A little background on my project and cooling system for those that don't know. (I'm putting this same post on a few boards that I haven't posted my project on.) I put a built 5.4L DOHC in my 2001 Lightning, with twin turbos to be installed as soon as I figure this cooling issue out. I am using a cobra coolant crossover pipe, t-stat housing, and hoses. For those who don't know what that looks like here's a pic. (Borrowed from Chad's http://www.2kgt.com web site.)
The hose on the lower right portion of the pic goes to the lower radiator. The hose in the upper left goes to the upper radiator. There is a hose that goes down from the crossover pipe and connects to the t-stat housing, and another that comes from the engine and connects beside that at the t-stat housing as well. When the engine gets up to operating temp +, both of those hoses are hot, but the lower radiator hose is not. Seems to me like there is no flow through the radiator, resulting in it not cooling like it is supposed to.
OK, here's the scoop my cooling issue. I tried bleeding the system, and realized once the temps got over 180 and rising, my lower radiator hose was not getting hot. OK, sounds like a bad or improperly installed thermostat, so I proceed to pull the t-stat and have a look. Well, it was installed correctly (spring portion towards engine heat.) I took it out (it was a brand new t-stat) and threw it and my Lightning t-stat on the stove and brought them up to temp. Both opened up, with the Lightning 180deg opening slightly before the new 180deg one, so I decided to reinstall it. Reinstalled the t-stat, refilled and bled the system. Same thing. I've bled it several times by getting it up to temp, letting it cool completely, and then I'm able to add maybe 3-4 oz of water to the crossover tube neck each time. Doesn't seem like much, but the water in the overflow tank is staying in exactly the same spot, so it must be filling up some air pockets in the system. I'm wondering if that's enough to prevent the water from flowing through the radiator?
I've done some searches and talked to a few people, and it seems like a lot of folks have a really hard time burping all the air out of a 4V cooling system for some reason. I was disgusted/discouraged to no end yesterday when I didn't get to drop off the truck to get the turbos put on, but I stuck with it and heat cycled the truck a few times trying to bleed it. I keep telling myself maybe once it's bled it will work fine, but I can't get it out of my head that there may be other possibilities for it not working right.
One other mod I did on mine was to knock out the freeze plugs at top back of the 4V heads, and drill and tap my intake to fit heater hoses. I T'd those together and used that as my input to the heater core. This is one variation of the "cooling mod" to help flow across the back of the heads. Here's my intake for those that haven't seen it.
I am also using the NAVI water pump with my setup, with my stock Lightning radiator and stock overflow tank.
Could it be that I still have air in the system, which is preventing the water pump from sucking water through the radiator? Or, by knocking out those plugs at the back of the heads and flowing that through the heater core, have I created an easy path for water to flow through that's keeping it from flowing through the radiator like it should? As with any custom project the things you least expect come out of nowhere to bite you, and this one has me stumped at this point. Anybody else have any ideas or suggestions?
My dad, an old school hot rodder, gave me a suggestion this morning. A trick they used to use to relieve any air pockets in a cooling system was to drill an 1/8" hole in the plate of the t-stat, which allows the water to equalize on both sides without having to heat up the engine 1st. I'm thinking I might try that if I can't get it to work right after heat cycling it a few more times. As a matter of fact, that gives me an idea. I think I will drill a hole in the t-stat, reinstall, and remove the overflow tank cap and the coolant crossover filler plug. Leaving the overflow cap off, I'll screw an NPT --> hose nipple fitting into the crossover tube, and hook up a garden hose to it. I should be able to use the garden hose to force water through the entire system since there will be a small hole in the tsat to let water through. I'll fill it up until water is coming out the overflow tank, and keep running water through for a bit to make sure all the air is out. Then I can siphon off some of the overflow tank. Am I crazy, or is this a viable coolant bleeding / burping idea?
The hose on the lower right portion of the pic goes to the lower radiator. The hose in the upper left goes to the upper radiator. There is a hose that goes down from the crossover pipe and connects to the t-stat housing, and another that comes from the engine and connects beside that at the t-stat housing as well. When the engine gets up to operating temp +, both of those hoses are hot, but the lower radiator hose is not. Seems to me like there is no flow through the radiator, resulting in it not cooling like it is supposed to.
OK, here's the scoop my cooling issue. I tried bleeding the system, and realized once the temps got over 180 and rising, my lower radiator hose was not getting hot. OK, sounds like a bad or improperly installed thermostat, so I proceed to pull the t-stat and have a look. Well, it was installed correctly (spring portion towards engine heat.) I took it out (it was a brand new t-stat) and threw it and my Lightning t-stat on the stove and brought them up to temp. Both opened up, with the Lightning 180deg opening slightly before the new 180deg one, so I decided to reinstall it. Reinstalled the t-stat, refilled and bled the system. Same thing. I've bled it several times by getting it up to temp, letting it cool completely, and then I'm able to add maybe 3-4 oz of water to the crossover tube neck each time. Doesn't seem like much, but the water in the overflow tank is staying in exactly the same spot, so it must be filling up some air pockets in the system. I'm wondering if that's enough to prevent the water from flowing through the radiator?
I've done some searches and talked to a few people, and it seems like a lot of folks have a really hard time burping all the air out of a 4V cooling system for some reason. I was disgusted/discouraged to no end yesterday when I didn't get to drop off the truck to get the turbos put on, but I stuck with it and heat cycled the truck a few times trying to bleed it. I keep telling myself maybe once it's bled it will work fine, but I can't get it out of my head that there may be other possibilities for it not working right.
One other mod I did on mine was to knock out the freeze plugs at top back of the 4V heads, and drill and tap my intake to fit heater hoses. I T'd those together and used that as my input to the heater core. This is one variation of the "cooling mod" to help flow across the back of the heads. Here's my intake for those that haven't seen it.
I am also using the NAVI water pump with my setup, with my stock Lightning radiator and stock overflow tank.
Could it be that I still have air in the system, which is preventing the water pump from sucking water through the radiator? Or, by knocking out those plugs at the back of the heads and flowing that through the heater core, have I created an easy path for water to flow through that's keeping it from flowing through the radiator like it should? As with any custom project the things you least expect come out of nowhere to bite you, and this one has me stumped at this point. Anybody else have any ideas or suggestions?
My dad, an old school hot rodder, gave me a suggestion this morning. A trick they used to use to relieve any air pockets in a cooling system was to drill an 1/8" hole in the plate of the t-stat, which allows the water to equalize on both sides without having to heat up the engine 1st. I'm thinking I might try that if I can't get it to work right after heat cycling it a few more times. As a matter of fact, that gives me an idea. I think I will drill a hole in the t-stat, reinstall, and remove the overflow tank cap and the coolant crossover filler plug. Leaving the overflow cap off, I'll screw an NPT --> hose nipple fitting into the crossover tube, and hook up a garden hose to it. I should be able to use the garden hose to force water through the entire system since there will be a small hole in the tsat to let water through. I'll fill it up until water is coming out the overflow tank, and keep running water through for a bit to make sure all the air is out. Then I can siphon off some of the overflow tank. Am I crazy, or is this a viable coolant bleeding / burping idea?
