13.8 How to Select Coolant

This section covers selection of the required coolant for MBE 4000 engines.

13.8.1 Definitions

To help ensure complete understanding of the information, the definitions of the following terms are provided:
Antifreeze — Ethylene Glycol (EG) or Propylene Glycol (PG) containing a corrosion inhibitor package and meeting an appropriate heavy-duty specification, i.e., TMC RP-329 “Type A” EG, TMC RP 330 “Type A” PG or TMC RP organic acid ethylene glycol.
Note : TMC RP-329 and TMC RP-330 “Type A” formulations are phosphate free.
Coolant — The fluid mixture circulating in the engine cooling system, typically a mixture of 50% water and 50% antifreeze.
Drop–Out — Precipitated sludge or deposit formation in or on cooling system components.
Fully Formulated Antifreeze — Contains all the necessary inhibitors to protect a diesel engine and does not, therefore, require a pre-charge of SCA before its first use.
Initial–Fill Coolant — The coolant that is used in a new or rebuilt engine, or any time the cooling system is emptied and then refilled with new coolant.
OAT — Organic Acid Technology : An inhibitor system based on organic acid inhibitors.
SCA — Supplemental Coolant Additive – SCAs are used in a preventive maintenance program to prevent corrosion, cavitation and the formation of deposits.

13.8.2 Approved Coolants

The approved and preferred coolants for MBE 4000 are . Listed in Table "Initial Fill Coolant Options" .
Once installed, these coolants should be maintained according to the procedures discussed under Maintenance in this section.
NOTICE
Required specifications for water, ethylene glycol, propylene glycol, inhibitor packages and inhibitor concentration are included in this publication. To avoid possible engine damage from inadequate or over-concentrated coolant, this publication should be read thoroughly before replacing coolant.
Coolant Fill Option
Product
Ethylene Glycol and Water + Conventional Corrosion Inhibitors <sup>1 </sup>
DDC Power Cool
Commercial Equivalent of DDC Power Cool
Fully Formulated TMC RP-329 Type A Antifreeze and Water
Propylene Glycol and Water + Conventional Corrosion Inhibitors <sup>1 </sup>
Fully formulated TMC RP-330 "Type A" Antifreeze and Water
Ethylene Glycol & Water + OAT Inhibitors
DDC Power Cool Plus
Water Only + Conventional Corrosion Inhibitors <sup>2 </sup>
Water + DDC Power Cool 3000
Water Only + OAT Inhibitors <sup>2 </sup>
Water + DDC Power Cool Plus 6000
Table , Initial Fill Coolant Options

13.8.2.1 Ethylene Glycol / Water + CONVENTIONAL CORROSION Inhibitor, propylene Glycol / Water + CONVENTIONAL CORROSION Inhibitor

These products are available as Fully Formulated, Phosphate-Free, Extended Service Interval (ESI) coolants. They are commercially available from Detroit Diesel (recommended) and other manufacturers as either a concentrated antifreeze or as a pre-mixed antifreeze. The pre-mixed antifreeze is ready to use, while the concentrated coolant must be mixed with water prior to use.
Detroit Diesel Power Cool ® Engine Coolant (P/N 23512138) is the preferred ethylene glycol coolant as Listed in Table "Initial Fill Coolant Options" . If other commercial brands of ethylene glycol are used, they must be equivalent to Power Cool . Detroit Diesel does not market a propylene glycol coolant. If a propylene glycol coolant is used, it must also meet the following requirements:
Fully formulated ethylene glycol-based, low silicate antifreeze or coolant must meet TMC RP-329 “Type A” requirements.
Fully formulated propylene glycol-based, low silicate antifreeze or coolant must meet TMC RP-330 “Type A” requirements.
Note : Fully formulated antifreeze does not require a dosage of SCA prior to initial use.

