280 ZX 6-cylinder aluminum Radiator Kit,
for ZX cars with the 280ZX 6-cylinder engine, includes aluminum radiator, hoses, linered hose clamps, brass splicers, brackets and hardware to install aluminum radiator into 6-cylinder ZX cars
#ZX-625, $320, including UPS Ground
280ZX with Aluminum Radiator
The aluminum radiator kit for the 1979–1983 ZX car uses a modern and
efficient radiator which works well on Datsun Z V8 Conversions. The
aluminum radiator kit (complete with brackets) weighs 5 lbs less than
a stock Datsun radiator, and provides better cooling. The kit, complete
with radiator, bracket, hoses and hose clamps is sold as part # ZX-625.
The kit is mostly a bolt-in, however, the Air Flow Meter must be
repositioned to make room for the upper radiator hose (see page 12-8).
This requires drilling two 5/16" holes in the bracket that mounts
the Air Flow Meter
If the ZX fan shroud is retained, it requires trimming the shroud,
drilling holes in the shroud and the radiator brackets, and fabricating
some small brackets from sheet metal. This can take several hours.
PARTS LIST (click links to jump to photo of part, below)
Hose splicer with air bleed valve, see below.
Part # ZX-129
for Datsun Z V-8 and 6-cylinder engines, Part # ZX-121
280 ZX V8 Aluminum Radiator. #ZX-121, $190 including shipping
This is what we feel is the best radiator for the V8 ZX. It also works
well on the six-cylinder ZX car, and it weighs about 5 lbs less (including
mounting brackets) than the stock 6-cylinder ZX radiator.
This radiator is made for Stealth Conversions. It is the base radiator
for the 1984-1986 V8 Camaros, but with a thicker core (1-3/8"
thick, compared to 7/8" for a stock radiator). It is light,
inexpensive, and does an excellent job of cooling. It has the correct
overall dimensions to fit in a ZX car, and it has an automatic transmission
cooler in the passengers side tank. The heavy-duty radiator
for a 1984-1986 Camaro has a 1-3/8" thick core, but it has an overall
width of about 30" (compared to 25.25" on the radiator shown
above) which is too wide to fit between the frame rails in the ZX car.
The radiator can be purchased separately as part #ZX-121.
The radiator shown above weighs less than 10 lbs pounds (empty). The
side tanks do not hold a lot of coolant, and this also saves weight.
When the radiator is filled with coolant, it weighs 15 lbs. The brackets
which hold the radiator weigh 7 lbs, for a total weight of 22 lbs.
By comparison, a stock 280Z radiator weighs 19 lbs (empty), and 27
lbs full of coolant.
The radiator is positioned about 18 inches forward of the front wheels,
so the actual weight reduction off the front wheels is about 6 lbs,
and about 1 lb is added to the rear wheels.
The radiator cap on the Datsun Z will fit on the Chevrolet style radiator
for 1984-1986 Camaro
core used on Radiator
sold by Stealth Conversions
Radiator Cores, above
The radiator core on the left is used on the base radiator for the
1984-1986 Camaro. The core width is 7/8" (.88"). The tube
width is .800".
The radiator core on the right is used on the radiator sold by Stealth
Conversions. The core width is 1-3/8". The tube width is 1.20".
The genuine Camaro radiator with the thin core does a good job
of cooling the V8 Z, but some people returned the radiators without
ever using them because they felt the radiator was too thin to cool
Radiator prices have dropped over the years and Stealth Conversions
can sell the custom made radiators for less than the wholesale cost
of radiators 10 years ago.
One of the reasons radiator prices have dropped over the years is due
to the low cost of aluminum (Russia is now a large source of the ore
used to produce aluminum). Another reason for the cost reduction is
because of competition from radiators manufactured from overseas. The
quality of the American made radiators sold by Stealth Conversions is
Style, typical of 1990 and Newer
cars and trucks
Radiator Core Designs
There are a lot of different radiator designs and different materials:
Copper-brass, aluminum, 1-row core, 2-row core, 3-row core, continuous
fin, louvered fin, straight fin, serpentine fin, dimpled tube, cross
flow, down flow, high-efficiency core, 1-pass core, 2-pass core... etc.
A lot of the different designs have more to do with marketing than
actual cooling ability.
