Hey Y'all. New user here and the title is the question. I seriously appreciate any advice on this though. Basically gonna be determining whether or not I'm getting rid of my baby.

2002 430 with 157k miles just overheated two days ago.
Couldn't say how long I was driving with it overheated, but I'm gonna guess at least half a mile (averaging 40mph but with stop and go) and when I finally saw the temp gauge, it was beyond maxed out. Pulled over, coolant leaking, steam under hood.

Considering the aluminum block and what not, what are the odds that even if I fix this, my engine/gaskets aren't totally warped? Any way to check before I swap the timing belt and water pump? Radiator is already yanked out.

 

Did it start after it cooled off?

Any oil in the coolant?

Do a leak down test on the cylinders

Have you determined why it overheated?

 

You can do a compression test without the radiator. As mentioned above check your engine oil dip stick for any milky substance. Good luck.

 

Haven't found oil in the coolant. I can try and do a leak test today.

Haven't verified 100% what the cause was. The mechanic told me it was a cracked radiator, which I pulled and have a new one ready to go, but I'm thinking based on the squealing pulley noise before/when it overheated (not just a steam squealing noise), it may have been a water pump too. I need to get to my timing belt anyways, so I'm thinking I should spend the extra money and give it a shot.

Either way, my only saving grace at this point is if the thermostat was reading just steam temperature and the engine didn't reach the stated temp on my gauge.

 

All you can do is fix it and drive it and see

 

Do this first. Do not do timing belt until you have done compression test and you are sure it is still in good shape. In fact if I were you, if compression test is good, I would install radiator, and drive it for a bit to make sure there is no surprises before doing TB.

 

So our cars would not go into any type of limp mode if overheated? I like the advice of putting the new radiator in, and driving for a while and observing. My guess is there is some tolerance for running overheated. Is it half a mile? Dunno. I would think that a temp gauge goes up gradually, so again, there has to be some tolerance. One of our cars has a oil temp gauge and no coolant temp gauge, just an idiot light. So there has to be something designed in such that the driver can overheat and then pull off safely...my .02

 

I hope the OP keeps us updated on the status of his car.

I'm kind of disappointed at Lexus for this design shortcoming. They could have easily incorporated some type of warning chime, message or light into the system whenever a overheating situation would arise instead of counting on the driver happening to notice a rather obscure temperature gauge. This is probably the 4th or 5th person that has had this issue happen to them since I started visiting this board in a little under three years. I'm beginning to think I need to proactively go out and change my radiator out within the next year or so...

 

I was shocked when one day in stop and go traffic my usually rock steady temp gauge really started to climb. I quickly got out traffic and popped the hood. The reservoir was empty and after it cooled off the radiator was half full (or was it half empty?). Turns out my radiator was cracked at the top. I was really stunned to discover that in a dash loaded with all kinds of warnings there is absolutely no “Low Coolant” warning. This was a major design oversight by Lexus.

 

It seems highly probable that owners of the LS430 with the factory radiator will experience radiator failure usually due to the upper seam seperating. I was lucky to have noticed a distinct coolant smell after parking. When lifting the hood I saw the coolant stains and knew I had the notorious radiator seam failure. It would not be unwise for anyone on this forum who believes they have the original factory radiator to replace it with a Denso aftermarket before a potentially catastrophic event occurs. Our radiators most likely will fail. Mine did around 120,000 miles.

 

I am not car engineer by all means but if I can play devil's advocate:
- Agree that it sucks the radiator is cracked. But we are talking about more than 10 years old, and probably over 100K miles. Nothing last forever right? Maybe radiator should be replaced as preventive maintenance? Also I have heard that regular coolant replacement can extend the life of radiator.
- Do we know if there is any cars MY2001-2006 that has low coolant warning? Is there any present car that has low coolant warning? I am not sure I want to say that it is a major oversight by Lexus.

I have a ScanGauge II hooked up into my Land Cruiser all the time to monitor water temp and transmission fluid temp. I know a few others in IH8MUD who has scanner hooked up all the time. I mainly pay attention to the temps when towing. Easy enough to have a ScanGauge or other scanners if you really want to monitor things in the LS.

I also believe that there has to be some tolerance in the engine. If you shut off the engine as soon as you see the temp rises, I think you should be ok. If you keep driving then the engine is toast for sure. My 2c ...

 

You know it's toast when the engine siezes up while driving.

 

I wonder if the day will ever come when we all can afford what is today a $3500 engine analyzer. Prolly cuz of the smartphone we think not much out of pretty slick free apps. But you go into industry and $3k doesn't buy much (say a Zebra scanner in a warehouse or a Panasonic core i5 (i5 not even i7) Toughbook). I saw a guy driving with one and I was amazed the screen split 4 times and showed him all 4 wheel speed sensors and one which had mph all over the place--he was confirming the bad sensor. It's interesting when things can be kept proprietary and the cost high. Even good ones for android that were minimal cost now have subscription fees, nuts when developers realize how much what they wrote is worth.

 

Well it was my first time doing anything besides brakes, but I replaced water pump, timing belt, thermostat, and radiator.

Just ran it for 15 minutes on the roads (104 outside) and with full AC, the temp stayed in the safe range (although idling with the exhaust sticking out of the garage got the coolant temp up to 205F).

I would really like to thank everyone who gave advice. I took all of it into account for my decision making. I've been working on no sleep to get this done so I can stop Ubering to work. I think I'm good to go, but only time will tell!

Either way, I'll be getting rid of the car most likely just out if fear of seriously hurting the lifespan of the car by overheating it.

 

Don't have a fear like that. It takes running the car for longer periods of time to damage the engine. Sustained overheating. They are very reliable engines.