Over the past few weeks the coolant loss has got worse and although the low buzzer has not come on when driving, after I park the coolant is dumped on the floor (from around the expansion tank) and when I get back in the low buzzer comes on. Top up the water and it is running fine but wont last for long, say 10 mls, before it happens again. Took off the (new) rad cap and lots of bulbes are coming up the coolant neck. Runs fine and starts hot or cold.
Kept an eye on the commander and the temps do creep uip in traffic to a point where it cant cool down and I have to stop.
Is this the dreaded water seal failure? Help :eek:
And do I need a rebuild and porting :D
Keith
Hows your rad doing?
Hi Freddy
It\'s only 2 months old being a new Knightsport V mount and I cant see any tell tale signs but I do know the coolant is dumped sometimes underneath the expansion tank. At first it was fine but increasingly worsening.
Keith
What about you AST cap? Mine had perished and dumped coolant. I replaced it and it never happened again.
Maybe a dumb question, but is the ast cap the same as the block rad cap?
Keith
AST cap has a spring in it, block cap does not.
If the AST cap is weak then does more coolant end up in the plastic reservoir next to the wheel arch. I seem to have too much coolant there and it is not being pulled back into the system after the engine has cooled down.
It would be good if someone could explain what the reservoir does please.
Keith
When the coolant get\'s hot it expands,so it has to have somewhere to go.
The expansion tank is there to allow this,when the coolant cools down again it then reduces in volume,but if the system was not sealed then the coolnat would not return to the engine.
Also the system runs under pressure which makes the coolant more efficient,the pressure cap on the AST should keep this at around 13 psi,once that pressure is reached and over then the AST cap allows the coolant to go to the expansion tank,because the pipe that goes to it is in the bottom of the tank,that is how the coolant get\'s drawn back into the engine when it cools,it draws it like sucking a straw because of the pressure dropping with cooling.
If the spring is weak in the AST cap then this process does not work so well,and the cap opens too early,allowing too much coolant to go to the expansion tank,and closing to early thus preventing coolant from returning to the engine,over a few engine heat cycles,you end up with a full expansion tank,and dumping on the road.
Regards
Carl
Quote from: CarlWhen the coolant get\'s hot it expands,so it has to have somewhere to go.
The expansion tank is there to allow this,when the coolant cools down again it then reduces in volume,but if the system was not sealed then the coolnat would not return to the engine.
Also the system runs under pressure which makes the coolant more efficient,the pressure cap on the AST should keep this at around 13 psi,once that pressure is reached and over then the AST cap allows the coolant to go to the expansion tank,because the pipe that goes to it is in the bottom of the tank,that is how the coolant get\'s drawn back into the engine when it cools,it draws it like sucking a straw because of the pressure dropping with cooling.
If the spring is weak in the AST cap then this process does not work so well,and the cap opens too early,allowing too much coolant to go to the expansion tank,and closing to early thus preventing coolant from returning to the engine,over a few engine heat cycles,you end up with a full expansion tank,and dumping on the road.
Regards
Carl
Best discription so far :guinness maybe a mod could put this as one of those stickies :D
Thanks Carl - great clarity.
I think the pipe that goes to the expansion tank is pierced along the way and the vacuum may be lost when the coolant gets sucked back. Gonna take the wheel and arch liner off to see whats what.
Thanks
keith :D
Had these probs with mine, took it for a pressure test, about 2 hour drive away lol by the time i got there, coolent water was brown
Starting from hot got worse and then from cold it would sound awful until (as Geff told me) the water was cleared out of the housing. The car was going ok but you cant turn it off to fill up with petrol. Although you get WI for free it\'s time to get it sorted.
So I\'ve blown a water seal.
But hey it\'s down at RE Worx now for a rebuild and porting and another chapter starts.
Just can\'t face the prospect of a heavy duty clutch so I\'m gonner stick to a new stock one and see how it goes.
Keith
:cool Well at least you have bitten the bullet and it\'s getting sorted. Nice to meet you on Saturday at Geff\'s mate. Keep us posted on how it all comes out.