Syed abbas

Gs 450h engine breakdown

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Could somebody help guess a diagnosis. I can’t pay 2000£ labour for diagnosis. It’s 2010 gs450h at 116,000 miles. Serviced 3 weeks before breakdown by Lexus. All of a sudden the car tried to stop while I was accelerating on the motorway, felt like a blown tyre, lost balance and speed. Could have been involved in a serious accident.  For safety concerns, I need support to warn other owners If there is a potential danger and common fault in the gs450h model that could prove dangerous. The manufacturer would never admit a flaw in the design, although some cars were recalled for safety concerns regarding the engine performance.

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Sorry to hear of your experience. Am not  sure if it’s anything to do with the model 450h in general as there are many examples with 120k on the clock still cruising around happily. I had one myself years back on an 08 plate and sold ito a friend at 55k six years ago and he is still using it till now without any issue

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On the face of it, that does sound bad but it's really difficult to tell over the internet.

As long as it's not an invasive investigation, I'd suggest you find a local mobile mechanic to have a look for you. They can at least give you a clue if it likely to be a significant mechanical issue as you suspect, or if it a failing/failed coil pack/fuel pump/injectors etc etc. Cost you a lot less than £2000. 

What is the history of the car? 

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i have seen a lot of complaints online regarding the engine and noise problems in gs450h so i was wondering it might be the same underlying problem but no one has posted any diagnosis. i have had it for two years, it has full service history. i replaced the suspension last year with the service and MOT. the recent service was done 4 weeks ago. when lexus put the registration number in their system, it came up as an IS300h. i am very confused.

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If it is a mechanical failure, it is unlikely - unless it was evident by noise - that it would be picked-up by routine servicing. Mechanical faults can develop very quickly, as I know to my own cost when a crankshaft sheared without warning (not in a Lexus). 

I see from Honest John you have already emailed him about it, and his feeling is "...reads like failure of the VVTI valve gear of the 3.5 litre V6 petrol engine". If his surmise is correct, you may get away with replacing the actuator. As I understand it - and I'm by no means an expert - failure of the VVTi system should not cause any stray movement of the valves and so no damage to the head or pistons. Yes, it will run rough, but it's not mechanically damaged other than the actuator (I would still keep engine running to a minimum though). Of course it's speculation on speculation, so I really would advise getting a mechanic to look at it. You look to be in Essex, are these people anywhere near you? Or these? Might be worth a call if nothing else.

If it's any reassurance I did have an actuator fail on a previous car (not a Lexus) and that was repaired and it ran fine afterwards. Not directly comparable I know, but all may not be lost. 

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Is the coolant level normal? Any evidence of leaks around the water pump? Decent amount of complaints over at the US clublexus forums for water pump failures on that generation of models. Hopefully that isn't the problem as it usually means a new short block at least, which pretty much translates to new engine, but to be honest an engine quitting like that doesn't sound good in the first place.

At any rate, off the top of my head:

-Check water pumps, both for the engine and inverter. Coolant level, leaks, pulley play (the 3rd gen GS has a belt-driven engine water pump), etc.

-Do a techstream readout of any codes present. You'll have to double-press the start button without having your foot on the brake, that way the car won't try to "ready" at all. Check the codes and work from there... this assumes that codes are present, but I'd be very surprised if they weren't.

-If it's engine-related... I'd pull the spark plugs and inspect the combustion chamber with a camera. Quick way to spot catastrophic damage. Can't offer much advice on this... My guess is that if you see white spots (melted anything), you're in for a new engine.

-If it's inverter-related, you'll most likely have to replace it. Used right hand drive inverters are cheaper and very easy to find for some reason (ask me how I know ^_^). Don't even think about getting a brand new one - the engine will look cheap in comparison. Things to check in case that it is the inverter:

->Clogged (internally and/or externally) or leaking inverter radiator/tubing (yeah it's separate)

->MG1 and MG2 windings insulation - read up on how to do this for a Prius transaxle, same principles apply. You'll need a megaohmmeter for this.

->Transmission fluid level. If it's the inverter and the transmission took awhile to shift gears (at 70MPH or so when being floored), then it's usually either this or seized bearings in the (external) oil pressure pump. Refilling a completely drained transmission (i.e. oil pump has been disconnected) takes more than just a top-up - there is a bleeding function that you can activate via techstream, a forced transmission learn that you can again activate via techstream… and some other things. Make sure that it is done right - get access to the repair manual. Lexustech, techinfo (US so for LHD cars, not sure how much of a difference), not sure what else is available. As for how this can cause issues with the inverter - it cools MG1 & MG2.

If it's none of those, then I'm out of ideas. Inverters used to fail on RX400h's/highlander hybrids, but those were recalled for fitment of improved units. I'm pretty sure that I'm missing something, so dig up as much info as you can and don't put blind trust/faith in any single source of information 🙂

Good luck and don't give up!

 

EDIT: Just noticed your other thread, shouldn't this be merged?

EDIT 2: I should've watched the video you attached with the audio on >_<

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