Coolant loss, no visible leaks

[Skylarking]

I read somewhere on the forum that the original cap pressure was 120 psi. & was then upped to 140 psi.

Thats probably the case but this numbers would be kPa not psi

120 kPa = 17.5 psi
140 kPa = 20 psi

120 psi = 700 kPa = 7 atm = 7 bar = 70 meters under water….

Never heard of any automotive cooling system at such pressures

To put that pressure into a non car perspective… a recreational open water scuba diveing certificate allows a diver to go down to 18m while recreational advanced open water scuba diveing certificate can go down to 40m. Diving beyond 40m requires specialist “technical” training and special gas mixes as air just won’t cut it if you want to avoid narcosis. Anything beyond 60m is classified as deep diving… 70m down is deep, really deep unless you are extremely well trained… but maybe not that deep…

In 2014, an Egyptian man dove to a depth of 1009 feet and 4 inches (307.6m), setting a new record in the Guinness World Record for the deepest ever-recorded dive. This dive took 12 minutes to get down, but 15 hours to ascend in order to properly decompress

 

[Fu Manchu]

Use the updated 140kPa caps from Holden.
Avoid aftermarket caps. There's no shortage of problems the people have reported over the years on forums. Genuine will cost the same ($30).

ALL air must be bled out. If all the air is not removed, coolant levels will drop considerably as air slowly escapes and coolant is drawn it to replace it. If there is so much air trapped that the entire volume of coolant from the reservoir is drawn in to replace the displaced air and more air is drawn back in, there will be issues. you might think it's all disappearing and it's not.

Bleeding the air out can only be done three ways. A vacuum fill. A low pressure bleed using a proper coolant air bleed funnel kit, or third way is to fabricate an air bleed funnel reservoir.

There can easily be several litres of air trapped in the cooling system. Most will be very fine bubbles.

 

[Terry57]

Thats is very friggin helpful.

My reservoir was empty again the other day. I'll bet thats the issue. Also when i replaced the cap 12 months ago Holden did not have one so they sent me over the road to buy aftermarket.

Ill bang an original one on and get my mechanic to bleed the system on the next service.

Thanks for the Info. Cheers

 

[Fu Manchu]

Hopefully he can do a vacuum bleed. There will be almost no air in the system.

If the mechanic just leaves the cap off, runs the car till some bubbles come out and replace the cap, you might see this continue until it’s bled correctly.

Most workshops tend to use the coolant bleed reservoir.

This method was taught to me by a Holden technician back in the late 90’s. Maybe early 2000’s(?)(it’s all a blur).

 

[Lex]

Thats probably the case but this numbers would be kPa not psi

120 kPa = 17.5 psi
140 kPa = 20 psi

120 psi = 700 kPa = 7 atm = 7 bar = 70 meters under water….

Never heard of any automotive cooling system at such pressures

To put that pressure into a non car perspective… a recreational open water scuba diveing certificate allows a diver to go down to 18m while recreational advanced open water scuba diveing certificate can go down to 40m. Diving beyond 40m requires specialist “technical” training and special gas mixes as air just won’t cut it if you want to avoid narcosis. Anything beyond 60m is classified as deep diving… 70m down is deep, really deep unless you are extremely well trained… but maybe not that deep…

In 2014, an Egyptian man dove to a depth of 1009 feet and 4 inches (307.6m), setting a new record in the Guinness World Record for the deepest ever-recorded dive. This dive took 12 minutes to get down, but 15 hours to ascend in order to properly decompress

Sorry, got it wrong, thought it was psi. KPA is the go.

 

[Skylarking]

Sorry, got it wrong, thought it was psi. KPA is the go.

No apology needed as it’s an easy mistake to make…

Heck even space exploration has been caught out with using wrong standards when NASA‘s Mars lander used celebration number in metric while another part of the system expected them in imperial … That didn’t end well as it was lost in translation and a rather expensive piece of hardware was lost

 

[johnmw1]

I'm having a similar problem in my VY which I have owned since new so I know everything at this point is still genuine as the old girl has never really missed a beat so far.

Anyway, I was going up a hill at 100 Km when suddenly my warning light came on telling me I was overheating. I pulled over to have a look expecting to see that my old belt had finally given up, but no it was still intact. Got home at a more sedate pace, let it cool down, to find the overflow hose into the reservoir bottle had blown off. Strange I thought, so I put a hose clamp on the overflow pipe. The reservoir was empty and to my dismay, I found some dirty oily sludge on the bottom of the dipstick. I topped up the reservoir and the radiator with more coolant.

I took it into a radiator specialist for him to say yeah we get this all the time. He took off the top plastic engine cover to show me coolant lying on top of the engine block. He says the inlet manifold gaskets are kaput and will need replacing along with a new radiator, hoses, etc all up about $1100. This was a bit of a shock to me money-wise, but as he said most of the cost was in the labour.

I took it to another mechanic for a second opinion but told him what I thought the problem was and could he quote me. He asked me to leave the car with him so he could investigate. An hour later I get a call to say I can pick it up. He came up with exactly the same prognosis and then promptly charged me $49.50 for 30 mins labour. I'm not even sure he even lifted the bonnet, and I have never been charged for a quote before. The quote all up from him was about the same $1100 also including a new radiator, hoses etc To be honest the charging me for a quote has put me off him despite the number of rave reviews he has online. Could have been different if he said if you go with us we'll take the cost of the quote off the final price, but no..

So after that long story, there is something else for you to maybe take a look at. One question though is, why does the radiator need renewing as opposed to giving it a pressure flush?

Cheers,
John

 

[J_D 2.0]

I just noticed a slow drip leak from underneath the car, right in the middle around where the engine bay starts. Probably a drop every 20 seconds. I’ll take it in to get looked at.

Probably the water pump or the filler neck o rings.

 

[Terry57]

Yer well i would not get to bent and twisted about paying for the quote simply because time is money and labour is friggin expensive these days.

He most probly forgot to offer the quote be included in the cost , that little mistake could of cost him that job. ?

If you do not want to pay for a new radiator you can tell them, they will do it but maybe not guarantee the job.

Up to you innit. They will take your money either way.

Oh yer, one more thing. I would not give him the Job simply because his labour rates are rediculously cheap.

Here in the West 150 buks per hour is considered quite the norm.

 

[Z31na]

I could be wrong, but based on what I have seen selling them, it looks like Tridon were the ones that supplied the Genuine caps. Tridon and CPC are the biggest suppliers of caps and will sell to others in home brand packaging. For Commodores, the OE and Tridon "aftermarket" have the exact same markings. Where as CPC are totally different.


Hell, Holden even had their own proprietary font for Commodore in the 2000's and theres a Tridon cap with that font stamped in it.