Temp Gauge!!????

[FLORIDA747]

So today i am driving along and then stopped at t/lights and watched the gauge fly up in to the red pulled away as loads of cars behind me and it went straight down!¬ then it was going from 1/4 to full red and back to 1/4 the red like a yoyo no steam coming from bonnet and i could hear the fan running.
Are ther any electrical issues that cause this or is it big money time??

HELP

[mud skipper]

the usual
rad cap
thermostat
rad flush
burp the system(air lock)

[Tallyman]

So today i am driving along and then stopped at t/lights and watched the gauge fly up in to the red pulled away as loads of cars behind me and it went straight down!¬ then it was going from 1/4 to full red and back to 1/4 the red like a yoyo no steam coming from bonnet and i could hear the fan running.
Are ther any electrical issues that cause this or is it big money time??

HELP

Have you checked the level of coolant in the radiator. If it's low, it could be that the guage is reacting to the hot water as the pump pushes it round when accelerating and as it slows down the sender is just getting hot air around it instead of water. Either way, you could have a problem. Would also help if you filled in your vehicle details so we know what model you are asking about.

[FLORIDA747]

Have you checked the level of coolant in the radiator. If it's low, it could be that the guage is reacting to the hot water as the pump pushes it round when accelerating and as it slows down the sender is just getting hot air around it instead of water. Either way, you could have a problem. Would also help if you filled in your vehicle details so we know what model you are asking about.

HI, have now put vehicle details in it is a 2.4 td auto.
I did look at the coolant bottle which was over the full mark, but then noticed there is another like rad cap? are there 2 points to check?

Thanks for the help!

[MattF]

No, there is one point to check. At the rad cap. The expansion bottle is exactly that. Nothing more. Take the rad cap off and refill your system. Also, unless you have been topping the expansion bottle up, (which is what I suspect), get a new rad cap for it, and preferably a new thermostat too.

[FLORIDA747]

No, there is one point to check. At the rad cap. The expansion bottle is exactly that. Nothing more. Take the rad cap off and refill your system. Also, unless you have been topping the expansion bottle up, (which is what I suspect), get a new rad cap for it, and preferably a new thermostat too.

HI, thanks for advice, where is the stat on these?

[MattF]

where is the stat on these?

Same place as the rad cap. You'll find three bolts holding the filler neck where the rad cap goes on. Take those bolts out and the thermostat is there. You'll want a new thermostat seal too, most likely.