Coolant Filler Cap on Manifold

[Trevor]

I hesitate to call it the "Radiator Cap" but....

Moroso makes a filler neck for Chevies that places the cap on the thermostat housing atop the intake manifold - the highest point in the system - to bleed air out of the cooling system.

 

I've seen those clamp-in-radiator-hose pipe / neck / cap in the JTR book,

but Was really looking for something RIGID like the Chevy part. I guess it's a lot more complicated because the thermostat housing mounts to the front of a Ford manifold, not the top. Also the bypass hose plumbing is part of the thermostat housing.

 

Seen those overflow / expansion tanks on big block Cobras with a filler cap, but they probably eat up some hood clearance....

[74_5.0L_Z]

I use the Moroso filler neck without any problems

 

[Trevor]

Thanks for the Picture looks better than I had envisioned. It might offer more flexible positioning, since I am looking at using all the stock accessories on the serpentine belt.

 

After a little more browsing....Hot Dog! Found the "right" part - just a little pricey, but a lot of machining goes into it.

 

[Here comes trouble]

Beware.....................I use the in Moroso inline cast aluminum radiator hose filler sold by Jegs...This radiator inline hose filler sets above the location of the more expensive chevy manifold filler neck and makes it easier to fit the non OEM radiator hose from the chev manifold to the Griffin aluminum radiator. The Griffin radiator top sets up higher than the "advertised" highest point of the Chevy engine making that manifold location for a filler cap. a "real hot pisser" when removing the cap when the top of the radiator is higher than the filler neck. I also had no clearance problems with the Tomahawk Z hood and the inline filler. It was a long stretch under the hood to the Griffin radiator to remove the filler cap on the radiator. Eyeball your radiator top and the location of the new filler neck......if radiator is higher ....Beware it's a pisser! Larry Johnson AKA Tomahawk Z

[Trevor]

Thanks Larry! Actually I am plotting this out for a Z31 300ZX + 5.0L swap. The radiator sits very low in the nose and is slanted forward, not as vertical as a 240Z's. Pretty sure it will be lower than the top of the intake. The nice part is without the frame rails restriction, I can use the wider (bigger) 29" radiator, even though it has a filler cap, it won't be accessible.

 

The 300ZX filler cap / thermostat housing for the 300ZX is actually on the top front of the engine block, so I am looking to duplicate that arrangement.