IS250 VVTI Controllers (cam gears)

[SiBro]

I've recently purchased (dealer) a 2008 IS250 SE MM, I've only had it 3 weeks, it has F/S/H, all but two done at Lexus, after hearing the dreaded rattle on start up, which happens intermittently, i researched this and found that this is a relatively common problem so it seems. I've read several threads on this subject, but there is a few questions i hope can be answered here.

Has anyone had a fault code for this (when plugged in), or is it just, hear the noise and diagnose it? Also how serious is this long term, i know its a big job to replace the cam gears 12/13 hrs labor + parts, which i believe are not cheap, is anyone just living with the problem, or is it a job that needs doing once the rattle starts? 

 

https://www.youtube.com/watch?v=-CdvBMdG2wc

 

[johnatg]

This is not a particularly serious problem and it won't raise a fault code. It is annoying and a bit worrying though. It is due to the hydraulic valve lifters (tappets) being bunged up due to insufficiently frequent oil changes - Lexus service interval is 10K miles and oil needs to be changed more frequently - preferably 5K mile intervals.

No point using a dealer for a 9 year old car. Go to a trustworthy indy and get them to change the oil to a good quality fully synthetic 5W-30 (I use Dexos2) and use an oil flush additive at every oil change. The noise will eventually get less and go away altogether, but don't expect instant results.

[Britprius]

Although this is a common problem on some Toyota/Lexus VVT engines the only cures I have found that work are either replacing the cam gears or adding a pre-lube system to the engines. I have a GS450H with the same problem.

Lexus did a recall to replace the gears on the non hybrid versions of the GS, but say on the hybrid versions it does not cause any problems. 

A pre-lube system consists of an inverted bottle with a solenoid on the outlet of the bottle. This in turn is connected to a flexible pipe to a "T" piece on the oil line to the oil pressure switch.

When the engine is running the oil under pressure near fills the bottle from the bottom under pressure air being trapped in the top above the oil. The one way solenoid stops the oil escaping when the engine is turned off. The solenoid is opened on a timer for a short period as the ignition is turned on. This releases the oil under pressure round the engine pre- pressuring the complete system, and so eliminating the noise also reducing engine ware.

When the engine starts, and comes up to full oil pressure the bottle re-fills with oil ready for the next start. Ready made systems are available, are comparatively cheep, easy to install, and save engine ware.

John.

[kellogsj]

I've read walnut blasting can sort sort this problem. It's, I believe a carbon build up issue.


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[SiBro]

Thanks for the advice, i guessed there would not be a code :(  , as I've had the car less than 30 days, i'm considering rejecting the car, i have been in contact with the dealer, who, even though is a member of the the motor ombudsman scheme, is not being that helpful. Basically, is the timing chain likely to snap if driven? also, how has anyone here with the same problem had it diagnosed, i assume it has not been stripped down to diagnose?

Thanks in advance. :)

[is200 Newbie]

I have experienced this with mine (but not as bad as what was heard in the video you posted) and John & John in their posts above are spot on when stating its the oil. Its an obvious issue but not one to worry about and sound worse than what it is.

You will sometimes have this when changing oil as the oil reservoir that John has mentioned is drained and the engine has no means to fill it without turning on - when turning on it will rattle a bit (for a second if that)

I got rid of mine after regular oil changes using an engine flush (Wynns) each time - oil changes I do every 6 months but use the right oil (5/30). You will probably get it if the cars not had the necessary oil changes - check the colour of your oil and I will bet its black which is a sure sign it needs changing. 6 months use of Magnatec when changing the oil will see the oil a dark tea colour (still opaque but starting to change)

Do an oil change with a flush regularly and you will be on the road to getting rid of the noise.

By the way - no - there is no code thrown up by this and it is not your timing chain judging by the sound on the video

[SiBro]

2 hours ago, is200 Newbie said:

I have experienced this with mine (but not as bad as what was heard in the video you posted) and John & John in their posts above are spot on when stating its the oil. Its an obvious issue but not one to worry about and sound worse than what it is.

You will sometimes have this when changing oil as the oil reservoir that John has mentioned is drained and the engine has no means to fill it without turning on - when turning on it will rattle a bit (for a second if that)

I got rid of mine after regular oil changes using an engine flush (Wynns) each time - oil changes I do every 6 months but use the right oil (5/30). You will probably get it if the cars not had the necessary oil changes - check the colour of your oil and I will bet its black which is a sure sign it needs changing. 6 months use of Magnatec when changing the oil will see the oil a dark tea colour (still opaque but starting to change)

Do an oil change with a flush regularly and you will be on the road to getting rid of the noise.

By the way - no - there is no code thrown up by this and it is not your timing chain judging by the sound on the video

Thanks for your input, and although i cant say what oil was used, the car had a full service in august, the oil colour looks like new, done less than 1k since service, i can say however, that i was able to contact a previous owner (1 before last) who confirmed to me that when he purchased the car in January 2016, he to had the same  problem & basically rejected the car and got a full refund, so 1) the problem has been there since, at least Jan 16 & 2) the car was sold to me with the fault present, which gives me more ammunition against the dealer.

