coolant usage

[scooterjohansen]

For some reasoon my vt uses way to much coolant. not sure why?? it does not overheat possibly due to twin thermos but for the life of me cant find a leak and pressure test comes up ok. it uses about 1/2 a litre a week. I just keep topping it up
what could be the problem.. any ideas. cheers

 

[BlackVXGTS]

When the engine is cold, get a torch and from the side of the engine look into the space between the bottom of the inlet manifold and the V of the engine block. If you have a leaking inlet manifold gasket what happens is that the coolant leaks out when the engine is cold and pools in the V towards the back of the engine. When the engine is hot it evaporates so that you don't seen any sign of a leak. With a torch you should be able to see the green coolant if the leak is from the inlet manifold.

 

[scooterjohansen]

cheers

will check this out and see if that is the problem will keep you posted

 

[scooterjohansen]

had a look

could not see any coolant. car was sitting for 12hours on a level spot.
bled system @ 90 degrees. reset computer. Tightened snorkel on CAI..
test drive proved something. The power was smooth and responsive. It liked to rev a fraction longer between shift stages. smoother definatly. Probably not as quick off the mark..See how it goes....hope no more coolant goes missing..

 

[holdenrules]

scooterjohansen, are you still loosing coolant, or has the problem been fixed?

My VT V8 5.0 is doing this also, in the morning, coolant cannot be seen when I take off the cap, I can just see the inside of the plastic elbow. I squeeze the top hose and still I see no coolant.

But when I fill the radiator and check it the next day, the level in the radiator has dropped again but the coolant reservoir has risen.

I think I might change the cap and see how that does.

 

[Don Sutton]

scooterjohansen, are you still loosing coolant, or has the problem been fixed?

My VT V8 5.0 is doing this also, in the morning, coolant cannot be seen when I take off the cap, I can just see the inside of the plastic elbow. I squeeze the top hose and still I see no coolant.

But when I fill the radiator and check it the next day, the level in the radiator has dropped again but the coolant reservoir has risen.

I think I might change the cap and see how that does.

I think you are on the right track for your vehicle but check for any vacuum leak between radiator and reservoir. Sometimes something will not leak under pressure but can leak under vacuum. The atmospheric valve on the radiator cap can stick shut also but you will rectify that possibility anyhow with a new cap. I have seen radiator hoses flattened overnight by this valve sticking and others where air is drawn in past water pump seal. A pressure cap tester can pick this up.

 

[2000V8]

I also had a coolant leak - "they" identified leak from top radiator hose. "They" retightened clamp and it doesn't leak any more. Had it to Holden three times to identify this leak - couldn't find it. Eventually took it to non-Holden garage and they fixed it.

 

[Hairy Eater]

my VX V6 was doing this too... coolant always low in the radiator when cold and wouldn't suck back from the bottle... the rubber seal on the radiator cap must have been faulty coz when i put a new cap on it sucked up from the bottle and fixed the problem.... BUT BEWARE... Auto Pro here first sold me a new cap just with a metal disk and not rubber seal on the cap... I had to abuse the salesman before he would change it... the metal disk new cap was far worse at leaking than the old cap.. after reading my Gregory's I found out there are 2 different preasure rating radiator cooling systems... rubber seal cap is the higher (135 kpa I think)...