After replacing head gaskets I decided to pay a little more attention to my coolant temp. As the stock temp gauge goes whacky when drawing an electrical load (windows, brake lights ect,) I installed a mechanical gauge, putting the sensor at the top plug on the radiator. (the only place that had room) besides the plug dripped anyway. I'm reading 180-210 and under low speeds some times higher. Is this normal? Also has anyone been able to check for a plugged radiator by timing how long it should take for a full radiator to drain? Say from full to empty after removing the bottom hose? I may do the Chev. fan clutch conversion and need to know the model, year clutch to buy. Thanks

 

Here's the clutch from Advance. Also note that you will have to enlarge the mounting holes in the fan to accomidate 3/8-16 by 1/2" bolts to mount it to the new clutch. (The original metric bolts won't fit.)

 

Sounds more like a battery issue then a cooling issue.

 

Actually mind does the same thing. It's amusing to turn on the A/C and watch the temp gauge flip up & down with the blinker on. Since the stock gauge is connected to the on-board computer, not the engine itself, it really seems like a weird software issue.

Anyway, the best solution is probably to get an Ultra-Gauge and ignore the temp gauge in the dash.

 

So, are we to assume that this is a D1? If so, they don't have as much of a problem as the D2's but still should be monitored.
Hold old is your t/stat, when was the last time you removed your radiator and had it professionaly cleaned?

 

Sorry- 96 disco 4 litre

 

180-210 is about where mine runs, with the A/C off on a normal day. ('98 D1 with 130K.) I've read posts from people who never run above 193-195, but I don't think 210 will hurt anything.

 

IMHO, on a D1, 210+ for extended time would indicate to me a sludged up or air blocked radiator, can have rodded out (it is copper and brass). Also that bung hole plug on the rad is quite some distance from the stat, so your actual engine temp is even higher.... I had my rad rodded out and with a 180F stat I run 180-183 up to 50 or so, and at 70 plus on interstate it may get to 187F when 90F plus outside.

As for temp gauge moving with electrical loads can also be a wierd ground cable problem somewhere. If your truck has an OBDII port, you can plug in a scanner and see engine temp from the ECT sensor. In a D1 they are separate from gauge, in a D2 it is one sensor, and the CPU drives the gauge in a dance of cold-normal-toast. In the pix the D1 gauge sensor is one on the left, the one one the right with square top is ECU sensor.