1HDT Overheating (6 Viewers)

[Ghostrider I]

Ok...have a 91 80 series with the 1HDT Turbodiesel. Replaced radiator (aluminium) and water pump 5years ago. A week ago, it was blowing gray exhaust upon idle after a 45 min highway speed drive. Water temp was around 180, oil 200.

Today did same drive, lots more gray exhaust and water temp was 220 oil 220. Coolant overflow tank was bubbling, fired on heat but no heat coming out of vents. It has never in my ownership has overheated, in fact literally ran cool.

Thermostat?

 

[duncanrm]

Are you losing coolant? If so I'd be pressure testing the cooling system, and I suspect it'd be closely followed by the cylinder head coming off.

If you're not losing coolant, I'd be doing a pre-emptive full cooling system rebuild - water pump, thermostat, viscous fan hub, radiator flush, block flush, heater core flush.

 

[Rigpig]

head gasket

 

[Eurasiaoverland]

Despite your confidence to the contrary in your other post, that sounds like a cracked head/leaking head gasket. Coolant is bubbling because combustion gases are getting into the coolant passages, heater does not put out heat because it's full of air. Faulty thermostat would not explain air in the system. Unless there was a major coolant leak, your coolant has gone out of the exhaust pipe. Which is your greyish smoke.

Steel head gaskets don't blow like fibre/bitument gaskets, so unfotunately it's likey to be more than just a gasket. But as per Duncan's post, I would elimiate the simple (cheaper) stuff before removing the head.

 

[Squash]

Check that the rad and overflow are in equilibrium.
If either is low you are losing coolant.
This may take a few days, but tighten all clamps, white spray paint will highlight coolant leaks.
Your overflow should always have some coolant, if this is dry, again a leak.