VS Radiator leaking around cap

[Kingo]

In the last week I've changed my radiator, thermostat and hoses.
After replacing the radiator, I noticed that there was a leak around the cap, so I got a new cap.
Still leaks around the cap with the new cap.
I've checked the overflow line is clear, and the overflow reservoir lines are the right way around. Coolant does seem to go in and out of the overflow, but its leaking around the cap!
Whats weird also is that the coolant that leaks out from the cap is real thick and kinda oily feeling.

Any ideas? Surely can't be the new radiator... and I'm fairly certain I put the thermostat the right way round...

[_R_J_K_]

Whats weird also is that the coolant that leaks out from the cap is real thick and kinda oily feeling.

Is it of a creamy consistency and texture? If so, this usually indicates a blown head gasket or inlet manifold gasket.

[Kingo]

No, its just thick, like coolant concentrate.
And inlet manifold gasket was done not too long ago.

I had a search around and some people have had this problem, but never got around to posting how/if they fixed it.
I think immortality had the same problem a few years ago, i'll shoot him a pm.

[pillzor]

i think from memory the cap should be 125 psi rated or something ( you probably want to google that ) , as i just changed my radiator myself and on advice from the mechanic i drove it round with the cap not fully tightened as the high pressure that ecotecs run in the cooling system was making it piss out of my busted radiator faster.
so blah blah anyway just check you have the right pressure rated radiator cap is what im getting at.

[lifeguard_aus]

did you make sure you bled the system fully using the bleeder valve?
If you have an air lock this will allow a build up of air pressure 3.8's dont like air locks....many radiators fail because of low water/ccolant levels and incorrect thermo/coolant changes.

[pillzor]

did you make sure you bled the system fully using the bleeder valve?
If you have an air lock this will allow a build up of air pressure 3.8's dont like air locks....many radiators fail because of low water/ccolant levels and incorrect thermo/coolant changes.

i should do this myself , is there a writeup you know of?

[Kingo]

Yeah I have a 135 cap, which is the right one apparently. And yes I bled the system, drove around the block, pulled up and opened the bleed valve until it ran straight coolant (done this a couple of times).
I've noticed that the cap doesn't go on overly tight, I can rock it back and forward (rock, not twist) and when i do this, it leaks pretty bad.
I'm gunna go bend the clips on the new cap and see if that holds it on better.

This is another post about the same issue, but slightly different circumstances.
coolant leak

[lifeguard_aus]

let me know how you get on...my brother is a mechanic for holden..i'll ask him tonight as well

[RX25SE]

Is the new cap a Tridon brand? Seems to be now stocked but Bursons, Repco etc. instead of the CPC brand.
I had the same issues and tried a couple of new Tridon caps, still leaked.
Bought one from Holden (about the same price) and was pleased to see it was a CPC brand. No more cap leakage.
If you compare the two, you will notice a difference in the top seal.

[levymetal]

yeah i bought a radiator cap from supercrap once and it didn't even have a rubber seal around the part that seals to the neck. man that leaked so bad it wasn't even funny. we're not just talking drips here, but absolute gushing.

probably the best bet is to get a better radiator cap from holden, and yeah bend the clips on the radiator (i did that once and it really helped). also check to make sure that the overflow hose from the radiator to overflow bottle isn't blocked. well, if VS' are set up like that

for anyone searching this in years to come, 135kpa = 20psi. if anyone has a 5ltr, they run a 100kpa/15psi cap

[Kingo]

Yeah the new cap is a Tridon brand.
The old cap was a Tridon too, the funny thing is the old cap worked fine on the old radiator, old cap on new radiator = leaks... new cap on new radiator = leaks...
I'll look into getting a CPC one then.

[RX25SE]

yeah i bought a radiator cap from supercrap once and it didn't even have a rubber seal around the part that seals to the neck. man that leaked so bad it wasn't even funny. we're not just talking drips here, but absolute gushing.

Sound like it was a 'non recovery system' cap.


As used in HQ!!

[immortality]

yeah, i had this problem. i tried a new trident cap and it leaked. i found that some of the plastic around the radiator cap fitting was damaged/worn a little from repeated removal of the radiator cap.

Yeah the new cap is a Tridon brand.
The old cap was a Tridon too, the funny thing is the old cap worked fine on the old radiator, old cap on new radiator = leaks... new cap on new radiator = leaks...
I'll look into getting a CPC one then.

in the end i fitted another CPC cap which i got from supercheap. i may also have bent the taps in a touch as well. the seal on the CPC cap is slightly different to the trident cap.

[Kingo]

Just put on a CPC cap, and after a short hard drive no leaks around the cap.
We'll see how it goes over the next few days.

[itchy123]

Is the new cap a Tridon brand? Seems to be now stocked but Bursons, Repco etc. instead of the CPC brand.
I had the same issues and tried a couple of new Tridon caps, still leaked.
Bought one from Holden (about the same price) and was pleased to see it was a CPC brand. No more cap leakage.
If you compare the two, you will notice a difference in the top seal.

ive just noticed today after reading this thread yesterday that my stupid piec of s%#t tridon bursons cap is leaking (only bout 2 months old)
i did notice it did this a while ago but i took it off and put it back on and it seemed to have solved it for a just over month lol
so the cpc are good?
thanks
adrian

[seraphic06]

CPC make the caps for GMH. Why buy something else?

[itchy123]

CPC make the caps for GMH. Why buy something else?

wish i knew this before lol
oh well there only cheap gettin a new one today

[Kingo]

Ok verdict is.... CPC caps are the way to go. I've been driving a fair bit and it hasn't leaked yet. But now I have found other problems! will this ever end?!?!

I thought a cap was a cap, didn't really matter what brand and I just asked for one at Sprint and got a Tridon.
My local auto shop (can't remember what they're called, used to be Motormate) had the CPC brand and even got one on the public holiday

[immortality]

LOL, fix one leak and then it moves. i had.......have that issue. go around a make sure all the hose clamps are tight. then the water pump went. then i did the intake gaskets. now it weeps through the thermostat housing bolts. oh well. i can live with that for now

[TrikkBen]

All the Holden caps are CPC from factory.