cruiser replied:

Had the same problem with my 93 petrol/LPG cruiser (243K)

Radiator place next to where I worked did a pressure check and told me what the problem was and when my mechanic had a look, he said they were right.

Turned out to be water leaking water into #6 cylinder.

Had head machined, 2 new valves in #6 and the rest ground and reseated, new headgasket kit - $1600 all up and no more problem until about 8 months later when I wrote the vehicle off (had an arguement with a 5 ton council tipper, and lost)

Hope this helps.

Kimberly Kruiser replied:

DickyBeach

Had simular prob with Tojo donk few years ago. Had cooling system thoroughly checked out and all came up ok. Further investigation came up with the worst scenario, crack in cylinder head and dumping water through the exhaust. Probably time to start the elimination process with a radiator centre yourself.
Above mentioned vehicle still in family and going strong four years after having head repaired.

Cheers
Wal

Member - Jeff M (WA) replied:

Could also be pin hole leaks inthe top tank, when the system works really hard and starts to heat up you could be losing steam out the top of the radiator. My surf was doing just that.

Peter Guy replied:

the leak could be at the front of the engine but the air from the fan is blowing the water back onto your firewall.
I believe the coollant pressure inside the engine remains constant at any speed so there is no reason for it to leak at high speed compared to lower speed conditions.
The pressure should be in the hoses/radiator therefore I'd be looking more closely at the coolling system.I had a tricky leak on the Patrol where I thought the Head gasket was leaking but luckily for me it was the thermostat holder pipe which had corroded from the out side in under the bottom radiatior hose clamp. The air from the fan was pushing the leaking water along the side of the head!
I hope your leak turns out to be a minor inconvenience.

Coops (Pilbara) replied:

as a preliminary - try replacing the radiator cap.
I had a similar problem not lonmg ago and this is all I did to rectify.
Not saying it will fix your issue but for $10 I now replace my cap every year

Member - DickyBeach replied:

Thanks everybody for the speedy and sensible suggestions.
I'll submit a post in due course and let you know what I discover.
DickyBeach

MichaelR replied:

Had a similar problem on my 80 series at 250000km and turned out to be a small hole in one of the radiator tubes. The 80 series radiators, and probably others, tend to crack the side, rather than the centrally positioned tubes, because of flexing and wear. The hole is often small and difficult to spot. It certainly leaked more at higher speeds and I don't know why. I repaired the leak but a new one developed so if this is your problem I would suggest a new radiator. It doesn't seem financially worthwhile replacing the core of the old one and it is a good opportunity to rid yourself of the plastic top and bottom tanks and get a metal one. About $350 if you do it yourself. A bit of a bugger of a job though.

Member - DOZER replied:

Well documented problems with the heater hose that comes off the back of the passenger side of the head, hard to get to, look for white residue or bulging hose...take to a mechnic you dont like...lol
Best seen from inside passenger front wheel well.
Andrew

Brian B (QLD) replied:

Howdy,

My son has an 80 series and he had the same problem as Dozer talks about in his reply. It was a dud section of heater hose which is situated at the rear of the engine close to the firewall. It was diffcult to access but once he got it the problem was sorted.

Cheers

Schevchenko replied:

which dicky beach are you anyway? sunshine coast?

Member - Karl replied:

Hey Dicky, isn't the speed limit along that road 110 Kph and if towing (in WA) it is 100 kph - not 120 kph - lucky you didn't get caught, saw a few who did when we were there recently.