Discussion
i appear to be loosing some coolant after slightly hard -> hard driving, trouble is i don't know why!
the car is in pretty good mechanical order, and its not too hot in temperature AND the car isn't running hot!!!
plus, there's no sign of head gasket failure... filled the rad up yesterday and drove it to work today, came back and there was a puddle under the overflow pipe...
hte lines and rad are both less than a year old and the car is well maintained with regular flush outs of the cooling system, so why am i still letting some go?
the car is in pretty good mechanical order, and its not too hot in temperature AND the car isn't running hot!!!
plus, there's no sign of head gasket failure... filled the rad up yesterday and drove it to work today, came back and there was a puddle under the overflow pipe...
hte lines and rad are both less than a year old and the car is well maintained with regular flush outs of the cooling system, so why am i still letting some go?
Older cars with no expansion tank can spew a bit of water out the overflow after the first good hard run since a refill - especially in warmer weather. It's just due to expansion.
Next time you give it a good run, let it cool and check the level. If it's still covering the tops of the flutes OK, then - assuming it doesn't spew any more out next time you run it - I wouldn't worry about it.
Still worth checking or changing the rad cap as suggested though.
Next time you give it a good run, let it cool and check the level. If it's still covering the tops of the flutes OK, then - assuming it doesn't spew any more out next time you run it - I wouldn't worry about it.
Still worth checking or changing the rad cap as suggested though.
Yup, i'd have a new cap on there 
The cap might well have a weak spring on the pressure side, but i'll also be suprised if the seal it's self hasn't gone off and either split or seal flattened.
the pressure in the cooling system raises the boiling point of the coolant, so a defective cap will allow the coolant to boil away. It can also allow the expanded coolant to push past the seal when the engine is off.
As the engine cools and the coolant contracts again, the vacuum valve in the cap allows the system to draw in a little air to equalise the pressure.
The cap might well have a weak spring on the pressure side, but i'll also be suprised if the seal it's self hasn't gone off and either split or seal flattened.
the pressure in the cooling system raises the boiling point of the coolant, so a defective cap will allow the coolant to boil away. It can also allow the expanded coolant to push past the seal when the engine is off.
As the engine cools and the coolant contracts again, the vacuum valve in the cap allows the system to draw in a little air to equalise the pressure.
One of my car was slowly using water, then one day it overheated terminally. It turned out to be a perished water hose that had cracked enough to let a bit of water through and finally split enough to empty the contents of the cooling system on the road.
It only cost £5 to sort in the end thankfully.
I would check all your hoses, especially the one it's difficult to check because these are the ones least likely to have been replaced recently!
It only cost £5 to sort in the end thankfully.
I would check all your hoses, especially the one it's difficult to check because these are the ones least likely to have been replaced recently!
well all the hoses were replaced last summer, as was the rad... but the cap is old... i will get a new one!
the car seems to be better now, just a tiny spot often appearing below the overflow pipe!
one thing that i was wondering that may affect it was that i was out of coolant to mix up with water, so topped the last little bit up with just water so the coolant was more diluted so therefore would be less effective... i suppose that could be the problem!?!
the car seems to be better now, just a tiny spot often appearing below the overflow pipe!
one thing that i was wondering that may affect it was that i was out of coolant to mix up with water, so topped the last little bit up with just water so the coolant was more diluted so therefore would be less effective... i suppose that could be the problem!?!
You won't have a problem on it in the short term.
But once you've got the water to stay where it should be, i'd recommend that the system is drained and refilled with the correct mix of antifreeze and water.
Antifreeze not only stops the water from freezing in the cold, but it also helps to raise boiling point a little and it has a mix of corrosion inhibitors in it too.
The inhibitors are worth the cost of the antifreeze on their own even more so if the engine has any alloy components.
But once you've got the water to stay where it should be, i'd recommend that the system is drained and refilled with the correct mix of antifreeze and water.
Antifreeze not only stops the water from freezing in the cold, but it also helps to raise boiling point a little and it has a mix of corrosion inhibitors in it too.
The inhibitors are worth the cost of the antifreeze on their own
even more so if the engine has any alloy components.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff