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Faulty Tridon thermostats

Cakey

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Is there anyone else out there that has been caught out with a faulty Tridon thermostat.Late last year I gave my cooling system an overhaul including a full system flush and new coolant blah blah blah.This was done to my VN SS my once a month weekend toy,Car hardly gets driven but started regulary.I noticed after drive a fortnight ago that the car was bleeding coolant.I went back over the cooling system to pinpoint the problem without a pressure tester,lo and behold I found a burst heater hose which indicated to me a pressure problem in the system.Which to me indicated thermostat,Pulled out the thermostat placed it in a pot of water brought up to boiling point guess what faulty thermostat would not open.So what I suggest to anyone who works on there own car is to check new thermostats before installing them as they can be buggered from brand new.
 

azzfox

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Ahh dont say that. I just bought one! :p

But I would like to point out that the thermostat wont cause pressure issues. It is closed until the engines propper operating temperature is reached. To my understanding the heater circuit is fed directly from the pump so it bypasses the thermostat anyway. I would be checking the radiator cap and make sure its the correct pressure rating. You never know, the hoses could have just been aged or had a manufacturing defect.

But I will be checking my thermostat before I install it. :)

EDIT: Mine tested all good.
 
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centy

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yes anything can be stuffed when brand new.
Your conclussion that the thermostat was the cause of a bust hose is completely wrong.
If the hose burst then they are old and need to be replaced.
reason i say this is the radiator cap IS a pressure release valve that limits the MAX pressure in the system. REGARDLESS of if the themostat is block or not the pressure variations in the system would be TINY, due to the way they are designed to have the valve closed at low temp. IF it was a pressure problem then the radiator cap would be the problem but that is very unlikle as they normally loose tension when fault not gain, which would be needed to increase pressure.

In sort, your hoses are old and need to be replaced. If one has failed then change the bloody lot, they will be due.
 

Yeah it's a calais

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I just got a used radiator and new thermostat and radiator cap 4 my VP calais, and the radiator burst. this is the 2nd time i had 2 replace a radiator, It's like it just has 2 much pressure in the system wtf!!!!!
 

azzfox

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Is the cap the correct pressure rating? Specs is 135 kPa (roughly 19.5 psi).

Also your taking your chance with a used radiator. Keep in mind that its roughly 15-20 years old! But Ive never had a problem with radiators bursting.
 

greenfoam

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The heater hoses allways break on the the 5 litre sooner or later. Down low near the water pump they bulge and POP. Nothing to do with the thermostat, you can buy the full set of heater hoses from Holden for pretty cheap. No more than aftermarket hoses cost anyway and the aftermarket ones are a bit rubbish
 

levymetal

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i'm getting coolant leaks from everywhere in my car. when i got my car i replaced the radiator cap (got it from repco, packet said it's for my car). then a few months later i had a water leak, turned out to be the pump. replaced that. then water still kept on leaking from the pump. tightened up the bolts, then the little 2 inch hose above the pump started leaking. got a new one of those. then the radiator cap started leaking. bought a new one from supershit, was 100x worse. took me a while to figure out that the radiator neck was busted, couldn't keep the cap on tight enough. bent that into shape. ok for a while. then some more water on top of block. tightened top radiator hose at engine side. then water leaking from radiator side of top hose. tightened that up. slowly loosing coolant. then i see coolant marks from thermostat housing. tighten that up. later i look under the bonnet, coolant spray over front of engine. sprung leak in radiator. this is all over about 3 months btw. WTF is going on.

as said above, it's like there's too much pressure in the system. when i take the radiator cap off, even after days of it sitting, the water still slowly starts coming out. should it still be pressurised after this amount of time?
 

greenfoam

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Not if there's a leak!:D
 

wrx884

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As some1 else said which i sorta lernt while doin all my heater hoses (plus its easier lol) replace the lot not just 1 the system will just go straight 2 the next weakest link in the system 2 try leak out of.

Try some No.3 NON-hardening loctite on the hoses fittings also and buy a genuine radiator cap ($50 from holden) ive been told the aftermarkets rnt that great in doin their job after i was gettin some sorta vacume sucktion into my system.
 

azzfox

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also and buy a genuine radiator cap ($50 from holden) ive been told the aftermarkets rnt that great in doin their job after i was gettin some sorta vacume sucktion into my system.
You will not get vacuum in the system. The cap has a small one-way valve in the middle so when the system cools and starts to create vacuum, the valve opens allowing coolant to enter from the reservoir bottle. Otherwise your radiator would implode. :)

when i take the radiator cap off, even after days of it sitting, the water still slowly starts coming out. should it still be pressurised after this amount of time?
Yes, but as soon as you remove the cap the pressure is lost. And because liquid cant compress it shouldnt run out, unless theres air trapped in the system. But will most likely be from a leak in the top hose drawing in air OR its just coolant entering from the reservoir out the hole in the filler neck due to the siphon effect.
 
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