Loosing Coolant

[tucktuck8]

So I first bought my 4runner about 3 months ago. When I bought it I checked all the fluids and topped off the coolant (it wasn't below the low level on the reservoir). I filled it to the full line. Today I was looking around and found that the reservoir was dry. It hasn't overheat and cold start ups are normal. I'm really praying this isn't a head gasket issue. I haven't noticed any leaks on the ground and I usually look so It's not that. Any suggestions on what it could be? It has 110k miles and I don't know if the coolant has ever been changed.

Thank you in advance

 

[BlackWorksInc]

Water pump most likely, its pretty common for the factory pump to start leaking around the time the timing belt needs to be changed (9yr/90k.) The headgasket issue is endemic to the 1GR-FE (4.0L V6), not the 2UZ-FE (4.7L V8).

 

[tucktuck8]

The guy I bought the 4runner from said he had changed the belt and the water pump at 90k but did not have the receipt. He seemed like a very trustworthy guy and his wife and kids were standing there when he said it. How could I confirm that it is the water pump?

 

[BlackWorksInc]

First thing I would do is top it off and keep an eye on it for another week or two. What probably happened is that the vehicle was not properly "burped" when they did the coolant flush which happens a lot. As you drive it the bubbles work themselves out and the coolant level goes down, so just keep an eye on it. The level should be between the "Low" and "Full" markers as the level will vary when its hot or cold.

As for checking the water pump, if the pump was leaking you should be able to see it with the gravel shield off if you look at the crank shaft pulley. The plastic cover there has a small drainage hole that will show crust if the pump has been leaking. Also if you look a bit above the A/C compressor at the plastic cover you should be able to see it (again from the bottom of the vehicle.

The issue is if the person who did the pump was lazy and didn't clean the crust off, it could look like its leaking when it isn't.

 

[paraordnance]

The guy I bought the 4runner from said he had changed the belt and the water pump at 90k but did not have the receipt. He seemed like a very trustworthy guy and his wife and kids were standing there when he said it. How could I confirm that it is the water pump?

The only way to confirm it is to tear it down and see inside. I was loosing coolant also and could not locate where it was going until I started doing TB service. Removed old water pump and bingo, I can see it was seeping through and evaporating somehow in little cavity between pump and engine block. Impossible to see from outside. The guy may not be very honest or simply unaware of the fact that water pump was changed when TB was done. It is very common in V8. I been driving with low coolant level for couple years before finding a leak.

 

[tucktuck8]

Thank you for all the tips guys! I'm hoping they did the water pump with the belt and that it was actually done. I just topped it off so if its just air in the system then that would be great! I'll take a look at the leak spots you described. Thanks guys!

 

[paraordnance]

Thank you for all the tips guys! I'm hoping they did the water pump with the belt and that it was actually done. I just topped it off so if its just air in the system then that would be great! I'll take a look at the leak spots you described. Thanks guys!

You cannot see the leak until you remove water pump.

 

[BlackWorksInc]

You cannot see the leak until you remove water pump.

That's not entirely true (first off if you take the pump off how can you tell where its leaking from! ), if you have the vehicle in the air on a lift or are under it with the skid plate off you can tell if the pump is leaking a lot.

Typically if its leaking bad enough that you see the coolant level dropping drastically you'll have a long crusty trail which drips down along the crank shaft and exits through a hole in the bottom of the plastic timing belt cover. There's also a space on the driver's side of the engine between the AC Compressor and block that shows crust as well.

I'll try to get pictures of this next time I see. But refer to the pictures of the 2UZ-FE engine with the covers off in my water pump thread to see how it travels:

http://www.toyota-4runner.org/4th-gen-t4rs/130732-2uz-fe-r-r-t-belt-water-pump.html