P38A Coolant pressure test

JOHN ELLIS · Feb 28, 2017

Hi all,

I have a P38 Range Rover 2000 4.6 V8.

I've got myself a coolant pressure test kit, it's a great tool to have but I was wondering how much pressure I should be putting the system under before any damage occurs.

I've been going as high as 1 bar / just under 15 psi.

What is the max pressure I can put the system under on this engine.

Cheers all.

John.

Grrrrrr · Feb 28, 2017

Don't know but I doubt it needs much.

JOHN ELLIS · Feb 28, 2017

Man I'm lucky, been looking online and found rave in PDF format for tablets and mobile view, max pressure for the v8 is 1 bar. Glad I didn't push it lol, I've posted a picture of the page I found.

Gazbo · Mar 1, 2017

JOHN ELLIS said:
Man I'm lucky, been looking online and found rave in PDF format for tablets and mobile view, max pressure for the v8 is 1 bar. Glad I didn't push it lol, I've posted a picture of the page I found.

Your cooling system only operates at one bar pressure but that pressure I would not class as a satisfactory test pressure, remember that your pressure test is only a static test, with the engine running the dynamic situation can be a bit different, I would be inclined to test the system to a little higher pressure to account for the system in a running condition, a hot hose may be more inclined to blow out at normal operating pressure than a cold hose, likewise a slipping hose spigot with a clamp not quite tight enough. Cooling systems are called on to run constantly at their maximum pressures/temps due to all the anti pollution legislation and equipment fitted to engines. There would be a test pressure stated for the cooling system which should be higher than the normal max operating pressure I think.

wammers · Mar 1, 2017

Pressure quoted is the cap release pressure. Any internal pressure slightly above 15 PSI will be vented via the cap. The cap is designed to fail completely at any thing above 22 PSI to prevent damage to the system. Two ways to use tester. Pump system up and check for leaks by noting pressure drop over time. It's then a matter of finding the leak. Or connect and start engine and watch pressure build up as engine rises to normal temperature. On the diesel at normal temp, pressure should be around 5 to 7 PSI, on petrol slightly higher due to higher temp thermostat. At no time idling at normal temp should the coolant pressure get anywhere near 15 PSI. If at anytime you have had an explosive expulsion of coolant past the cap due to an airlock Etc. Change the cap. The tool should have cap release pressure test adaptor.

JOHN ELLIS · Mar 7, 2017

wammers said:
Pressure quoted is the cap release pressure. Any internal pressure slightly above 15 PSI will be vented via the cap. The cap is designed to fail completely at any thing above 22 PSI to prevent damage to the system. Two ways to use tester. Pump system up and check for leaks by noting pressure drop over time. It's then a matter of finding the leak. Or connect and start engine and watch pressure build up as engine rises to normal temperature. On the diesel at normal temp, pressure should be around 5 to 7 PSI, on petrol slightly higher due to higher temp thermostat. At no time idling at normal temp should the coolant pressure get anywhere near 15 PSI. If at anytime you have had an explosive expulsion of coolant past the cap due to an airlock Etc. Change the cap. The tool should have cap release pressure test adaptor.

Thanks wammers, I didn't even know you could run the engine with the test kit attached that's brilliant information mate thanks.

JOHN ELLIS · Mar 7, 2017

I might as well continue this thread.

I've been loosing coolant, so I've had the test kit on and in total I found 5 loose hose clamps causing the leaks, so drove to work Monday and no coolant on the ground....result, or so I thought, checked the coolant today and it's almost empty, aaaaaarrrrrggggghhhh, so under the bonnet again having a good look round and I noticed the throttle body housing (see the photos attached), is there an emoji for banging your head against a brick wall lol

brianp38dse · Mar 7, 2017

From what I can recall, a lot of guys just bypass the heater job done.

JOHN ELLIS · Mar 7, 2017

brianp38dse said:
From what I can recall, a lot of guys just bypass the heater job done.

Maybe something I look into, me and don1 did this job only a couple of years ago, we will see for the bit of work it is I think I'll just sort it.

P38A Coolant pressure test

JOHN ELLIS

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Grrrrrr

Technician, Bodgit & Scarper Ltd

JOHN ELLIS

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Gazbo

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wammers

No longer with us, RIP

JOHN ELLIS

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brianp38dse

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JOHN ELLIS

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