Knocks on cold start

[peter.winter250@btinternet]

Hello, can anyone help?  I have an 18 month old RAV4 Hybrid with a 2.5 petrol engine.  When starting from cold there is a knocking sound coming from the engine which lasts for about a second, then it's gone.  The garage (Westover Toyota) from where I bought it are looking into it and have asked Toyota for help but I thought that I would see if you guys might have experienced a similar problem.  Thanks in advance.

[FROSTYBALLS]

Welcome to Toyota Owners Club.

Moved to the Rav4 club.

[Gerg]

Has the car been started but not warmed up ( e.g. maneuvered on a drive briefly) , before the knocking noise happens on a subsequent, cold start?

If so, this has been noted on 1.8 Prius hybrids.  A remedy of sorts is to try not to cold-start the engine for just a few seconds, that is to say, run the engine until it shuts itself off (ideally with the heater turned off, otherwise the engine will run until the engine coolant is able to warm the car interior, a longer period of time!).

On the Prius it would seem that condensation forming inside the inlet manifold after a short engine operation is drawn into the engine on a subsequent start-up, causing pre-ignition for a short while until it is cleared.

I don't know this engine, someone who does will doubtless have a better insight.

HTH