1995 Lexus Water Pump Weep Hole

[w140amg]

I had my 95 LS Water Pump, Timing belt, etc. repaired 2 years ago at 118K miles. Car now has 150K miles.

I took the car to replace my high pressure steering hose and my mechanic (Different than the previous repair and trustworthy) said the WP's weep hole is leaking. I saw residue of coolant. Is this possible??

Or is a small leakage ok?? I hope I don't have to replace the WP again.

[landar]

I had my 95 LS Water Pump, Timing belt, etc. repaired 2 years ago at 118K miles. Car now has 150K miles.

I took the car to replace my high pressure steering hose and my mechanic (Different than the previous repair and trustworthy) said the WP's weep hole is leaking. I saw residue of coolant. Is this possible??

Or is a small leakage ok?? I hope I don't have to replace the WP again.

Yes it is possible. Unfortunate, but possible. And no, a small leak is not ok because you have an interference fit engine and if the pump goes, it can take the timing belt with it (and valves/pistons). The weep hole is put into the pumps to release coolant that is getting past the seal and into the pump bearing and to inform you of impending failure of the pump. It could be days, weeks or months of running but it will eventually fail. You will have to go thru the process of replacing the water pump again and you might as well replace the timing belt while in there because much of the cost is labor. Given the implications of a leaking pump, you might want another mechanic to verify or have this mechanic recheck to make sure the leak is not coming from a hose up above. Trust but verify.

Did you use a Lexus OEM water pump or aftermarket?

[jaswood]

I thought, think, the sepentine accessory drive belt is used to drive the water pump...

Am I wrong..?

[jaswood]

I had my 95 LS Water Pump, Timing belt, etc. repaired 2 years ago at 118K miles. Car now has 150K miles.

I took the car to replace my high pressure steering hose and my mechanic (Different than the previous repair and trustworthy) said the WP's weep hole is leaking. I saw residue of coolant. Is this possible??

Or is a small leakage ok?? I hope I don't have to replace the WP again.

It is not at all unusual to be able to see/observe the residue left over from slight weep hole leakage. Consistent wetness around the weep hole is another, more serious matter.

[curiousB]

Am I wrong..?

Yes

WP driven by timing belt. Serp belt drives PS, AC, Alternator, but not WP...

[curiousB]

It is not at all unusual to be able to see/observe the residue left over from slight weep hole leakage. Consistent wetness around the weep hole is another, more serious matter.

I would check for crusted up coolant residue in addition to wetness. As the water evaporates from the leaking coolant some of the residue is left behind. Its pink in my model year but I think was green in older models. If you see that crusting it means its been leaking for a while and a seized water pump is much more likely. Given a seized water pump can snap the timing belt and cause and interference engine to become a disposable chunk of steel and aluminum you probably dont want to risk it.

Here are my Top ten pet peeves with the Lexus LS:

1. Water Pump driven by timing belt. High risk of engine damage (if WP seizes) and overly complicated repair (have to do a TB repair to get at the WP.
   
2. Interference engine. OK I get the performance benefit but the downside risk of a snapped TB is a new engine. Ouch pretty severe. For what 5-10 more HP?
   
3. Starter motor buried in deep V of engine. Have to remove intake manifold to get at starter motor.
   
4. Starter solenoid attached to starter motor. If you are going to bury the starter motor how about putting solenoid in the engine compartment so it can be repaired easily.
   
5. Sealed transmission with so called lifetime fluid. No dipstick to check level and fill/drain ports in most inconvenient location.
   
6. Limited and tiny jack lift points for working on your car (jack stands and jack points).
   
7. Silly SST shields on mild steel exhaust Y-Pipe with low quality clamps. A corrosion nightmare.
   
8. Silly brake wear sensors that cost more than pads and fire off well before pad is done. Sensor not repairable just an expensive replacement item.
   
9. Poorly designed axle height sensor for AFS system. Water and road grim ruins bearings and device seizes.
   
10. Expensive and fragile parking sonar sensors.
    

I had to think long and hard to find ten. Some of these are admittedly pretty tiny. So I guess the moral of the story is these are just great cars.

Happy New Year to all!

[landar]

I thought, think, the sepentine accessory drive belt is used to drive the water pump...

Am I wrong..?

Jaswood, when you get a chance, you should look at the internals of the Lexus V8 and V6 engines to understand how the cams are run and how the timing belt is looped around the pulleys and the water pump. It is a pretty clever design (aside from the replacement labor). It is not a design that is unique to Lexus. A lot of other manufactures use this configuration as well..Honda, Ford, etc.

As curiousB points out, it seems a bit risky to make an interference fit engine longevity dependent upon the timing belt. But thats the nature of the basic design. Now, Toyota and Lexus are going away from the belt in favor of a chain. This will help with a significant (expensive) service item on newer models.

[landar]

• Starter solenoid attached to starter motor. If you are going to bury the starter motor how about putting solenoid in the engine compartment so it can be repaired easily.
  

I thought about this same issue too. My old Ford has the starter solenoid mounted on the sidewall. Now, what if I wired my Lexus starter such that the infamous solenoid contacts were always connected. Then fed the whole starter with the firewall-mounted relay? Would it work? I would, of course, leave the Lexus starter solenoid in place and have it "fire" with the starter main so that it would throw the gear into the flexplate. Actually, I know it would work, electrically, save for one tiny issue. The timing of the gear mesh and the armature turning. The starter motor would already be torquing before the solenoid had reached its full travel. Might be some grinding going on between the flexplate(flywheel) teeth and starter gear.

[curiousB]

I thought about this same issue too. .......The timing of the gear mesh and the armature turning. The starter motor would already be torquing before the solenoid had reached its full travel. Might be some grinding going on between the flexplate(flywheel) teeth and starter gear.

I wasn't assuming they would just add a solenoid to the existing starter motor. Rather they would come up with a two part scheme with a starter motor that has some Bendix like (or whatever it has evolved into) mechanism that mechanically engages the starter gear to the flywheel upon start up and then retracts after the engine fires. Just get the high current contactor (relay) away from the starter motor and easily accessible for repair. I'm sure cost is driving this. An integrated all in one solution has to be cheaper than a two piece. I'm at 112k miles on the original starter so I guess its not like it is a chronically failing item.

[landar]

I wasn't assuming they would just add a solenoid to the existing starter motor.

Nor was I. I was just musing over modifying the existing design as a DIY project to have separate relay contacts that are accessible. At a minimum, I could put a timed delay between the main rotor current and the solenoid to give the solenoid xxx number of milliseconds head start to engage the gears before hitting the rotor with full current.