On the left is a modern style radiator core used in everything from
new Corvettes to new trucks. The tube width is 1-1/4", and the
tubes are spaced at 7/16" interval. The wide tube has more surface
area that contacts the cooling fins than the radiator cores shown to
the right. The greater surface area results in better heat transfer.
The center radiator core is a two-row copper-brass design that is used
on a lot of cars built in the early 1980s. The tubes are 3/8"
wide and they are spaced at 7/16" intervals. The core on the right
is also a two-row copper-brass design. Its tubes are 1/2" wide
and they are spaced at 9/16" intervals. This design was used through
the 1970s, and is similar to the stock radiator core in a ZX.
The one-row core design is the best for cooling and the lightest weight
of the three radiators shown. Copper has better heat transfer characteristics
than aluminum, but the aluminum is more easily formed into wide tubes,
and it is lighter and less expensive than copper.
Custom 4-row core radiators do not cool the ZX as well many people
believe because it is difficult to get air through the thick core due
to aerodynamic restriction. Also, once the cooling air has gone past
the first row, the air is heated up so that it cannot cool the second
row as much as the first row, and this pattern continues to the fourth
row, which does not provide much additional cooling.
The aluminum one-row radiator is the best radiator we have found for
the V8 ZX, as well as the 6-cylinder ZX.
Datsun ZX Radiator Mounting Kit , Part #ZX-625
280 ZX Radiator
Brackets, for Aluminum ZX radiator,includes, rubber isolators, aluminum reinforcement brackets, nuts and bolts, #ZX-125, $100
RADIATOR MOUNTING BRACKETS
For durability, it is important to completely rubber mount the radiator
using Chevrolet radiator pads, and making sure that nothing rubs on
the radiator core.
The aluminum radiators need to be rubber mounted to protect from vibration
and from electrolytic corrosion. One of the reasons the all-aluminum
racing radiators don’t last long on street cars is because they
are often mounted metal-to-metal.
The Stealth Conversions brackets shown above, use Chevrolet rubber
mounting pads (from a 19862004 S-10 Truck) that isolate the radiator
from vibration and electrolytic corrosion. The brackets come with the
rubber mounting pads (GM part #12338053).
The brackets have alignment holes which hold the rubber pads in place
for installation purposes, but silicone sealant must be used to hold
the rubber mounting pads to the radiator brackets.
The brackets shown are made from Zinc Plated steel to prevent rust.
Other parts included in the mounting kit are aluminum reinforcement
brackets (see below), and the hardware
(nuts and bolts).
The mounting kit can be purchased separately as part # ZX-625, and
also includes the aluminum reinforcement brackets (see
LOWER RADIATOR BRACKET INSTALLATION
The lower radiator bracket is installed first, using the stock radiator
mounting holes. The original ZX radiator bolts are used with the supplied
After installing the lower bracket, install the radiator onto the lower
bracket and check for clearance between the passenger side frame rail,
and the radiator side tank. There should be 1/8" to 1/4" clearance.
If the clearance is not correct, remove the radiator, and move the lower
radiator bracket for proper clearance, and then tighten the mounting
The reason to keep the radiator close to the passenger side frame rail
is to improve clearance between the upper radiator hose and the air
flow meter. It will also help with mounting the fan shroud (if used).
RADIATOR MOUNTED IN CAR
The radiator is mounted in this car as a bolt-in.
Two aluminum flat bars hold the top and bottom radiator brackets together
as a rigid structure, so that thinner metal can be used for the mounting
brackets, and reduce weight.
The flat bars can also be used to hold an electric cooling fan. The
upper and lower brackets can be drilled to reposition the aluminum flat
bar so that an electric cooling fan can be mounted to the flat bar (see
UPPER RADIATOR HOSE AND AIR-FLOW METER
Upper Radiator Hose and Air Flow Meter
On the 280ZX, the air-flow meter interferes with the upper radiator
hose the air-flow meter must be repositioned. On this car, the
bracket holding the air-flow meter was moved over about 1/2" and
two 5/16" holes were drilled to mount the bracket to the car.
Also, the flexible rubber air ducts attached to the air-flow meter
must be re-adjusted to compensate for the relocated air-flow meter.
Relocating the air-flow meter as shown will probably take about 1/2
hour, which includes a lot staring at the parts. If you do a second
car, the job will take less than 5 minutes.
On this installation, there is about 1/2" clearance between the
upper radiator hose and the air-flow meter.
