Rattle on start-up
Q We bought two new Toyota Yaris Series 2s on the same day in September 2010. They have been very reliable and both now have a mileage of about 70,000. They are identical apart from colour, with the 1.33 Dual VVT-I 1NR-FE engine and six-speed manual box. Servicing was via the supplying Toyota dealer for the first five years. Engine oil was initially Toyota 5W-30 and then Toyota 0W-20 after the carboning-up issue that Toyota had with some of these engines. From year six, I have home-serviced both cars using a Toyota 0W-20 oil and filter annually.
Just recently, one of the them has developed quite a loud timing chain-type rattle for the first second or so when starting and is perhaps a little noisier at tickover than the other. Having read on the internet about timing chain issues with these models, do you think the noise is the tensioner, chain or variator playing up? How do I diagnose the problem precisely and repair it? What is the likely cost at an independent garage?
My Haynes manual only covers the previous 1.3 engine, which appears to have a strong duplex timing chain and, if maintained correctly, is generally regarded as bulletproof.
Ian Wallace
A Having had the vehicles serviced regularly and been using the recommended 0W-20 oil, it would be nice to think that you would have avoided any timing chain issues.
You will appreciate that without hearing the noise it is difficult to give a direct answer. However, if the noise is only for the first couple of seconds on start-up and does not occur at all after that, I suspect it may be the tensioner or one of the VVTI actuators. Another possibility is that there’s slack in the chain due to the chain having stretched – this would take a couple of seconds for the tensioner to fully take out and eliminate the noise. Likewise, if one of the actuators is draining down, the tension in the chain will be affected until the oil reaches the actuator and adjusts accordingly.
As you mention that the engine seems to be a little noisier when ticking over, my first course of action would be to remove the cam cover and physically check the condition of the timing chain. Although it’s unlikely that will you be able to see much of the plastic guides, you may just see something to indicate where the problem lies. This is not a quick job and has a book time of 1.2 hours. However, if the problem is due to the timing chain or driven gear, rectifying it will involve the removal of the engine and has a job time of around 10 hours.
Due to the fact that your engine has been regularly serviced, it may be worth trying an engine flush before your next oil change, which should clean out any deposits in the VVTI system that could be causing the problem.