SPECIAL PUMP MODIFICATIONS

When using an O.E. coolant pump with low outlets, and especially those on all 90-degree and 60 degree V-type engines, installation of an air bleed at the top of the pump is required. (Alternative procedure: jack up one side of the vehicle at first start-up after installation of cooling system. See the third paragraph of this section.) The purpose is to bleed air trapped in the impeller cavity which may cause air-lock problems at start-up due to the higher viscosity of EVANS NPG Coolant.

If the outlet of the pump is below the top third of the pump (as in a Chevrolet V-8 pump), then frequently during the refill most of the pump impeller cavity remains full of air. Therefore the pump will remain "air locked" and will not pump coolant. This is easily identified by turning on the heater during the initial warm up and by feeling the heater hot air discharge (or, alternately, the inlet heater hose) while checking the engine temperature gauge. If the temperature of the engine is rising and not that of the heater, then the pump is "air locked". See "bleed" instructions below, and on Page 11.

An air bleed, or elevating one side of the car to raise the pump outlet above the center of the pump with the engine running, will correct the problem. This will most often move the air bubble out of the pump. If the pump remains "air locked," revving the engine several times while the side of the car is elevated will, in most cases, "unlock" the pump (see Diagram 1). If elevating the side of the car does not "unlock" the pump, then one of the alternate methods below must be used. Unlocking of the pump is usually necessary only at the initial start-up after conversion. With the coolant in an EVANS NPG Cooling System, the pump generally remains "air-free" once unlocked, unless coolant is subsequently drained again. Following are two alternate methods for installing a bleed:
 

• Method One: Drill a hole and tap it to 1/8" NPT in the top of the pump into the impeller cavity (see Diagram 2). Install a bleeder fitting (EVANS Part #E2807), or a brake-bleeder repair fitting available from auto parts stores, in the pump casting. This permits air to vent during filling, when the bleeder is open.
• Method Two: Drill a hole and tap it to 1/8" NPT in the top of the pump impeller cavity (see Diagram 2). Install a -4 AN pipe fitting. Take another -4 AN pipe fitting and modify it as follows: close the opening, either by filling with epoxy or welding it shut. Then drill a .060" diameter hole in the fitting. In the intake manifold coolant cross-over, drill and tap a hole to 1/8" NPT. Install this second modified fitting in this tapped hole. Connect the two fittings with suitable -4 AN 1 line. This method will provide a full-time air bleed system, parts available as EVANS kit #EKFTB.

9

	Diagram 1

EVANS PUMP-BLEED

Make sure that the pump being used has an air-bleed as depicted below and described under, SPECIAL PUMP MODIFICATIONS, Page 9. The air-bleed is tapped into the impeller cavity, as shown below, and not into the inlet cavity. If the pump is air-locked, with a large air pocket (bubble) as shown in Diagram 1, it will pump poorly, or not at all.

         TYPICAL PUMP CROSS-SECTION (Example: Chevrolet/GMC Pump)
 

	Diagram 2

EVANS TOTAL FLOW THERMOSTATS

EVANS Cooling offers direct replacement improved flow, high performance 180ºF and 195ºF, original equipment-style (OE) thermostats for Chevrolet V-8, Chrysler V-8, and Ford V-8. These thermostats offer much higher flow rates and reduce back pressure between the pump and thermostat. Other high flow thermostats are available, please call with your vehicle/engine application.

In order to achieve maximum cooling from the radiator, EVANS Cooling offers a special design Total Flow Thermostat for many vehicles, which allows the internal bypass circuits of the coolant pump to be blocked. The bypass circuits which reduce the occurrence of pump cavitation in OE water systems (not necessary with EVANS Cooling) cause significant volumes of coolant to bypass the radiator, when the engine is hot. The Total Flow Thermostat assures that 100% of the hot coolant flows through the radiator.

