fluctuating temp gauge

ok so as many of you may know dan and i have had some problems with our new sir. about 3 weeks ago it over heated on the way to gympie. we concluded that the water pump needed to be changed. after 2 long weeks of trips up and down the north coast we finally finished changing the WATER PUMP, TIMING BELT AND THERMOSTAT all with new honda parts, except the water pump, i believe it was near new. anyway, after everything had been done we filled the car with water and let it run for half an hour. no overheating. so we closed the bonnet and left gympie, it ran fine for about 20 minutes, then the temp gauge started creeping up, i took my foot off the throttle and it went back to normal. this happened a few times before it went all the way up to hot and then in about 10 seconds dropped back down to normal temp, this happened the whole way home. does anyone have any ideas on what it could be?i think it may be a sensor or switch. any ideas would be helpful.

Blocked Radiator, get the radiator replace

radiator has been flushed out

i had the same problem on my civic and it was a blown headgasket not white smoke no oil coolant mixing or anything. drain the coolant out of the radiator and see if u can smell exhaust fumes

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Originally Posted by 1perfectday

radiator has been flushed out

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in what way ?

running water through it ?

the only way to unblock a shagged radiator is to remove the top tank and poke a wire down each cappilarie.

it does sound like your radiator is blocked. or you fuel/ignition mixtures are way off ( lean mixtures can cause overheating as well )
is your ECU stock ? correct MAP for your engine ?

hmmm... we have already flushed out and checked for things like that. did it fluctuate rapidly?

well we just bought the car and the guy who sold it wasn't dodgey and said it was running fine before we bought it. I think the ecu is aftermarket not sure though. the cooling system also has a weird white thick calcified buildup through it

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Originally Posted by 1perfectday

well we just bought the car and the guy who sold it wasn't dodgey and said it was running fine before we bought it. I think the ecu is aftermarket not sure though. the cooling system also has a weird white thick calcified buildup through it

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Should be blown head gasket then drain the radiator coolant and see if u can smell exhaust fumes or take it to a radiator shop they can do a few tests to tell u whats wrong

but if it was a blown headgasket it would be idleing weird and the water would be massivley boiling when you have the radiator cap off

mine would idle fine and didnt throw coolant anywhere for a while until it started getting worse. hopefully its not the same for u though.

cas our mate that helped us fix if turned on his crx with a blown head gasket and it was completely different. AND we left it for half an hour just idleing and it didn't overheat then?

if its really minor it wont overheat till u put ur pressed the accelerater but like i said after a while it started getting the problems u stated