overheating

[toutie]

hi all i purchased the surf about 6 months ago and a couple of months back the head cracked so off comes the head and replaced it with a brand new one and a complete new head set and new water pump and thurmostat and a rad flush. and it still overheats but only if i,m doing over 40mph so i took the thermostat out to see if that helps but no change still does it

hoping someone can help . many thanks eddie

[BUSHWHACKER]

Is the engine fan clutch working correctly?
The fan should spin easily when the engine is cold, but stiffen up when engine is hot.

Where the heaters set to hot when you topped up the coolant?

[toutie]

Is the engine fan clutch working correctly?
The fan should spin easily when the engine is cold, but stiffen up when engine is hot.

Where the heaters set to hot when you topped up the coolant?

hi mate there is some resistance when you try and spin the fan by hand when cold . and i have just noticed there is no air con belt would that make a diffrance ? and is the air con belt also attached to the water pump?
many thank eddie

[NiftyNev]

Resistance when cold is normal and as engine warms up it will decrease somewhat. When the engine is at operating temperature the fan will not spin as fast as engine speed. It's when the engine gets to a stage where the radiater and airflow through it can not dissipate the heat that the viscous clutch will lock up more and make the fan spin faster till airflow again cools things down. If you can spin the fan freely when the engine is at operating temperature (engine off of course) then you have a problem.

Air con belt is for aircon only. Water pump runs of a twin belt setup from the crank which also operates the alternator. Make sure these aren't slipping and correctly adjusted.

Nev

[toutie]

Resistance when cold is normal and as engine warms up it will decrease somewhat. When the engine is at operating temperature the fan will not spin as fast as engine speed. It's when the engine gets to a stage where the radiater and airflow through it can not dissipate the heat that the viscous clutch will lock up more and make the fan spin faster till airflow again cools things down. If you can spin the fan freely when the engine is at operating temperature (engine off of course) then you have a problem.

Air con belt is for aircon only. Water pump runs of a twin belt setup from the crank which also operates the alternator. Make sure these aren't slipping and correctly adjusted.

Nev

hi when the engine is up to normal running temp there is very little resistance
but the engine temp only goes up when you get it into overdrive

many thaks eddie

[Sancho]

hi when the engine is up to normal running temp there is very little resistance

There's your problem then. As for it only coming on when you're in overdrive, that's probably just because the engine's working harder then.

How's your transmission fluid? If it's very old, I guess your cooling system's going to have to work harder to keep it cool.

[toutie]

hi all what type of gearbox oil do you recomend ?