NOTE:  If a coolant heat-spike is observed during extreme cold weather, usually it may be attributed to the internal thermostat by-pass circuit of the conventional cooling system. An EVANS Total Flow Thermostat should then be installed and the by-pass modified. If spiking still occurs then a Stage II system must be installed.

EVANS EXPANSION TANK PLACEMENT

If your vehicle does not have an OE coolant expansion tank (typically a plastic tank located on an inner fender panel and connected to the radiator filler neck by hose), an EVANS expansion tank (several styles are available, refer to price sheet), or equivalent, must be installed for the non-pressurized EVANS NPG Cooling system to operate properly.

NOTE: Be certain the tank has a bi-directional vent line to the radiator, and that it is not just a dump tank (“catch can”). Select a tank of adequate size. For every gallon of coolant required in the system, the tank should hold at least 1/3 quart of coolant.

IMPORTANT

The proper placement of the expansion tank is critical to the ability of the system to maintain the coolant "dry of water" and restrict the absorption of additional water, thereby effectively staying free of water. The expansion tank must be located under the hood, within the engine bay, and on the engine side of the radiator (outlet air "hot" side). The higher average air temperature under the hood will heat the coolant, within the tank, and the higher vapor pressure of any water content, within the coolant, will force the water out of the coolant into the atmosphere leaving the concentrated EVANS NPG Coolant behind (in the tank). Any other water content within the coolant of the entire system will gradually move to the "dryer" coolant of the expansion tank and the continuing cycle in the warmed expansion tank will move it outward to the atmosphere as water vapor.

In basic terms; when the coolant is warm (above 70ºF) the water portion, no matter how large or small, evaporates faster than the EVANS NPG Coolant. The rate can be as high as 100 times as fast so the water content will stay low (2% or less), but you will see no loss in the EVANS NPG Coolant level as the system moves water vapor out through the vent, to the air.

HEATER LINE RESTRICTION

The heater circuit must be restricted by a 1/4" I.D. in-line restrictor anywhere in either the inlet or outlet heater hose. In some vehicles this is already installed by the manufacturer. A solid plug drilled 1/4" through the center, placed firmly inside the hose will work Additionally, the installation of a shut-off valve in the heater line is recommended for maximum cooling during high ambient temperatures.

INSTALLATION INSTRUCTIONS AND DIAGRAMS

Use of the OE as mounted or an EVANS expansion tank, properly located as described above, and shown in diagrams 3 and 4.  Diagram 3 is for cross-flow (side tank) radiators, and Diagram 4 is for vertical flow (top tank) radiators.

INSTALLATION OF TYPICAL CROSS-FLOW (SIDE TANK) SYSTEM: (See Diagram 3, Page 13)

Step 1.  Drain coolant and flush system of residual water (see description, Page 6).

Step 2.  Check for proper heater restrictions.

Step 3.  Install new thermostat as required (see EVANS Thermostat, Page 11).

Step 4.  Check for proper expansion tank (see Evans Expansion Tank, above).

Step 5.  Select method to bleed pump of air, if necessary (see Special Pump Modifications, Page 9)

Step 6.  Remove the original vent hose connecting the radiator cap vent tube to the expansion tank. The vent hose (or metal tube) of earlier vehicles without expansion tank systems overflows to the ground.  If there is no tank, an EVANS expansion tank, or equivalent, must be installed see Page 13).

	Diagram 3

IMPORTANT

The radiator cap and vent must be on the "cool tank" side of the radiator which connects to the coolant pump, as shown in Diagram 2. If the cap and vent are on the "hot tank" side, use the vent line installation shown in Diagram 3 (see Step 6, page 12) or loss of coolant will occur.

As shown in the diagrams, route the vent line so it becomes the highest point in the cooling system, Point "A" Connect the line to the expansion tank inlet which connects to the bottom of the expansion tank. In operation, the tank will cycle air out of the system and store reserve coolant. The tank may be located at any elevation in relation to the engine as long as the vent loop "A" is installed. Note: The tank must be installed in a higher temperature area under the hood (see EVANS Expansion Tank Page 12). The level "B" in the tank will rise and fall with coolant expansion whether it is mounted low (solid lines in diagram) or high as a topping tank (dotted lines in diagram).

