Stifler

I have a coolant leak that judging from the small spots under it are coming from the passenger side middle/rear of the motor. I have been under the car and cant see where its coming from. I am currently replacing the valve cover gaskets so I have a pretty good view of things right now. I will be going to get a coolant system pressure testing kit today to try and find the source of this leak. Any thoughts or places to start looking for the source of the leak on that side of the motor? What psi do I do the pressure test at?

salimshah

Try to stay close to the PSI stamped on the radiator cap and remember to change Pascal to PSI.

I borrowed/loaned the tool from Autozone and the only thing I could do was test the cap ... never figured out how to attach their unit to the radiator itself.

Heat exchanger, overflow reservoir, engine block drain (I only could find the one near the oil filter side).

Liquids tend to travel so you will have to trace.

How much are you loosing each day -> tell you how big a leak you have.

Salim

hypervish

Welcome to Club Lexus!

Based on the location you described, the water pump could be a suspect.

Baetke

If you remove the right front wheel you will see a plastic access panel held on by a couple of 10mm bolts. Remove that panel and you will have a good view of the water pump weep hole and will likely be able to follow the path of the coolant drip by tracing the stains back up to their source. Look just above the timing reticle.

fastnoypi

you don't need to pressurise your coolant system to the psi of the cap. Have someone pump while you check for the source of leaks. 8-10 psi is plenty.

Stifler

Well lucky me, its the water pump. I guess that gives me something to do on my next days off.

salimshah

So how old is the current water pump? What type of coolant you have been using?

You may like to spend extra $50 or so and and replace the timing belt too.

Salim

Stifler

The current water pump went in about 4 years and 40k miles ago when the timing belt was replaced. I will for sure be replacing the timing belt when I am in there, it would be silly not too. The coolant was the red/pink toyota stuff.

hypervish

That's early for a WP to fail. Did you use a genuine Aisin water pump when it was replaced?

Stifler

Come to think of it I believe it was a lifetimer from autozone, which wont be going back in. Which brings my next question which timing belt/water pump, pulley, tensioner kit is the best to go back in with? Where is the place to buy that kit?

fastnoypi

Gates usually has very good timing belt/water pump kits packaged with good components but i dont have any experience with them in the Lexus world.
I spotted a kit on ebay with packaged with alot of parts by well known OEM suppliers, though not sure who supplies the OEM lexus components.

Baetke

I believe AISIN is the OEM manufacturer for Lexus. They make a nice kit that includes everything you need to do a timing belt and wate rpump. Search on Amazon for "RX300 Timing Belt Kit".

salimshah

Lexus gets parts from different manufacturers.
Aisin for water-pump only.
T belt is mitsubochi and the kit I see says mitsubishi .. which makes me wonder.
Idler and tensioner roller and tensioner are made by others [NSK makes one and I forget who makes what].

I think Aisin for timing kit is misnomer but it has become popular. Asian market is full of second quality and copied stuff and I cant vouch for any seller as to where they are getting their stuff from. So do your home work and buy from reputable seller.

I personally believe that folks who optionally (without verifying a need) opted for non-oem water-pump at 90k down graded their machine. ymmv.

I would price out the kit from a Lexus dealer and then make a choice. Not so long ago I was replacing a bearing on SC400 and traced down the manufacturer and located the part. Then I checked with Lexus and was surprised that Lexus had superseded with another part number (same manufacturer). Had to give extra $$ to get the new part, never the less learned a lesson.

Salim