Cab heater shutoff valve

[Ratau]

If I look inside the radiator at the filler cap I can see the water flowing from the under dash heater into the radiator. Is there a shutoff valve some ware in this coolant line?

I installed manual temperature and oil gauges. The coolant temperature sender unit is mounted in the hole next to # 1 glow plug. The temperature gauge reads 176

[britannic]

There's no shutoff on my 1985, instead, the heater core is always flowing hot coolant. The heater temperature control moves a flap that allows air to flow over the core and into the cab.

[Ratau]

Britannic

I hardly ever uses the cab heater, if I put a ball valve inline to the heater will the engine coolant temperature rise?

My first questions: Is the engine not to cold at 176

[britannic]

IMHO, I would leave it flowing, it provides another heat sink for engine heat and the coolant is always routed from the crossover to the radiator - even when the thermostat is closed. However, installing a ball valve will allow you experiment and may come in useful for other purposes.

There's a thread running right now, that'll answer your questions about where measure coolant: Thermostat (and where to measure the temps). (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=002787)