Should the trickle of water be audible when driving or sometimes even when idling at a light? I think it would be the water pump right? Just want to make sure it's a normal noise I'm hearing and not a sign of imminent failure or something. I'm going to get my timing belt etc. replaced, but was going to schedule next month rather than like... next week.

Thanks!

 

Just wanted to bump this as I've not driven another LS430 before for comparison.

 

You hear this inside the car?

 

The short answer is No. I have never heard that in mine.
If you can hear water trickling then something is wrong.

However, don't assume that it is water/coolant as could be something else causing a similar sound.
Coolant circulates into the passenger compartment as it is used to heat the car via the heater matrix.
Air-con refrigerant also circulates into the passenger compartment.
The air-con system condenses water from the air and that drips from a hose under the car.
It could be the transmission fluid doing something abnormal.
I'm assuming that the car hasn't gotten wet recently as there are drains from the moonroof that go down the A and C pillars.
So many possibilities.

 

The trickling happens at times when accelerating or decelerating, and generally stops when I'm at a stop (though not always immediately). It sounds like it's coming from the front left of me while driving. There's no major leaks and I don't drive the car in more than a light rain.

 

How is your coolant level - remove cap and look inside the radiator.

 

Omg....bone dry. Just filled it up with 50/50 and will see if that does the trick...ha.

Another ding against the dealer's pre-purchase inspection....

 

That said....still can hear the trickle even through the rain (because I know to listen for it) post coolant fill.

 

You have to completely get all the air out of the system. Starting from a stone cold engine, remove radiator cap and put the climate control on max hot setting. Start engine and allow engine to warm up. That way a valve in the cooling system opens up and fills the heater core with hot coolant and pushes air out, Keep your eye on the radiator and top off as needed, when the engine is warm, shut down and put cap on. Check every few days, top off as needed.
There are companies such as Lisle that make a radiator fill funnel that is really useful for this task.

I'm betting the water tricking sound you are hearing is still coolant and your system is still not completely full. Add fluid to the overflow reservoir as needed too. I had a VW that made similar noises - sound of coolant flowing into and out of the heater core. With the Lexus, you should not hear any sound at all when the cooling system is totally bled.


Re: dealer pre-purchase inspection, given this fiasco, there is no substitute for doing your own due dliigence and checking everything. The other question is - where did all the coolant go? Do you have a leak somewhere? Get to the bottom of that question too. You may not have leak but I would assume you do until proven otherwise. The one thing that can kill the 3UZ-FE is a cooling system failure.

 

The coolant leak thing is definitely on my mind so I'll be monitoring the level as I go...what are the most likely culprits? As simple as an old cracked hose?

 

Look for tell-tale pink crystals anywhere and everywhere in the cooling system path. Some possible culprits (not all):
a bad seam in the radiator, e.g., along the top edge;
a bad hose from the cap to the bottom of the overflow reservoir;
loose/worn hoses or hose clamps; or cracked hose
water pump - more rare.

Toyota OEM hoses and clamps are exceptionally high quality. If they have been replaced with aftermarket - look out and replace them with OEM. Also, you should never see a worm screw type hose clamp in a LS430. If you do, replace that with an OEM clamp. That means someone was in there and did not know what they were doing and probably used poor quality hoses too.

Radiator failures or other kinds of leaks/failures can be caused by excess pressure in the cooling system after shutdown when the fluid is hot, e.g, after high load or high speed driving. this pressure is supposed to be relieved by the radiator cap. If the cap is bad bad things happen. So, replacing the cap with OEM might be a very good idea, they are not expensive.

Check the condition of your engine oil. If milky that is bad bad bad . . . .

 

You have a leak, until the leak is fixed you will hear that sound which is coolant mixed with air.

 

It could not be a leak since it's not a closed, sealed system. Years of neglect can also necessitate a top up. If you see white or pink stains on nearby hoses or around the edges of the radiator or reservoir tank, then you have a leak.. or someone free-poured coolant without a funnel (it happens).

Not only do you need to top up what's under the radiator cap to the very top, but also top up the side reservoir to the MAX line. You also need to set your heater on MAX HOT and after the car heats up, run for 10-20 minutes at max to bleed air out of the system, then recheck/refill coolant levels after it is cooled, then repeat until coolant levels stay maxed out. Don't open cap when system is hot unless you want to risk severe burns from pressurized coolant spraying everywhere. Use Toyota Pink Super Long Life Coolant (SLLC) and pour straight in, no distilled water required.

Agree with TominPT above, check for weak hoses, and absolutely do not use worm-drive hose clamps or aftermarket hoses, that stuff is for rookies asking for near-future failures.

 

Had the timing belt changed earlier this week with a coolant flush, and the mechanic said he saw no sign of a leak (not that he was looking too hard). It may well be that coolant was never topped off in the last belt change which was April 2012....