Overheating Issues

[scrimple101]

I have a R31 Nissan Skyline 1989 sedan which is overheating. I have checked the water pump and it is fine and i have replaced the thermostat. It has new radiator fluid and all belts have been replaced. Oil changed and correct level. Does anyone know what could be causing it to overheat. I have thought about replacing the radiator cap but apart from that i'm not sure what else i can do. Regards, Rob Lane.

[lachlanw]

run your hand accross the radiator core when the car is hot . it should all be too hot to touch . any cool spots and it is blocked

[2LV8ETR]

I had this issue many years ago and it turned out to be the radiator cap.

It was the last thing I thought of and that's all it was.

[scrimple101]

run your hand accross the radiator core when the car is hot . it should all be too hot to touch . any cool spots and it is blocked

Is the radiator core the part where all the insects get caught?

[s14_boosted]

take the thermostat out nd stick ur finger in, sumtimes crap just gets built up, if u got a spare 100 bux just go wreckers nd get a rb30et radiator, theres almost twice the thickness, you should be sweet after that

[Jmaac]

blocked radiator, or blown head gasket

[scrimple101]

It's not a blocked radiator or a blown head gasket because i've had the radiator cleaned and flushed and the head gasket has gone and i fixed it. I think the only thing it can be now is the fan clutch as i've checked everything else. New thermostat, radiator good, water pump good, new belts. Anyone think of any other possibilities? Regards, Rob.

[adoboy666]

i would say yeh the fan clutch as youve eliminated everything else does ur clutch fan seem loose (worn out) eg. with the engine going can u stop the clutch fan? (use something like a rag to stop it)

anyway should only be like $30 for a second hand clutch fan

another suggestion may be the stock guage is reading wrong like most skylines

try an aftermarket gauge as itll be tons more accurate

[2LV8ETR]

Defective fan clutches are a common and often overlooked cause of overheating. The sheer characteristics of the clutch fluid gradually deteriorates over time, with an average loss in drive efficiency of about 200 rpm per year. Eventually slippage reaches the point where effective cooling is no longer possible and overheating results. On average, the life of a fan clutch is about the same as a water pump. If one needs to be replaced, the other usually does too.

Sometimes a lower radiator hose will collapse under vacuum at high speed and restrict the flow of coolant from the radiator into the engine. This can happen if the reinforcing spring inside the hose is missing or damaged.

Also, if the coolant is overflowing from the overflow tank, replace the radiator cap.