Coolant Loss

60Muzz · 17-11-2008, 02:51 PM

1999 AU is suffering coolant loss over two to three weeks. The level will drop from midway between the max and min level to the min mark over this period. There is no sign of coolant leakage at the radiator, water pump or heater hoses but there is a dry stain where the coolant over flow hose discharges onto the inner mudguard panel, have not seen it wet there and with the coolant level at mid way I cannot see how it would be reaching the point where the cap would be releasing coolant, engine temp appears to be running normal as is the car generally. I note that with the engine running that the coolant bypass line from in front of the thermostat housing is discharging into the reservoir with a bubbling action that would appear to be normal as the return coolant hits the internal divider in the reservoir tank - is this correct? There are no signs of oil in the coolant. No emulsification of the engine oil or level increase either.
Any thoughts on where a coolant loss may be occuring, seeing as it is a relatively slow loss? Only point that I can think of which is not easy to confirm would be into the auto trans ( no dip stick ), but I would have expected to see some oil in the coolant if this was the problem area.
Maybe someone has had a similar problem that they have been able to identify. Any thoughts would be welcome.

NC1183 · 17-11-2008, 02:56 PM

V8 or I6, i have a I6 that has a slight weep from the pipe that runs from the back of the block to the front under the exhaust manifold. Yet to replace/fix it.

60Muzz · 17-11-2008, 03:06 PM

Thanks NC1183,
Its an I6. Thats the heater supply line you are referring to. I will have a closer look at it under the manifold cover as there is no leakage where it comes out of the water pump.

MaTTe · 17-11-2008, 04:15 PM

The cooling system is probably due for a flush anyway, drop all the fluid out and refill the system, then run some stop leak with the new mix. If its a minor leak it'll seal it, if it's leaking into the engine it probably wont.
Also check the radiator cap, make sure it still has the right tension on the spring, otherwise it may be releasing pressure when it doesn't need to.

EvilChief · 17-11-2008, 04:25 PM

welsh plugs? heater core?

60Muzz · 18-11-2008, 05:35 PM

Thanks MaTTe and EvilChief (Love Townsville) for your thoughts. I don't think the cap is the problem as the coolant level is no where high enough to reach it. Welsch plugs maybe, but there is no sign of leakage under the engine or any indication at the bell housing area that would point to the rear welsch plugs. Heater core is a good possibility as a minor leak would tend to dry up with the air flow through that area and not be too noticeable. On what you have indicated it looks like more searching is to be done. I am not all that big on stop leak products as I see them as a short term fix masking a real problem that needs to be addressed. Thanks again for your input.

GK · 18-11-2008, 10:57 PM

Quote:

Originally Posted by EvilChief

welsh plugs? heater core?

I've just discovered a leaky welsh plug on the exhaust side. Getting all of that side replaced next week.

All the best sorting your issue.

GK

NC1183 · 18-11-2008, 11:08 PM

Quote:

Originally Posted by 60Muzz

Thanks MaTTe and EvilChief (Love Townsville) for your thoughts. I don't think the cap is the problem as the coolant level is no where high enough to reach it. Welsch plugs maybe, but there is no sign of leakage under the engine or any indication at the bell housing area that would point to the rear welsch plugs. Heater core is a good possibility as a minor leak would tend to dry up with the air flow through that area and not be too noticeable. On what you have indicated it looks like more searching is to be done. I am not all that big on stop leak products as I see them as a short term fix masking a real problem that needs to be addressed. Thanks again for your input.

The water level wouldn't have to be at the cap for it to be the problem, as when the water gets heated it presurises and expands.

EvilChief · 18-11-2008, 11:37 PM

k.hlkllllllllllllll//////////////////////////////////////////////////////////////////////////////

EvilChief · 18-11-2008, 11:39 PM

sorry guys, my cat somehow got it managed to post that ...

what do i learn from that? do not lend ur lappy to ur cat ...

bodes-sh · 19-11-2008, 09:16 AM

cap. i had the same problem. when driving around in hot weather i could actually smell coolant. replaced the cap and it's been fine since...

greenguzzler · 19-11-2008, 09:40 AM

Yep, replace radiator cap. I had same problem in my old ef. Coolant was disappearing then on a really hot day saw coolant running out of the front of the car, quickly opened the bonnet and saw coolant coming from the overflow.

mik · 20-11-2008, 10:56 AM

if it persists whip it up to a radiator place they can test the whole system.

BillC · 20-11-2008, 04:46 PM

My son has the same problem with his VS commondore (intentional spelling error). Had NATRAD do a test and it came back positive for ehhaust gasses which means that gas is bing released into the cooling system. Diagnosis is that the heads need to be removed and serviced at a cost of about $2,500. Typical commodores. A mate mechanic of mine said if its a slow leak don't fix it just keep topping up the cooling system.

Go to a radiator place and get it checked. I hope its not your head.