Knocking On Cold Start!

[Grumpy Cabbie]

I'd read about it but this morning it happened to me!!! :o

I didn't drive the car yesterday due to the consumption of many alcoholic beveridges the night before ;) and last night it was cold -4 and there was 4 inches of snow last night. Cleared the snow off the car and got in and pressed the on button to put the car into ready. I then switched the rear heated window on and the engine switched on and knock, knock knock! :(

I quickly turned the engine off and then gingerly restarted it and all was fine

Have read up on this on the US Prius chatroom and it appears to be a rather common problem on the Gen3. Has anyone else had similar problems? Is it mechanical or a software issue? Will it do any damage? The chatroom seems to suggest that it occurs if the car has been left for a day or so and/or if it is a cold day.

So am I alone with this in the UK? Anyone from Toyota got any ideas or are you even aware of it? Be interested to know.

[GIDDLEPIN]

My Roadster has done it all the time when first starting in really cold conditions, eight years old and 80,000 miles now and it still goes like a good one ;)

It's usually just a bit of piston slap which makes it sound like a diesel when everything is very contracted, I just leave it on tick over for a minute or two and it soon disappears

Les

[Grumpy Cabbie]

My Roadster has done it all the time when first starting in really cold conditions, eight years old and 80,000 miles now and it still goes like a good one ;)

It's usually just a bit of piston slap which makes it sound like a diesel when everything is very contracted, I just leave it on tick over for a minute or two and it soon disappears

Les

No it's not piston slap. It seems to eminate from the hybrid side of the engine and is a real knock. It's almost like big end knock but more severe! The car literally shook with each knock it was that violent. There are a few US Prius owners who have also experienced it.

[GIDDLEPIN]

My Roadster has done it all the time when first starting in really cold conditions, eight years old and 80,000 miles now and it still goes like a good one ;)

It's usually just a bit of piston slap which makes it sound like a diesel when everything is very contracted, I just leave it on tick over for a minute or two and it soon disappears

Les

No it's not piston slap. It seems to eminate from the hybrid side of the engine and is a real knock. It's almost like big end knock but more severe! The car literally shook with each knock it was that violent. There are a few US Prius owners who have also experienced it.

OUCH!! :(

[Fujisan]

Strange,

I haven't noticed anything and the car was stood for 4 or 5 days before tuesday, like a block of ice and it just started normally.

Again the car was stood all yesterday, covered in snow and ice and it started OK this morning.

Strange one GC, hope it is just a one off.

[Sagitar]

I'd read about it but this morning it happened to me!!! :o

I didn't drive the car yesterday due to the consumption of many alcoholic beveridges the night before ;) and last night it was cold -4 and there was 4 inches of snow last night. Cleared the snow off the car and got in and pressed the on button to put the car into ready. I then switched the rear heated window on and the engine switched on and knock, knock knock! :(

I quickly turned the engine off and then gingerly restarted it and all was fine

Have read up on this on the US Prius chatroom and it appears to be a rather common problem on the Gen3. Has anyone else had similar problems? Is it mechanical or a software issue? Will it do any damage? The chatroom seems to suggest that it occurs if the car has been left for a day or so and/or if it is a cold day.

So am I alone with this in the UK? Anyone from Toyota got any ideas or are you even aware of it? Be interested to know.

I have started mine a few times in the last week after it has stood in very cold conditions for more than 24 hrs, but with no sign of any problem. The engine uses an unusual cycle to achieve economy so we could speculate some problem with that leading to pre-ignition or some such, but I'm probably entirely wrong.

I hope you get it sorted out successfully and please keep posting.

[Grumpy Cabbie]

Oh it's defo a weird one. Cold start this morning and all ok. I don't think it happens every time and has only happened once over the last 5500 miles. It's a known problem that only happens once in a while. Just making you all aware of it so you can report it if you get it also.

Doesn't stop me being pi**ed off about it and will be paying a visit to the dealers afterthe new year.

[StephRG]

Hi,

Just had the same this morning.

1) Immediately turn power off, then started the engine again, exactly the same problem

2) So immediately turned off again. Started in EV, drove a few meters, switch to normal... and it worked.

Not sure if switching to EV solved it, and don't really hope to be able to double check anytime soon.....

Will contact Toyota, but don't expect any (useful) feedback.....

[Grumpy Cabbie]

Hi,

Just had the same this morning.

1) Immediately turn power off, then started the engine again, exactly the same problem

2) So immediately turned off again. Started in EV, drove a few meters, switch to normal... and it worked.

Not sure if switching to EV solved it, and don't really hope to be able to double check anytime soon.....

Will contact Toyota, but don't expect any (useful) feedback.....

Nasty isn't it. According to the US forums, it's a software problem to do with the motor not firing the engine or releasing or something like that. Also, the Gen2 did it too but as I never had one I can't comment.

I've not had it since.

