BarryDawson said...FormulaNova said...
Sorry, I guess the thought required was too abstract for you....
If a car does a lot of city driving it tends to spend a lot of time in first and second gear. If the same car was used in country driving instead it would spend a lot more time in the higher gears and as a result rev less.
Normally in traffic situations an average driver would change gears in traffic keeping engine revs to somewhere between 1500 to 2500 rpm. As it would happen, sitting at 110kph or thereabouts most vehicles will sit on or about 2000 to 2500 rpm therefore you could draw the conclusion that this should not make much difference at all. Further, should the cooling system be in good condition the operating temperature should also be in range and also make very little difference at all. The only variable I can see would be time, time spent in traffic to do 100,000kms compared to time spent on the open road would be much shorter and therefore the O2 sensor on the open road vehicle will have less running time.
When manufacturers recommend specific intervals for timing belts, O2 sensors, spark plugs, pollen filters, high tension leads, fluids etc etc etc it is based on an average.
It's your car at the end of the day and you chose what to have replaced or ignore. You take the risk on what you leave and if that component doesn't let you down you have had a win. If that component does fail be prepared to replace it and any other components due to consequential damage.
I agree, but I think some things are hard to determine if they really need to be changed, unless it is the ECU that tells you. I hope that these days an oxygen sensor can be tested by the ECU to see if they are in range. I think there are even ways to tell if your leads (if you still have them) and plugs are running properly by measuring the current taken to fire them.
I had a manual VN commodore and I remember that it would trigger the check engine light every now and then when going on a really long cruise on the freeway in 5th gear. It did it because it figured that it had been running really lean for too long and assumed that there was something out of whack. If they can do that on a 1989 model car, I hope that they are now able to pick up on a sensor that starts to fail.
After all, if you have 4 sensors, you have a good chance on picking up if one of them is out of range to the others, even if they are all on different manifolds.
Timing belts are a very different story. A lot of engines now are interference designs, so when the belt lets go, you have an expensive fix on your hands. I think Holden got caught with a model of theirs when the belts were letting go earlier than expected so they reduced the service interval. I think a few of these engines require major work to replace the belt, so you wonder if they really thought that through.
I do get worried though that some newer cars appear to need to be babied so much, yet a car that was made 30 years ago seems to run despite the owners lack of maintenance. I know there is a huge difference between the quality between then and now, but why does a car need to be serviced every 5000km? Unless a timing belt is showing major damage, you would never know if it was just about to break or if it would last another 100,000kms. A regular service is not going to prevent that breakage, although not replacing it at its scheduled interval would be flirting with danger.
Having said all this, I am the sort of person that when I get a faulty radiator, I replace all the hoses at the same time. It doesn't take that much extra time or money and I see it as insurance against a failure later on.
Cracked the head for a start, and no wonder it would not turn over!
