever trying to find a strange whining noise on your V6 check your air intake system for leaks - even a small leak is apparently enough to make a lot of noise!
I still haven't had a chance to tackle the cruise control yet as I have to make the time to hacksaw off and replace two of the bolts for the underneath rubber flaps before I can even get access to it, but I hope to do it before the winter as I really do miss my cruise control...
In other news the garage roof is nearly repaired (only guttering remains to be fitted) so I can start making use of it, and my mum is over from NZ for a few weeks starting Friday...
Oh and the house is still calling out for the kitchen and bathroom to be finished....
One more job I think I should do soon is the aux belt - that is looking rather cracked - does anyone have any recommendations for a source of a good quality aux belt for the V6 of the right size ?