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The coolant level goes down 1/4" (in the reservoir) in 8 months

Is it normal that the coolant in my 2006 Matrix goes down 1/4" (in the reservoir) in 8 months? I checked and found no leaks, except a little sipage of coolant from the weep hole of the water pump. This is water pump was installed two years ago by Toyota dealer, and it puzzels me a bit. My Matrix is still under 5-year/60000miles powertrain warranty. I went to the dealer and showed them the dried coolant splatter. They did not want to replace the pump but put dye in the radiator instead, and ask me to come back after driven the car for 200 miles. It’s been more than 200 miles, but I have not seen coolant sips out of the weep hole yet. Does this mean the water pump is ok?

It does say OK to the shop. They won’t change it if it passes their test.

The dye they puy in likely requires a blacklight to see. Stop back and let them take a look.

It’s good that you’re monitoring your coolant. Too few people do. In my experience 1/4" in 8 months is not normal, but also not enough to cause serious concern. What I think I’d do is pressure test the system. If I found nothing, I’d be inclined to carefully examine every visable element of the system with a good worklight. If I was still unsuccessful, I’d just continue to monitor it. That’s about all anyone can do.

Hey, perhaps with the UV lamp they’ll see something.

I would not worry at all about 1/4" water loss in 8 months. I am sure that all four of my cars loose that much water at least. My wife’s BMW has required a half cup of water to top it off every 3-4 months since it was new. I never gave it a thought. I put a splash of distilled water in the radiator to top it off when I refill the windshield washer.

However, it is not a good sign if you see any evidence of water from the water pump weep hole. Is it possible that the leak is actually at the gasket behind the water pump and it is running down to the weep hole? If it is coming out of the weep hole, I would keep bugging them to try to get another water pump while it is still under warranty.

Thank you so much for your help. I will try to continue to monitor the coolant level, and to have the system pressure tested at the dealership and post the result later. I’ve seen several new cars with very low coolant levels. But in my past experience, coolant level should remain the same, if there is no leak in the system.

Your coolant is 50% water. Water evaporates. Your reservoir is open to the atmosphere. You can expect a slow, steady loss due to evaporation…

The reservoir level in my 2006 Matrix has dropped about 1" in the 3 years I’ve owned it.
As long as it doesn’t reach the ‘ADD’ mark I’m not worried.
I would however worry about coolant out the weep hole.
I’m draining and refilling the coolant at 5 years (next year) anyway.

The reservoir gets warm under the hood, and that speeds the evaporation Caddyman mentioned.

A large amount of coolant finally came out from the weep hole, and I took the car to Arlington Toyota (the best Toyota dealer in Chicago area) instead of going back to Libertyville Toyota (the worst Toyota dealer in the area who refused to replace the water pump even with the evidence of dried coolant spatters; now, I’ve learned that the quality of the dealer service does make a huge difference). Artlington Toyota confirmed the leak was from the water pump and replaced the pump immediately. I am glad this is done before my 5-year/60k warranty expires, and am thankful for your suggestions and the truthful mechanics at Arlington Toyota. I am going to flush the system to get rid of the old coolant with the greenish dye, and replace it with a long life after market product.

Thanks for posting back, and I’m glad you found a solution.

I’m slightly perplexed why they didn’t do or offer a flush-n-fill since they were doing the water pump. All the coolant must be drained to get the pump off, and they just put the same old crappy junk, with some new contaminants from the drain tub they used, back in the car when done? Why? Coolant is fairly cheap, and this car should use only 1 gallon ($13) that will be cut 50/50.

I would caution you about ‘long life’ coolant. The only coolants I know of that claim to be long life are OAT (organic acid) coolants. I tried that in two of my cars once. Doesn’t mean much to have a 5 year change interval on the coolant if it dissolves the seals in your cooling system in two years. I recommend using OAT coolant ONLY if the original factory coolant for your car is OAT, and some folks have had trouble even in that instance (Google the GM OAT lawsuit).

On a related topic, from reading this forum I have learned that the color of the coolant (green/yellow/blue) apparently means nothing. It is all dye and the manufacturer can put in any color dye they want.

Congrats on finding the weep. I tip my hat to you.

As Manolito suggested, I’d avoid using anything but the Toyota coolant. It’s worth the extra few bucks to have the correct stuff. Incorrect coolant can in some cases cause problems. “Long life” can best be achived by drainang and refilling the cooling system every few years, taking car to run the heating system to get the fluid into the heater core, and to purge the air from the system when you do the changeover. New fluids replenish the corrosion inhibitors.