1991 GMC Suburban 2500 Q&A

1991 GMC Suburban 2500 Question: why is air bubbling back through coolant resevoir

air bubbles back through coolant resevoir constantly pushing coolant into the reservoir & not allowing it back into cooling system thus causing "low coolant" light to come on.this happened after an overheating episode when i noticed my temp go up to about 210 briefly. i immediately replaced thermostat & radiator which was leaking a little. the bubbling reservoir started after these repairs. -
Answer 1
I'm suspicious you have a blown head gasket or two. A mechanic could check for combustion products in the coolant fumes to detect carbon moxide (CO). If there's CO ion the coolant, you have a head gasket problem. I'd check that first. Here's a directory list for you: http://repairpal.com/directory?address=22980&car_brand_names=GMC -