Hi all, I'm wondering if anyone can suggest why my 1997 2.0L/auto petrol Spacewagon is loosing coolant. This problem started 3 weeks ago when it overheated, even replacing the coolant caused almost immediate overheating so I dismissed it as a sticky thermostat and removed it, now running without it.

This seemd to fix the problem although I could still occasionally smell anti-freeze from the engine bay area when coming to a stop after engine acheived full operating temperature. Also routinely noticed a small puddle after parking it and upon opening the bonnet I can see the collant was leaking via the overflow tank. Today for the first time since the overheating 3 weeks ago I noticed the temp guage creeping above the usual 1/2 way. This was at idle and it settled right back down to 1/2 upon accelerating. I know I'm getting a little low on coolant and it's a matter of time before there isnt enough coolant to keep the guage at 1/2.

I have checked the dipstick and there is no evidence of anything milky on it. Heater core is only 1 year old and the radiator itself appears to be in good order visually.

I though maybe it needs a coolant flush and I am considering using Holts Speedflush but unsure as to whether or not that would work or if I'm better off going to the garage for a flush. I need to keep costs minimal.

Any suggestions greatly appreciated.

replace the radiator cap if it is old

check that the thermatic fans are working
check all the hoses for holes/splits /cracks and clamps are tight :)

if you do decide to replace your radiator pressure cap ask for the highest pressure one that will fit your radiator. the higher the pressure in your radiator the low it will keep your coolant temperature. check to see if your fan for your radiator has had some kind wiring malfunction. a grounded out wire can run your fan backwards which will cause your engine to overheat even if the coolant is on the cold side.

try to stay away from a radiator flush they are hardly worth the money they cost. you can just take your radiator out pull it apart and clean out most of the clogs by hand or a pressure washer at your local car wash. if you still seem to have a overheat problem after everything chain rattle and i have told you to check, you may need your water pump replaced.

Thanks for your replies. I've been sort of wondering about the fan situation as it seems to let it get pretty warm before it kicks in, sometimes 3/4 way up the guage. If thats a problem, I'm not sure it's the only problem because the car has been running at normal temps lately yet still loosing the coolant. The one and only time it really overheated was 3 weeks back when this problem resulted in not having enough coolant left to adequately stop it from overheating, thats when I first knew something was wrong. I can keep topping up the coolant every week or so and the car would go on running without overheating, but this would get very expensive over time.

As for the water pump, it has roughly 20,000 miles on it and showing no sign of leak.

The radiator cap is another possibility as it seems to be a little easy to manually push the mechanism up on it, though I'm not sure just how much resistance would be normal. But it's definatly a thought.

what happened before it overheated.
ie radiator flushed, long sitting in traffic, radiator system refilled etc
this can help locate the problem.
to me it sounds like one off two problems air lock in system, or fan not kicking in and radiator not cooling.

It happened during normal driving, no different circumstances than usual. It ran at normal temperatures and only got overheated once the coolant was extremely low.

looks like the system needs flushing then checking to make sure theres no air lock on the pipe work

mine was doing this without the overheating mind but 3 bottles of speed flush ran thogh for a couple of days and the drain. then disconnected top hose and ran car kept topping up rad. seems fine know tip wood.

I've done basicly the same with the drain and flush. The odd thing is I can drive all day on a highway and not lose a drop, city driving is even OK as long as traffic moves along smoothly, but it's only in the first 2-3 minutes after shutting the engine off when I lose about 1/2 litre or so out the overflow tube. Heavy stop and go traffic will also cause marginal coolant loss.

I've yet to solve this problem. :(

yeah but mine took 3 or 4 goes at bleeding and flushiong before fixed. for a while i was just flushing with water and top hose off until water ran clear.( using a high idle to blow the stuff out). if its only doing when engine is shut off it's deffo air trying to escape so would try again. BUT! also check the head gasket, if she over heated she might be slightly blown and now drawing air in.