Coolant still running low but no leaks?

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Themasteryeti
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Coolant still running low but no leaks?

Post by Themasteryeti » Sun Oct 30, 2022 10:27 am

A while back I posted about having a coolant leak and overheating issues, so one member suggested a rad pressure tester, so I got one and sure enough when up to pressure the coolant was leaking out the ends of one of the hoses so I replaced the clip with a better one and it seemed to be fixed, no overheating, no leaks, this was a few weeks ago now but I've just checked my coolant level and it's already gone back to the minimun But as far as I can see there are no leaks at all, I don't suppose anyone would be able to share some wisdom on this 😩
1973 vw beetle
1993 480s

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jamescarruthers
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Re: Coolant still running low but no leaks?

Post by jamescarruthers » Sun Oct 30, 2022 11:49 am

Could it be your leaky hose clip allowed coolant out but also air to be sucked in to the coolant system when it’s level was low? How about you top it up and check it out after a bit of bleeding and driving? If you are lucky it may just have needed that little bit of air bled out and all will be well in time?

If not, engine oil/coolant heat exchanger behind the oil filter and automatic gearbox oil/coolant heat heat changer (if you have an automatic gearbox) could be culprits for sneaky coolant losses.

Also, as recently my discovered by my less than triumphant no-show at the last UK 480 meeting, the coolant pipe at the back of the engine, to the interior heater matrix, can spray on to the exhaust manifold. Mine was quite dramatic steam, but yours could be tiny and just evaporating?

Another piece of cooling system that you can’t see is the interior heater matrix. Have a feel under the carpets on either side of the centre console inside the car. If it leaks, it soaks the carpet insulation nicely first.
1987 Volvo 480 ES, 507274, 217 - Red (Ness)
2006 Citroen C6 Exclusive 3.0 petrol/LPG
2008 Mini Cooper convertible (Mau)

Previous 480's:
J123 CFU -- ES
J449 MNL -- ES auto
D864 CPV -- ES
L691 JFC -- Turbo
F70 MNR -- ES
H858 FGV -- Turbo auto
E981 KHM -- ES (509849)

jifflemon
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Re: Coolant still running low but no leaks?

Post by jifflemon » Sun Oct 30, 2022 12:00 pm

What did you pressurise the system to?

The cap is rated at 150kpa, which is around 22psi. I did to 15psi, fixed all my leaks. I realised i should have gone higher, and found more!

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Themasteryeti
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Re: Coolant still running low but no leaks?

Post by Themasteryeti » Sun Oct 30, 2022 4:52 pm

jamescarruthers wrote:
Sun Oct 30, 2022 11:49 am
Could it be your leaky hose clip allowed coolant out but also air to be sucked in to the coolant system when it’s level was low? How about you top it up and check it out after a bit of bleeding and driving? If you are lucky it may just have needed that little bit of air bled out and all will be well in time?

If not, engine oil/coolant heat exchanger behind the oil filter and automatic gearbox oil/coolant heat heat changer (if you have an automatic gearbox) could be culprits for sneaky coolant losses.

Also, as recently my discovered by my less than triumphant no-show at the last UK 480 meeting, the coolant pipe at the back of the engine, to the interior heater matrix, can spray on to the exhaust manifold. Mine was quite dramatic steam, but yours could be tiny and just evaporating?

Another piece of cooling system that you can’t see is the interior heater matrix. Have a feel under the carpets on either side of the centre console inside the car. If it leaks, it soaks the carpet insulation nicely first.
I didn't think about that, how would I go about bleeding it?

&& Didn't realize there were so many bits to check, I'll give them a look and see if there's anything noticable, I did check the carpets and lucky that was dry so that's at least one thing I can tick off the list 😂
1973 vw beetle
1993 480s

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Themasteryeti
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Re: Coolant still running low but no leaks?

Post by Themasteryeti » Sun Oct 30, 2022 4:53 pm

jifflemon wrote:
Sun Oct 30, 2022 12:00 pm
What did you pressurise the system to?

The cap is rated at 150kpa, which is around 22psi. I did to 15psi, fixed all my leaks. I realised i should have gone higher, and found more!

I did read about a chap on here that did the same thing so I made sure to go to 22psi, but apart from the original leak there was nothing else, not that I could see anyway!
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1993 480s

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Re: Coolant still running low but no leaks?

Post by jifflemon » Mon Oct 31, 2022 11:34 am

That chap was likely me!

How long did you leave it? Generally I pressurise and leave for half an hour. There should be no drop in pressure (and no leaks!)

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