From the December 15, 2012, Wheels section in the Dayton Daily News:
The case of the luke warm Buick
Bill B writes by e-mail:
"I have a 2005 Buick Lacrosse. I bought in 2010. It had 20,000 miles. It has 34000 now. In June of 2011, I changed the anti-freeze. I used Prestone flush and fill. I put a tee in the top hose coming out of water pump. I connected the water hose to it and flushed the system. I put a new lower radiator hose on and filled it with the Prestone extended life anti-freeze.
The heater worked well last winter, but now it just blows luke warm air. Every once in a while it does blow hot air, not often. I put in a new thermostat a few weeks ago, but it didn't help. I think I should put DEXCOOL in it.
What do you think? I hope you can help. Thanks"
I wonder why you replaced the coolant with just 34,000 miles on a two-year old vehicle? As many know who read this column, I recommend that technicians and vehicle owners follow what the vehicle manufacturer recommends. In this case, Buick (General Motors) recommends that the coolant be replaced at 100,000 miles and that DEXCOOL be used.
Almost all coolants are ethylene glycol with about 3% additives. It is the additives (the 3%) that change the coolant. There are three types of coolant:
1. IAT-Inorganic Additive Technology- This is the old green anti-freeze.
2. OAT-Organic Acid Technology (DEXCOOL is one brand of OAT)
3. HOAT- Hybrid Organic Acid Technology (can be many colors depending on the additive package) Most "long life" antifreezes are HOAT type.
The water used with the antifreeze is very important too and some vehicle manufacturers, such as Honda and Toyota, recommend the use of premixed coolant only. By the way, coolant is 50% antifreeze and 50% water. Some tap water is high in mineral and chlorine making it unsuitable for use in coolant.
I think your problem is caused by air trapped in the system. Follow the recommended procedures when refilling the coolant, such as opening a bleeder valve, to help keep air from being trapped in the system.
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