2003 5.3 heads

2006crewcab · April 29, 2014

My friend has a 2003 silverado with a 5.3. Hes been haveing ploblems with coolant dissapearing. His mechanic told him he might have a cracked head. Is there any way he can check this?

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txab · April 29, 2014

Check all obvious leak points first. Water pump. WP gaskets, radiator leaks, hose leaks, heater core leaks.

http://www.agcoauto.com/content/news/p2_articleid/148

http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf

XYZ · April 29, 2014

On my truck, it was the heads, had the 706 Castech castings. Got a rebuilt set of 862 casting heads, all new gaskets, that solved it.

2006crewcab · April 30, 2014

I read another article about the heads cracking. Hes had it in the shop twice going in tomorrow for the 3rd time. First 2 times only leak was the oil pan. Im leaning more towards the head but didnt know which casting number is bad or whatnot.

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2006crewcab · May 2, 2014

He took it to the shop and of course the heads are cracked. The mechanic also said that he would have to replace the engine in it? Said because it got antifreeze in the oil it "deprived the motor of oil"? Any ideas on that?

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gapost · May 2, 2014

He took it to the shop and of course the heads are cracked. The mechanic also said that he would have to replace the engine in it? Said because it got antifreeze in the oil it "deprived the motor of oil"? Any ideas on that?

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Unless he ran it for a long time (months or longer), I doubt it ruined the engine. I've had two GM vehicles with cracked heads and just replace them and engine is strong as ever. In fact, I just picked up a replacement head yesterday because I had a cracked one on my 03 Sierra. One was cracked and the other wasn't so just going to replace one. And both were 706 castings and replacing it with 862.