Coolant temperature

[GTXGTXGTX]

The coolant in my GTX was looking a bit brown (last changed a year ago) so I drained the system then flushed with clean water and refilled with coolant. Pretty sure I have got all the air our but now car is running hotter than it used to. temp gauge always used to be exactly 12 o clock now it's higher. Fan cuts in in traffic no problem and temp goes down a bit if heater is on hot. any ideas?
Thanks

[GTXGTXGTX]

Have changed pressure cap.

[mark1gls]

Did you make sure the heater was set to hot when emptying and refilling the system?
You can try and start the engine with the heater set to hot and with the expantion tank cap off and see if you are getting a little dribble of coolant in the expantion tank from the thinner hose from the radiator and it should increase in volume when the engine is revved, let the car warm up (but not hot) with the cap off and this should bleed out any air locks, refit cap and system should start to pressurise, wait for the fan to kick in then take it for a drive and see if any better.
What coolant did you use and at what mix or was it pre mixed?

[GTXGTXGTX]

Thanks for the advice. will give it a try.
The coolant was Halfords, not sure of exact type. The return hose to the expansion tank spurts coolant intermittently whilst car is idling.

[mark1gls]

There should be a constant flow so you may just have a small air lock somewhere, try and bleed the system as above and see if that helps.
What colour is the coolant?

[james butler]

if you dont know what you put in then theres a good chance you may have put in the wrong type or wrong concentration.
putting the wrong type in can cause cross contamination in the engines circulation system which in turn goes to sludge/ slurry blocking up important coolant passages.
if you put the wrong concentration in it causes the engines temperature to fluctuate dramatically hence why theres a winter concentration and a summer concentration.
to be fair in britian it pretty much rains all the time and the weather is consistently rubbish so a 30% mix will suffice but having to richer concentration of antifreeze in the coolant will cause overheating.

but its quite important for us to help you diagnose the problem we need to know WHAT type of antifreeze you put in the car and WHAT was the concentration.

[GTXGTXGTX]

Blue.

Silicate 50/50

System was flushed through thoroughly before refilling.

[the edmundator]

If it was brown, I would suspect that it has had something close to water in the system in the past and the radiator is rusted inside. I'd be considering a new radiator.

[james butler]

yeah 50/50 is too higher mix. try draining some out and filling at least a litre of water in there to thin it out and see if its the same.
if that doesn't work then re flushing the system is the next course of action.
if you can catch the coolant in a tub then you can reuse it seing as its new.
like ed says if the coolant was brown then flushing it may have dislodged crud and rust and blocked the radiator.
fortunately they're not that expensive to replace.
but try thinning it out first and see what happens and if that doesnt work try flushing it again, before splashing cash on anything else.

[mark1gls]

I used to use a 50/50 mix when I used to buy concentrate antifreeze and had no problems with temperature, the gauge sits on the 1/2 way mark.
I now use the ready mixed blue stuff from Euro car parts so don't have to bother mixing the stuff up.

[james butler]

I used to use a 50/50 mix when I used to buy concentrate antifreeze and had no problems with temperature, the gauge sits on the 1/2 way mark.
I now use the ready mixed blue stuff from Euro car parts so don't have to bother mixing the stuff up.

if your cooling system is in good nick (new rad, water pump and thermostat and no crud in the system) then yes you probably will get away with it and like wise i use euro car parts ready mix blue anti freeze but on hot days mine creeps over half way. putting a litre of fresh water in the system helped it a great deal so now it rarely goes over halfway.
but if the cooling system isnt quite up to scratch it can cause these issues especially if your running 25+ year old origenal equipment.

[mark1gls]

Yes Rad is newish and so is the water pump and no crud in the system so perhaps that's why I don't have a problem.

[GTXGTXGTX]

A quick update. It looks like I had the OAT coolant in before so I flushed and backed flushed the system three times. The radiator had a tiny split in the plastic at the top so I replaced the rad and re-filled the system with the Comma G48 coolant diluted 60/40. all good now, temp needle sits at 12.00. Job done.