Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[JamesV6CDX]

My 3.0

Engine is as strong as an ox. Starts/runs brilliant and bags of power

It's not losing coolant as I thought it may be, if it is, it's a tiny loss

This is the issue. Every v6 I've known always has good pressure in the coolant system.

This one, even after a long run, take the header cap off, and not even a hiss, hoses totally soft

Done pressure test, it pressures (but not lots, until the cap hisses) and no leaks visible

Tried new cap on tank, known good from my 2.2

No overheating temp gauge does as it should

Anyone had this or got any ideas?

[chrisgixer]

If it was loosing pressure it would boil over no?

What's the temp gauge doing?

[Entwood]

check around the neck of the expansion bottle .. not unknown for tiny cracks to occur ... use a soap solution to check for pressure loss ??

[Dan282]

I was think similar, either expansion cap seal or a crack in the filler neck.

[JamesV6CDX]

Temp gauge is fine.

Thanks entwood

[chrisgixer]

Temp gauge is fine.

Thanks entwood

Oi, where's mine and Dans thank you?

[JamesV6CDX]

Temp gauge is fine.

Thanks entwood

Oi, where's mine and Dans thank you?

Sorry

I'm pondering your point re boiling over..

What you say is true, but its still not holding pressure ...

[Entwood]

Temp gauge is fine.

Thanks entwood

Oi, where's mine and Dans thank you?

Sorry

I'm pondering your point re boiling over..

What you say is true, but its still not holding pressure ...

If its running at 85 it won't boil over ...although you may get the odd spot of very hot water/steam in the bowels of the engine due to low pressure....   but will lose a little by evaporation

pressure simply increases the boiling point ...  at 85 you've not yet reached it ..

[JamesV6CDX]

If left to idle, temp creeps up to just under 100, fan kicks in, then back to mid way

[chrisgixer]

If left to idle, temp creeps up to just under 100, fan kicks in, then back to mid way

So it would boil over if not for the fans. So its loosing pressure, or sounds likely.

[AndyStobbs]

You say you've done a pressure test, are we to take from that, that you've proved it wont hold pressure? But that you cannot find the leak?

[Kevin Wood]

The pressure arises because you have a sealed system where the coolant expands as it heats up. It's getting up to temperature so the only reason for not pressurising will be a leak somewhere. If you're sure there are no coolant leaks anywhere, then the leak must be from the air space at the top of the expansion tank.

The cap would be the first suspect. As this has been substituted, my guess would be that the neck of the tank has cracked, as mentioned, or that the cap is not forming a good seal against the neck of the tank. This might be because the lip is cracked or uneven, perhaps?

I would have thought enough coolant leakage to prevent the system pressurising would be very noticeable. Air leakage less so.