Cant get my CA to hold temperature

[210boostpimp]

i'm about ready to pull my f*** hair out. i can't figuere out why my ca wont stay warm.

the car is a 74 datsun b210, with a ca18det swap. the car has a stock motor with the following mods. mandrel bent three inch exhaust, custom cold air intake, fmic, nismo adjustable fpr, booting about 11 pounds, electric fans. this little beast runs perfect other than the fact that it does not want to hold temperature.

here's what it does. if i let the car idle the temp will go up to 215 and then the fans kick in and cool the car down to 190. the car will do this all day long. after the car is fully warmed up i drive the car and temperature starts crashing down to under 100. the gauge starts at 100. i have pulled over to see if the fans are turning on before the temperature hits 215 and they do not. i have changed the thermostat three times. two from kragens and one from autozone. i ordered the stat for a nissan pulsar se 1987, temp is 180. the radiator is 27 inches by 19 inches, with one inch horizontal core (this was my vets old radiator). the fill line on the radiator is two inches above the thermostat. it has 50/50 coolant water mix. i have also replace the temp gauge twice. i don't belive its the gauge becuase the air coming out of the heater is not even luke warm at best. i dont even run the heater beacuse it will take longer to warm up.

i don't know what to do and it's really cold right now. should i try a stat from nissan? or???????????

[sjbsuperman1425]

is the radiator and hoses getting physically hot to the touch?

[r34 gtr]

Is your radiator just too awesome? Seems like a good problem to have... Does the temp go back up if you drive the car really hard?

[210boostpimp]

the radiator is physically hot to the touch but not hot enough to have to move your hand away because it will burn you. the upper hose after the thermostat is also warm after the stat opens.

the temp starts to slowly go back up when i am idling at a light for too long or waiting for a train or the drive thru. if i drive hard the temp will still come down slower than when i just cruise it.

this was my vets old radiator. when i switched over to a stroker small block, i replaced the stock radiator with a dual two inch core set to cope with the extra heat. is it possible that this radiator is just too dam big for this engine?

the problem is the same in the summer time.

[roast]

it's not a good problem to have, can you fit a stock CA (KA) radiator in your b210?

[210boostpimp]

will a stock 240sx radiator be enough to keep the CA cool?

i can definitely fit a stock 240 radiator.

[roast]

I'm pretty sure it will... There's a Koyo on my silvia but that was installed because the stock system was messed up from rust...

[sjbsuperman1425]

yea the stock radiator is enough for the CA. That Vette radiator is probably way to big for this little engine..

[s13drifter88]

I have a CX 3 core and mine doesnt have any problems like this. it takes FOREVER to get warm (about 20 min for the needle to lift in the winter) but once it does I have no problems afterwards. Thats strange. My therm stuck open in my old jeep i used to have and i covered half the radiator with a peice of cardboard so it would get warm till I bought a therm and replaced it. try doing that just to see if it makes a difference. If it does then youll kno u may need to step down your radiator

[float_6969]

The raditor isn't the problem, it's the thermostat. It doesn't matter how big the radiator is, the thermostat SHOULD just close more and maintain temp. The problem is that aftermarket thermostats are un-reliable. My father-in-law quit using anything but thermostats from nissan/toyota/honda/etc years ago because of problems like this. My current thermostat is a Stant from Advance auto and it acts up till the engine is totally heat soaked. It will show the temp is good, but if u rev the motor the temp drops till the evs drop. It will do this till the engine and radiator are completely hot.

The only other possibility is that you installed the thermostat wrong. Is the longer part installed towards the motor and the jiggle valve at the very top?

[210boostpimp]

float,
the spring actuated part with the coper thingy is installed towards the motor. it will not go in the other way around, since i'm using a ca18de fwd water outlet.

i'm going to bite the bullet and just get a nissan t stat.

[float_6969]

And just to make sure, you made sure this

was facing up, right?

[210boostpimp]

And just to make sure, you made sure this

was facing up, right?

yes