A liquid seal, isolating air from the coolant jacket, is formed by the combination of the high loop in the vent line and the cold engine liquid level remaining above the vent line inlet to the tank (after filling). The vent line prevents siphoning of coolant from the engine and the induction of air, and excessive water vapor will be driven out through the open vent during operation when the tank coolant is above 90ºF.

Although not commonly encountered, sometimes the radiator or the radiator "hot tank" inlet is below the top of the cylinder heads. In such cases, in order to properly evacuate from the system any entrapped air, water vapor, or non-condensable combustion gases which accumulate at the highest point of the cooling jacket, it is advisable to install one of the following air/gas bleed-off systems.

The valve should be installed at the highest point in the engine cooling jacket (shown as the thermostat housing, point "F" Diagram 3) by drilling a hole at that point and tapping it to 1/8" NPT. At the initial system coolant fill, in order to release entrapped air before starting the engine, open the valve after filling the system with coolant and bleed off the air. Close the valve when coolant appears and recheck coolant level in the expansion tank. After this initial till bleed, it is only necessary to bleed the air off a few times. With the engine shut off, open the valve after running the engine and bleed off any trapped gases; then close the valve when coolant appears. Once all the air is out of the system it is not usually necessary to constantly check for air.

B) CONTINUOUS BLEED-OFF (FULL TIME) MODIFICATION

NOTE:  This system is particularly useful when the system is required to be drained frequently such as in a rare car. A constant-flow, in-line restrictor with a 0.060" orifice is installed in a small (1/8" to 5/16" line passing from the highest point in the engine cooling jacket (shown as point "F" Diagram 3) to the main vent line at Point "E". The attachment Point "E" must be on the engine side of the main vent loop, before Point "A". The in-line restrictor may be at either end "E" or "F" or at any point along the bleed line from "E" to "F".

The 0.060" restrictor orifice will pass all entrapped air and gases out of the engine through the vent line to the expansion tank and allow an insignificant amount of coolant to pass back down the main vent line to the pump.

The restrictor may be fabricated or ordered from EVANS. It is a "T" fitting to be installed at Point "E" with a built-in restrictor for bleed-line attachment routing from Point "F". EVANS Part #E1001 (5/16" bleed line), or Part #E1003 (3/8" bleed line).

As shown in the diagrams, make certain that main vent Point "A" is above the complete cooling system, paying close attention to the location of the upper hose and thermostat, as well as to the elevation of the heater core and hoses. Looping the hose to the highest point of the firewall will work. Tie wraps are included in the EVANS basic installation kit for securing the vent hose.

Step 7.  Install hose clamps supplied with the EVANS "Basic" installation kit on all vent line connections.

Step 8.  Fill the radiator and engine with full-strength coolant through cap/vent opening on the top of radiator. DO NOT ADD WATER! Use 100% EVANS NPG Coolant (Part #NPG) from the container as supplied. See warning about the use of improper coolant (Page 3). Open air bleed on pump, if used, to purge air from pump impeller, and close when coolant appears (see Special Pump Modifications, Page 9)

Step 9.  Low-mounted expansion tank start-up: Fill the tank 1/2 full with full-strength EVANS NPG Coolant and the radiator to about 3/4 full, leaving off the radiator cap. Warm up the engine until the thermostat opens and coolant is observed pumping through the radiator. Have a container of extra coolant and the EVANS Zero Pressure Cap (EVANS Part #E2006) ready and nearby the radiator. With the aid of a second person, and the engine up to operating temperature (thermostat open), raise the engine to approximately 2500 RPM until the coolant in the radiator drops to a stable level, as seen by looking in the cap opening. Hold the engine at the elevated RPM while topping off the radiator and installing the Zero Pressure Cap, and then drop back to idle. Let the engine cool. Then refill, or drain, expansion tank to 1/4 full when engine is cold.