The only difference in the cooling system between air-conditioned ZX
cars, and non-air-conditioned ZX cars is that a fan shroud and coolant
recovery tank came on air-conditioned ZX cars. The fan shroud improves
cooling efficiency, and makes the air-conditioning work better by drawing
more air through the condenser (which is mounted in front of the radiator).
On air-conditioned ZX cars, the stock fan shroud is extremely important.
A shroud is not necessary with the Chevrolet style radiator in a Datsun
ZX that does not have air-conditioning.
The fan shroud can be installed onto the Chevrolet style radiator,
but it needs to be trimmed to clear the upper radiator hose, the lower
radiator hose, and the probe on the passengers side of the radiator.
Trimming can be done with a band saw, or a grinder.
There will be a gap between the radiator and the sides of the shroud.
Foam can be glued to the sides of the shroud to seal the gap, but it
is not necessary.
It will probably take an hour or two to test fit and modify the fan
shroud, and install brackets, but if your vehicle has air-conditioning,
and you dont want to run an electric cooling fan, installing the
fan shroud is worth the effort.
The three hoses shown above are listed as the upper radiator hose for
a Datsun 280ZX.
As you can see, they are all different. The hose on the left was purchased
from a Nissan dealer, and the other two hoses were purchased from local
automotive stores. The hose on the right is a Goodyear brand, part #61267,
which works well for the aluminum radiator conversion.
The purpose of showing these hoses is to explain why it is often necessary
to cut and splice hoses to fit an application, and why parts that are
suppose to work for the same application sometimes dont work.
LOWER HOSE ASSEMBLY
Lower Radiator Hoses
The hose on the top is a stock 280ZX lower radiator hose. The Goodyear
brand of hose (Goodyear part #61167) is an exact match for the Nissan.
The stock hose (or Goodyear #61167) is cut off to at the dotted line.
The upper section is then attached to the elbow with a splicer and a
hose reducer bushing. The elbow is a section of the lower hose from
a 1998 Chevrolet Truck with a 350 V8.
The finished hose is shown on the bottom of the photo.
Note: The lower section that is cut off is used on the upper
radiator hose where the hose connects to the radiator. The tight bend
will help with the clearance between the upper radiator hose and the
air flow meter, and it curves upward from the upper radiator fitting,
which will provide clearance when using the ZX fan shroud.
LOWER RADIATOR HOSE INSTALLED
Lower Radiator Hose Installation
The stock 280ZX lower hose connects to the elbow with the hose splicer
and the 1-1/2" to 1-1/4" hose reducer bushing.
Installing the rubber elbow onto the radiator is slightly difficult.
To make the installation easier, put a little liquid soap on the radiator
outlet, and the hose should slide on easily.
UPPER RADIATOR HOSE ASSEMBLY
Upper Radiator Hose Assembly
The upper hose assembly is made from a section of the stock 280ZX lower
radiator hose (Goodyear part #61167), and a replacement upper radiator
hose (Goodyear part #61267).
The two sections of hose can be connected with a 1-5/16" diameter
hose splicer, or for people who want to quickly purge all the air from
the cooling system, a splicer with an air-bleed valve can be used to
splice the hoses.
UPPER RADIATOR HOSE
Upper Radiator Hose
The stock Z upper radiator hose is too short for the Chevrolet radiator.
In addition, the radiator hose needs to make a tight turn where it
connects to the radiator in order to clear the air-flow meter, and it
needs to clear the fan shroud (if used).
The upper hose assembly was made by splicing two radiator hoses together
(Goodyear #61167 and Goodyear #61267), using a 1-5/16" diameter
hose splicer (shown above).
The section that makes a tight bend next to the air flow meter is cut
from a 280ZX lower hose (see above).
The shape of the hoses is critical in allowing normal engine movement,
without putting stress on the radiator. The section going from the thermostat
housing to the hose splicer is intentionally long so that it can flex
as the engine moves during normal driving.
For people who race, and need to quickly purge the air out of the cooling
system, the hose-splicer with the purge fitting can be purchased from
Stealth Conversions, part # ZX-129. (shown immediately below)
280 ZX Radiator
Hose kit for 6-cylinder cars using aluminum radiator, includes GoodYear hoses, brass hose splicers, linered hose clamps, and hose reducer bushing. #ZX-502, $79, including shipping
Radiator Hose Splicers, and Hose Reducer
Hose splicers and a hose reducer bushing are required when connecting
hoses to the Chevrolet radiator. Assembled hoses are shown here: upper,
If you want to use your existing hoses, or you can purchase hoses cheaply,
Stealth Conversions sells a hose splicer kit which includes two 1-5/16"
brass hose splicers, and one 1-1/2" to 1-1/4" hose reducer
bushing as part # ZX-502. Shipping weight is 1 lb.
