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New dumb LS question: Where to route the coolant bottle?

Broke4speed

Well-known member
Joined
Oct 5, 2009
Location
Marionville, Ontario, Canada
Ok, next question...

I've got the OE coolant bottle on the passenger strut tower, and was just planning on running it into the lower coolant hose as usual...but then I realised the thermostat is in that lower hose. On the redblock setup, the coolant bottle connects to the side of the rad without the thermostat...so I'm not sure on where to route the bottle now. I've tried to look up some LS build threads but I could never see where the hose goes out of the bottom of the tank.

I don't want to delete the bottle because it's nice and high.
 
On mine I put the smaller top line to a fitting on the radiator neck. And the larger bottom line I put on a short hose to a T in the heater loop, so bubbles would tend to go up into the reservoir.
 
And really, it's not all that active a part of the cooling system, it's just a place for the coolant to expand into, and contract out of.
 
The lower coolant hose connects to the rad, and the stock redblock setup does it that way. My only concern is that the location of the thermostat on the LS is opposite the OE redblock setup, which means the lower hose will now be the one that goes to the thermostat. Is it ok to tee into that line, even though it's technically 'after' the rad? I'm beginning to think I'll have to tee into the 'upper' hose, since it's technically before the rad in the flow direction.
 
On mine I put the smaller top line to a fitting on the radiator neck. And the larger bottom line I put on a short hose to a T in the heater loop, so bubbles would tend to go up into the reservoir.

Ah, the heater ports. That's an idea. Thanks John :).

And really, it's not all that active a part of the cooling system, it's just a place for the coolant to expand into, and contract out of.

Good to know. I wasn't super sure how big of a role it plays or if it had to be tee'd into a specific spot, so I defaulted to trying to emulate the stock redblock setup.

I swear, I've never asked so many dumb questions in my life, lol. This LS swap is certainly new territory for me.
 
It's not like the turbo coolant lines on a turbo car. The expansion tank doesn't really have coolant actively going through it. Just a sort of passive repository for the coolant to go in and out as it expands and contracts with changes in temp. So I don't think it matters.
 
And since we're talking about the heater circuit, you need some sort of bypass valve on it. Coolant always needs to be flowing through that loop, even if you have the heat shut off in the cabin. With the Volvo motor, it wasn't important, so the heater valve just shuts off all flow. This will lead to potential overheats on an LS setup - it needs the heater circuit to be flowing to bring hot water to the side of the thermostat that needs to sense the temp. I think once the thermostat opens it isn't as much of an issue?

Many newer cars have a 'active' valve in the heater circuit, either cable or vacuum operated, which sits between the lines leading to the heater core, and either sends the coolant to it, or bypasses the heater and sends coolant back down the line. It does NOT shut off the coolant flow on the engine side.

I found a 'passive' valve which does the same thing for mine: https://www.amazon.com/ACDelco-15-5...000C9J4HY/ref=cm_cr_arp_d_product_top?ie=UTF8

It's spring loaded. With the Volvo heater valve open there's no resistance and the coolant flows through the heater core. With the Volvo heater valve shut, pressure builds up and the spring valve opens and coolant flows back to the engine. Making the quirky way the thermostat works on an LS happy.
 
I found an aftermarket one on Amazon for $12 :).

https://www.amazon.ca/gp/product/B004AF34DQ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1


I have just been further down the rabbit hole of LS swap cooling than I've ever been...whoa. This link is amazing:

http://billavista.com/tech/Articles/Cooling_Bible/index.html#LSCoolingSystems

LS%20cooling%20system%20-%20numbered_resize.jpg


This is exactly how the Volvo cooling system works, with the surge tank, so I'm going to add a port to my stocker (or try to find an aftermarket one that fits well) and run mine like this.
 
I found a 'passive' valve which does the same thing for mine: https://www.amazon.com/ACDelco-15-5...000C9J4HY/ref=cm_cr_arp_d_product_top?ie=UTF8

It's spring loaded. With the Volvo heater valve open there's no resistance and the coolant flows through the heater core. With the Volvo heater valve shut, pressure builds up and the spring valve opens and coolant flows back to the engine. Making the quirky way the thermostat works on an LS happy.

You wouldn't happen to have a pic of it installed, would you? I'm trying to wrap my head around all this new cooling info and just can't put it all together without a visual.
 
My somewhat messy engine bay:
a5omU4gh.jpg


Up from the water pump, under the strut bar, then the bypass valve (just left of the brake booster). On through that (when the heater is on) to the heater core, and back to the bypass valve. And from there back around the turbo downpipe, through the strut tower to under the coolant tank, where a short hose on a T leads right up into the tank. The hose leads on straight from the T around the turbo and back to the other side of the water pump.

I'd have probably routed it a bit more neatly, but I was in 'get it ****ing done' mode at that point. Works fine, and I haven't had any urge to mess with it since then.
 
There really needs to be a FAQ for LS swapping these cars. I just learned aboutall this and I've been reading swap threads for months.

If my chinese valve fails, I'm definitely grabbing that LOJ one :).
 
My somewhat messy engine bay:
a5omU4gh.jpg

Looks clean from here. I have a side question - do those cleaner intake plenum/manifolds fit the 'truck' versions ? My motor is the 4.8l LR4. I'm having a hard time determining which of the stock car intakes swap over - the TB port 'looks' different.
 
There are two types of intake port on the Gen III LS-based engines: cathedral and rectangle. The 4.8 LR4 will have cathedral ports which means only certain 'car' intakes will fit. There are two types of throttle body flange as well: three bolt and 4. The LR4 has a three bolt, which again means you need to use a specific car intake if you don't want to mess about with converting. The LS1 and LS6 car intakes are three bolt and cathedral port, so those are the ones you want to hunt for IIRC.
 
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Looks clean from here. I have a side question - do those cleaner intake plenum/manifolds fit the 'truck' versions ? My motor is the 4.8l LR4. I'm having a hard time determining which of the stock car intakes swap over - the TB port 'looks' different.

Mine was a truck motor too, an alu 5.3 LH8 from a Hummer Alpha. LS parts all swap back and forth pretty extensively, I think (talking Gen 3 and 4) the only thing you have to look for are the older 'cathedral' ports vs. the newer 'rectangle' ports.

Err, and after googling up a pic, apparently there are 2 types of rectangle ports now:
235181_ArticleSection_XL_4ca496bf-aca9-40ea-848a-378a7dea24d6.png


Other than that I suppose there could be some oddball interferences between car intakes and truck accessories, and vice versa. In terms of front end accessories poking up where the lower car intake's throttle body needs to be.

My motor came from a front-crashed truck, I was pretty much starting with a blank slate, so I used Corvette front end stuff, it's is about an inch shorter (length, not height) than the car stuff (Camaro/GTO), and a couple of inches shorter than the truck stuff.
 
After a quick google, an LR4 should have cathedral ports, if you want a lower car intake, you'll want to find an LS1/LS2/LS6 intake.

In terms of the stock intakes, the LS6 intakes flows better than the LS2, which is slightly better than the LS1. And often priced accordingly.

I stuck a cable throttle on mine, I'm not using a stock ECU so no desire to mess with an electronic throttle body.
 
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