13.8.2.2 Mixing EG or PG Antifreeze and Water

If a concentrated Ethylene Glycol (EG) or Propylene Glycol (PG) antifreeze is purchased, mix the antifreeze with water meeting the required quality standards and fill the cooling system. For water requirements , If a concentrated EG or PG antifreeze is purchased, mix the antifreeze with water meeting the required quality standards and fill the cooling system. For water requirements , refer to "Water Requirements" . If a pre-diluted, fully formulated coolant is purchased, simply fill the cooling system.
For best overall performance, a coolant consisting of 50% concentration of antifreeze (50% antifreeze, 50% water) is recommended . An antifreeze concentration of over 67% (67% antifreeze, 33% water) is not recommended due to poor heat transfer, reduced freeze protection (IEG only), and possible silicate dropout. An antifreeze concentration below 33% (33% antifreeze, 67% water) offers too little freeze and/or corrosion protection and is not recommended .
Always verify that the freeze point and nitrite concentration of the antifreeze/water mix are correct by using a POWER Trac ® 3-Way Test Strip. If chemical analysis is used, elements in the coolant must fall within the limits as listed in Table "Fully Formulated Glycol Coolant Limits with TMC RP-329, TMC RP-330 Chemistry Type A (50/50 Coolant/Water Mixture)"
Fully Formulated Glycol Coolant Concentration Limits
Boron
125 – 500 PPM
Nitrite
900 – 3200 PPM
Nitrate
200 – 3200 PPM
Silicon
50 – 250 PPM
Phosphorous
0 PPM
pH
8.0 – 11.0
Table , Fully Formulated Glycol Coolant Limits with TMC RP-329, TMC RP-330 Chemistry Type A (50/50 Coolant/Water Mixture)

13.8.2.3 Recycled Antifreeze

Antifreeze or coolant recycled by reverse osmosis, distillation, and ion exchange, properly re-inhibited to meet TMC RP-329 “Type A” or RP-330 “Type A” requirements has been demonstrated to provide service equivalent to virgin antifreeze. Recycled antifreeze or coolants of these types are preferred. Other recycled coolants, especially coolants recycled through filtration processes, are not recommended .

13.8.2.4 ETHYLENE GLYCOL / WATER + OAT INHIBITOR, PROPYLENE GLYCOL / WATER + OAT INHIBITOR

Ethylene glycol and propylene glycol are also available with an Organic Acid Technology (OAT) corrosion inhibitor package. These coolants require less maintenance over the useful life of the engine. The cooling system should either be equipped with a “blank” coolant filter or the coolant filter and piping may be omitted from the system.
OAT fully formulated antifreezes are available as concentrated and pre-mixed. Concentrated antifreezes should be mixed at 50% (50% antifreeze 50% water). OAT coolants should not be mixed with conventional coolants. If OAT and conventional coolants are mixed, no damage will result, but the long-life advantages of the OAT coolant will be lost. In this event, the coolant should be maintained as a fully formulated ESI (Extended Service Interval) coolant, not as an OAT coolant.
Detroit Diesel markets OAT-inhibited ethylene glycol coolants – DDC POWER COOL Plus and POWER COOL Plus Marine (30% glycol, 70% water). POWER COOL Plus coolants contain all of the required inhibitors. If a non-DDC OAT antifreeze is used, it must conform to TMC RP-338 specification. Do not add extender to new OAT antifreeze or coolant.

13.8.2.5 WATER ONLY + SCA, WATER ONLY + OAT INHIBITOR

In warm climates where freeze protection is not required, water only with corrosion inhibitors is approved for use. Water-only systems need to be treated with the proper dosage of corrosion inhibitors. Detroit Diesel-approved conventional SCA or OAT corrosion inhibitors must be added to the water to provide required corrosion and cavitation erosion protection. Initial fill options are listed in Table 1. OAT inhibitors such as POWER COOL Plus 6000 are available for water-only systems. OAT inhibitor should be mixed at 7.5% – 10% by volume with water. Refer to "Power Cool Engine Products" for a listing of POWER COOL products.
Conventional SCA ( POWER COOL 3000) can also be used to protect the engine. Listed in Table " Power Cool 3000 Concentration Limits (5% Power Cool 3000/ 95% Water)" are POWER COOL 3000 coolant concentration limits.
Note : Do not use Power Trac 3–Way Test Strips to test OAT coolant.
Power Cool 3000 Coolant Concentration Limits
Boron
125 – 500 PPM
Nitrite
900 – 3200 PPM
Nitrate
0 – 1000 PPM
Silicon
50 – 250 PPM
Phosphorous
0 PPM
pH
8.0 – 11.0
Table , Power Cool 3000 Concentration Limits (5% Power Cool 3000/ 95% Water)
POWER COOL 3000 SCA inhibitors should be mixed at 5% by volume with water (1 quart per 5 gallons of water). These additions can be made by adding liquid SCAs available in a variety of sizes. Coolant filters are also available for different cooling system capacities. These filters release the proper amount of SCA at initial fill.

