How to fix blown head gaskets on a 1996 tahoe

It sounds like the thermostat has stuck in the closed position, it may just need to be replaced. If the truck ran hot it may have caused more serious problems. I would change the thermostat and run it, If the problem then occurs, check for a blown head gasket or a cracked head. but change the thermostat first. Hope this helps....

check coolant fluid level, after vehicle is cool allow vehicle to run adding coolant/water till the tank is full, then let it run for one minute and shutoff, allow engine to cool and **** in fluid, and more water and coolant (dextron coolant) and start the vehicle back up after it has cooled complety down. with the cap off the coolant place hand over cap, if you get immediate back pressure this isnt from thermal expansion is from a blown head gasket. also for this check to ensure water pump isnt leaking, because the pressure generated by a blown head gasket will blow out water pump seals, if there is no back pressure, but a leaking water pump, just replace the water pump.

Brown gunk is either oil from a blown head gasket or 'stop-leak'. The head gasket is expensive to fix.

If you have over 150,000 miles probably cheaper to replace the car if the head gasket is bad.

GL,
Td

If you plugged the original leak (which sounds like the head gasket) and then the radiator was leaking, and you are having water coming out of the exhaust, then you need to replace the head gaskets. It sounds like you had a blown head gasket from the start. Here's what to do.

1. Replace the head gaskets (will need intake manifold gasket as it need to come off for this procedure).

2. Replace thermostat, radiator cap (if radiator is still good)

3. Replace water pump; the water pump may have stopped working (mechanical), which in turn caused the pressure to build an blow the head gasket (the cause of the pump would be a bad thermostat. If the truck was overheating, then the thermostat was bad to begin with, then the pump, then the head gasket, so then the only place left for the water to go is out the exhaust.

Here is a list of replacements:

^ water pump
^ thermostat
^ head gaskets
^ valve cover gaskets
^ radiator cap (if radiator is good)
^ radiator : if leak from cap caused any damage to radiator (should still be good)

**Also check the radiator hoses to ensure they do not have any "bubbles". Hot water over time (with anti-freeze) erodes the inside of the hoses, and begins to "dig" holes and grooves in the hose, which evetually cause leaks. Consider replacing these as well for safe measure.

Please, let me know if you need further assistance.

carsandcomps,

Guru, Premium Expert @ Fixya.com

if it wont start immediatly after it overheated then you may have blown the head gasket, or melted a coolant temp sensor or other sensor or wire. look closly for the melted stuff. remove radiator cap and fill with water to the top of the rim. have someone crank it and if a air bubbles come out while cranking then a headgasket is most likely blown. some little bubbles at first dont mean nothing. its a steam of bubbles the whole time its being cranked that indicates head gasket

blown head cylinder gasket , check if there is oil in your coolant ,

replace it.

It sounds like it may be a stopped up radiator or a possible blown head gasket. You need to take it to a repair shop and have the radiator flow checked and also check for the presence of hydrocarbons in the coolant which would indicate a possible blown head gasket or a cracked cylinder head.

Putting is 100 percent coolant is not good, the coolant will not work well, it needs to be mixed with water to work properly. You can buy pre-mixed coolant at any parts store.

Have the cooling system pressure tested to check for leaks.

The cooling system relies on a set presure to work properly, If the system has a pressure leak, it will not work properly

If you are not seeing any coolant dripping from the underside of the car then my guess is you have a blown head gasket or a cracked head and the coolant is going into the cylinder

Pull the spark plugs out and see if they have a brown tint to them and smell funny. You can tell a lot by the spark plugs. That could tell you if you're getting anti freeze in your cylinders. These engines are bad about head gaskets and cracked heads. To replace the head gasket you're probably looking at about 480.00 labor and about 200.00 in parts and machine work, unless the head is cracked, then you're looking at more money.