Bouncing temperature gauge, strange?

Hey guys,

My P38 started to overheat on the way to work the other morning due to loss of coolant. As soon as the temp went up and the light popped on I pulled over and immediately switched the engine off.

Waited for it to cool, topped up coolant and continued to work - didn't overheat although the gauge was a TINY bit higher than normal, about a millimeter higher.

Now the car drives for a few mile but then all of a sudden the temperature starts rising, then it BOUNCES back down, it repeats this and it seems that each time it gets higher, then bounces back, then gets even higher and bounces back etc.

What could be causing this? I've recently put some radweld in and topped up with antifreeze after the overheating incident.

Thanks,
Dale.

dodgy thermostat?

i agree,it sounds like thermostat,mine did exactly the same,but everyone one said it was the dreaded head problem so i changed it anyway.problem solved

try putting lights/other electrical equipment on then off after a few seconds see if the guage responds to the power usage!!

seems to only be after a while, or when i'm stopped for a bit though so does that seem like a real problem rather than just a dodgy thermostat? as it does actually seem to be happening when the engine would be most likely getting hotter. just dont get why it bounces back :/

Yer put "Rad-Weld in did yer .....sounds like it could do with a reet good flush out to me bet the bottom of the rad is Sludged up to Fook .....

This would also follow on from Jonbill & rangie 123 sayin a dodgy Thermostat a huge lump of "Gunge" is floatin about in yer cooling system ....

FLUSH IT NOW before it ****s up yer engine completely!!!

Hi mate firstly thanks a lot for the advice!

Secondly, have you got any links to good guide on flushing? Never had to do it before

I'll do a searchy now though.

Poppers ... Heres a guide from Castrol ... this'll help yer no end mate ...

Oil Change - Castrol Motor Oil


Have a good Christmas mate....

I know the link says "Oil Change" but it isn't its a coolant flush guide!!!


Keith

Thanks a lot, have a good Christmas!