Faulty Tridon thermostats

[Cakey]

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]

Ahh dont say that. I just bought one!

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.

[centy]

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]

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]

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]

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]

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]

Not if there's a leak!

[wrx884]

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]

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.

[wrx884]

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.

.

Well thats wat happend and a few members on here said so 2, its somthing 2 do with the seals on the caps not doin their jobs (prolly exactly wat ur explaining now) but as soon as i replaced the cap 2 a genuine 1 i had pressure back in my top hose and i didnt get that squashed hose look wen cold.

[azzfox]

Hmm k. Yeah the hoses shouldnt be squashed when cold lol. Did you make sure it was a coolant recovery cap? Will have it written on the cap, and can be easily identified by the valve in the middle. It could be possible that you bought a cap of the correct pressure rating but with no recovery feature. If not, you can test the valve by simply pulling on it, it should be lightly spring loaded.

[rob drag racer]

at least your rad cap didn't let go all together i ended up with 3rd degree burns wile i was working on my old vp race car and the cap let go and dumped the hole cooling system on me and to boot the thermos didn't kick in so it was relay hot all i can say is when you take your shirt off and you peel several layers of skin with it it relay hurts

[wrx884]

Hmm k. Yeah the hoses shouldnt be squashed when cold lol. Did you make sure it was a coolant recovery cap? Will have it written on the cap, and can be easily identified by the valve in the middle. It could be possible that you bought a cap of the correct pressure rating but with no recovery feature. If not, you can test the valve by simply pulling on it, it should be lightly spring loaded.

Thats possible the repco guy gave me the wrong type but i just had a look at the cap its spring loaded and in the middle of the larger seal it has a smaller 1 that moves and has an opening under it so i assume thats the release valve??

[azzfox]

Sounds about right. Odd that it failed. Not a very complex device . My cheapie cap from supercheap hasnt failed yet. What brand was yours?

[centy]

1. Do you have water or coolant in the radiator?
2. Have you used a cleaner to flush the system?
3. Are ALL the hoses and clamps new?
4. Did you use sealant on the top hose when fitting it?
5. Do you lean on the fan shroud when working on the engine?
Answers shoud be
1 coolant
2 yes
3 yes
4 yes
5 HELL NO

the reason for these answers pretty blood obvious except for the last one.
5 if you lean on the fan shroud the extra stress can cause the tanks to get a fine crack near the mounts.
A real pain in the arse and hard to find, mine didn't leak till it was hot and then only a very fine spray.

[rob drag racer]

my cap was a proper holden cap

[azzfox]

my cap was a proper holden cap

*sings* Irony...

Missed that post. All I can say is ouch!

[rob drag racer]

it happens i killed that car not long after that and i must say i enjoyed it lol

[levymetal]

the strangest thing happened to me yesterday, i didn't have a leak for 2 weeks now, so i was pretty happy with that. decided to check the coolant levels just to see what was going on, and in the overflow the tube was still in the water but it was pretty low. so i decided to top it up. drove to work, then when i had finished work there was a massive puddle of coolant leaking directly from the radiator. drove home, woke up today and yet another massive puddle of coolant (same spot). it doesn't make sense to me what the level of coolant inside the overflow has to do with my car leaking (unless of course it's harder to push the coolant into the overflow if it's got a higher level, nothing the system shouldn't be able to handle), but there is not a chance in hell that this is a coincidence... now that the level inside the overflow is dropping again, i am going to see what happens with the leak. i bet it is going to stop again once the level gets lowish. maybe i'll just leave it and monitor it, as long as that tube is in the water then it's ok i guess.

[HoZy]

Thought I'd throw up a post here,

I've got a new 82degree thermostat, She didnt open, temp got to 1/2 on the 5litre an it still didnt open...

cheers
MaT

P.S- It's a Tridon..


EDIT:

All good, She got to 3/4 temp then thermostat opened, Now she's good!!!

[levymetal]

bringing up this thread from the past again, hozy, did your thermostat get better? i just got a tridon 88deg one, and when i drive my car from cold the temp gets up to 3/4 before the thermostat opens! and when it does, it drops back down to between 1/4 and 1/2 and stays like that. i thought it might just be the first time it opened, but it's done it twice now. it makes me feel very uneasy