Ok. here goes it, my water pump failed...so i replaced it. Immediate overheating issues after the replacement of the water pump. This rover has never had an issue with overheating in its past. So I replaced the thermostat and the coolant reservoir, bled the system of air bubbles...went for a ride and again over heating. Tore the motor down and replaced the head gaskets/valley gasket/valve cover gaskets/exhaust manifold gaskets as well as having the heads re-surfaced. Put it all back together and went for a ride...overheated. Now when I say "overheat" I do not mean the vehicle red lined, i just saw the temp gauge begin rising and I immediately pulled over and waited for it to cool. So Im assuming I failed to bleed the coolant system properly. Went home and drove the rover up on blocks on the passenger side and bled the system again. Went for a drive. I thought I fixed the issue, 17-20 minutes into the drive...almost home and there goes the gauge again. Pulled into the driveway, turned the rover off and the secondary fan was on. My hoses aren't rock hard and theres no sound of coolant boiling. No white smoke from the exhaust or sweet smell of burning anti-freeze. The radiator is hot on top and fairly hot on the bottom. Where do I go from here? Im pretty beat up over this. Any help would be amazing. Thanks guys.

 

How's the viscous fan? Fan Shroud back in place correctly after replacing the water pump? New parts are occasionally bad. I put a water pump on my D2 that leaked within 6 days of install...

finally, have you ruled out a bad sensor? I had a temp sender go bad in my 200tdi, I stopped driving it for months until I caved and bought an IR temp gauge and figured out that the sender/gauge was bad. (Replaced both sender AND gauge to solve)

 

Viscous fan clutch....Im a moron. I should have replaced that when I did the water pump. I guess if thats not the solve Ill be borrowing an IR temp gauge and checking to see if the sender/gauge is reading proper.

 

Harbor Freight has an inexpensive IR gun. I caved and bought one last year. I have 10 bucks on fan clutch though

 

Im one of the lucky few who live within 45min of the atlantic british warehouse, so monday morning Ill be headed over to pick up a fan clutch. Thanks Rob

 

Spend a few bucks and get yourself a real-time OBD2 reader so that you can see the actual values of the coolant temperature. You'll be surprised and amazed at how high it spikes before the dash gauge starts to move, near as I can tell the dash gauge is ornamental and is only there to clue you in at the worst possible time that something bad has already occurred. Also, check for any pressure leaks in your cooling system, especially around the expansion tank, and if you still have the black one in there replace it before it grenades on you

 

Ive basically replaced the entire cooling system at this point, including my coolant over flow expansion tank as I previously stated in my OP. However I am beginning to realize how what your saying is correct in regards to the dash temp gauge. With my D1 wouldn't I be looking for an OBD1 reader as opposed to the OBD2 reader?

 

A '98 DI is OBD2.

'94- '95 = OBD1. '96 and up = OBD2