The 1-1/2" to 1-1/4" hose reducer bushing will stretch onto
the 1-5/16" hose splicer.
The reducer bushing should be trimmed so that it overhangs the splicer
by less than 1/4" so that it will not obstruct coolant flow.
The splicer with the air bleed fitting part # ZX-129. (shown immediately
280 ZX Air-Bleed
Valve. #ZX-129, $27,
AIR-BLEED VALVE Part # ZX-129
The air-bleed valve mounted in the upper radiator hose, as shown above,
allows all of the air in the cooling system to be quickly purged out.
After filling the radiator and coolant recovery tank with coolant, install
the radiator cap. Then, squeeze the lower radiator hose, and open the
air-bleed valve. Any air in the cooling system will leave through the
air-bleed valve. While still squeezing the lower radiator hose, tighten
the valve. As the lower radiator hose expands to its normal size, it
will draw coolant into the radiator from the coolant recovery tank.
Repeat as necessary until all air is purged from the cooling system.
Chevrolet and other manufactures use air-bleed valves on production
cars. As an example, the LT1 Camaro and LT1 and LS1 Corvettes come from the factory with air bleed valves mounted at the
highest point in the cooling system.
ELECTRIC COOLING FAN AND MOUNTING
ELECTRIC COOLING FAN AND MOUNTING
A thin electric cooling fan can fit between the engine and the radiator,
but it must be offset towards the drivers side to clear the water-pump
pulley. The fan shown is a flex-a-lite® model 116, which is 16"
diameter and 3-1/4" deep. It draws about 10 amps. It is about the
largest fan that can be used in the 6-cylinder ZX.
When using an electric cooling fan, it is important to protect the
radiator by not attaching the fans to the radiator core. The bolts that
attach the fan to the aluminum bar stock are 1/4-20 UNC, by 5/8"
to 3/4" long and need to be secured with Loctite® or some other
bolt adhesive to prevent loosening because the plastic brackets will
break if the bolts are tightened too much.
The aluminum flat bar must be tapped for a 1/4" - 20 UNC thread
for the bolts because there is little room between the radiator and
the aluminum bar. Using nuts is not a good idea because they may protrude
into the radiator core. Fine threads (1/4-28 UNF) do not work well in
With the radiator and fan combination shown above, the fan will only
run in stop and go traffic. Once the car is moving over 15-20 mph, the
radiators efficient core design allows enough air to go through
the radiator for adequate cooling.
The fan should be wired to turn on automatically when the coolant gets
hot. We dont like to see the coolant get above 200° F. Adjustable
thermostats are available at many auto part stores.
ELECTRIC COOLING FANS AND AIR-CONDITIONING
If the car is air-conditioned, the fan should be wired to turn on whenever
the air-conditioning is turned on, unless a pressure switch is installed
in the air-conditioning hoses to turn the fan on when the pressures
get high. For most people, it is easiest to wire the fan so that it
turns on whenever the air conditioning is turned on. Most electric fan
kits have instructions for wiring the fans when using air-conditioning.
STOCK RADIATOR (above)
ALUMINUM RADIATOR (below)
This is the finished installation in a 1981 280ZX, with the fan shroud
The stock Datsun Z radiator cap fits on the Chevrolet radiator, and
the hose to the coolant recovery tank was shortened, and connected to
If your car has an automatic transmission, the Datsun transmission
cooler hoses will have to be cut, and spliced to the Chevrolet radiator
using transmission cooler fittings available from automotive stores.
The Chevrolet radiator uses 5/16" inverted flare fittings.
JTR engine swapping manuals are available directly from JTR Publishing, As well as through a number of retailers, including:
• Summit Racing (S-10: Part #JTR-S10; Jaguar: Part #JTR-JAG), • JEGS (S-10: Part #116549; TPI &
TBI: Part #117942), • Steve Smith Autosports (S-10: Part #S212; TPI & TBI: Part #S195), and • Classic Motorbooks (S-10: Part #116549; TPI & TBI: Part #117942;
Jaguar: Part #118438; Datsun Z: Part #115501; Volvo 200: Part #122587).