Is it overheating??

Hi all,
My landys after market temp gauge was disconnected when I got it 7 months ago. I’ve just reconnected it an gone for my usual 20 minute drive(I’d forgotten I’d connected it so didn’t watch) when I arrived it was off the scale, max 120.
I assumed the sensor was busted as surely it couldn’t drive around at that temp without showing sign?? Surely it would pop a gasket or just pop!
I left it for an hour and when I came back I noted the radiator was stone cold. This changed my thinking to a thermostat not opening. I let her cool right off and drove home......very tensely!!!
Back home I checked the rad straight away and it was hot! Could it have cooled that much quicker than the block when I’d left it earlier?

How tough are these engines (19j 2.5td) with regards to heat? I’m tempted to get a new thermostat and temp gauge anyway but hoped you guys could share your thoughts.

I’m struggling with whether it’s overheating and being tough about it or whether it’s just a duff gauge.

Many thanks as always,
Mike

Is it wired to the 12 v or stabilised 10v supply? Makes a big difference to the readings.

It’s a simple task to run it whilst feeling top and bottom hoses for temperature differences. The bottom hose should be much cooler than the top.
You would also smell the block cooking if it was over temperature. If all seems well manually then it points to the readings being cocked up.

Lazy thermostat.

Col

I bought one of those infra-red laser temperature gun jobbies off tinternet when I changed my engine to a 2.5N/A just in case the sender wasn't tied to the dial. It cost less than a tenner and works a treat.

My 2.5NA was running hot for 2 years I changed every thing from sender to gauge flushed the system new water pump and thermostat and still ran hot.
After all that someone mentioned you could get different temp thermostats so I changed to a cooler one which worked . They are tough engines did mine no damage.

19J are very prone to damage by overheating best get gauges sorted , buy your self an infared temperature gun off ebay good for checking temps of all ,parts of engine.