13.8.2.6 Water Requirements

Distilled or de-ionized water, which eliminates the adverse effects of minerals in tap water, is preferred. High levels of dissolved chlorides, sulfates, magnesium, and calcium in some tap water causes scale deposits, sludge deposits and/or corrosion. These deposits have been shown to result in water pump failures and poor heat transfer, resulting in overheating. If tap water is used, the mineral content in the water must be below the maximum allowable limits listed in Table "Satisfactory Water Limits – Make-Up Water Only" .
NOTICE
Do not add additional SCA to new, fully formulated antifreeze or coolant. This can result in dropout and/or the formation of deposits.

13.8.3 Coolants Not Recommended

The following coolants are not recommended for use in Detroit Diesel engines.

13.8.3.1 All Antifreezes And Coolants Containing Phosphate

These coolants are not recommended. Drop out, overheating and water pump seal failures can result from the use of coolant or inhibitor packages based on phosphate.

13.8.3.2 Automotive Type Coolants

These coolants generally contain high levels of phosphate and silicate, offer no liner pitting protection, and are not suitable for use in Detroit Diesel engines.

13.8.3.3 Methyl Alcohol-Based Antifreeze

This must not be used because of its effect on the non-metallic components of the cooling system and its low boiling point.
Maximum Allowable
Parts per Million
Grains per Gallon
Chlorides
40
2.5
Sulfates
100
5.8
Total Dissolved Solids
340
20
Total Hardness – Magnesium and Calcium
170
10
Table , Satisfactory Water Limits – Make-Up Water Only

13.8.3.4 Glycol-based Coolants Formulated For HVAC

These coolants formulated for Heating/Ventilation/Air Conditioning (HVAC) should not be used. These coolants generally contain high levels of phosphates, which can deposit on hot internal engine surfaces and reduce heat transfer.

13.8.4 Additives Not Recommended

The following additives are not recommended for use in MBE 4000 engines.

13.8.4.1 Soluble Oils

Soluble oil additives are not approved for use in Detroit Diesel engine cooling systems. A small amount of oil adversely affects heat transfer. For example, a 1.25% concentration of soluble oil increases fire deck temperature 6%. A 2.50% concentration increases fire deck temperature 15%. The use of soluble oil additives may result in engine overheating and/or failure.

13.8.4.2 Chromates

Chromate additives are not approved for use in Detroit Diesel engine cooling systems. Chromate additives can form chromium hydroxide, commonly called “green slime.” This, in turn, can result in engine damage due to poor heat transfer. Cooling systems operated with chromate-inhibited coolant must be chemically cleaned with POWER COOL Twin Pack cooling system cleaner/conditioner (or equivalent sulfamic acid/sodium carbonate cleaner) and flushed. POWER COOL cleaners are listed in Table

13.8.5 Coolant Inhibitor Test Intervals

The coolant inhibitor level should be checked at the intervals listed in Table "Required Coolant Inhibitor Test Intervals" .
Service Application
Inhibitor Test Interval
Long Haul — Highway Truck & Motor Coach — operates more than 60,000 miles (100,000 kilometers) per year
20,000 Miles (32,000 km)
Sort Haul — City Transit — operates up to 60,000 miles (100,000 kilometers) per year
6,000 Miles (9,600 km) or three months, whichever comes first
Severe Service — Fire Truck or Crash/Rescue Vehicle — operates up to 6000 miles (9,600 kilometers) or under severe conditions
6,000 Miles (9,600 km) or three months, whichever comes first
Table , Required Coolant Inhibitor Test Intervals
WARNING
HOT COOLANT
To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.
If topping off is needed, add coolant which is identical to the initial fill coolant.

13.8.5.1 Supplemental Coolant Additives for Fully Formulated Coolant

The concentrations of some inhibitors will gradually deplete during normal engine operation. SCAs replenish the protection for cooling system components. The coolant must be maintained with the proper concentration of SCA. Detroit Diesel Power Cool maintenance SCAs are recommended.
The proper application of SCA will provide:
pH control.
Restored inhibitor levels to prevent corrosion.
Water softening to deter formation of mineral deposits.
Cavitation protection to protect wet sleeve cylinder liners.

