Hello,

I have had some issues with my 4.3L 2001 Chevy Blazer LS right hand drive.
It got overheated today way right up to 125 degrees Celsius in a really quick period before I could pullover.
As soon as this happened I got a check engine light and it gave me P0300, the misfire cylinder.
Recently I replaced the fan clutch, thermostat and have given it a complete coolant flush. This was at the time when I got a P0128 code. The car stayed too cold.
A few months ago I gave it coolant sealant as my heater core was leaking. This was fixed after that.
A few weeks ago it already started to lose coolant and heating up as well.
Therefore I added head gasket sealant as well.

I am strongly thinking I might have a blown head gasket. I have the current symptoms:

- Gets overheated after about 5 min.
- No milky substance
- Water dripping from tailpipe as well as some white smoke
- When radiator cap opened some smoke is coming from this place as well.
- After the car got overheated the coolant smelled quite burned. Can it be severely damaged? It hasn't run too hot for very long.

Would anybody be able to help me with this issue? I don't want to spend a lot of money on fixing the head gasket if it isn't the problem.

Thanks in advance.

 

The best way to check for a cracked head or bad head gasket is to jack up the front (or point the nose uphill) and fill the cooling system completely with water on a cold engine (keep filling until full and don't put the cap on). Then take off the water pump belt and start the engine. If you have a cracked head or bad head gasket between cylinder and cooling jacket, you will soon have a huge geyser from the leak of combustion gases pushing the water out. Don't mistake a bit of water expansion for a bad head gasket and don't run so long it starts to boil the water out. Should happen in the first minute or so if it's going to happen.

So first your engine was too cold, and now it's too hot? I would check the new thermostat. Should open in a pan of boiling water.

Water dripping or some whitish smoke when cold can be normal condensation. But lots of white smoke when fully warmed up indicates a problem.

Stop putting sealants in your cooling system. They do more damage than good.

Good luck and best wishes for a successful repair.

 

Thanks for your reply! Will try that and see how I go!
So if I’m right I will see a huge geyser from the radiator cap or where my crack would be around the head gasket?

 

You should see a geyser from the radiator cap if combustion gas is blowing anywhere into the cooling system from a cylinder (crack or bad gasket)

 

Update! I have just tested what you have suggested. I let it run for a few minutes and nothing other than some expansion happened. After a while the level dropped all of a sudden, does this mean I haven’t put enough coolant in? I’m not sure what it could be now. It doesn’t overheat really soon now and haven’t tried longer distance yet. I have completely flushed the system and put new coolant in it. This may got rid of all the rubbish that was in it from the sealants?

 

The level dropped when the thermostat opened and the air had a place to exit. Of course if you had the belt off, there was no circulation of coolant. Yes, this indicated that you need more coolant. Sometimes you can get a cooling system vapor locked where there isn't enough water in it to pump. People have reported trouble getting Blazers to fill up, but I have not personally had this problem. But then again before starting the first time with an empty cooling system I always raise the front end and keep filling with coolant until I can get no more in.

I recommend that you let your vehicle cool down completely, then jack up the front off the ground (or park on a steep hill) and fill until no more coolant will go in, radiator is completely full, and level stays there for extended period of time. It's important to keep adding if coolant level goes down, until the level stays at the top. Then put the radiator cap on, fill your coolant recovery tank slightly over the mark and drive. As the coolant temperature cycles, air will be further purged through this tank, and the coolant in it will be drawn into the system until no more air is present.

If you can do this and drive it for a week with no overheating - then cool it down overnight and take off the radiator cap - is the radiator still completely full? If so, all is well with your cooling system.

Best wishes

 

Hello,

I have just tried to fill up my coolant system when I had it jacked up and could put a bit in it again. Stopped the engine a few times and started and could fill it up again. However, after it got to operating temp it had white smoke coming from the radiator and it blew a bit of coolant out of the radiator when I turned the engine off. As soon as I started it it dropped again. I have teat driven the car and it still gets too hot. I can drive for about 3 minutes before it gets to about 110 degrees Celsius. The coolant also smells burnt. I’m a bit confused what it could be now.. Thanks for your help!

 

Sorry, but it's not sounding good for your engine (head gasket or crack getting combustion gas in the cooling system) Last resort, take the thermostat out and put it in a pan of boiling water. Does it open?

 

Update, tonight I took the thermostat out, this one is functioning alright as it is a new one and tested it. Let it run to temperature but still gets too hot so I am afraid the head is cracked or gasket blown. The only thing what makes me still confused is that after I flushed the system the heating inside worked but after a few times driving it gets clogged again. Could this block the cooling of the engine? I might need to do another flush with cleaning stuff? What a shame of a nice car..

 

Hi StijnV
If you have a Autozone or Advance Auto , possibly some other part stores , you can rent a simple tool that will let you know if you have a crack in a combustion chamber , or a bad head gasket . It's often called a Combustion Leak tester , it's basically a tube that you put the fluid in , set into the radiator neck & pull the vapor above the coolant , if the fluid turns color & changes , then you have a bad head gasket , or crack in the combustion chamber !
Hope this helps