Chem1

I have a 2007 ES350 that just rolled over 90,000 miles and I am getting ready to replace the water pump. My question is should I also replace the hoses while I am doing all of that? And if so, how many of them are there on this engine?
Thanks in advance!

oldgrump

Why are you planning to replace the water pump? Noise? Leaking? Wobbly drive pulley? As far as hoses go, if none of them are bulging/swelling with the engine hot then I wouldn't automatically replace any of them because of your mileage or the age of the car at this point. The "cold" hoses will probably never need replacing, and the "hot" hoses I wouldn't get my knickers twisted for another three or four year at least.
About thirty years ago the quality of automotive hoses really seemed to improve and I think it was about thirty years ago that I replaced my last hose, come to think of it.

John U

I hope you're changing the timing belt while the front of the engine is off.

oldgrump

There is no timing belt......it would be a good time to check/replace the accessory drive serpentine belt if it hasn't been recently replaced, I suppose. Replacing the coolant pump on these cars is not for someone who is not mechanically inclined, or who does not have the shop manual or equivalent info. I believe this link for the cooling system inspection, which includes among other items the replacement procedure for the water pump. http://www.doc88.com/p-316746265729.html (It does take awhile to load the full document).

LexBob2

Correct. The 3.5 V6 used in the 2007-2014 ES350 has a chain.

John U

Dam, that's good news! I feel richer now.

Chem1

Thanks oldgrump! The water pump is not leaking, or making any noise. I guess it is just my OCD tendencies kicking in and me trying to apply some preventative maintenance. I will replace the serpentine belt while we are in there and I thought that for just a few more $$'s maybe I should replace the hoses. Which ones are the "cold" hoses? Are they the 3 other hoses that don't connect directly to the radiator?

oldgrump

The "hot" hoses would be the engine out/return hose (the upper, large dia. hose) to the radiator, and the engine to heater core hose. Some people also consider the heater return hose to be a "hot" hose as well. The heater hoses are about 1" or so in diameter. There are two small diameter hoses (short) that are the throttle body supply and return hoses that I doubt will ever be an issue (the Parts Catalogue calls these "bypass" hoses). The large diameter hose from the radiator to the engine is a "cold" hose and in fifty years I've yet to replace one. Whatever hoses that you remove or replace I would replace the factory spring clamps with screw band clamps. Do not apply a large load to the plastic connectors on the radiator, or to the heater connectors. This may be of some help: http://lexus.sewellparts.com/oem-cat...S350-2007.html