k here goes. this is an interesting one. i work as a courier and the hiace that i have needs to be running for a full day with only a few intermittent stops. i purchased an older hiace (1996) with a 3L engine (2.8l) to use as my main van due to the wear and tear. when i purchased the van the owner advised that it was overheating and he believed the head needed to be looked at. i gave the van to a "friend" who was a mechanic who advised that he had fixed the head. even after this was done it still overheated. i then thought it would be best to take it into a proper workshop to look at and they advised me that it was the radiator. the head appears ok as they teekay tested it and did a pressure test as well (so it appears that if indeed the head had been done it was done properly). they then advised that the radiator was screwed and i put a new one in. when done they advised it was all fixed. took it out to work and a couple of hours later same thing. i took it back straight away and after looking at it again they came back saying that my viscous fan was not working. this was then remedied and again advised that it was working. bear in mind that this is a proper workshop and it is costing me a fortune. took it out again and same thing, it starts overheating after a while.

this time i took it back to that guy who suggested we do the cambelt and waterpump which i did. when he did the waterpump he called to tell me that behind the pump set into the block are some water channels and that they were completely stuffed and corroded. he advised that this was causing it to overheat as the water was not circulating properly. he said he would pull out one of the springs out of the thermostat to let it open sooner and this would help. unfortunately she still overheats.

ne suggestions as ive talked to a few other people who have advised that the channels shouldnt affect it too much and its likely the head. ive also noticed a water leak under the overflow bottle which i hope to remedy this week. dont know how much itll help but will post it up.

may be the head gasket?

hie am from malawi (africa), down here my friend its hot very hot. The 3L is a problem as well but we have known how to deal with it.
two things we do, take out the thermostart and lock the fan. clean the radiator (since you have a new one no problem)

others have said that if you remove the thermo you dont allow the coolant to cool in the radiator enough but hey it work for us, am talking teperatures of more than 50 degrees burning hot and they dont boil at all

I'm having a similar problem. I've replaced everything in the cooling system. Even hot tanked the block and rebuilt the engine. Still wants to overheat in 10 min. Did you ever figure yours out?

You could try flushing the radiator, buy a "radflush" type product in an auto store. You pour it into the coolant, drive for ten mins then dump the coolant and put new in, it gets rid of the crud that might hav ebuilt up.

Also check compression, it may be that a head gasket has gone between a cylinder and a water gallery and is pressurising the water, but if your head was recently off a new head gasket should hav ebeen used. Also try re-torquing the head bolts, you should do this at leats onc eafter removcing a head as they can work loose.

Check also that it's not leaking coolant onto th eground, or that its not leaking coolant into the oil. Drain the oil, if its milky looking it's full o f water.

Other than that get hold of a manual and systematically check every component of the cooling system. there's only a finite number of things that can go wrong. These are simple engines that have been around for years, it can be fixed.

Failing that, try to find a toyota specialist rather than just a mate to work on it, as he'll know what to look for.