[Britprius]

There is a small filter hidden inside a banjo oil feed pipe "two on the V6 engines" that can become partially blocked reducing the oil flow to the cam timing gears. It may be worthwhile "since it is such an easy job" to check, and clean or replace this.filter.

John.

[Britprius]

Having research this further there appears to be a spring loaded plunger inside the timing sprockets that locks them in a retarded position until oil pressure pushes it out of the locked position. If the spring that pushes it into the locked position becomes week or brakes this could cause the mechanism not to lock when the engine is turned off, and to chatter until it is filled with oil. It would then work normally. 

I can see know other reason for the existence of the plunger, and know it should release at 21 psi oil pressure. This pressure could not be reached until all the space in the mechanism was full of oil.

There is a video on the tube that shows this on a Toyota engine, but the guy doing the video could not work out what it was for.

John.

[SiBro]

12 hours ago, Britprius said:

Having research this further there appears to be a spring loaded plunger inside the timing sprockets that locks them in a retarded position until oil pressure pushes it out of the locked position. If the spring that pushes it into the locked position becomes week or brakes this could cause the mechanism not to lock when the engine is turned off, and to chatter until it is filled with oil. It would then work normally. 

I can see know other reason for the existence of the plunger, and know it should release at 21 psi oil pressure. This pressure could not be reached until all the space in the mechanism was full of oil.

There is a video on the tube that shows this on a Toyota engine, but the guy doing the video could not work out what it was for.

John.

thanks. do you know what is rattling, which part?

 

[bobmc]

17 hours ago, Britprius said:

There is a small filter hidden inside a banjo oil feed pipe "two on the V6 engines" that can become partially blocked reducing the oil flow to the cam timing gears. It may be worthwhile "since it is such an easy job" to check, and clean or replace this.filter.

John.

I think some pictures or, preferably a video guide, would be useful information if anyone felt able to oblige 

 

[Britprius]

7 hours ago, SiBro said:

thanks. do you know what is rattling, which part?

 

If you play the video from about 3 min 15 sec in after the plunger has been removed you can see the two parts rotate separately until they reach the end of travel. This is where the noise comes from as they rattle back, and forth each time they turn a cam over the highest point until the gaps are full of oil. If the plunger was doing it's job of locking them together there would be no noise.

Once the mechanism is full of oil, oil is fed to the tapered end of the plunger opposite to the spring. When the pressure reaches 21 psi the plunger is pushed against the spring to unlock the timing mechanism. If the spring is week, broken, or the plunger is jammed in the open position the mechanism will rattle back, and forth until there is enough oil to stop it moving.

John.

[Britprius]

2 hours ago, bobmc said:

I think some pictures or, preferably a video guide, would be useful information if anyone felt able to oblige 

 

Go to this video at about 3 min 25 sec in, and you will see the filter removal. This varies slightly from engine to engine, but are all much the same principle.

John.

[Linas.P]

I had this issue, but oil flush and more frequent oil changes solved it. If you don't flush the engine then I would advice changing oil after around 5000 miles, you can go up to 6000-7000 before problem manifests itself (at least in my experience with Magnatec 5W30). If you flush the engine then the oil stays clean for longer and I guess you can go around 8000-9000 miles. As I do ~15k miles a year that is exactly what I am doing, changing oil once during normal annual service with Lexus and then changing it after 7000-8000 miles and flushing it with indy in between services. That makes average mileage for oil change at around 7500 miles and flush every other time.

Since I start doing it, I never heard of this problem again - even though my car is no 173k miles and definitely had the problem before. Few other tips - I do let the car idle for 10-15s before driving-off, I try not to rev it unnecessary whilst the engine is cold (especially in winter). If you live where it is colder you can use thinner oil e.g. 0W30 or even 0W20 which would allow for better lubrication from cold start (I heard that is what Lexus Edinburgh puts in IS250 during the service). I have tried using 0W40 as well, which I personally consider upgrade, thought unnecessary one unless you doing extended motorway journeys in -20C.

[johnatg]

There are two lines of thought with this query. Firstly, the original diagnosis - cam gear wear. IMHO, this is very unlikely unless the car has done a stratospheric mileage and not been maintained properly, especially after the Lexus SH. I don't know about it being common - not in the UK it's not. It may be in the USA - for some reason different problems beset cars there - not sure why - different climate, driving conditions, servicing, oil - who knows? But often different problems get prominence compared with UK.

Now I don't want to be rude and I appreciate that you're concerned about the noise and have the opportunity to reject the car. BTW - fixing it, if it is cam gear wear, will cost way more than the car is worth (at least to get it done by a Lexus dealer and I'm not sure that I would entrust a V6 engine strip to any old garage). But I'm afraid, other things being equal, the cam gear diagnosis is automotive hypochondria.

