slosurfer

I have a wierd coolant leak that I think I have traced back to the water pump. It doesn't seem to leak while I am driving, either that or what little is leaking is being burnt off, but I don't seem to lose any coolant while driving. It doesn't leak when it is cold, (ie nighttime, early morning), but if it is sitting in the driveway during the day it will start to slowly leak. It seems to be coming from behind the thermostat housing, but between the water pump and engine block. Where exactly are the weep holes on the water pump?

I am actually planning on doing the water pump/ timing belt soon anyways, but I thought this was weird and am not sure if it is the waterpump. Any suggestions? It is so hard to see in there.

Another ?, I want to do a coolant system flush. Should I do the flush right before I tear into the waterpump/ timing belt or should I flush it right after. I think it would be nice to have it flushed before and instead of refilling everything, do the waterpump, etc.. and refill after. Thoughts?

Targetnut

Actually it is not that wierd. waterpump leaks can be very finnicky as you have found. and a leak like that can go on for a long time or start dumping sometime later today.

Depends on how rancid your coolant is. if it is really nasty I'd flush it thoroughly before the waterpump.

4Crawler

iTrader: (3)

Weep hole is on the bottom of the housing where the pulley attaches to. Hole is there to let any coolant that leaks past the inner seal (and bushing) drip out so you know the seal is leaking. Coolant will wash any lube out of the inner bushing and it will not last long like that.

slosurfer

I can't tell if it is from the weep hole or from the gasket but either way I am going to do the wp/ timing belt. 103,000 miles and I am pretty sure it is the original for both.

It is time for a coolant flush also, the coolant looks fine, but I don't know the last time it was flushed so I think I will do the flush except for the final refill, then I will do the wp. That way when I am done with the wp/timing belt, I just have to refill and be done with it.

Since this isn't our DD anymore, I should be able to take my time and with the help of yotatech, do it right.

006roadster

Could be a hairline crack in the block; when it's hot the metal expands and seals the crack; when cold it starts to leak.

slosurfer

Ended up being the waterpump. Put a new one on 03/11, went to Death Valley the next weekend and jarred the heck out of the 4runner on the washboard roads, has been leak free since. I could see that it had been leaking out the weephole once I got down to the WP. I didn't know that the weephole is actually offset to the driverside and that is why it leaks out that way. I always thought the weephole was directly below, so I was confused why I wasn't seeing coolant there.

006roadster

Belive it or not I'm getting a similar leak; too weird. The leak only happens when the truck is sitting for a couple of days. When you said it leaked from the drivers side did you see the leak coming between the themostat housing and the crack pully?

slosurfer

not sure what the crack pully is, but the coolant was (looking at the front of the engine) to the left of the thermostat housing. At first I thought it was from the thermostat housing but then I could tell that it was coming from higher up, so that left either the wp or the wp gasket.

slosurfer

http://forum.ih8mud.com/showthread.php?t=146310

not mine, but the picture looks just like how mine did when it was leaking

006roadster

Thanks for the pitcture, that's exactly where the coolant is coming from. I guess I need to tear appart the front end. It's a little worrying the that timing belt runs the water pump. If the water pump fails so can the timing belt and the very quickly the engine.