Overheating?

2003 BUICK RENDEZVOUS
163,500 MILES • 3.5L • 6 CYL • 2WD • AUTOMATIC
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JULIANNEB02
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Thge vehicle listed above is overheating. When bought 3 years ago the radiator, water pump, and thermostat were all replaced. No heating issues until this last weekend when the car overheated on the freeway after an hour of driving. When inspecting under the hood, coolant was all over the left side of the block. The next day, upon further inspection, no overheating was happening, all levels were good, water pump not loose. Drove it around for a few days with no issues. No troubleshoot and avoid future issues, did a coolant flush through a shop. No issues following that. The next day replaced the thermostat. The system was inconsistent in temperature. This morning drove it about 1.5 miles, and it overheated again but had no coolant sprayed under the hood. Replaced the thermostat again and the water pump with no resulting change. Our thoughts are there is a block somewhere or the heater core is shot. Thoughts?
Mar 15, 2025 at 2:19 PM
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JULIANNEB02
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There is also no cabin heat nor is there any oil in the coolant or coolant in the oil.
Mar 15, 2025 at 2:23 PM
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STRAILER
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Can I ask if when the engine was overheating were the radiator cooling fans on? If so, this sounds like the head gaskets are leaking. You don't need to have coolant in the oil to have this be true. I would lower the coolant level about 2 inches in the radiator and then do a chemical test, here are two guides to help us figure out what is wrong. You can rent the chemical tester from the auto parts store.

https://www.2carpros.com/articles/head-gasket-blown-test

and

https://www.2carpros.com/articles/recognizing-the-symptoms-understanding-a-blown-head-gasket-in-your-vehicle


Please go over these guides and get back to us.
Mar 17, 2025 at 10:29 AM
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