Sorry, but I don't agree with changing out the water pump, just because you are changing the timing belt. If it's not making a bearing noise or leaking out the bearing weep hole, it's fine. That would be S.O.P. for any car or truck,
I mean, if you have the timing belt and everything off.. the water pump is seriously only 4 more bolts to remove. Considering that many of these trucks have the original 25+ year old water pump in there, it really should be changed anyways.
Not an auto or truck mechanic, don't have an ASME certificate, have done more than the average person's share of mechanical and engine work. Just what do you think goes bad through any other process than use? Water pumps die when their bearing seal get worn out from rust or by making millions of revolutions. Then the bearing eventually get ruined, but audibly lets you know. Not a leather seal or or a shaft stuffing box, but a synthetic seal exposed to a fluid at a temp below 212F. My point is that the water pump isn't a trivial expense, why replace it needlessly. Do change the anti-freeze and thermostat, hard to tell its condition when you first get the vehicle. Water pump change doesn't require the timing and crank pulley removal, pretty trivial to do so when needed.
The Aisin branded pump is only $35 on Rockauto.. while not exactly zero, I would hardly call it outrageous, and is a reputable brand to boot. The peace of mind of fixing an issue *before* it becomes a problem is worth it in my book when it is a vital component of an engine with many hard to find, discontinued, and otherwise expensive parts. $35 now is better than potentially $2000 later.
Point well taken with the $35 pump. I've seen pumps listed for over $100 for my model. How did you find a replacement pump on Rock Auto, as an example they have no listing for Subaru Sambar. Lots of people importing and selling high priced part "kits" on the internet for Kei trucks. Truthfully, starter is more likely to fail and strand you without warning.
There is no real easy way to find them, as they are not listed under any model... but a search for the specific part numbers do come up with them. RockAuto has both the Aisin and GMB pump for the sambar, but of the two I trust Aisin more. Here is a link to it: https://www.rockauto.com/en/parts/aisin,WPF001,water+pump,2208 As for the starter, I am not really sure what your point is there. A starter failing could indeed strand you, but not cause catastrophic engine damage like a failed water pump could.
Water pumps don't start leaking without giving warning and I don't understand how you could completely lose cooling without knowing it. If your engine temp is going up dramatically, stop and check. Maybe you'll need a tow if you are to far from home to let it cool off, top it off and drive slowly back. No engine damage if you play it smart. Has you experience been different with a vehicle? My point is a starter is more likely to fail without warning and strand you. They do really wear themselves out, especially since these vehicles are meant for the short hop and not long distance trips/
I do agree that there are *usually* signs that the pump has failed, but there are always the edge cases that could fly under the radar until it is too late. This is really one of those "while you are already in there" sort of things, but certainly not a requirement. It is the same reason why we suggest doing the Cam and Crank oil seals during the job.. Sure they won't actually strand you or cause any engine damage, but if you are going to take the time to take all of the stuff off in the way, you might as well replace those at the same time regardless if they are leaking or not. Either way, if you don't want to replace your pump, nobody here is making you do it. You do you. We are only making suggestions to try to make life a little easier.
Thank you and I appreciate the sound advice. I'm trying to learn as much as possible about the maintenance and replacement intervals for these vehicles. I'm sure it's out there, but not in one handy place. Received my English translation of the 1990-2006 Sambar factory manual just the other day.
