Temp gauge high

[Splant]

Me again! They say problems come in 3s hope it's the last! Cars always registered just below half creeping up to half in traffic then back down once on the move ,but last few days it's on 3/4 even ambling along steady , I've drained refilled coolant, had thermostat in the saucepan ( opened fully) . Just wondering if it's normal when weather's hot? Cheers. I've took thermostat out and it's ok now! Plus I shoved a twig up expansion tank return hole and felt a bit of resistance ,so I don't know which fixed it ?

[KevJTD]

For a cooling system to work properly, assuming the engine itself is OK as regards head gaskets and pump etc, then it needs a couple of basic things
The coolant needs to be able to flow throughout, so radiator not blocked and all pipes running clear, little things like the fitting on the expansion bottle where the small bore return pipe goes rusting up internally and becoming blocked will cause issues.
Likewise a thermostat needs to work correctly, not only opening when the temperature reaches it's set opening point but remaining closed to allow the engine to warm up.
It sounds like the thermostat isn't closing fully which doesn't allow the engine to rise to proper working temperature.
A proper working thermostat will allow the engine to warm up relatively quickly then remain at or around the normal running temp whatever the ambient temperature, the only difference will come when sat in traffic as there is no air flow over the radiator so no cool coolant available, which is where the rad fan comes in but it's not sufficient to replicate moving airflow which is why the temp in stationary traffic rises.
On the move it shouldn't matter if it's 15 degrees outside or 35 if everything is as should be.

[Splant]

How high does gauge usually go before fan cuts in?

[KevJTD]

Thermostat usually operates in mid 80's degs, fan usually in low 90's

[Splant]

Still running high ( 3/4) but wondering if having the thermostat out may make it run hotter as there's a hole in the housing that might be the by pass hole and maybe this needs to be blocked when the thermostat opens fully ?

[Sud 145]

Don't know where you live but in the UK yesterday with temp' in the mid 30's my Sud ran slightly higher,warmed up much quicker and the fan cut in 3x when sat in traffic.

[LooLooSud33Spider]

Tony. Stephen lives in Stoke about 10miles from me and yes it was stinking hot yesterday 30+ deg and Last night we had the most impressive thunderstorm I’ve seen in a few years I’d say his temp being a little high is normal Given for the current Heatwave we’re all having .
Temp

[alfadave]

I've found the best way to keep the engine cool, is to put the heater on full, with the fan blowing.

[KevJTD]

I've found the best way to keep the engine cool, is to put the heater on full, with the fan blowing.

That is the best way to assist in keeping the engine cool, it assists the cooling system really well having that little bit extra portion of the cooling systems water being cooled, assuming you can withstand it inside the car! Which with this short heatwave is very uncomfortable.
As has been said, a little higher reading is acceptable with high ambient.

[alfadave]

Just wear your swimming cossie and flip flops!
Can't wear mine at the moment.....its got a hole in the knee.

[alfadave]

I got the autospark to fit a manual over ride switch on the rad fan.
I turn it on as soon as I get in traffic

[KevJTD]

Just wear your swimming cossie and flip flops!
Can't wear mine at the moment.....its got a hole in the knee.

[Splant]

Yes that hole plugged with no thermostats ,cooled it till my thermostat arrives it makes all the water go through the radiator and not through that rubber pipe that goes across the top of the engine ,for once Haynes is right, the fans never kicked in so that thermo switch must be kapute, I'll wire a switch in too.

[Sud 145]

Check the switch first with a link-wire and turn the fan over by hand, it may have seized up like mine did.

[alfadave]

Before I had the over ride switch fitted, I used to disconnect the 2 wires from the thermo switch, and link them with a metal paperclip.
Fan runs permanently then.
Bit of a palaver stopping and opening the bonnet though.

[LooLooSud33Spider]

Check the switch first with a link-wire and turn the fan over by hand, it may have seized up like mine did.

But be careful you don’t chop your fingers off if it suddenly starts!! Fingers are really usefull for doing things with Like counting to ten

[KevJTD]

Best to use a stick for that job

[alfadave]

I thought Count von to Ten was a German aristocrat.

[Sud 145]

Check the switch first with a link-wire and turn the fan over by hand, it may have seized up like mine did.

But be careful you don’t chop your fingers off if it suddenly starts!! Fingers are really usefull for doing things with Like counting to ten

Not both at the same time Lou, I'm a bloke I can't multi-task.