Kind Of Odd

[Bwilliams]

I've been eperiencing this symptom with my 91 LS for 5 MONTHS NOW. Finally, the mystery was solved today. Here is what you do when your engine temp is higher than normal/disappearing coolant from a closed system with no leaks.

1. NEW Radiator cap OEM. DO NOT buy Aftermarket.

This solved my problem. after months of being *BLEEP*ed off, taking the car in to get diagnosed over and over again and having the lexus mechanics shaking their heads and telling me that there is nothing wrong. My initial thought was that the water pump was on its way out but low and behold, the temp is down to normal again.l

2. Thermostat

This could be causing the issue. Replace it, they are around 25 dollars and take only 15 minutes to install.

3. Water Pump with timing belt replacement. (AKA you're *BLEEP*ed)

typically a thousand dollar plus job. Timing belt must be removed to access and remove water pump. belt is only around 40 to 50 dollars, better replace it or you will pay this plus $800 dollars later to have the *BLEEP*er torn down to get to it. I do not know the longevity of the water pumps in these. Typical junk cars only get about 80k or so on one from what I read. Mine has 165k and is still on the original.

I cannot believe that simply putting a new OEM radiator cap made my car stop leaking coolant and running my temp gage above halfway but it seems it worked. DONT BUY aftermarket radiator cap. Hope this helps, I'm sure anyone with a car around my mileage has experienced this annoyance. :o

[jcrome04]

Just an update to my coolant loss. What a noob move I pulled, when I removed my throttle body to clean it, I didn't put the clamp on far enough, for the coolant passage, so it was dripping out of there. hahahaha oh man, thank god it was nothing serious.

Changed my oil today with Mobil1 full synth 5W-30. Toyota Genuine filter. It was easy peasy! Just over $30 too :) A full synth oil change at the local jiffy lube is +$80 with tax.

Thanks for the advice, but the problem was solved last April! B)

[Mike Floutier]

I just bought a 2002 LS430 with 143,000 miles on the clock and I too have this "two cups a week" coolant loss.

The dealer maintainance records show that the timing belt was replaced at 125,000 miles BUT no record of the water pump being replaced. There is some noise coming from the v-belt area which I suspected might be from one of those many rotating items. I guess it would make sense to get the water pump changed at the next belt change.

Are there any tests for a failing water pump OR any tricks for lubricating it to quieten it - my Ford Scorpio had a little hole in it's pump that you could drip oil into.

Great to find this site, you guys are so helpful and friendly - although I'm an Englishman my daughter lives in CA and my son is in US Army serving in Iraq.

Thanks

Mike

[jcrome04]

Two cups a week????? Jesus if your LS were a human I'd say get to a hospital ASAP!!!! haha

But seriously all kidding aside you should get that checked out.

Did you JUST buy it like 2 days ago? Or JUST buy it 2 months ago?

[acflye]

I have a 92 LS 400, i recently changed the serpentine belt, water pump....and I still get fluid running out of the overflow tube....car is not running hot, just got in from Houston today ran car about 80mph for 2 hundred miles with no problem....so as i park I hear a rumbling sound and fluid is coming out by driver side wheel......what could my problem be......thanks

[vroom8]

I have a 92 LS 400, i recently changed the serpentine belt, water pump....and I still get fluid running out of the overflow tube....car is not running hot, just got in from Houston today ran car about 80mph for 2 hundred miles with no problem....so as i park I hear a rumbling sound and fluid is coming out by driver side wheel......what could my problem be......thanks

is your reservoir too full?...mine does this when i fill it past the 2nd line when it its cold. i try and keep it on the 1st line-cold. blacktop mentioned that we are filling the tanks too full and they are blowing it out thu the overflow valve.

i also had a radiator hose that was cracked and opening up when it got hot--the whole system was making noises- sort of gurguling-- until i

had it replaced, so check your hoses for cracks.

[rtd111]

.....

1. NEW Radiator cap OEM. DO NOT buy Aftermarket.

....

For 91 LS400...

Anyone here can provide Lexus / Toyota part number for the rad cap? Prefer Toyota part number (that is, get from a Toyota parts shop, not LX but either is fine). Thanks.

While at it, Lexus/Toyota part number for Gas Tank cap? Double thanks.