Help please! Running hot

[The Milkman]

I'm after some advice please guys. My rocco seems to run hot, when you're driving the gauge creeps up but when you keep moving (and put the heater on) it settles back down again.

Started her today as she hasn't been run for a bit and within a couple of minutes (choke still on) the gauge crept right up



She was idling at about 1100 rpm for a couple of minutes.

Thought I'd put the heater on and see if the temp came down a bit but this time there was no heat out of the blower.

Also the fan hadn't kicked in by the time I turned it off, and the gauge was almost at the max.

Any ideas please? I'm used to air-cooleds, we don't have to fanny around with all this water malarky!!

[ianaudia4]

Check your fan fuse first, if okay then the thermo switch. Water pump working? I know it is like sucking eggs but do you have enough coolant (and the right type G11)?

[The Milkman]

Check your fan fuse first, if okay then the thermo switch. Water pump working? I know it is like sucking eggs but do you have enough coolant (and the right type G11)?

Cheers Ian. I'll have a look at the fuse tomorrow, (but it was still getting hot before and the fan was working then). Er....where's the thermo switch? And what's the best way to check if the water pump is working? Looking in the top of the rad it looks like there's enough water in there.

[mark1gls]

If it's heating up that fast you may have an air lock, take the cap off the expansion tank and start the car up, look for any water flow into the expantition tank from the thin pipe coming from them top of the rad, the flow should increase with the engine revs.
If there is some sort of flow then pop the cap back on and while the car is heating up feel the water hoses to check they all get hot, the big hose to the bottom of the radiator should be the last one to get hot but keep an eye on the temp gauge and try the cars fan blowers on hot to see if they blow hot air.

[DannyH]

If it's a black radiator cap bin it and get a blue one, they are a common cause of such problems.

[The Milkman]

Cheers for the replies guys. I've changed the rad cap to a blue one already.

It doesn't have an expansion bottle, just a rad. It's a 1.5 JB engine, if that helps.

[mark1gls]

It's even easier to get an air lock if there is no expantion tank as I've found out in the past. A new water pump later and I still had the same problem so pop the top radiator hose off the radiator end and pour in some antifreeze and water till it starts to come out then put it back on the radiator. Start the car and see if it's any better and check the heater is blowing hot air.
If you are still getting the problem then either the thermostats is stick shut or the water pump has stopped working.

[The Milkman]

It's even easier to get an air lock if there is no expantion tank as I've found out in the past. A new water pump later and I still had the same problem so pop the top radiator hose off the radiator end and pour in some antifreeze and water till it starts to come out then put it back on the radiator. Start the car and see if it's any better and check the heater is blowing hot air.
If you are still getting the problem then either the thermostats is stick shut or the water pump has stopped working.

Cheers mate, I'll give it a go

[Nate]

Sticking thermostat worth a look too.

[The Milkman]

Cheers for the advice guys, turns out it was an air-lock