I've got a 2010 GMC Sierra 5.3 that overheats at highway speeds!
7 Answers
Are you sure it is actually overheating? Some gauges just go wonky after a while. A scanner with live data should give you what the computer is seeing with regards to engine temperature. Or you can install an analog temperature gauge temporarily.
Oh and make sure the fan is running the right direction.
Yes its actually overheating the scanner indicates it gets up to 240 degrees and boils over! But only after driving at highway speeds! The coolant is not flowing properly through the engine like theres a restriction within the engine! with the water pump removed I backflushed the engine block and water only comes out of the side of the block where I'm putting pressure into either the top or bottom hole's it dose not transfer across the engine from side to side like there's a restriction in the intake or cylinder heads as pf yet I hyavent been able to locate a flow chart to see if it's supossed to! The cooling fans are operating properly!
Sounds like your going to Kate to pull the intake and maybe the head that getting hot. Definitely sounds like you have a blockage.
How can you get Kate from have? Spell check glitch.
beatupchevy answered about a year ago
Did you plug a hole with a rag when you had it apart to keep crap from getting in the engine while cleaning a gasket surface ?