[DONFRAMAC]

Many cars use hydraulic tappet capsules, and similar capsules for thrust on the cam-chain tensioners (instead of a spring). Also, the oil-filter often houses the prime-retainer valve for the oil pumping system.

A brief lack of oil on start-up can easily give a brief knocking, until oil gets to where it needs to be.

The GEN 3 needs 0W20 engine oil, just as the 2009 Aygo does, but supplies are not commonly stocked, but it is required for fast delivery of oil on start-up. Even 5W30 oil has to be avoided, for your engine, especially in our winter temperatures. Some Toyota dealers have been known to be ignorant of the importance of oil grade. ( a lot of these modern high-spec oils are not recommended as a top-up, only as a full service oil-change ) Check this on Opie Oils website, full pdf details on oil of choice, and that site can recommend the correct oil for your car :-- request gets a reply via Email the next day.

The Toyota stores network does have their own 0W20 oil available, on special order if not held in stock locally, and probably a good price, as no postage fee.

[StephRG]

Many cars use hydraulic tappet capsules, and similar capsules for thrust on the cam-chain tensioners (instead of a spring). Also, the oil-filter often houses the prime-retainer valve for the oil pumping system.

A brief lack of oil on start-up can easily give a brief knocking, until oil gets to where it needs to be.

The GEN 3 needs 0W20 engine oil, just as the 2009 Aygo does, but supplies are not commonly stocked, but it is required for fast delivery of oil on start-up. Even 5W30 oil has to be avoided, for your engine, especially in our winter temperatures. Some Toyota dealers have been known to be ignorant of the importance of oil grade. ( a lot of these modern high-spec oils are not recommended as a top-up, only as a full service oil-change ) Check this on Opieoils website, full pdf details on oil of choice, and that site can recommend the correct oil for your car :-- request gets a reply via Email the next day.

The Toyota stores network does have their own 0W20 oil available, on special order if not held in stock locally, and probably a good price, as no postage fee.

Hi,

I still haven't had any oil change (I'm around 6500m), so my question: Does the car arrive at dealer with oil or does the dealer top-up before delivery? Which might explain the difference in consumption between some cars, if some dealers fill them with 5w30 instead of 0w20.

Thanks,

Stephane

[Grumpy Cabbie]

Many cars use hydraulic tappet capsules, and similar capsules for thrust on the cam-chain tensioners (instead of a spring). Also, the oil-filter often houses the prime-retainer valve for the oil pumping system.

A brief lack of oil on start-up can easily give a brief knocking, until oil gets to where it needs to be.

The GEN 3 needs 0W20 engine oil, just as the 2009 Aygo does, but supplies are not commonly stocked, but it is required for fast delivery of oil on start-up. Even 5W30 oil has to be avoided, for your engine, especially in our winter temperatures. Some Toyota dealers have been known to be ignorant of the importance of oil grade. ( a lot of these modern high-spec oils are not recommended as a top-up, only as a full service oil-change ) Check this on Opieoils website, full pdf details on oil of choice, and that site can recommend the correct oil for your car :-- request gets a reply via Email the next day.

The Toyota stores network does have their own 0W20 oil available, on special order if not held in stock locally, and probably a good price, as no postage fee.

Hi,

I still haven't had any oil change (I'm around 6500m), so my question: Does the car arrive at dealer with oil or does the dealer top-up before delivery? Which might explain the difference in consumption between some cars, if some dealers fill them with 5w30 instead of 0w20.

Thanks,

Stephane

I don't think it's the oil. This was more a knocking noise from the hybrid side of the vehicle and that is in line with the descriptions of many on the US Prius forum too. In fact one of them has videoed it on his mobile and posted it on youtube. It isn't piston slap and it doesn't sound like the wrong oil to me. It is a definite knock, knock, knock as if something isn't lined up correctly. Some of the US guys have said it might only ever happen once if at all.

It's not easy to explain the sound and I guess I'm gonna have fun trying to convince my dealer that it happened at all

[kevin h]

Many cars use hydraulic tappet capsules, and similar capsules for thrust on the cam-chain tensioners (instead of a spring). Also, the oil-filter often houses the prime-retainer valve for the oil pumping system.

A brief lack of oil on start-up can easily give a brief knocking, until oil gets to where it needs to be.

The GEN 3 needs 0W20 engine oil, just as the 2009 Aygo does, but supplies are not commonly stocked, but it is required for fast delivery of oil on start-up. Even 5W30 oil has to be avoided, for your engine, especially in our winter temperatures. Some Toyota dealers have been known to be ignorant of the importance of oil grade. ( a lot of these modern high-spec oils are not recommended as a top-up, only as a full service oil-change ) Check this on Opieoils website, full pdf details on oil of choice, and that site can recommend the correct oil for your car :-- request gets a reply via Email the next day.

The Toyota stores network does have their own 0W20 oil available, on special order if not held in stock locally, and probably a good price, as no postage fee.

