Loud Knocking noise

Pj101 · June 24

When I start up my 2007 is250 when the engine is cold. A loud knocking noise starts for half a second. Then if i turn it off right after that and turn it back on it’s gone. Does anyone have any idea to why this happens?

NemesisUK · June 24

Oil starvation, when was it last serviced?

steve2006 · June 24

Could you post up a video of the noise?

Pj101 · June 24

5 hours ago, NemesisUK said:

Oil starvation, when was it last serviced?

A couple of weeks ago

NemesisUK · June 25

6 hours ago, Pj101 said:

A couple of weeks ago

Was the knocking heard before the service?

Pj101 · July 1

On 6/24/2024 at 1:33 PM, steve2006 said:

Could you post up a video of the noise?

steve2006 · July 1

Does sound like oil starvation, have you checked the oil level since the service? Also is it a genuine Toyota oil filter?

Linas.P · July 1

4 hours ago, Pj101 said:

IMG_5198.mov
36.09 MB · 3 downloads

This is common VVTI gear/chain rattle. My old 200k miles IS250 used to have it on cold starts.

What resolved the issue for me was simply more frequent oil change, 10,000 miles "extended" service intervals are not suitable for these engines (in fact most should even qualify). So ideally oil has to be changed after 5,000-6,000 and I would recommend doing it twice a year, or whichever is sooner i.e. 6,000 miles or 6 months. If ignored for long enough this may become bad enough where VVTI gears/chain has to be replaced at significant cost. In US there is TSIB for it, not sure if Lexus still honours it and what is required to qualify, but outside of US there is nothing that can be done.

Now that you said it was serviced just "few weeks ago", it must be either low oil, wrong grade oil (both effectively results in same issue as infrequent service - not enough oil pressure/volume to the VVTI gear at the start-up). Or something else related to oiling system is messed-up, like maybe packaging not fully removed from the filter. Also - has this started after the service, or the sound was always there?

That said, again unless it really becomes very bad this should not affect the car in any significant way.

Notamech · July 1

As stated above this sounds like the vvti actuator rattle. Common on most toyotas of that generation. The only real fix is a new vvti actuator. For a lot of engines toyota updated the part at some point. Its not worth fixing on most old cars. You can ignore it. By the time any meaningful damage is done the car will probably be at the end of its life anyway. Here's some more info

steve2006 · July 1

There are also the 2 VVTI oil micro filters which could be clogged up as they are not a service item.

Harry Wright · July 2

Make sure you haven't locked one of the kids in the boot.

GMB · July 2

I had a loud knocking noise on the M1 at about 70 mph. A few seconds later it was blue smoke and the engine exploded. Nothing much to worry about really.

Linas.P · July 2

5 hours ago, GMB said:

I had a loud knocking noise on the M1 at about 70 mph. A few seconds later it was blue smoke and the engine exploded. Nothing much to worry about really.

Yeah, but your problem wasn't VVTI rattle I assume, nor it was IS250?

If VVTI adjustor would fail, which I have never heard of happening yet, then the result of it is not valve hitting the piston, you simply lose the variable timing, meaning your engine will be locked into (if memory serves) 12 degree retarded timing on that side. Rough running, maybe some misfiring and obviously Christmas tree worth of lights on the dash will be the result, but not engine explosion.

GMB · July 2

1 hour ago, Linas.P said:

Yeah, but your problem wasn't VVTI rattle I assume, nor it was IS250

Absolutely right. It was a Vauxhall Victor FBW 1600cc. An exchange reconditioned engine was fitted by a Regent garage in London - cost £90!. It lasted about 10K miles before that blew up too.🙄

RadicalCoupe-Fuji · July 9

I had the same vvti issue on an old Nissan with an sr20 engine.

Linas.P · July 9

I would add that engine flush helped a lot in my case. Without flush the knocking was back after 4000 miles after service, with flush it was not back even after 6000 miles. So flush definitely helps to unstick whatever is sticking, but regardless I would recommend 6 month/6,000 miles oil service. 10,000 miles is absurd and most cars don't actually qualify for it, but Lexus wants to please fleet owners and forgets to mention that to qualify for 10,000 miles service one has to be using car "lightly". For example service manual states that if you doing any of following - towing, driving on motorway at high speed (above 60MPH) or driving in city (start/stop traffic), then you do not qualify for 10,000 miles "extended" service interval... in fact if you doing all of those things then you do not qualify even for 6,000 miles service and recommendation is to do it every 3,000 miles.