Lower temp fanswitch with stock thermostat ? early 944

[Hamad89]

Greetings guys,

I'm currently replacing the old radiator off my 83 with a stock new one.
The stock 87c thermo-switch was previously replaced with a 75c switch by a local tech

I drove it with the stock thermostat which is probably 80c or 83c for about 15k miles , the temp never crossed the third mark and was generally fine , only recently while driving in peak summer , the temp crossed the 3rd mark and got stuck there

I'm just wondering if pairing the stock thermostat with a lower temp thermo-switch will damage the operation of the thermostat over time,

or may it thermally shock the hot side of the radiator and result in cracks ??
should i just revert back to the stock temp switch?

i live in a very hot climate country with temperatures reaching up to 50c in peak summer, and also deal with small roads that are most of the time heavily congested with traffic and slow drivers .

the lower temp switch was recommended to help keep the engine cool in these driving situations ,

Thanks alot ,
Yours sincerely,
Hamad

[originalowner]

A lower temp switch will not hurt the thermostat, but the stock one will work just fine. The stock one comes on at the third mark. If the radiator & fans do not have enough capacity to keep the engine cool when the fans come on, it does not matter which temp switch you have.

[Jfrahm]

Yes changing the thermostat and fan setpoint only changes the operating temp assuming you have enough total cooling. And it needs to be high enough to dehumidify the oil.

If you do not have enough total cooling to run at the selected temperature the system will be limited by the cooling capability of the radiator and fans, or it will overheat.

The exception to this is a car that overheats after a short full-throttle blast that would not overheat if the blast started from a lower temperature, but that's uncommon.

Later fans are an upgrade to the 83 IIRC, and there is probably a bigger radiator, Turbo radiator, that could be fitted instead.

[Hamad89]

Originally Posted by Jfrahm

Yes changing the thermostat and fan setpoint only changes the operating temp assuming you have enough total cooling. And it needs to be high enough to dehumidify the oil.

If you do not have enough total cooling to run at the selected temperature the system will be limited by the cooling capability of the radiator and fans, or it will overheat.

The exception to this is a car that overheats after a short full-throttle blast that would not overheat if the blast started from a lower temperature, but that's uncommon.

Later fans are an upgrade to the 83 IIRC, and there is probably a bigger radiator, Turbo radiator, that could be fitted instead.

Thanks , I'll try replacing the 3-blade early fans with the late style fan that are 6-blades , while using the stock early radiator since i already ordered a new one. hopefully they fit in the stock fan shroud.

i read that only the lower radiator hose needs to upgraded to prevent scrubbing.

i found that the 6-blade fan part number is superseded with what appears to be a 5-blade fan

https://www.pelicanparts.com/More_Info/94462402105.htm?pn=944-624-021-05-OEM&fc=Y

should i go ahead with it or look for a OEM 6-blade fan that has the old part number ?

[Hamad89]

Originally Posted by originalowner

A lower temp switch will not hurt the thermostat, but the stock one will work just fine. The stock one comes on at the third mark. If the radiator & fans do not have enough capacity to keep the engine cool when the fans come on, it does not matter which temp switch you have.

its the lack of road mass and traffic free roads that makes it difficult on the stock cooling system,

The later 6-blade fans fits the 83 fan shroud , only the 90 degree connectors will need some ziptie to keep them away from auxiliary belts and the lower rad hose must be replaced with a later one(944-106-237-07)

the part number (944 624 021 03) is superseded with 944-624-021-05 , which appears to be a 5 blade fan from the images , its quite confusing to me

Thanks a lot,
Hamad