The noise is much, much more likely to be hydraulic valve lifter chatter - it is very common on all cars with hydraulic tappets simply because oil changes are too infrequent when carried out according to manufacturer's intervals - those intervals are geared to fleet maintenance costs over a limited mileage (less than 100K miles). Your choice whether to reject the car - otherwise proceed on the basis of doing some oil flushes and oil regime procedures as Linas says. Lexus do approve the use of 0W-20 oil on all IS250 engines but it's pretty damned expensive and probably not necessary, but it might clear the noise more quickly.

[is200 Newbie]

After watching the video it makes sense that an engine flush and regular oil changes should resolve this - likelihood of the spring breaking? or the valve clogging with dirt? I would bet on dirt building up and after seeing the same resolution from users who have experienced this then it does make sense.

With the immediate start up after an oil change then that also makes sense that it rattles a bit at this point as the valve is not pressurised which is what I have experienced.

Its possible that the last user has made one oil change which is not enough to resolve the rattle and also you do not know if a flush was used.

[Britprius]

On the GS300 there was a recall for this because on a number of cars the vibration from the timing sprockets at startup was enough to undo the four bolts holding the front plate one or more of the bolts falling into the timing chain. Lexus investigated this, and found that with the GS300 having a normal type starter motor the startup speed was lower extending the duration, and severity of the vibration enough to loosen the bolts.

The recall replaced the timing sprockets with an updated design.

On the hybrid GS450H because of the high speed of the transmission motor starter did not suffer the bolts coming loose so did not recall these. There has however been one reported incident of this happening on a GS450H here on LOC. There obviously must have been more than this one isolated case here in the UK, and other countries.

My car suffers from this noise at cold startup or if the car has been standing long enough for the oil to drain out of the sprockets. I checked both the valve and the filters, but both were clean. I did not wish to dismantle the cam timing mechanism as this is a long job. Fitting a pre-lube system has removed the noise completely, and was very easy. It also has the advantage of reducing engine ware because oil pressure is there before anything begins to move in the engine at startup.

John. 

[Farqui]

John@Britprius, which pre lube system did you use?

I had a very quick scan yesterday and mainly found suppliers in the US.

[Britprius]

7 minutes ago, Farqui said:

John@Britprius, which pre lube system did you use?

I had a very quick scan yesterday and mainly found suppliers in the US.

I made my own using an empty small propane bottle, a 12 volt solenoid, a grease gun flexible hoes, a brass "T" piece, and made my own timer.

John.

[Linas.P]

1 hour ago, is200 Newbie said:

With the immediate start up after an oil change then that also makes sense that it rattles a bit at this point as the valve is not pressurised which is what I have experienced.

That is spot-on in my experience as well. I don't know if it rattles when done by Lexus as I obviously get car with warm engine after "road test", but when indies changes the oil, first few seconds it rattles before oils gets evenly distributed in all crevices including valve lifters and what not. After that 6000-7000 miles silky smooth v6 roar... 

@Britprius - that is impressive! 

[Farqui]

14 hours ago, Britprius said:

I made my own using an empty small propane bottle, a 12 volt solenoid, a grease gun flexible hoes, a brass "T" piece, and made my own timer.

John.

I should have know really shouldn't I, duh!

Did I miss the How To guide somewhere? [emoji6]

How's space in the engine bay for plumbing in the bottle?

I really must get a good look around mine at some point. If only the household DIY would let up #sigh

On a related yet somewhat off topic note, I've always fancied fitted an engine pre heater. I worked through a few Swedish winters and loved their warm car tech. Although we don't tend to get too many really cold days over here to warrant fitting them, I've still got the itch.It wouldn't surprise me if John has already cooked up a whiz bang kit for his GS 

[Britprius]

12 hours ago, Farqui said:

I should have know really shouldn't I, duh!

 

Did I miss the How To guide somewhere?

 

How's space in the engine bay for plumbing in the bottle?

 

I really must get a good look around mine at some point. If only the household DIY would let up #sigh

 

On a related yet somewhat off topic note, I've always fancied fitted an engine pre heater. I worked through a few Swedish winters and loved their warm car tech. Although we don't tend to get too many really cold days over here to warrant fitting them, I've still got the itch.It wouldn't surprise me if John has already cooked up a whiz bang kit for his GS, LOL

On the GS there is plenty of space for the oil bottle. If you look down between the front grill, and rads you will see lots of space. Further the oil filter, and oil pressure switch are mounted just in front of the bottom pulley at the bottom of this space. So the take off point for the oil bottle "the oil pressure switch" could not be better positioned.

The switch is removed, and replaced with a "T" piece. One outlet on the "T" is used for the pressure switch, and the other for the feed hose. The hose is connected to the solenoid that is in turn connected directly to the bottom of the bottle.

I worked in northern Sweden for a while, and yes it was cold. I also worked in Canada where it was even colder. The cars there had a heater in the oil sump to stop the oil turning to jelly.

A block heater could be made from a towel rail heater available from B&Q in various wattage's. For the V6 engine you would need the highest wattage version.

John.