13.8.5.2 Maintenance Intervals

Check the nitrite concentration at the regular intervals listed in Table "Coolant Maintenance Intervals" with a Power Trac 3–Way Test Strip.
Coolant
Interval <sup>1 </sup>
Action
Antifreeze / Water + SCA Inhibitor (DDC Power Cool )
20,000 Miles (32,000km) or 3 Months*
Test nitrite concentration with test strip. Add SCA or dilute coolant as needed.
300,000 Miles (480,000km)
Drain and clean system. Refill with new coolant.
Ethylene Glycol / Water + SCA Inhibitor
or
Propylene Glycol / Water + SCA Inhibitor
20,000 Miles (32,000km) or 3 Months*
Test nitrite concentration with test strip. Add SCA or dilute coolant as needed.
300,000 Miles (480,000km)
Drain and clean system. Refill with new coolant.
Ethylene Glycol / Water + OAT Inhibitor
or
Propylene Glycol / Water + OAT Inhibitor
Test at 1 Year.
300,000 Miles (480,000km) or 2 Years*
Add Power Cool Plus Extender
600,000 Miles (960,000km)
Drain and clean system. Replace with new coolant.
Water Only + SCA Inhibitor
20,000 Miles (32,000km) or 3 Months*
Test nitrite concentration with test strip. Add SCA or dilute coolant as needed.
300,000 Miles (480,000km)
Drain and clean system. Replace with new coolant.
Water Only + OAT Coolant
300,000 Miles (480,000km) or 2 Years*
Add Power Cool Plus Extender
600,000 Miles (960,000km)
Clean and drain. Replace with new coolant.
Table , Coolant Maintenance Intervals
NOTICE
Failure to properly maintain coolant with SCA can result in damage to the cooling system and its related components. Conversely, over-concentration of SCA inhibitor can result in poor heat transfer, leading to engine damage. Always maintain concentrations at recommended levels. Do not use traditional SCAs with OAT coolant.
Additional SCA must be added to the coolant when it becomes depleted, as indicated by a nitrite concentration of 900 PPM or less. If the nitrite concentration is greater than 900 PPM, do not add additional SCA . If the nitrite concentration is above 3200 PPM, the system is over-inhibited and should be partially drained and filled with a 50/50 mix of water and EG or PG.
In this case the EG or PG should contain no inhibitors and should conform to ASTM D4985. This will dilute the over-concentrated inhibitors.
Note : In non-OAT systems, nitrite concentration of 5000 PPM or higher on a MBE 4000 engine suggests problematic additive over-concentration. This condition must be corrected by immediate draining and flushing of the cooling system. Refill the system with new fully formulated or pre-charged coolant. Check the nitrite concentration level at the next with a Power Trac 3–Way Test Strip.

13.8.6 SCA Test Procedures

Detroit Diesel Power Trac 3–Way Coolant Test Strips should be used to measure nitrite and glycol concentrations. Part numbers are in refer to "Power Cool Engine Products" and refer to "POWER TRAC Coolant Testing And Analysis Products" . Cavitation/corrosion is indicated on the strip by the level of nitrite concentration. Freeze/boil over protection is determined by glycol concentration.
WARNING
HOT COOLANT
To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.
For best results make the test while the coolant is between 50° – 140° F (10° – 60° C). Wait at least 60, but not longer than 75, seconds before reading the nitrite level. Use the test strips as follows:
1.
Dip the strip into coolant for one second. Remove and shake briskly to eliminate excess fluid.
2.
Immediately compare the pad end (% glycol) to the color chart on the container.
3.
Sixty seconds (one minute) after dipping, compare the nitrite pad to the color chart.
4.
Color change of the additive indicator (middle pad) indicates the presence of inhibitor that is not approved by Detroit Diesel.
Promptly replace and tighten the test strip container cap after each use. Discard unused strips if they have turned light pink or tan.
A factory coolant analysis program is available through authorized Detroit Diesel service outlets. Part numbers are in refer to "POWER TRAC Coolant Testing And Analysis Products" in the Specifications section. To verify coolant acceptability, submit a sample for coolant analysis every two (2) years, 300,000 miles (480,000 km), or 10,000 operating hours, whichever comes first.

13.8.7 Need Release Coolant Filters (Non-OAT Systems)

Spin-on coolant filters are available for Detroit Diesel engines. Membranes in the filters release SCAs before the coolant approaches a corrosive condition, protecting the engine from corrosion. The elements release the SCA charge as needed, as opposed to the maintenance SCA elements, which instantaneously release the SCA charge. Coolant filter elements should be replaced after one (1) year, 120,000 miles (192,000 km) or 2,000 operating hours, whichever comes first.

