Why am i losing coolant????

[letsgoplaces Advanced Member Find all posts View Profile Close letsgoplaces]

Hi all,

I am losing coolant which is most obvious after driving in hilly terrain and lately it has only been on bitumen. On Sunday we went up to Mount Crawford via the Freeway through Balhannah, Oakbank etc. I was doing an under bonnet check on Monday and found the radiator and reservoir took just shy of 4 litres!
4 or 5 weeks ago the thermostat was replaced and the engine was pressure tested and the result was no loss of pressure over a period of an hour. The night before i had driven up to Mount Osmond and found the reservoir bottle actually boiling.
Late last year i was having overheating problems and the radiator was 70% blocked and as side note, this time the temperature gauge isn't going above normal operating temps.
So the coolant must be going out of the reservoir... but how? And why isn't the temp gauge reading High?
Any ideas would be appreciated as i think i have my mechanic stumped after this morning's phone call.

Cheers

[minh Member Find all posts View Profile Close minh]

Firstly do not rely on the factory gauge. It will not move until your coolant temps hit 105 degrees.Do a double check and make sure there isnt some slow leak somewhere. Like a heater hose or the water pump!

if you believe and truly believe there is no external leak then I would look at your head gasket next.

[glen_ep Addicted PP Member Find all posts View Profile Close glen_ep]

Was the entire radiator replaced last year? Have you replaced the radiator cap?
I've had some troubles with cooling as well. It's heated up twice - once during beach driving on a hot day (understandable) and once when offroad on a very cold raining morning (WTF?). The temp guage would only be slightly higher than usual, the overflow would be boiling, and it seemed to loose coolant slowly over a period of time. I've done the following things: proper coolant flush (with a cleaner), thermostat, radiator cap, 50% glycol mix, topped up the vicous coupling oil. It seems to be fixed, but I've said that before...

[letsgoplaces Advanced Member Find all posts View Profile Close letsgoplaces]

Cheers guys, turns out the radiator cap was knackered. Funny how something so small can have such an impact :P

[scooter Junior Member Find all posts View Profile Close scooter]

good to see you got it sorted, nothing more frustrating than a leak you cant find.

Just for reference we had a similar thing happen...although it turned out to be one of the original hose clips (those useless ones that gradually lose their grip over time (constant tension I think they are called) and you cant tighten them). Had to drive the car for a bit before any coolant managed to escape, the clip held until heat and pressure built up. The coolant left a trail under the hose after use so it was fairly obvious where it was coming from so replaced it with a decent clamp and presto all fixed.