Alfa777z

Hi everybody! I have started to hear a grinding sound coming from water pump location on my 2007 RX-350 with 120K miles on it. This could be a water pump going bad, but what is really confusing me is absolutely no coolant leak at all. It's been for a 5-6 months since the some sound has appeared and now it's getting louder. My mechanic did a quick check by removing the serpentine belt and the noise was gone. It still there (noise) with AC off or on. My question is: Is there absolutely HAS TO BE a leak of the coolant when the water pump goes bad? Maybe I hear a sound of some other spinning parts going bad like tensioner or idlers? Thank you for your help.

kiwi

if the bearings are bad, then you could have a noisy pump with no leak

but the puzzling thing here is how bad your mechanic is: The water pump runs off the timing belt, not the serp belt. thus; if he removed the serp belt and the noise went away, it cannot be your water pump, it has to be something on the path of the serp belt.

So where to go from here. find a new mechanic, cuz if he didnt know that, he shouldnt even change your oil.

Rainbird

A few facts are in order here. The 2007 RX350 does not have a timing belt. It has a timing chain. My 2007 RX350 water pump was replaced under warranty at 60K miles. The leak was caused by a faulty gasket.

kiwi

my bad, Rock auto lists a timing belt for a 2007 rx350, 30 bucks.

Alfa777z

Thank you for your response. Well, my mechanic IMHO is the best. He has serviced all my five Lexuses for the last 12 years and saved me tons and tons of money. The best thing to have your own mechanic is really to be a part of the whole process of the work done on your car. Starting with check up, inspection, buying parts, the work itself until the job is done. My mechanic and I will discuss the possible problem; he will SHOW me the problem on the spot, explain the cause of it and honestly name the price of fix. I can observe the whole process of the repair if I want to and I don't have to sit in horror in the dealer's waiting room blindly guessing the verdict which is most likely will break my bank. My question is the same. Is there absolutely HAS TO BE a leak of the coolant when the water pump goes bad? I just need a second opinion from you guys. It doesn't ever hurt, does it? I really like this forum. Thank you all.

Alfa777z

Thank you Rainbird. You do know the cars and it shows.

tomit

IMHO, a noisy pump bearing leads to a failed pump bearing which leads to a failed coolant seal and a coolant leak. It's your money (and this is not a cheap repair) and if you won't be taking any long trips you can wait until the seal fails, but engine over-heating and engine damage become a possibility it the pump is not replace now.

robbyk

Your mechanic should be able to answer your question. One time I had a noisy water pump in a Toyota Corolla and no coolant leak. The grinding noise was really bad, sounded like if you have a bearing spinning with no oil. Eventually the water pump busted from the bearing neck creating a big mess leaving me stranded.

Alfa777z

Thanks for the response. This is what my mechanic said. He said he can fix the pump now or wait until the leak appears. The absence of the leak was a reason for me to post here in the forum and to ask you guys for the second opinion. As I wrote in the original post the grinding sound with no leak made me suspect a failure of other spinning by serpentine belt parts like tensioner, idlers, alternator shaft and so on. One day the sound is loud, the other is barely noticeable. By removing the belt my mechanic determined that there's nothing wrong with the crank shaft and the problem most likely is a water pump. I wish there would be different sizes of the belt to bypass each spinning part to clearly determine which one went bad and started to produce the sound. I just want to make sure that the sound doesn’t come from other spinning parts which I listed above, before I buy a new pump and coolant to make him to fix the problem.
Do you guys believe that this sound can be produced only by a water pump going bad and by nothing else? Thank you all for your help.

Alfa777z

Thank you for your response. I don't feel any pressure from my mechanic. He said if I'm not sure I should wait until the leak appears. Well, it's been already 6 months since the sound appeared and he did the first quick check by removing the belt. And what is really puzzling me there's still no leak. Well, I guess I have to take preventative action and just to go ahead and replace the water pump, hoping that was the problem for sure.

Alfa777z

Guys, I'm thinking to buy the water pump from e-bay. I'd prefer OEM. Any particular brand I should consider? My budget for the pump is $100 -$120. Thank you very much.

tomit

The water pump in my 1995 Avalon (3 liter) lasted 180,000 miles, but I"m very **** about changing the coolant. I wonder if the OEM pump has been updated since installed on your car so it is more reliable? If that is the case, ebay might not be the place to purchase it. Changing the water pump on a 3.5 engine is quite labor intensive, so spending money to get the latest and greatest OEM pump (if there is one) may be worth it.

Rainbird

OEM for Lexus is Denso.

NVAKeith

iTrader: (1)

In theory the noise could be produced by any of the spinning pulleys that the belt travels on: AC, PS, water pump, tensioner, alternator, etc. You didn't mention whether your mechanic rotated each one by hand individualy to see if the bearings felt rough. Then again rotating by hand is different than the engine running at 800+ rpm.

The water pump job is so pricey that it may be worth a second opinion. We just had ours replaced under warranty on our '07. We noticed a rumbling noise start for about four months before it started leaking. Even had noise checked out and serpentine belt replaced at dealer 600 miles before it started leaking but they "couldn't reproduce the noise".

Years ago on a previous car I had a whining noise come up suddenly, the dealer diagnosed it as the AC compressor and gave me a $1k repair estimate. Since it was October and I didn't want to shell out that much $ at the moment I cut off the AC belt myself and ran without it for the winter. When the belt was off I spun the AC pulley and the tensioner individually by hand. It was obvious to me the tensioner bearing was shot. Next spring I took car back to dealer and had them replace the <$100 tensioner and put a new belt on. AC compressor was still fine when I sold the car 50k miles later. Fortunately that car had two accessory belts so it was easy to isolate the AC from the PS & alternator.

robbyk

This should help you determine where the noise is coming from. It would be worth the $20 investment.