Cooling System Questions

[OziSteve]

The cooling system on the GTR with LS7 I just purchased is set-up like this:



Both the expansion and header tanks were full to the brim when cold. From what I have read on here and seen on other systems, I am not sure about the routing of the vent lines being correct or the caps being on the right tanks. Is this the correct factory layout?

I pressure tested the system and found several leaks in the main hoses which weren't able to be fixed by tightening the clamps so I am going to empty the system and replace those hoses and clips. Any tips for refilling to avoid air locks? How full should the tanks be when cold?

Thanks

Steve

Edited by OziSteve on Thursday 20th December 02:38

[rossins]

Morning
I'm running standard system with LS7 & left hand header (passenger side in uk) full & right hand tank about half full. When refilling ensure the heater is on the full position as this helps get rid of any air in the system.
Cheers Simon

[OziSteve]

It seems to me that the expansion tank (right-hand tank) is not acting as an expansion tank at all the way the piping is set up on this car. It is connected to pressurised water sources including the cylinder head, the main radiator and the pressurised side of the header tank and has no pressure release, so it is acting just as an extended part of the coolant system. The header tank (left hand tank) on the other hand, has a pressure cap which simply vents to atmosphere, so there is no way for coolant to be recovered.

Am I wrong?

[humble]

If the system is plumbed like the picture shown, it is incorrect.

The smaller vent hose should tee into the steam lines from the heads and then go into the swirl pot (which should have the pressure cap but doesn't by the illustration). The vent from the swirl pot should go to the bottom of the catch tank (without the pressure cap) to recover expelled coolant when necessary, and the expansion overflow should go out of the engine bay to ground, preferably behind the rear wheels. The proper setup will be sealed but still release excess pressure/coolant, and the properly plumbed steam lines will help reduce captured pockets of air/steam in the radiator and heads.

Will

[OziSteve]

Thanks Will,

Yes that's exactly how it is now and you have confirmed what I thought.

I am changing the setup as follows, running the steam vent into a T with the radiator purge and into the top of the left hand header tank (swirl pot) with the pressure cap venting to the right hand tank, now acting as a conventional unpressurised recovery tank.

I think that's right?

[humble]

Thats exactly how it should be, and how the factory sets up the coolant system.

Will

[BogBeast]

OziSteve said:

Thanks Will,

Yes that's exactly how it is now and you have confirmed what I thought.

I am changing the setup as follows, running the steam vent into a T with the radiator purge and into the top of the left hand header tank (swirl pot) with the pressure cap venting to the right hand tank, now acting as a conventional unpressurised recovery tank.

I think that's right?

Surely the pressure relief cap should on the right-hand tank?

Else how would the 'expansion' water return back into the cooling system once its gone through the pressure cap?

BTW I run Evans waterless coolant and something like a 2 psi cap. I work wonderfully for me.

[OziSteve]

As I understand it, it works if the radiator cap on the left tank is a double seal type cap designed for recovery systems, so bidirectional.

Under pressure when hot it opens to allow coolant out into the recovery tank on the right. Under vacuum when cold it opens in the opposite direction to draw coolant back into the systemfrom the recovery tank.