I've recently replaced the CA18DET in my 1200 with a freshly rebuilt one but now I'm getting temperature spikes. Twice I have come off the freeway with the water temp gauge showing 80 degrees only to have it spike to over 100 within 2 kms of suburban driving.
I have an SR radiator with twin 10" thermo fans and a 77 degree thermostat. I'm going to check the ignition timing tomorrow as I have had it get hot before when the timing was too far advanced.
I don't understand why it would be getting hot when I'm just tootling around with it under minimal load or sitting at the traffic lights. Any other suggestions?
Thanks Matty

As it was working before..I can only think of sticky thermostats or leaky heater hoses (My current nightmare).

Depends on the coolant gallery condition of the block are you using coolant? And is it still a lovely green colour?

The old air locks are not causing you probs?

I can't think of any quick solutions.

Thanks for the reply. The water galleries were in great nick. I have had a couple of minor heater hose leaks but nothing that could cause the motor to get hot.
I use Redline Water Wetter instead of regular coolant.
I don't think it could be an airlock as I jacked the front of the car right up and let it idle with the radiator cap off for ages to get rid of them.
I'll get the timing right and replace the thermostat and see how I go.
Thanks again Matty

I place my bet on a sticky thermostat!!
I have had this problem before. Genuine nissan thermostats are better but a lot more $$$$ I used one from a Exa Ca18de they are made from stainless in 82 or 80 degrees.
Cheers Andrew

Hi Andrew
I bought a new 71 degree thermostat today. I'll install it tomorrow and see what happens. I'm also planning on venting the bonnet somehow to let the heat escape. The two radiator shops I've been to have both said that there's nowhere for the hot air to go once the thermos have sucked it through the radiator so the whole engine bay gets heat soaked. It's mainly getting hot after I've had to stop at a set of lights after a decent rev.
I had a guy test it with one of those radar style heat guns today and the top and bottom radiator hoses barely had any difference in temperature after it's been idling for awhile.
Matty

this cant be a normal Cadet conversion problem as no one seems to have mentioned it before?...must be something wrong somewhere, but most conversions dont stick with the stock radiator.

have you cut away all the front panel blocking the radiator vents? what radiator is it?....

I have a Ca18det radiator for my Aseries and it still can run hot everynow and then. there only a single core radiator and shouldnt be used in a 1200 with the Ca18det, i dont reckon there good enough in the confined 1200 bay. i think you will need at least a twin or 3core radiator. Edit: just realised you said you have SR one...are they single core?

Yeah the SR is a single core too. The thing is that the car ran fine with the old motor but runs hot now. That's why I want to check the timing as the only time I had any issues with the old motor was when the timing was too far advanced. I replaced the thermostat today but haven't had a chance to test it yet. Hopefully get to drive it Friday afternoon.
Matty
p.s. I have considered going to a twin core radiator if need be but if it's a case of the hot air not being able to escape the engine bay it may not help much. I'm trying to find some bonnet vents that aren't too obtrusive to see if that helps.