Hi
Just topped up my coolant after a low coolant warning (only came on briefly after exiting my fairly steep driveway, then went). I followed JTIS procedure fwiw.
I've been keeping an eye on the coolant temperature both before and after the change; when warm in commuting traffic I am at 99-101 C, sometimes 102 C; is this normal? At reasonable speed she cools down to 99, but slow down and soon enough its back up to over 100.

 

Are you monitoring actual temperature with Torque Android or similar? The temperature gauge is useless and doesn't move up until the engine is becoming seriously overheated.

See WhiteXKR's information about his Real Gauge for details:

XK8 / XKR / XJ RealGauge - TheJagWrangler

A sticking thermostat is a regular cause of elevated temperatures.

Graham

 

That is pretty close to mine, even going up to ~102 when stopped in traffic.

The temp has always seemed a bit high, but is quite stable and consistent over the years, even after changing the thermostat, so I don't worry about it any more.

 

Yes, I'm looking at actual temperature via the dashcommand app.
Fans come on no problem, so I think that means the thermostat is ok...is there a specific temperature at which they should switch on?

thanks ccfulton, that's one vote for normal registered :-)

and Graham - I took a look at WhiteXKRs FAQ on realgauge, he gives a normal range of "190 F to about 215 F" which is ~ 87 to 102 C.
I'm pretty consistently around 100..

 

Fans come on around 101 or 102, so they are limiting the temperature as they should. The behavior you see is normal in a stop and go situation.

When cruising at 55 mph I would expect to see more like 96 or 97 max. (with no fans) if the cooling system is in top shape, but if you are at 99 I do not think there is any danger.

If the system has ever had tap water (only distilled water should be used) mixed with coolant for some time, it could have mineral deposits built up that have reduced the cooling system's efficiency.

 

Brilliant, thanks for that. Sounds just right. I only get a single straight of 60 mph zone on my way in to work; so there's not a lot of time to cool down. Especially when there's not much traffic, hehe...

 

On the highway yesterday with 96F (36C) outside temp and I stayed at 200F (93C). When I pulled off the highway and hit stop and go traffic, with the A/C working, it hit 215F (102C) at the red lights and the fans came on.

I'd say you were normal. They just seem to run warm. Ironic on an engine that hates to be overheated.

p.s. this is using Steve's RealGuage for temps.

 

They do run pretty hot, I think to improve mpg (hahaha, scary or what).

 

Thanks all! Looks like I've got little to worry about! (touch wood!)