ses12r

Our 2008 IS250 has started having some knocking issues. I have read through a lot of stuff on here but have found nothing that sounds like what we are dealing with. When I start up our car and pull out onto the street especially on cold mornings the engine has a pretty loud knocking noise that speeds up or slows down depending on acceleration. We have taken to the dealership three times for the same sound and every time thaty come up with a different answer for the problem. The first time they replaced some timing parts that were covered under some TSB and it made no difference. The second time we took it in they fixed nothing and told me it's piston slap and it's fine because it goes away when the engine warms up. This past time to the dealership they fixed nothing and told me it is something called hydraulic shock (WTF is hyraulic shock?) and that it is normal. This stupid little noise is about to drive me crazy. If it is something that is normal and only does it when its first starrted then why didn't it do it when we bought it new. The car has 28k on it and the noise started about 10 or 15k ago. Please help!!! Should I try a different brand or weight of oil??? Thanks, Stephen

BTLS250

iTrader: (1)

I'm no expert but maybe it's your valves knocking? I heard using low octane gasolines can cause this

07SGM

I think my car is having the same problems as yours, but the noise does not go away when the engine is warm, it just gets quieter. I took it to the dealer and they say it is normal too, but I disagree. Have you taken it to the same dealer all 3 times? Have you just recently had an oil change done before this noise started?

XhyDra

iTrader: (8)

Before they give you excuse #1,000,001 try this. It might be a little costly but anything for the good of solving a problem. First up change your oil. Use something like Amsoil Signature 0W-30 just for this experiment, it's great for cold weather and cold starts overall. Buy an Amsoil P.I. Injector cleaner and run two bottles. Not together but in two different fill ups. When you do change your oil and get the Amsoil P.I. Put the highest octane available in your state, this is a must always because I've seen people fill up on 87 with IS250's. Big mistake! This cars compression is too high to give it cheap gas. You'd be doing more damage than good loading up on cheap stuff. Next after filling up and dropping in a bottle of the Amsoil P.I. Drive around to get the engine at good operating temperature. Next get on a highway and stay on the slow lane, put the car in sport mode and run it on 3rd gear at almost about 60mph for say 5min or a couple of miles. Sure it will eat gas like crazy but were trying to get the system burning off carbon, also any sludge that might be in the heads. The Amsoil signature 0W-30 should do a good job protecting the engine and cleaning up any bad residue that's been there.

Then report back to us and let us know how your car is runnning

shui3000

what octane gas do you use?

if it's piston slap, it IS a problem. it will wear your engine out quicker. if it really is piston slap, the only thing that can fix it is a whole engine rebuild.

however, are you sure it's not just the direct injection sound? a lot of people confuse that sound as being a problem.

a few other possible scenarios would be that something like a rock is stuck to your tire, unbalanced tire, something with the axle, serpentine belt, etc.

take it to another dealership

ivanz

Does it sound like a diesel engine? If so, its the direct injection.

gnode

Seriously, if it is piston slap, that is bad.

Is your car still under warranty?

Definitely try taking it somewhere else to see what the deal is. It sounds like the people you are using don't know what they are talking about.

lobuxracer

iTrader: (2)

Piston slap? Are they complete idiots? It sounds like it. That's a guess and a really bad one. It's crap like this that makes me wonder if there is anyone honest in car repair anymore.

XhyDra

iTrader: (8)

+1 sounds like it Lance, it's almost sad that they can't figure out what they're supposed to know like the back of their hand.

OP if you can maybe take a sound clip or some video to give us some insight on how this sounds. Also for the sake of ruling things out give the technique I mentioned above a try. I know for a fact that when my car is cold the "tractor" sounding noise of direct injection is louder.

ses12r

When I went to pick the car up last night I spent some time talking to the head diagnostic person and he seemed to have some good input. He says the noise is the high pressure fuel pump. He told me that there is a three sided lobe on the front of the cam shaft that pressures up the fuel pump and as it does this it makes the noise. He said for whatever reason the sound is louder in cold weather. He claims that the noise is always there, you just notice when the engine is cold. Is this the direct injection that you guys are talking about??? I try to run 91 in it as much as I can and the lowest I will ever put in it is 89 octane. I also try to find straight gas with no ethynol but thats becoming very hard to do. The car is still under warranty, only 28k miles on it and we bought it new. What kind of bothers me is that it did not make the noise when it was new or at least not loud enough to hear it and they can't explain that. I wish I had another dealership but they are the only game in town. I would have to drive 2 hours min to the next dealership.

Kurtz

iTrader: (1)

The lowest you should ever put in is 91.

(higher does nothing for you either, but lower is not a good idea- 91 is the minimum required octane for the engine to operate properly).

shui3000

WELL THERE'S YOUR PROBLEM! YOU'RE USING NON-PREMIUM GAS!

Quit putting cheap gas in there, just get premium. It even states in the manual, put premium gas in there, minimum 91.

UNOHOO

iTrader: (3)

+1 rep, thats some pretty good advice there bro, i dont own a 2nd gen IS but i can definately see the benefit in doing a proceedure like this

Koz

These engines are very loud until they warm up (Slight knocking and whining). Low octane fuel will make it worse. Try to stay off the gas until warm and use 91+ octane.

Koz

ses12r

Thanks for all the info.