NOTE:

If the Evans Zero Pressure Cap supplied with the "Basic" installation kit does not fit your radiator (some imported vehicles), then the original pressurized cap may be modified to work by cutting off the pressure foot and lower seal. A cut made about midway in the spring and through the support shaft will remove the foot, lower seal and spring. Make sure that all these pieces are removed in order to avoid blocking of the vent system.

NOTE: Do not cut just the spring!

Step 10.  High-mounted expansion tank start-up: After filling the radiator, replace the radiator cap with the EVANS Zero Pressure Cap provided in the EVANS kit, or use a modified OE cap, as described above, if the EVANS cap should not fit. Fill the high-mounted expansion tank one-half full, warm up the engine to full operating temperature, let it cool, then refill or drain, as required, to set the tank to 1/4 full when engine is cold.

Step 11.  Once the cooling system has been filled, as outlined above, the radiator cap need not be removed for checking coolant level. The expansion tank will add coolant to the engine as any small quantities of trapped air are moved out the open vent during the cycling of the system over the first days of operation. It is important during the initial days of use to monitor the cold engine coolant level in the expansion tank to make sure the level is 1/4 full and the ventline connection is always covered by reserve coolant.

INSTALLATION OF VERTICAL-FLOW (TOP TANK) SYSTEM: (See Diagram 4, Page 16)

Step 1.  Drain coolant and purge system of residual water (see DRAINING OF OLD COOLANT Page 6).

Step 2.  Check for proper heater restriction (see HEATER LINE RESTRICTION, Page 12)

Step 3.  Install new thermostat as required (see EVANS TOTAL FLOW THERMOSTATS, Page 11)

Step 4.  Check for proper expansion tank placement (see EVANS EXPANSION TANK PLACEMENT, Page 12)

Step 5.  Select method to bleed pump of air, if necessary (see SPECIAL PUMP MODIFICATIONS, Page 9)

Step 6.  Remove the original vent hose connecting the radiator cap vent tube to the expansion tank. On earlier vehicles, without an expansion tank, the vent hose (or metal tube) overflows to the ground.

The original radiator cap and vent normally will be on the "hot tank" (top tank) which is pressurized by pump pressure acting against the core. In alternately designed systems, the cap and vent may be connected to the "hot top tank" by a hose, from a remote "fill". The resultant core resistance during engine operation will force coolant out of the open vent if main vent line is connected to this tank. Because of the pressure in the top tank induced by the coolant pump, the connecting point for the main vent line to the EVANS expansion tank must be in the bottom "cool tank" (C-1), lower hose (C-2), or pump inlet (C-3), all of which are at a low pressure during operation.

	Diagram 4

Air, which enters the cooling system during the conversion, or whenever the system is opened, and any combustion gases which may enter the system due to a slight head gasket leak, must be vented from the system. To vent all entrapped air and combustion gases (if present) an air-bleed line with an in-line .060" restrictor "D" must connect to the highest point of the existing system. The restrictor may be fabricated, or ordered from EVANS (Top Tank Radiator Vent Kit, Part #EKTTC38 for 3/8" OE vent hose lines, or Part #EKTTC516  for 5/16".)

The "Top Tank Radiator Vent Kit" includes the .060" restrictor combined into a T-fitting which installs at point "E." Also included is a fitting for vent hose attachment at points C-1, or C-2, or C-3, and the necessary clamps for installation. The highest attachment point is often the high point of the top tank (hot tank) side of the radiator, and is usually between the pump outlet to the engine and the radiator, shown as Point "F" in Diagram 3. Frequently it is the original vent line point of attachment at the radiator cap neck which becomes open to the atmosphere when the Evans Zero Pressure Cap is installed.

Alternate attachment points could be the upper radiator hose, or thermostat outlet, whichever is the highest location.

