LexiBanna1

So as of Monday my very quiet, very smooth riding LS400 has started sounding very rough all of a sudden. It sounds like just...a straight up raggedy old car. On Monday, I went to an appointment about 15 miles from my house in the morning, came home, and then when I went back out for another appointment that I had that afternoon, it was like the car had been transformed. It started making noise when I got on the interstate, and I pulled over in a panic but since I was in a bad location (on a bridge) I got back into traffic after some time and crept to the next exit, which was maybe 2-3 miles down the road. Once I got off the exit, I went for some time (was heading to the nearest mechanic shop I could find) but at the first traffic light I stopped at, the car overheated and started sending white smoke profusely, which it has never done. It made a huge scene as it was a busy intersection. I went to a couple of mechanics and they all said it's the catalytic converter. I am not convinced as this happened so suddenly. One put in a new resonator and cost me $200 bucks and of course that did not fix the problem. The car also has a weird smell if it idles for some time. The other mechanic (at a chain) said the valve cover gasket is cracked, coolant reservoir is cracked, and the thermostat gasket (?) housing needs to be replaced. I asked if fixing those things will fix the noise and they said they cannot confirm that it will, but that those things need to be fixed regardless. What I don't understand is how the car can be perfectly fine one minute and something then dramatically goes so wrong the next. I have taken it to three shops but no one seems able to address my real concern. What could possibly make my car go from sounding like.... a Lexus.... to sounding like an old beat up Ford Pinto?

LexiBanna1

Sound is here:
and also here

Lexusdk

Bring it to a Lexus dealership and not to an unknown disreputable independent shop. Have a true Lexus (or Toyota) technician diagnose it properly. You will most likely have to pay for a 1-2 hour diagnosis. If your engine is overheating and causing a change in sound, I say start by looking at the water pump or anything related to the cooling system. In the mean time, don't drive the vehicle until it is properly diagnosed or fixed. Driving with the engine overheating, will damage the head gasket or engine entirely.

dicer

I can't tell for sure the sound. At first I thought a bit of a miss, and the second one could be exhaust leak, and somewhat normal over amplified by the recording device valve lash.
One thing you said "it over heated and sending white smoke profusely" so did the temperature gauge go into the red or show hot? Where did the white smoke come from? If it over heated and has a coolant leak you really need to make sure there is coolant in it. And any leaks need to be found before driving it any great distance.
Okay did these mechanics show you the cracks and leaking thermostat gasket? The reservoir is an easy fix, you could do it your self with a few simple tools.
People here can show you a picture of where it is an exactly how to replace it. You can either get a new one at lexus or an auto parts store. What year your car is likely makes the location and how to change it different, so please post the year. Also does the check engine light come on or did it come on when it over heated?

LexiBanna1

The temperature gauge never went above the half mark. I am not sure if it is completely accurate but it will show cold upon initial startup and then go up from there. There is adequate coolant, I checked and the mechanics checked and it is fine, at least for now. I also keep some with me in the trunk, but it was showing pretty full yesterday when I checked. I drove it around the block and started smelling a smell that was similar to burnt rubber. The mechanics did not show me anything regarding the reservoir or the gasket housing. They did say it was a fairly simple fix. In which case, I can totally do that myself.

It's a 1994. The check engine light did not come on. None of the indicator lights have, so far. There is a slight oil leak also but nothing substantial. Can starting the car without pressing the brake cause problems? Recently someone pointed out to me when I started my car that I didn't press the brake, which, usually I do but it's possible that I've done it more than once before in the past few months without even thinking about it.

The white smoke...not sure actually. I am inclined to say the driver's side, mostly, though.

CELSI0R

In modern cars, you need to depress the parking brake in order to start the car as a safety feature. Not depressing the brake has no affect on your car at all, nor does it on most cars before push start buttons. I never press the brake before starting, and only hold it when releasing the parking brake or switching into gear.

The sound coming from your 1994 is definitely abnormal, but it is hard to diagnose without being there. A video of the engine bay with the hood open may be more useful.

I would not recommend running the car for prolonged periods of time, but see if you can figure out where the sound is coming from. With the hood open, listen around the engine bay carefully.

Check out this video on how to diagnose the location of engine sounds. Be especially careful around moving parts, such as the bearings, belts, and fans. Also, do not touch hot areas, such as the exhaust. I always prefer to wear gloves and take my time, but do not overheat the engine of course.

UNCNOR

iTrader: (1)

Water in gas?

LexiBanna1

I will upload a video with the hood open later this morning. However, it doesn't sound very loud from the top of the engine, it's definitely louder on the underside of the car.

dicer

Wow ! What goofs that would tell you to push the brake to start the engine, and hint that it would damage something. I guess its know nothings trying to impress someone with their total lack of knowledge, sorry that just gets to me. If that person had a brain the size of an ant, they would know that if you have installed or install your self a remote start system, you are not even going to be sitting in the car when you look out your window of your house or appartment and use the device. Did they know it was a 94?

djamps

Sounds like a exhaust leak - EGR pipe? Catalyst?
Erratic tach needle, possible misfire - ECU capacitors going bad? If the ECU is bad that could quickly lead to plugged catalyst and blown out exaust...

Spartan536

It seems like every day I turn around and I am talking about the blasted ECU's in these LS400's.

I agree about the exhaust leak, it sounds like my old 1995 Camry when it had an exhaust bolt sheer off from the downpipe, causing the header and downpipe to have a separated connector p!ate where exhaust was coming out considerably.

As for the ECU, that sulfur smell is one of the most known indicators...

White smoke... Power steering fluid entering the engine through the IACV perhaps?

LexiBanna1

here is the sound as heard from the top of the engine:

dicer

Possible exhaust leak. I think the video recorder muffles the noise some, could be a hole in one of the mufflers, exhaust flange leak, like someone said egr pipe, even exhaust manifold to head kinda rare though. Did you drive over something recently and have it hit under the car? Funny it has air suspension and not trac.

LexiBanna1

Ok now I've got a symbol as well

Moarpower

check the afm. I had white smoke. Fixed it.