LS Swap coolant system - just wanted to confirm ive set my LS swap coolant system correctly

so ive got a coolant tank with a feed out the bottom to the top of the radiator, done away with the pressure cap on the radiator and therefore now have pressure cap on my coolant tank, also the engine steam vent, vents into the top of coolant tank and then theres a black pipe out the top of coolant tank , to release excess pressure pics below - does that sound right?

 

Sounds about right if you're gonna run a surge tank. I'm not running one so i can't answer directly.. I ran my steam lines to upper radiator hose and done. Nothing wrong with your setup either.

 

Here's a helpful link.

https://www.pirate4x4.com/tech/billavista/Cooling/

 

You just have an overflow hose from the radiator to exit on the ground?

 

They came that way from the factory in 69

 

I don't. I run the factory 79 plastic overflow reservoir which ties into the radiqtor. Sounds like the op does have an open ended hose or "pipe".

 

I'm asking because I just have an overflow hose to the ground right now (LS1/T56) and I'm really short on space for an overflow bottle. I don't have a prob like it is as long as I don't get coolant on the bottom of the car. May have to figure out something.

 

yep black pipe goes to bottom of chassis

had the car running today, was cooling etc with no issues, Had to top up surge tank, so air must have come out

thanks guys

 

I only have 1 hose from radiator to the 79 overflow reservoir. I'm running a dewitts radiator for a 79 ...not an ls swap radiator from them. It looks like the 79 overflow res does have a vent of some sort on top. It's way under the fender and i don't remember if the little piece if open ended or not. Maybe someone else can chime in. Not sure what year car you have slofut.

Corvettedave383, that 4x4 link i posted earlier does recommend if you run a surge tank to still run an overflow reservoir too. I'm sure there's some verbage to back it up. There's a lot of good info on that site for ls swap options from coolant to pcv connections and so on.

Ryan

 

My boat's plumbed like that and it works just fine. Just make sure that there's a point in the system that is above the top of the block, be it the radiator or an overflow tank. Cap over pressure vent to the ground & the steam line running into the tank is fine.

 

Ive got a dewiits rad aswell, but cut the pressure cap corner off and welded on a corner on, to square it off, with that -8 an fitting welded in - the system seems to be working fine just now

 

Thanks, yeah the surge tank is higher than everything else, cheers

 

I got confused as hell on the cooling with ls1 having the opposite inlet than normal cars and combining with heater system that as a vacuum that closes is off...



2 Questions if you dont want to read;


1. High pressure cap on the radiator OR surge tank

2. Bottom hose going to lower radiator hose OR heater IN hose


I have found a diagram that shows the surge tank tapping into the LOW pressure side of the heater hose rather than the heater hose running into the swirl pot and than out again like in some pics..

The green highlight shows the LOW pressure side of the system.


It seems that everyone agrees that the surge tank should be on the low pressure side for two reasons: (1) bubbles are only going to migrate to an area of lower pressure and (2) a low-velocity, low-pressure air pocket will facilitate deaeration.It seems that everyone agrees that the surge tank should be on the low pressure side for two reasons: (1) bubbles are only going to migrate to an area of lower pressure and (2) a low-velocity, low-pressure air pocket will facilitate deaeration.



The swirl pot according to that website must have the bottom port linked to a LOW pressure side.
The option is the lower rad hose or the Heater In side.


However, since my 1980 C3 Corvette with LS1 has a vacuum operated shut off valve on the heater side, im not sure if the heat IN line always has flow when not in use (is this even a concern?)...
Would it be better to use the lower radiator pipe which once thermostat is opened will have a continually flow of low pressure water (that has a suction effect) that the swirl pot gets any trapped air?


This website suggests to connect the bottom port of the expansion tank to the lower rad hose.
http://www.swartzgarage.com/radiator




So once that is decided..

Next question is the pressure cap. On the radiator or surge tank ?



On https://www.pirate4x4.com/tech/billa...vista/Cooling/ it says

If you add a surge tank to a system that already has a rad cap on the radiator, you need to permanently seal the radiator rad cap location, or at least install on the rad a cap with a rating significantly higher than the surge tank cap will have, so that the radiator mounted cap will not open before the surge tank cap.

If that is the case the rad vent port #15 that sends vented air to the surge tank would never open ??? The air would be trapped in there until the system over pressurizes.


The diagram from swirl pot shows only a rad seal cap should be used not a higher pressure cap...


Reading http://www.swartzgarage.com/radiator...e.com/radiator



The surge tank is topped with a radiator cap, making the tank both the fill point and the pressure relief point for the cooling system. (IS THIS SAYING THEY ALSO SUGGEST PRESSURE CAP ON THE SURGE TANK?)

The tank is mounted as high as possible within the engine compartment to maximize its efficiency as an air collection tank, a surge and expansion tank, and a coolant system fill point.


Then they go and say this


The surge tank became a pressurized coolant recovery tank , nothing more than a convenient location for the radiator cap. The radiator no longer had a low pressure tank to vent into so the radiator vent was relocated to the swirl pot (aka the system tank), which was an inept decision since the system pressure in the swirl pot is higher than it is in the radiator.

This change in the cooling system design was ill-advised. The air being trapped in the radiator needs a functional vent system.