Overheating woes PLEASE HELP

[G15OST]

Right! Ive changed the Head (brand New) all gaskets and bolts, changed thermostat, water pump and radiator and cap, when surfs on fast idle its fine (heaters not getting particularly warm) temp never goes above half way. But as soon as i drive it or rev it above 3-3.5 rpm it goes up towards the red, i have locked the fan up and its still the same. and the heaters dont tend to get that warm (they did before head change). ive now parked it with the front raised and brimmed with water and will leave overnight but surely theres something wrong somewhere???

Please Help and Many Thanks...G15OST.

[BUSHWHACKER]

Right! Ive changed the Head (brand New) all gaskets and bolts, changed thermostat, water pump and radiator and cap, when surfs on fast idle its fine (heaters not getting particularly warm) temp never goes above half way. But as soon as i drive it or rev it above 3-3.5 rpm it goes up towards the red, i have locked the fan up and its still the same. and the heaters dont tend to get that warm (they did before head change). ive now parked it with the front raised and brimmed with water and will leave overnight but surely theres something wrong somewhere???

Please Help and Many Thanks...G15OST.

Could be a blockage in the front heater matrix or pipes preventing circulation of the coolant.
Try by-passing the heater matrix by joining the two heater hoses that go through the bulkhead and keep an eye on the temp gauge as you go for a drive.

[NiftyNev]

I've noticed that quite a few have overheating or cooling system bleeding problems after a head change. Why is this? The cooling system is relatively simple to bleed so, is there another cause? I have read previously, that there is possibly a difference in head gaskets. This difference is in the number, or location, of water passages in the gasket. I have seen where others have had to open up a couple of passages in the gasket so they match the openings in the original. I can't say if this is your problem, as many other things, such as blockages elsewhere from poor cooling system maintenance, can cause problems as well. This is somehing everyone should check before replacing the head.

Was a genuine Toyota or an aftermarket gasket used? Do you still have the old gasket? If you do can you post a pic? Can you also post a pic/diagram of replacement gasket or at least name the type and brand so maybe a comparason can be made?

Nev

[BUSHWHACKER]

I've noticed that quite a few have overheating or cooling system bleeding problems after a head change. Why is this? The cooling system is relatively simple to bleed so, is there another cause? I have read previously, that there is possibly a difference in head gaskets. This difference is in the number, or location, of water passages in the gasket. I have seen where others have had to open up a couple of passages in the gasket so they match the openings in the original. I can't say if this is your problem, as many other things, such as blockages elsewhere from poor cooling system maintenance, can cause problems as well. This is somehing everyone should check before replacing the head.

Was a genuine Toyota or an aftermarket gasket used? Do you still have the old gasket? If you do can you post a pic? Can you also post a pic/diagram of replacement gasket or at least name the type and brand so maybe a comparason can be made?

Nev

I told him about the gasket yesterday Nev, but this thread keeps starting over!

[coolsv650]

Could be a blockage in the front heater matrix or pipes preventing circulation of the coolant.
Try by-passing the heater matrix by joining the two heater hoses that go through the bulkhead and keep an eye on the temp gauge as you go for a drive.

.....or the radiator is blocked.... oh no forget that it's got a new rad!!

If the system is filled with crud it could well have blocked the heaters, I found the turbo & rear heater pipes were blocked solid on mine. 2 hours persisting with a hose pipe finally cleared it out.