Carina E 2.0 Mad Temperature Fluctuations

[teambonzer]

Hi all

I have a high mileage 1996 Carina E, and for last few months have had a problem with overheating. I will drive down the motorway at a reasonable 70+ speed, after an hour or so the temp guage will start fluctuating rapidly. Basically the guage will go from flat line middle to near red in 4-5 seconds, sit there for 4-5 seconds then fall back to normal in 4-5 seconds. This cycle will repeat every minute or 2. Once off the Mway seems to settle down and stop happening. This now happening on any long journey (over 45 mins) - but never a short journey.

In the early days I used to panic and pull over when the guage touched red, but now i just wait for it to drop down again. On one occasion I opened the bonnet and saw that the top-up tank was merrily boiling away - I guess that this was caused by back flow from the radiator.

Any ideas which bit to change first? or has anyone had similar experience?

I have a short video of the fault in action if that helps.

Cheers

TB

[gazza1286]

There may be an air-lock being forced around the system. the temp will spike as the air passes the temp sensor.

Air is getting into the system somehow: either:

There could be a leak in the hose from the expansion bottle to the rad (not likely). or:

The metal radiator cap may need replacing (cheap solution - probable cause).

Assuming that you aren't loosing any coolant (levels in the expansion between the limits and coolant visible if you remove the radiator cap) I would be surprised if it is anything more sinister.

[Neuroner]

A word of caution, do not remove that metal cap when the engine is hot.

However, removing it when the engine is cool for a while might allow any air

trapped in there to escape safely.

I'd also like to suggest that your heat sensor might be damaged, or that condensated

water may have damaged the print board on the backside of your heat-indicator.

Keep us posted on how you work this out mate