Missing coolant (aka, well crap...)

[YotaFun]

Quick question, you said the truck has 110k on it, have you done a timing belt and water pump on it yet?

In my time at Toyota, doing timing belts, majority of the time during disassembly I would find the water pump leaking, usually 9 time out of 10.

On the 3.4l it is really hard to see because the fan pulley being right there.
When I first got the truck I always had a slow leak but didn't think anything of it cause it wasn't overheating or running well just as you described, when it finally came time to do the belt, during disassembly I found that my pump had definitely been the cause for the slow leak.

Keep and eye on it and see if it persist.

[CJM]

When I did my timing belt I ran into an interesting issue: The spring loaded hose clamps dont seal all to well if you put new hoses on and clean up everything. The t-belt had last been done about 120k ago and I guess the corrosion and whatnot had made it seal. once i did the job it leaked at the rad and the engine. Replaced the clamps with screw on clamps, no more leaks.

[4x4mike]

Avi and others, regarding the water pump. Does a factory water pump say Toyota or have a part number on it? I was deep in the front of my engine for some time today messing with the belt and the fan. I think that maybe my water pump has been replaced and I was wondering if I can tell if it was a factory part.

On my radiator support there is a sticker that says the timing belt was done at 59,xxx miles. Six years ago when I was looking to buy a 4Runner it was extremely common to pop the hood and find one of those stickers. I think the dealerships just had a roll of stickers and put it on there. Why else would the timing belt be done so early.

[Seanz0rz]

Service interval for "severe conditions" is 90k miles for the timing belt. Basically, towing, driving in hot conditions, offroad, etc, etc.

I have always considered it to be 60k, especially in hot and dry SoCal. I don't even see a listing of recommended time to replace timing belt for "normal" conditions.

Being a non-interference engine, the timing belt is not as critical as it is on an interference engine. That being said, it is not worth the hassle of being stranded for $300 in parts.

[DHC6twinotter]

IIRC, my water pump says Aisin on it, but not 100% sure. I'll have a look tomorrow when it's daylight.

[CJM]

IIRC, my water pump says Aisin on it, but not 100% sure. I'll have a look tomorrow when it's daylight.

I got mine from the ebay seller with the t-belt kits and mine says Aisin on it.

[slomatt]

Quick question, you said the truck has 110k on it, have you done a timing belt and water pump on it yet?

In my time at Toyota, doing timing belts, majority of the time during disassembly I would find the water pump leaking, usually 9 time out of 10.

On the 3.4l it is really hard to see because the fan pulley being right there.
When I first got the truck I always had a slow leak but didn't think anything of it cause it wasn't overheating or running well just as you described, when it finally came time to do the belt, during disassembly I found that my pump had definitely been the cause for the slow leak.

Keep and eye on it and see if it persist.

As far as I know the timing belt has never been done so it is definitely overdue and on the list of things to take care of, but I haven't had time yet. I might just break down and have a shop do it since my plate is full of house remodeling projects.

It does appear that something is leaking a small amount of coolant from the front driver's side of the engine down onto the top of the oil pan, which could possible be the water pump. That would make a lot of sense.

Anybody in the Bay Area know of a good shop where I could get the timing belt done? Preferably in the East Bay?

- Matt

[YotaFun]

I can't remember exactly what was on it.
I don't think a part number is but I believe Aisin is printed on it.

Also while you are at it, iirc there is a small rubber hose that connects to the side of the water pump, for you Cali guys with the dry heat you might want to get it replaced.

[slomatt]

I took the 4Runner on a ~250mi trip this weekend and it did fine, no apparent coolant loss. My guess is I have a very slow leak on the water pump so I'll keep an eye on the coolant level until I change out the timing belt and the water pump.

Later this year we're taking the truck on a week long trip around Oregon so I've got some other preventive maintenance to do for that trip. LBJs (already bought), O2 sensors, and engine/trans/diff fluids. I might also look into swapping out the clutch because I'd like to not have to deal with the heavy clutch issue for an entire week.

- Matt

[Robinhood4x4]

I used to go to autotron in Pleasanton. They offered to evacuate my R12 while I worked on my AC over the weekend, then they ended up adding some more for free.