The other end of the air-bleed vent line connects to the main vent line at Point "E" and before Point "A" (see Diagram 4). Restrictor "D" will pass all entrapped air and gases out of the vent line to the expansion tank and allow only a small amount of coolant to return down the vent line, to the pump (at C-1, C-2 or C-3) and back into the engine. Although this small volume of coolant will bypass the radiator, it has no meaningful effect upon the cooling performance because the quantity by-passed is negligible.

As shown in Diagram 4, route the vent line so it becomes the highest point in the cooling system, Point "A." Connect the line to the inlet at the bottom of the expansion tank. In operation, the tank will cycle air out of the system and store reserve coolant. The tank may be located at any elevation in relation to the engine, as long as the high vent loop "A" is installed. However it must be located at a higher temperature area under the hood, (See EVANS Expansion Tank, Page 12). The level "B" in the tank will rise and fall with the coolant expansion, whether it is mounted low (solid lines in diagram) or high to a topping tank (dotted lines in diagram). When the engine is cold, a liquid seal isolating air from the cooling jacket is formed by a combination of the high loop in the vent line and the liquid level remaining above the vent line inlet to the tank. This liquid seal prevents siphoning of coolant from the engine and eliminates the induction of air through the open vent during operation. The location of the tank, as described, will force water out of the system, maintaining the coolant essentially water free (see Page 12). Make certain that point "A", as shown in the diagrams, is above the complete cooling system. Pay close attention to the location of the upper hose and thermostat, the elevation of the heater core, and hoses. Usually looping the hose to the highest point of the firewall will work. Tie wraps are included in the EVANS "Basic" installation kit for securing the vent hose,

Step 7.  Install hose clamps supplied with the EVANS kit on all vent line connections.

Step 8.  Fill the radiator and engine with full-strength coolant through cap/vent opening on the top of radiator. DO NOT ADD WATER! Use 100% EVANS NPG Coolant (Part #NPG) from the containers as supplied. See warning about the use of improper coolant (Page 3). Open air bleed on pump, if used, to purge air from pump impeller, and close when coolant appears (see Special Pump Modifications, Page 9)

Step 9.  Low-mounted expansion tank start-up: Fill the tank 1/2 full with full-strength coolant and the radiator to about 3/4 full leaving off the radiator cap. Warm up the engine until the thermostat opens and coolant is observed pumping through the radiator. Have a container of extra coolant and the EVANS Zero Pressure Cap (EVANS Part #E2006) which is part of the "Basic" installation kit, ready and nearby the radiator. With the aid of a second person, and the engine up to operating temperature (thermostat open), raise the engine to approximately 2500 RPM until the coolant in the radiator drops to a stable level, as seen by looking in the cap opening. Hold the engine at the elevated RPM while topping off the radiator and installing the Zero Pressure Cap, and then drop back to idle. Let the engine cool. Then refill, or drain, expansion tank to 1/4 full when engine is cold.

NOTE:

If the Evans Zero Pressure Cap supplied with the conversion kit does not fit your radiator (some imported and antique vehicles), then the original pressurized cap may be modified to work by cutting off the pressure foot and lower seal. A cut made about midway in the spring and through the support shaft will remove the foot, lower seal and spring. Make sure that all these pieces are removed in order to avoid blocking of the vent system. NOTE: DO NOT JUST CUT THE SPRING.

Step 10.  High-mounted expansion tank start-up: After filling the radiator, replace the radiator cap with the EVANS Zero Pressure Cap provided in the EVANS kit, or use a modified OE cap, as described above, if the EVANS cap should not fit. Fill the high-mounted expansion tank one-half full, warm up the engine to full operating temperature, let it cool, then refill or drain, as required, to set the tank to 1/4 full when engine is cold.

Step 11.  Once the cooling system has been filled, as outlined above, the radiator cap need not be removed for checking coolant level. The expansion tank will add coolant to the engine as any small quantities of trapped air are moved out the open vent during the cycling of the system over the first days of operation. It is important during the initial days of use to monitor the cold engine coolant level in the expansion tank to make sure the level is 1/4 full and the ventline connection is always covered by reserve coolant.