241steve wrote:What does it say in the book is what I was interested in? Google says 30 seconds everything Ive owned this century (petrol) its never hurt to start it put it in gear and drive off.
I would imagine that "what is said in the book" will likely vary from year to year as changing technologies in oil viscosity and component manufacture changes.
What I said above is basically true for ANY engine, diesel or petrol, and the length of time "REQUIRED" will vary dependent on many factors that although they include things like oil viscosity, component manufacture processes, they are not limited to these things alone as things like how a previous owner might have looked after an engine will vary, even how different mechanics do their services will vary, some will use cheap shyt oils for example.
30 seconds is not bad, I'd suggest if you're worried about it, then a full minute would be beneficial, however I don't know of any specific figure. Doing a warm up versus not doing a warm up while benefitting the long term lifespan of an engine, I'm only guessing here because I don't know of any actual scientific tests that have been carried out for this, "MIGHT" make the difference between a million kilometre engine and (for arguments sake) a 900 thousand km engine. Just guessing of course.
If Toyota is actually interested in running such a test then I'd be happy to volunteer for the job, but to do it properly it would have to be done with a strict set of criterion upon which accurate measurements could be recorded throughout the entire testing regime.
Things like 2 identical vehicles driven by the same person throughout the testing period, driven in the same way and through the same conditions, serviced exactly the same the only different between the 2 being whether they are "prewarmed" before driving off.
It'd be really interesting to be involved in something like this.
I tend to prewarm during the colder months quite often, not so much in summer. Even this kind of "individual personal preferences" would need to be recorded in any proper testing that is done.