Hi,

I still haven't had any oil change (I'm around 6500m), so my question: Does the car arrive at dealer with oil or does the dealer top-up before delivery? Which might explain the difference in consumption between some cars, if some dealers fill them with 5w30 instead of 0w20.

Thanks,

Stephane

I don't think it's the oil. This was more a knocking noise from the hybrid side of the vehicle and that is in line with the descriptions of many on the US Prius forum too. In fact one of them has videoed it on his mobile and posted it on youtube. It isn't piston slap and it doesn't sound like the wrong oil to me. It is a definite knock, knock, knock as if something isn't lined up correctly. Some of the US guys have said it might only ever happen once if at all.

It's not easy to explain the sound and I guess I'm gonna have fun trying to convince my dealer that it happened at all

Hi, kev hear.

Good to talk on Thursday.

Dealer recreated the noise by inducing a missfire. Drained the fuel tank (Toyota insist it was bad fuel) and I've filled up with non supermarket fuel (Esso) 95 octane.

So far so good, mpg seems better, but we shall see.

I've done 4500 miles and the knocking has happened three times.

I'm just waiting for another morning of knocking and I.m back to the dealer, will let you know if it happens.

in the meantime, lets continue to find any other sufferers so that we can disprove the fuel excuse.

Regards

Kev

[tore]

Hi from Oslo, Norway.

The engine knocking/vibration phenomenon happened to me on sunday jan 10th, after returning from a holiday trip to Tenerife. My car was parked in a parkinghouse at the airport close to Oslo, but ambient temp. had been very cold during my 10 days absence. Between minus 15 and 20 centigrades (+ 5 to -4 F ) and same temp. when I returned. Before parking, I had been driving approx. 50 km in normal higway speed, and engine temp was between 70-80 degrees © when I parked. The hybrid system started normally but the ICE kicked very quickly in, and the VERY strong noise and vibration started. I felt as if my car would fall apart and all panels inside the cabin vibrated loudly.

I was so confused by this that I unfortunately didn`t think of using my video camera, but engine noise sounded much like the Prius 2010 in the You Tube video. But the vibration inside cabin was awful!! I started to drive home, and noise was gone when pushing the acc. pedal, but returned when releasing the pedal and ICE was back to low RPM ( 1200-1400 ) according to SG II . This continued for about 10-15 minutes when driving and then slowly decreased.

I have not experienced this during the last three days, but my car is parked in a garage, and I use it every day for work commuting.

Anyway, I have been speaking to a friend of mine who is working as a technician / instructor at Toyota Distributor headoffice in Norway close to Oslo, and he admitted that they some days before did a video of a similar problem when visiting a dealership. Also during this trip it was very cold in the dealership area ( -15 to -20 C)

They now would investigate further and send this video to Toyota in Japan, hoping for some feedback in due time.

However, based upon the many similar cases only in this forum, I believe this should be a priority issue for Toyote in Japan. Maybe some ECU software upgrade ??

[DONFRAMAC]

Perhaps these engines run better on Super-Unleaded, as it has a more gentle flame velocity, and I know that My Wife's Aygo can take 99 RON, as the label at the fuel filler states so. If you have the same label, it may be worth trying, although the ECU will take more than one fill-up to adapt to the good-stuff. (My Fiesta cannot adapt, so I won't be wasting my money, just to coke-up my engine/lambda probe/cat.)

[Grumpy Cabbie]

Perhaps these engines run better on Super-Unleaded, as it has a more gentle flame velocity, and I know that My Wife's Aygo can take 99 RON, as the label at the fuel filler states so. If you have the same label, it may be worth trying, although the ECU will take more than one fill-up to adapt to the good-stuff. (My Fiesta cannot adapt, so I won't be wasting my money, just to coke-up my engine/lambda probe/cat.)

The knock I experienced wasn't the sort of knock you get with low octane. More a knocking missfire/clunking/shaking and only on cold start after being stood.

Does anyone know if the Prius has a knock sensor and adjusts according to fuel type? Maybe this knocking is a dodgy knock sensor? Though I'm slowly turning to the idea that there is a batch of dodgy coil packs out there.

[Hicardo]

Three years late in replying is better than not at all!

Just before i traded in my 2009 Gen 3 Prius about 6 weeks ago, i had this engine knock you describe, after leaving the car in the drive unused for around 5 days in the bitter cold weather we had recently. It was quite alarming actually. Thought it had fired up on 1 cylinder, there was loads of body vibration and clanking. So i quickly turned it off, and after a few seconds, attempted to re-start, and it was fine. Could not make it happen again. I've now sold the car to Mr T. It was more than a bit worrying, and certainly cant have been doing the engine any good.

[johalareewi]

Toyota issued a service bulletin for this last year...

http://priuschat.com/threads/new-service-bulletin-for-engine-knocking-at-startup-t-sb-0012-10.102200/

[Chris Dance]

Two weeks ago I had cold start knocking. I have not had it again since then. The car goes for second year service at the end of March so will report it then to the dealer. I will mention the service bulletin.