Engine slowly over heating

[back_in_black]

Took a short trip into town this morning driving handy but on the way home the temp guage was rising slowly. Got as far as 3/4 to the right by time I got home. Return to normal temp after few min at idle in the drive fan working away.

Could it be the rad cap causing this?

[pjmazda]

Thermostat dodgy maybe

[back_in_black]

Checked for air in cooling system this morning and seems fine. Not losing any coolant either. Went for a spin and when driving handy everything fine but if you push a bit the temp will rise. Ease off, idle or put the heater on full it'll drop to normal again. Flow looks ok in the top of the rad when up to temp so drained system down to have a look. Only about 5 litres of coolent came out so I'm guessing something's blocked. It's the original rad so I'll hope a new one will solve it.

[Fergus]

I think the entire coolant system only holds around 6L of fluid ?
Check the thermo.
How old is the water pump ?

[back_in_black]

Hi Fergus

Water pump, thermostat, and thermostat switch new. When the engine comes up to temp you feel the top hose get hot when thermostat opens and the fan will come on a bit later. Cars only on the road about 2 weeks and I've been watching the gauges constant but yesterday was the first time it happened. I put a rad flush through about 10 days ago and after draining and flushing water through the rad everything seemed clear but when re-filling with coolent it only took about 4.5l. That's kinda why I'm thinking the rad might gunged up.
What u think?

[rhysmate]

did you bleed the system? as in run the engine with the rad cap off for a while

[back_in_black]

Yeah and tried raising the front of the car heater on full same thing.

[back_in_black]

Change the rad this evening and everything seems fine so far. Fingers crossed!