SW20 very low coolant temp and high idle

[mynameisrodney]

Hi Guys,

The SW20 is being a bit painful at the moment and just wanted to get some advice. For the last few weeks the coolant temp has been sitting pretty much at the bottom of the gauge, occasionally it will rise up to about 1/4 of the way. The other day I was driving with the fan on, and after about 10 minutes it seemingly instantly started blowing hot air and I realised it was on heater. There was no gradual warm up of the air from the vents. Also, not sure if related, during this time the car has been idling quite high for extended periods after starting.

I checked the coolant level and it looks ok. From the weird heater behaviour I'm thinking its unlikely to be a sensor fault. Maybe thermostat is sticking? Or water pump on it's way out? Any other ideas?

Cheers,
Chris

[trdee]

air bubbles in coolant, give it a thorough bleed.

how you got said air bubbles in the first place though??? probably a leak somewhere....

[Hiro]

air bubbles in coolant, give it a thorough bleed.

^this. Thermostat stuck open would explain everything except the instantaneus hot air (although it could be a combination of both).

[mynameisrodney]

Brilliant, thanks guys. I'll have a go at this tomorrow.

[woggin]

My sw had no thermostat and the gauge sat on a quarter, got a new stat, chucked it in, happy days, in regards to the heater, mine used to get stuck in the cold position, so I'd have to get out and manually move the tap over to hot again, was annoying esp when it was 3 degrees outside at 5am!

It used to drink a bit of coolant too, never found the source of it, did bleed and bleed and bleed it, came to the conclusion it was a leak.

[mr75]

High idle might be because it is trying to warm it up to operating temp. If these suggestions dont fix it try replacing your thermostat