Coolant leak in 4Runner after flush and tstat replacement

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arcteryx

arcteryx

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I just picked up an 86 4Runner, 5 speed with about 194K on it. The PO said that around 160K, the chain, seals, water pump, etc were replaced.

I noticed the temp gauge going upward the other day, so I did a flush/fill of the rad. It was gross. Looks like the PO had run just water. I ran a flush fluid in there for 3 driving hours. In between driving it, no leaks. I also replaced the tstat which became open after the first flush.

I put 50/50 antifreeze/distilled water into the rad and started it up and took her for a spin. The temp gauge was fine. Upon returning, I noticed coolant coming off DS. Tracing it upwards, it seems to be coming from the water pump, but not where the gasket/assembly meet the block. It appears to be from the pulley area.

How would regular maintenance cause it to leak coolant from the pump, especially since it was replaced about 30K ago. Any ideas on what may be causing this?
 
3 hrs of flush fluid might be too long a period with many flush solutions?Tighten all hoses and bolts etc ,try a little barrs stop leak as last resort?? I did a pre winter flush and new anti freeze etc etc,had a leak afterwards - I had forgotten to re- tighten a hose clamp.
 
Joe - I used Peak Flush. Directions said to drive for 3-6 hours.

ray - The PO did this. I would think it would be aftermarket, based on the other parts used. Is there a location I can tell on the water pump to look?

BTW, the leak did stop for the moment since the car is off. I have not gone driven it again, but will examine it next time I do.
 
arcteryx said:
Joe - I used Peak Flush. Directions said to drive for 3-6 hours.

ray - The PO did this. I would think it would be aftermarket, based on the other parts used. Is there a location I can tell on the water pump to look?

BTW, the leak did stop for the moment since the car is off. I have not gone driven it again, but will examine it next time I do.
Click to expand...

Should say Aisin right on it.......pic below........It will be upside down, I believe.
Weep hole points down, need to find out if it is oring seal or the weep hole that is leaking.
Aisin.webp
 
Based on other discussions here on the topic of OEM vs. Aftermarket parts, there seems to be a broad concensus that the water pump is one of the last parts that you would want to use aftermarket. FWIW.
 
The water pump is OEM- says AISIN and Toyota in the cast.

I have not driven/started it yet, but it is the weep hole on the bottom that is the source of the leak. I put a little pressure on the return line to the rad and it came right out.

So, how do I fix the weep hole?
 
The weep hole is there for a reason, when coolant comes out that hole it is telling you that the seal on the water pump shaft has failed. Time for a new one.

BTW, it probably failed prematurly because the wrong type (or perhaps no) coolant was in the system. The Toyota red coolant has a special lubricant in it to keep these seals working for a long time.
 
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Thanks for the link- good price for sure. I am surprised since it only has 34K miles on it. How hard/long of a job is this?
 
I wanted to give closure on this.

Thanks everyone's help/advice. I received the pump and replaced it over the weekend. So far, no leaks, but I have not driven it much.
 
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