Dump Valve Noise

[chrisyg]

Hi everyone, just wanted to know if anyone else's IS300 makes a dump valve type noise on up shifts. It normally happens when the transmission is under load/hard acceleration. I had a JCW mini before the lexus and it sounds a bit like that on gear changes. The gear box in the IS300 is one of the highlights of the car and mine is silky smooth and operating well but I was wondering about this noise? Should I be concerned?

[noby76]

wont say i have experieced a dump valve kinda sound on up shifts.. only different sound i experience is throtier engine note above around 4000rpm in ECT PWR M mode but both my up shifts and down shifts sounds normal. does it jerk quite harshly when you experience this sound on up shifts? when was the last time the gearbox oil got replaced? maybe worth having the gearbox oil drained and refilled with fresh one and see if it cures it. Lexus recommends only Toyota Type IV for these boxes.

[chrisyg]

Hi John thanks for your reply, it's like a rush of air or the sort of noise you hear if you quickly unscrew the lid on a slightly flat bottle of lemonade! The gearbox works great and the cars done less than 50k but one of the next jobs will be transmission fluid as it's not included in the 10yr service that I recently had done! The diff oil however was included which seems a bit strange. Is the transmission oil change a difficult/expensive job and how often should it be done? My cars on a 03 plate so 10yrs old with full main dealer history. Would it have been part of a previous service? If anyone online your opinions/thoughts on the dump valve noise would be appreciated! If it's needs a new gearbox I will just get rid and just get an ISF on finance :)

[noby76]

just go for the IS-F matey.. :) !! seriously..if you can finance and insure IS-F why wait?? get one even if you own for only 12months.. as you already know IS300 is a capable wolf in sheeps clothing..just last night i put a 13 plate 530d BMW in its place after we got past 2nd gear. a lot of them feel like they own the road and can cut in front of any car because they have a blue and white badge on the bonnet he wondered where all his 550NM torque went! anyway going off topic now..

back to the point your gearbox shouldnt be making that noise. its not a difficult job as its only drain and refill had mine replaced at a Toyota/Lexus Indie and all he did was unscrew the drain bolt underneather the gearbox to drain olf fluid out into a pan, he then measured the amount of fliud which came out as he had one of these measuring containers with mm and litres labeled on it, he then screwed the bolt back on and refilled the exact litres of fliud which came out with the help of a funnel. started up engine, left it idle for about 20mins for new fluid to make its way back into gearbox/torque convetor then shifted through PRND32L each time waiting for about a sec with each shift then shifted back from L to P again left it idle for about 10 more mins for fluid to make its way through the box and warm up took it for a quick drive and job done. could have actually done it my self tbh but dont have the work space and tools like Jacks and stuff. he also confirmed its worth changing the fliud every 50-60K. dont get rid of the car yet as it drives ok just replace the fluid first and see if it cures it.

[chrisyg]

Hi John just making sure that I stay on the gearbox topic i'm sure everything is fine the shifts are really quick and precise. The e-shift was really the reason the I bought the IS300 as I no longer wanted to drive a manual car. As I understand it its the same 5sp transmission used in all 6/8 cylinder lexus's up to 2005 so it must be strong box if its good enough for the V8's. With reference to the ISF i'm in a bit of a dilemma, my plan was to throw 5/6k at the IS300 getting to the way I want it i.e wheels/suspension styling mods such as LED's, DRL lights etc possibly even a colour change respray as I think the silver is bland. I would end up with great car and no doubt be very pleased with it. But with the purchase price of 4K, I would have invested about 10k into car that is still only going to be worth 4K. O.K they enjoyment of doing it would be great and it really interests me, but is it sensible? Or do I just bite the bullet and buy an ISF with the used values now dipping 25K its looks tempting. Yes insurance/petrol even road tax are a massive issue but if you want to drive a 400bhp car then you've got to pay for it. I'm not a wealthy guy, far from it, but I am seriously thinking about it. One other really massive issue is where do you actually drive the thing!!! I live in the Southampton area and live 2 miles from where I work. With police/speed cameras and busy roads do you have to wake up at 2am and just hope you don't get caught! I've honestly not really had a chance to push the limits on the IS300, i've certainly not had it up to top speed or anything like that. Anyway about that gear box thing!! Staying on topic of course ha ha!

[Mr.Rudus]

yes I have had that dump valve kind of noise. I know what you mean.

I was trying to figure out what it was' sounds cool though. its not loud no where near as a real dump valve on a turbo engine.

I always notice it in the evenings when the temp is cooler and the engine is hot.

it always happens when driving gently in mid rang up to 4k rpm using e shift controls.

not sure what is though -

off topic with noby76, talking about 530d, I am playing with E46 m3's getting infront always. we have an E90 330d m sport in the family and gave it a run. it cant stand well with the is300 in no angle. . IS300 is a undercover beast. not many know its capabilities. its a superb cruiser with hard reliability & the quietest engine I have owned with 215 bhp. and it certainly goes a lot more quicker than the book figures..

I never knew this until I owned one for 2 years.. for the value I would say the best motors out there. it certainly fixes up the big headed german owners!

