2003 Buick Rendezvous over heating

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2003 Buick Rendezvous over heating

Unread post by TSaldana » Mon Feb 15, 2016 1:45 pm

I replaced my thermostat several months ago due to it over heating. Then, about a month ago, i topped off my radiator fluid, and forgot to put on the cap, resulting in all my fluid escaping and over heating my car. i added fluids and the worked fine, no over heating issues. Howeer, it the temp guage would never go above cool. So, i replaced the tstat again, thinking this was the issue. Now my car seems to want to over heat. goes all the war to 3/4 hot. What do i do now?


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Re: 2003 Buick Rendezvous over heating

Unread post by carriedi » Tue Feb 16, 2016 3:31 am

first thing is, when does it overheat? Will it overheat if you just sit and let the engine idle? Does it only overheat if you are driving? Or does it over heat no matter what the engine is doing?

normal operation is to have the gauge at right around 210 degrees. If the engine starts to exceed the halfway and reach 223 degrees your low speed fan should come on. It should bring the temperature back down to below 210 (sometimes down to the 190's). If the low speed fan does not bring the temp down and the temperature gets to 230 degrees the high speed fan should come on. If the engine still does not cool down there will be a light that comes on at 262 degrees and an audible warning.

You need to see if the gauge is accurate. If your fans are working at the right temperatures. If the only change is the thermostats, I would wonder about the quality of the parts if on is too cold and another is to hot. I can't tell if it is a part problem or if you have another problem with your cooling system. I can tell you this though, if you have overheated your engine, even if it has only happened one time, you may have damaged the head gasket. It may be a few months before it shows up as excessive steam out the tailpipe, or rough running when you first start the engine after sitting overnight, or you notice that you are loosing coolant over time but don't see any external coolant leaks. Not saying this is your problem but just a warning that it does happen.

I would verify the temperature with an infrared temp gun and see if it matches your gauge. If it does, try another thermostat, just to make sure it isn't another defective one. Maybe even put the one that ran cool just to make sure you don't have a cooling system problem. If you put the one that ran too cool and it goes back to running cool, that would pretty much you're dealing with defective products. If it still runs too warm you're going to need to do some cooling system diagnostics.
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