I'm a new ZD28 owner (2003 72" prodeck with 525 hours) and trying to make sure everything is operating normally on my unit. I notice at start-up that my temperature sensor oscillates from cold to hot about 5 times before settling in at a middle temperature. It sounds like this is normal as the thermostat is helping to get the engine up to temp, but what concerns me is that it will red line for a good 5 second before rapidly dropping back down to low temp. Is this typical...or should I replace my thermostat?
I drained the coolant and flushed the system last night because there was some brown/gray sludge at the drain cock and having no service history on the mower I figured it was a good idea. For all I know, the prior owner may have mix coolant types or the sludge was a remnant from a previously blown head gasket. The thermostat physically looked OK and after refilling with a 50/50 distilled water/green coolant mix the temperature oscillations were still present. There's a bit of white smoke at start-up but gone prior to getting up to temperature.
I'm new to diesel equipment but learning rapidly so any advice is greatly appreciated.
I drained the coolant and flushed the system last night because there was some brown/gray sludge at the drain cock and having no service history on the mower I figured it was a good idea. For all I know, the prior owner may have mix coolant types or the sludge was a remnant from a previously blown head gasket. The thermostat physically looked OK and after refilling with a 50/50 distilled water/green coolant mix the temperature oscillations were still present. There's a bit of white smoke at start-up but gone prior to getting up to temperature.
I'm new to diesel equipment but learning rapidly so any advice is greatly appreciated.
