Dodgy Thermostats?

[IBOO57]

Has anybody had any dramas with seemingly dodgy Thermostats?

I replaced my water pump awhile ago and put a new thermostat in at the same time and it will sometimes get up to 110 C

on the Power FC readout then will suddenly drop down to 85 c for awhile then climb back up to 110 and so on.

(radiator is reasonably new Aluminium) So i figure the Trident thermostat i bought was a bit dodgy so i put a new one in today

and now the freakin thing is getting up to 119C before it drops back down slightly at wich point the bottom rad hose was all but cold!

Surely i couldnt be that unlucky to have scored 2 dud thermostats?

Anybody else had similar probs?

PS has all new rad hoses as well and theyare not closing up or anything either.

[Craved]

just checking that you completly bled the cooling system after you changed them .. as air pockets will read as a high temp spot that can cause fast fluctuations in teh temp readings

[IBOO57]

just checking that you completly bled the cooling system after you changed them .. as air pockets will read as a high temp spot that can cause fast fluctuations in teh temp readings

Yeah gave it a good bleed both times.

I am thinking that that wierd little 3 pronged cage thing on the thermostat is sticking in the sleeve in the block that it runs in

causing thermostat to not easily open.

Have had thermostat out and wont even get up to 60 c

[Godzilla32]

Make sure you fit the thermostat with the bleed hole at the top. If your radiator hose is still cold it means the thermostat hasn't opened. Once it does it will never completely close just vary between fully open and slightly closed. Its more so the fan that will control coolant temperature especially at standstill.

Like previously mentioned it sounds more like you havent bled the air completely from the system...make sure you have your heater on full and its a good idea to disconnect either a heater hose/manifold heater hose etc while your filling/bleeding the air out of the system. Leave the hose off until coolant flows from it then put it back on.

Goodluck, can be a pain.

Deren

[Duke_R32]

Had the same problem with my stepdads VL, same prob through 3 thermostats.

and by that time i was pissed off so i place the thermostat in boiling water ontop of the stove and check to see if was opening then put it into warm water and see if it closes.

i did this about 3 times and put it back into the car now its all sweet.

so what im saying is test the thermostat in boiling water before putting it into ur car.

[RB30-POWER]

Only use genuine Nissan thermostats, the characteristics of some of the aftermarket ones are dodgy.

You may have air in the system as well.