Can't remove the drain plug on the back of the engine block.

[ashj22]

Hi everyone. I have a 1995 Toyota Celica ST202. 

I went to do a coolant flush and replace the coolant, I drained the system by taking off the bottom hose, flushed the radiator by running water through it until clear.

Now we come to this absolute *****! of a bolt on the back of the engine block so what happened was it would loosen slightly but it would get to a point where it just felt absolutely solid, also i could see slight shiny metal on the threads and i was starting to round it off as it's a ****** to get the socket seated on the bolt.

In the end i just tightened it back up and left it because i was worried about snapping the bolt or rounding it off.

So what should i do ? is there a easy way to get to it by taking things off ?, will old engine coolant corrode the cast iron block if i leave it ?

There is no issues with how the car runs, engine sounds healthy and it dosen't overheat it dosen't even go over half way.

[Scarlett Arrow]

Why not just use tap water in the system to flush the engine block?, before using the Red LongLife once it is clear of old coolant.

[ashj22]

I did fill it with tap water and ran it for 5-10 minutes, i did this a couple times but when i drained it all and filled it with toyota coolant it's only taking around 4 liters when the capacity is 7.5L.

[DerekHa]

Just a thought Ashley,

Could you have an air lock inside the cooling system, there's usually provision for bleeding air out of the system. Or perhaps are the heater controls set to cold as this will stop the coolant circulating and filling the heater matrix properly.

[ashj22]

I don't think there is an air lock, i bled it for around 15-20 minutes with the heaters on full and the blowers off and the temp gauge dosen't even go above half way no matter how hard you drive it.