[chrisyg]

Yes its a great car loads better than I thought it would be. I was looking at 330i beemers when I bought mine absolutely no regrets what so ever. Its actually the first car that i've owned that I genuinely love driving. Everyone talks about what the IS300 does well but does anyone have any opinions on what it doesn't? For me its the handling, I just don't think you can leave it as it is. For any enthusiastic driver its just to soft, very comfortable though. On the dump valve noise I didn't really think there was much wrong with it as some of the guys on the American forums have talked about it!

[noby76]

Same here got tired of shifting my self and decided to try auto/manual for once! It’s the same A650E gearboxes used in the LS400/430’s and the GS300/430’s so its quiet a strong box. I did used to mod my cars in the past but these were Renaults and mainly Fords but got to a point I realized
it sometimes cheaper getting a car which has all the toys and the go from standard don’t get me wrong sometimes its good to make a car more yours enjoy it for a couple of years but loose out when its time to sell it as the buyer will still pay market rate and won’t care about the mods. Maybe unless it’s a Cosworth, Supra or Skyline.. and I know what you mean. ISF’s can be picked up for less than 20K and have seen quite a few on autotrader with reasonable miles done on them but the question is where will you get the chance/road to actually ‘DRIVE’ the thing without speed camreas here and there or under cover police cars pulling you over?? So the question is will it be money well spent if you upgrade to a more powerful car and only get to ‘DRIVE’ the thing only on track day events?? Thing is most will backout once they see those quad exhaust at the back of the ISF maybe M3/M5,Audi RS, STI or EVO drivers might take you on but that’s it and how many would you encounter on a daily basis? so you left driving a powerful car which you can t actually ‘DRIVE’ if you know what I mean..but is IS300’s case its not overly powerful and cus most don’t know there was a 3 litre version of the gen1 IS, you get a lot of them try it on.. and I agree the handling is quiet soft and has its moments..some days it can take and still to corners like glue and some days its all over the place its fine on sweeping corners but show it some tight corners and its not too sure.. two things I will fix is the on limit handling and backend sliding out during for some reason it doesn’t stay planted. Was looking at 330i Beemers and 3.0 Audi A4’s when I was hunting didn’t even know IS’s came in 3.0litre models until I saw one in B’ham and thought yes.. ended up trading in my V6 ford Cougar for one within 2 weeks as I wanted something unique, a bit of guts which won’t draw too much attention..

ok went off topic for a sec..back on topic sounds like MR Rudus gets the noise aswell really strange I don’t or maybe I haven’t actually listened to experience it.. but will suggest having the existing gearbox fluid replaced to be on the safe side. For handling most recommend Eibach springs as its claimed it won’t make the ride too harsh but will stick round the corners.. :)

[chrisyg]

One of the slightly appealing factors is the IS300 is its rarity. Having owned mine for nearly a year I have taken interest every 1st gen car i've seen and unbelievably i've only seen one other. If you look on autotrader sometimes there's only 4/5 for sale excluding sportcross models. Would I be right in thinking that lexus probably sold one IS300 for every hundred or so IS200 sold? I think you can tell the difference between and IS200 and IS300 by looking at the rear wheels, think the offset is slightly different. They seem to look like that anyway. Going back to the transmission thing if Lexus had sold manual IS300's here would you have been tempted?

[noby76]

mmh thats a tough one as am still a 'manual' man at heart! would depend on if the manual version offers better performance/ mpg comapred to the auto but from owning mine almost 2 years, it can easiy return 33-35mpg when cruising on motorway which is 4 cylinder manual car consumption. and one can pick and hold which ever gears they want in a given situation with the auto IS so not sure what advantage a manual will bring compared to the auto but i wont know until i tried one. read an article a while back and it was confirmed the Lexus enginners realised a manaul will only be about 0.2 seconds quicker than an auto so didnt bother with one untill those in US(biggest Lexus customer) cried out for a manual IS300 as 328i - 330i E36/E46 BMW's were offered in manual spec hence only the US market had it. the 300's are a rare sight and as you confirmed only a few on autotrader.. which was a shame and good at the same time.. it was a shame because i dont think Lexus marketed this Lexus well and for the price the IS300 was going for at that time, most in Europe would rather pay that money for a BMW/Audi/Merc and over looked the IS300. fact that it did not have a manual version might have also contributed to poor sales as IS200's sold quite well compared to the 300. but its now good cus we get to drive a rare car, with one of the best 6 cylinder engines ever produced.(every tuner swears by a 2JZ Block), :D

[Mr.Rudus]

hmm that noise? as say its only with e shift mode where there seems to be more throttle & torque.

i better have another look under the hood incase lexus made a hidden small bolt on turbo running next to nothing psi boost & giving off the baby dumps -

in my opinion the handling is not as good as the IS200.. i think may be of the engine weight & 18'' alloys. both have the same suspension setup & geometry. it feels heavier in bends than the 200 too. i guess don't realise might be doing a lot more speed in the 300 than the 200 in to bends as the 300 is a lot more comfy & quiet. upping the tyre pressures help stiffen it up a bit.

[chrisyg]

Yes weight does make a difference to cars, I've not had the pleasure of driving an IS200 but the 300 certainly feels a bit Lardy in the bends. Having said that I don't think either car is particularly heavy by today's standards. The dimensions of the car are fairly small as well when you park next to modern saloon cars you can really see it. IS200's do come with manual boxes which certainly is a plus but some people seem to be complaining about clutch judder, don't know if it's a problem.