Never should have modified

Many thanks to you Pete and all the other interested readers and advisors.
I will absorbe all the suggestions.

The motor generally runs below (just) boiling in normal circumstances - towing a caravan certainly over stressed the system!! Petrol vs gas didn't seem to differ - about 30 litres per 100km ~ $ wise gas cost is acceptable(?) but petrol would send me broke - thus my fuzzy logic~ slow the revs ~ reduces the firing (fuel consumption?) ~ reduces the temperature!!

Hi Ross many thanks for your comments. No shroud is fitted! Will have to check my ever growing 'used parts' heap to check on the removed fan.

Again many thanks - like your 'name'!

Again many thanks ~ I've been misleading - the radiator capacity is a little over 3 litres and another 4 for the motor ~ seems too little? someone has suggested installing a header tank to increase the volume - the thermo fans appears to work OK ~ with motor stopped - from boiling to thermo cut-out is about 4 minutes with cut-in maybe another 4-5 minutes accounting for convection?

Again thanks ~ With all the good advice I'm sure the problem will be solved

Thanks again- Will check the tyre size currently installed (I'm in the city - the troopers up the bush!) Current tyres are Dunlop Supergrippers.

Hi Wayne ~ my misleading the total current coolant capacity is 7 litres. The current radiator is a custom job (probably an adapted FJ45) to fit the narrow frame space - moved forward to accommodate the thermo fan. Any comments on a 'header tank'?
Thanks for the support

wayne you doodle brain. the total contents of the cooling sysytem is also the amount out of the head and the heating system too . i think a landcruiser is about 16 litres. ok ok

OOPS....
ha ha.....thats kinda what i meant....the raiator on it is massaive, bigger than my pootrol, and 14l comes from specs in manual......

Hi RosscoH,
Yes I've mislead everyone with the coolant capacity ~ total 7 litres! still seems low. I'm wondering whether there are obstructions in the block. The engine was 'fully reconditioned' but who knows how well! Many thanks

Sorry that should be water coming out the top and get sucked in through the bottom hose radiator should be cooler at the bottom not the top. Totally the opposite way round was thinking of my water jackets that I use at work. Regards Steve M

Hi Steve
I thank you and all the others for the support! I guess your've seen the comment re 7 litres vs 4 litres! Still low?? The radiator is OK as I have had it professionally opened and checked. I'll absorbe all the comments, reach for the matches and let everyone know the results!!

No doubt you have, but have you removed the thermostat just to make sure its not that. I have replaced old thermstats with new ones over the years and have had a dodgy one that was opening far to late and running hot. Obviously there is no obstructions in front of grille driving lights etc blocking air flow. Does it have air con ?? if you have changed over radiator maybe fins arnt matching up there fore air not going directly through the air con condensor then radiator. I think what has been said previous about getting a radiator from a gen3 engine and fitting if possible. I know even ignition timing will make them run hot if its out but not normally to that extreme. As said above do you have a shroud fitted so its pulling air through the rad and not sucking around it eg hot air already around engine bay. Presume water pump is correct one and in good nick, It might pay to pull out and make sure all the fins are ok. Was a new one installed when you had the motor done. Maybe the impellor is slipping on the shaft and not turning properly although they are normally one piece. I had a chev in my old car so just trying to think why it would be running so hot. I never had any issues except on 35/40d days but still wouldnt overheat just run warmer than normal. Will ask my other mate hes a chev nut will show him this web page and he can have aread maybe might come up with some thing. He also races and knows a reasonable amount about chevys. It sounds like its not holding enough water in the system my VX commodore use to hold 11 litres V6 ecotec motor. Problem even with a say five core radiator its still only narrow so all the heat is in a small area instead of spread across. My wifes new car the radiator is a wide as between the headlights and only singe core. I think over the years they have realized that the wider the better not neccisarily the depth as hot air is getting pushed through say 5 cores but maybe only 50cm wide where as now I have noticed alot of the new cars are say 1M wide but only single or double core but obviously the water spends more time in the radiator cooiling down. Just my opinion thats all trying like the others to give you some thing else to check out. Regards Steve M