LT1 Coolant Hoses Help (2 Viewers)

[Poppa T]

I just put in a 93 LT1 350 in my FJ60. Everything went smooth except coolant plumbing. No coolant is getting out of the stock radiator into the water pump. I have read so many forum's I'm blue in the face. Baffled by all the "not sure" comments of how the heater hoses, reverse coolant flow, etc should be hooked up. I need to see some pics or hear from someone who has hooked up the coolant / heater hose lines on a LT1 to a stock FJ radiator. Thanks for considering to help.
Poppa T.
87 FJ60

 

[Elbert]

not sure this will help you, but on 5.7 vortec I've found bleeding the system to be a pain, so anytime all the coolant comes out for some type of maintence...when I get things back together I start the coolant fill this way (1) I take the thermostat housing off the intake and fill the engine as far as it will go until almost to the thermostat housing (i'm filling through the hole in intake manifold where the thermostat housing resides), then place the thermostat housing back on and bolt down. Then I fill the radiator. You might want to post up some pics so people can see what you have for hoses and plumbing now.

 

[GLTHFJ60]

Lt1! Damn, old school! Love the intake on those engines.

How did you hook up the water pump and thermo to the radiator?

Have you pulled the hoses off to make sure there's not a rag in there, and no rag in the tanks on the radiator? If it's a 100% blockage, it must be something simple like that.

 

[Poppa T]

Lt1! Damn, old school! Love the intake on those engines.

How did you hook up the water pump and thermo to the radiator?

Have you pulled the hoses off to make sure there's not a rag in there, and no rag in the tanks on the radiator? If it's a 100% blockage, it must be something simple like that.

Thanks for the reply. I ran a new flex hose from the thermo outlet to the top of the rad (which normally would be the return) and the other side went to the bottom of the rad. No rags, new hoses, new KoolFlow water pump. Filled the rad and resovoir up but nothing leaving tank, etc. Plumbed the heater lines like shbox.com tech page shows. Coolant flow to the heater from the lower left port on water pump and return heater hose on the upper left port. Blocked off the right port on the water pump, but had it as the flow into the heater at first. Will try to post some pics. If anyone reading this post has some pics of a street rod LT1 hooked up to an old school rad I'd love to see them. Thanks- PT

 

[Poppa T]

I just put in a 93 LT1 350 in my FJ60. Everything went smooth except coolant plumbing. No coolant is getting out of the stock radiator into the water pump. I have read so many forum's I'm blue in the face. Baffled by all the "not sure" comments of how the heater hoses, reverse coolant flow, etc should be hooked up. I need to see some pics or hear from someone who has hooked up the coolant / heater hose lines on a LT1 to a stock FJ radiator. Thanks for considering to help.
Poppa T.
87 FJ60

Thanks for the resposne. I'll try to post some pics of plumbing...

 

[GLTHFJ60]

If there's no blockage, then air lock. How did you bleed the system? How much coolant were you able to fit in it?

Confirm it's not the radiator by disconnecting the coolant hoses and running straight water (from a spigot on your house) through the radiator, top to bottom.

 

[lt1fire]

Two things about an lt1 engine that I'm sure you know.
Its reverse flow, great design not sure why more cars don't do it.
Lower radiator hose should be connected to the thermostat housing and upper hose to the water pump.
Also are you using the stock thermo? If you put a new one in make sure it is a dual thermo like the lt1 needs. It let's water in and out of that motor. If it isn't the right one it will act just like the problem you are having. Normal motors thermos only regulate at the engine output this one does both and won't let any in if it is wrong.

 

[lt1fire]

this picture will help you figure out if you have the right one.

 

[Poppa T]

this picture will help you figure out if you have the right one.

this picture will help you figure out if you have the right one.

Two things about an lt1 engine that I'm sure you know.
Its reverse flow, great design not sure why more cars don't do it.
Lower radiator hose should be connected to the thermostat housing and upper hose to the water pump.
Also are you using the stock thermo? If you put a new one in make sure it is a dual thermo like the lt1 needs. It let's water in and out of that motor. If it isn't the right one it will act just like the problem you are having. Normal motors thermos only regulate at the engine output this one does both and won't let any in if it is wrong.

 

[Poppa T]

Hey guys, thanks so much for the info. It had the wrong thermo in it for sure (SBC) that and air lock is obvisously the main problem. Really appreciate the help. Double checking the rad / heater hoses, too.

 

[lt1fire]

Hey guys, thanks so much for the info. It had the wrong thermo in it for sure (SBC) that and air lock is obvisously the main problem. Really appreciate the help. Double checking the rad / heater hoses, too.

Glad it was an easy fix for you..... yeah if it is the wrong one you won't get any coolant from the rad into the engine.

The lt1 was an amazing engine it is just eclipsed by the LS design with it's amazing heads. So the gen II engines lt1 and the real vortec motors from the 90s are kind of the forgotten small block since the. Only ran for 8 years total compared to the 40 plus for the gen one.

If you are looking to tune it get a cable and download lt1 edit. It still should be a free download. I picked up quite a few hp and to after doing bolt one and the tuning it.

 

[lt1fire]

94-95 94/95 LT1-Edit
96-97 96/97 LT1-Edit

 

[Poppa T]

Hey, thanks for the help, just making sure on your comment that the thermo outlet hose goes to the bottom of the original FJ60 radiator? (Which is the opposite of normal LC coolant flow.)

 

[GLTHFJ60]

The radiator doesn't care which direction you flow it in. Hook it up whichever way works best for your setup.

 

[Poppa T]

Makes sense....thank you.