How to change head gasket - Chevrolet 2004 Chevrolet Aveo

Exactly which gasket did you change? There is a gasket on the valve cover and a gasket between the cylinder head and the engine block, the Head Gasket. It's the Head gasket you need to change. Then you need to flush the Oil system and the coolant system to clean them out.
Changing a head gasket is a Big job where you remove the top half of the engine exposing the piston tops. If the gasket has been changed 'several' times your probably looking at a cracked cylinder head or engine block, a VERY expensive repair. If this is the case it's usually easier to replace the whole engine.

If you've already changed the head gasket why would you need to get the cylinder heads pressure tested now? It's too late for that. That's something you do BEFORE you replace head gaskets.

why did you need to change the head gasket in the first place ?
There may be a reason the gasket failed like a crack in the head or a warp in the head of the engine.

Could be a leaking cylinder head gasket or a small crack in the cylinder head. Is the head aluminum? Make and mileage of the vehicle will sometime help as some vehicle makes are notorious for head gasket problems. This allows coolant into the oil and causes this goo on the inside of the cap. Have a trustworthy shop check it out to be sure.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/michael_2496c4f07ad24453

if you replacing head gasket it will be first then replace valve cover gasket after reinstall the intake manifold and its new gasket.

where is the watter coming out from? did you follow torque sequence / did you have head resurfaced? check block / did you find any thing wrong with the old head gasket? please give more info, so we can give you better assistance , Thank you for using Fixya.

If you have white smoke from the tailpipe, coolant in the engine oil, engine oil in the cooling system, that indicates a head gasket failure. However, the most definitive way to test is to have a hydrocarbon test done on the cooling system (checks for exhaust gasses that obviously don't belong in there).
If the system comes up clean, you still can have either a leaking intake gasket, partially obstructed radiator (many times flush will go around obstructions not through them), a malfunctioning electric fan or fan relay, or even an obstruction in front of the a/c condenser or between the condenser and radiator (leaves, plastic bags etc) Don't forget though even if the cause is other than a gasket, if repeatedly or severely overheated the head gaskets can also fail. That is why complete testing is very important.
good luck

hi, if you are changing the head gasket then it may be worth checking the water pump and thermostat as it could have been one of these that failed causing it to over heat and then blown the head gasket so check the water pump and thermostat once you have the cylinder head off.

You may need the head checking to see if it has been warped but this is unlikely on this make of vehicle.

Once you have done the gasket make sure that when you fill the coolant up you only trickle the water in to prevent any air lock as this will cause it to over heat again, check for any bleed screws on the coolant system to let the air out whilst filling the coolant up,

Its best you check in the workshop manual for these as their may not be none as it could be self bleed system.

It also worth checking if the head bolts need changing as they do stretch and can cause the gasket not to seal properly so replacing these may be a good idea.

Let me know how you get on or if you need further assistance ok.

ps what makes you think the head gasket has gone??

use bars leak head gasket repair. you may need 5 bottles. then change your oil and filter.

I would change both, as well as use new head bolts. Make sure your heads are not warped or cracked, especially the one that is leaking. There may not be any need to change the head if it is not cracked. These are prone to blowing a gasket especially after 150K miles or so. It will not cost a huge additional amount to change both head gaskets since the engine will have to be disassembled down to the heads anyway. Hope this helps you, Rick