well ive replaced thermostat, swaped water pump for an a-14 one which i discovered today is a better design and swaped from the four flat blade fan to a seven curved blade fan of a 2ltr escort/cortina (bolts straight on) put a radiator cap with two seals for overflow and flushed the block and radiator with the garden hose

i then ran the car and left it sitting in shade on a normal temp day (maybe 22 celcius) for about five minutes, she slowly went up to half then settled but started to creep over and the idle starting changing up and down

i havent got a shroud but i dont think thats the prob, is it likely that its running lean and causing overheating?

i used green stuff too

do you still have the heater hoses connected?

yes, i need a heater, i think it is actually required for rally

coz your car will be under prc rules it says you ahve to have a heater does not necessarily have to be a 1200 one though you need to have demisters or else you will be in trouble if it starts to fog up

Quote:
Don't forget that the Datsun 1200 system doesn't get the air out too well after changing the coolant ... maybe it just needs more water, and it'll be alright after this.

whats the deal with the heater causing over-heating??? i heard it said before but cant see how this is possible

On 1200s,

When changing radiator fluid, the heater must be fully open (hot). Otherwise an air pocket sits in there and the system will not fill properly. I always recommend filling it, turning the heater to hot, and drive around the block. Shakes the air pocket back to the radiator, and then top up the radiator. Keep an eye on it for the next time you go out too.

Chris.

got a germini rdiator today, pick-a-part had em on special for $20, its in great condition but has had chemi-weld or something in it so im gonna get it flushed and try that, just in case the side tanks on the alfa radiator i have are contributing somehow, i will try the heater thing too

prob is my soft mounts on my carbies today have started leaking air and shes poping and crackling now so i gotta get her fixed up, im gonna put the su's on and try em this week i guess

The heater cannot cause the engine to overheat, unless it's leaking coolant.

If the heater is working correctly, it can actually cool the engine down a little, as it will shed heat out of the engine coolant into the passenger compartment. I used to do that on hot days when the needle approached the Hot mark (before I upgraded to the larger B210 radiator). You could see the temp gauge go down slightly with the heater on in the summer ... though it wasn't pleasant. It is much better to get a little bit bigger radiator.

a good idea is to have the front of the car pointing up hill a bit this helps the air come out when ya fill it and allways have the heater tap open when ya refill .. its a good ideas to use the heater tap every few weeks helps prevents em from sezing up same as running air con in winter