Coolant issue

[Neo666]

Hi all I'm a little stumped with a cooling issue. The story goes, had a cracked thermostat housing, changed it over, temp gauge after a few miles would go up to the red, come back down, back up then down etc. Ordered another as I assumed it was faulty, changed over the water pump too just in case. Replaced  the thermostat again, flushed system etc, new coolant, system bled, and still the gauge goes into the red. I checked on the dashboard test menu, and at one point the temp jumped to 126 degrees which was very worrying. Anyone have any ideas?

Any feedback will be most appreciated. 

Car in question is Mondeo mk3 2.0 auto estate 2001. BWY CJBB.

[Neo666]

I should also add,that the car had no cooling issues before the original leak

[nicam49]

That's a good one! I would have said water pump, but you've eliminated that. Does the heater still pump out heat when the temp rises, 'cos if if doesn't then I'd say pump. Else nothing springs to mind at the mo. 

[Neo666]

Still pumps out heat, no issue with that. It's a puzzler isn't it

[m50e30]

Dodgy gauge or faulty temp switch

[nicam49]

When it gets hot, does the stat open... does the top rad hose get hot...are the fans kicking in? 

[Neo666]

Top hose get hot and the fans come on

[nicam49]

You're not helping!! 🙂           Sorry, I'm  stumped!... can you get one of those infra red thermometers so you can test the real temperature. I know Lidl had them on sale 2-3 weeks ago