Getting too hot

[Guest]

Hello everyone
I took my Mk 1 Stag to Wales at the weekend and it was running quite a bit hotter than usual. Everything else was as normal. On the temp gauge the needle usually sits around 90 and at one point it was approaching 110 so I stopped to let it cool down. I have a Kenlow fan which I switched on but that only made a little difference. I was driving around 60mph and what was weird was there was no particular pattern to the ups and downs of the needle. On one long uphill stretch it went up (more than usual) and on another uphill stretch it didn't. I have plenty of antifreeze in the system and the coolant was flushed about a year ago, since when I have only done a few hundred miles. The weather was pretty hot but I have driven in hot weather before and not had the car get so hot. Any thoughts welcome!

[martin]

Hi Lex, the temps are not a worry, but the wide variation is worth dealing with. It sounds like an air lock to me, get the front of the car a little higher than the back, and let her idle for 10 minutes with the pressure cap off, and the heater on full, the level should drop a little, then let her cool and top up. If that doesn't work, come back on and we'll come up with other solutions. This of course assumes you don't have any leaks, Martin.

[Dan stag]

It might be just the thermostat playing up.. Mine was doing similar things. I flushed mine through and took the stat out, cleaned it, checked it was opening in boiling water and put it back in and has been fine ever since. I think there must've been some crud on it that was stopping it opening fully. News ones are cheap so might be best to replace it but I'm on a tight budget and cleaning it worked for me so happy days.

[Guest]

Thanks - will do that and see what happens!

[ChasR]

Mine was a little more consisent than yours but it went cooler when I hit patches of shade in the countryside, and not motorway jaunts. My radiator had seen better days.

Is the bottom of your radiator cool once the car has full warmed up? Airlock also sounds plausible.

Some cheapo thermostats seem to give poor readings, but others are super stable (the Calorstat item in my Stag warms up quickly and now with the new rad keeps the temp in near enough the same spot .

[Motorsport Micky]

Intermittent slipping clutch on Thermostatic radiator fan ? (assume you still have fitted ) ? try spinning it by hand.

Micky

[Staggard]

Intermittent slipping clutch on Thermostatic radiator fan ? (assume you still have fitted ) ? try spinning it by hand.

Micky

Viscous coupling, Micky I dont understand clutch or Thermostatic radiator fan Graham

[Motorsport Micky]

Hi Graham,

Sorry slipped into Truck speak, works the same way as a viscous coupling on a Stag.

Micky.