13.8.8 Dropout

Excessive amounts of some inhibitors in the coolant can cause a gel or crystalline deposit that reduces heat transfer and coolant flow. The deposit, called “dropout,” takes the color of the coolant when wet, but appears as a white or gray powder when dry. It can pick up solid particles in the coolant and become gritty, causing excessive wear of water pump seals and other cooling system components.
WARNING
PERSONAL INJURY
To avoid injury when using caustic cleaning agents, follow the chemical manufacturers usage, disposal, and safety instructions.
The wet gel can be removed by using a non-acid (alkali) type heavy-duty cleaner, such as Detroit Diesel Power Cool On-Line Cleaner (sodium nitrite/sodium tetraborate). Part numbers are in refer to "Power Cool Engine Products" .
Note : If the gel is allowed to dry, it is necessary to disassemble the engine and clean it with a caustic solution or physically clean individual components.

13.8.9 Coolant Extender Inhibitor Additive for “OAT” Coolant

The inhibitors in OAT coolant must also be maintained, but less often than traditional SCA-type coolants. A portable test is available to test the levels of OAT inhibitors in coolant. Where this is not used, fleet testing has determined that a OAT coolant extender package should be added to the coolant at 300,000 miles (480,000 km), two (2) years, or 5,000 hours, whichever comes first. The proper maintenance dosages for all OAT coolants are listed in Table "Coolant Maintenance Intervals" , reflecting 0.6% by volume extender. This dosage should be added to the water-only and the glycol systems at the same interval.
The proper application of extender to OAT coolant will provide:
pH Control
Restored inhibitor levels to prevent corrosion
Cavitation protection to protect wet sleeve cylinder liners
Note : Do not use traditional SCAs in OAT coolant, and do not use OAT extender in traditional coolant.

13.8.9.1 OAT Coolant Drain Interval

A properly maintained OAT-inhibited coolant will last 600,000 miles (960,000 km), four (4) years, or 10,000 operating hours, whichever comes first. At this time the coolant should be drained, and the cooling system should be thoroughly cleaned, flushed, and filled with new, properly inhibited OAT coolant.

13.8.10 Chronic Coolant System Problems

The most commonly seen coolant system problems result from maintenance and formulation factors such as:
Hard water
Dilution of the coolant by the addition of untreated water
Over dosage or under dosage of corrosion inhibitors
Improper corrosion inhibitor (most often phosphated)
Mixing SCAs
Improper testing

13.8.11 Detroit Diesel Cooling System Maintenance Products

The following products are available to do maintenance on the cooling system.

13.8.11.1 Power Cool SCAs

Power Cool SCAs are water-soluble chemical compounds. These products are available in coolant filter elements, liquid packages, and in fully formulated Power Cool antifreeze.
Note : Power Cool 3000 liquid SCA is more compatible with hard water than Power Cool 2000 SCA.

13.8.11.2 Power Cool Coolant Filter Elements

Power Cool coolant filter elements (spin-on canisters) are available in various sizes suitable for cooling systems of varying capacities. Selection of the proper element size is vital when pre-charging non-fully formulated coolant at initial fill and at s. A fully formulated antifreeze must not have SCA added at initial fill. Do not use SCA-containing filters with OAT antifreeze or coolant. The need for maintenance elements is determined by the results of the nitrite concentration test performed at each cooling system interval. Do not automatically install maintenance elements at maintenance intervals, unless the nitrite concentration falls below 900 parts per million.

13.8.11.3 Power Cool Cleaners

Power Cool Liquid On-Line Cleaner is used for light deposits. Power Cool Dry Chemical Cleaner/Conditioner is used for heavy deposits or scale.

13.8.12 Summary of Coolant Recommendations

WARNING
HOT COOLANT
To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.
1.
Always maintain the engine coolant to meet Detroit Diesel specifications.
2.
Only use water that meets the specifications listed in Table "Satisfactory Water Limits – Make-Up Water Only" . Distilled, de-mineralized (reverse osmosis) or de-ionized water is preferred.
3.
The proper dosage of inhibitors must be included in the coolant at initial fill for all Detroit Diesel engines. This dosage is usually included in the fully formulated antifreeze used, or it may need to be added if water alone or if less than 50% antifreeze is used. The user is urged to refer to the full text of this section to determine the proper dosage. Mixing of different manufacturers' technologies (brands) could cause cooling system problems.
4.
Maintain the inhibitor at the prescribed concentration. Test the nitrite concentration by using a titration kit or Detroit Diesel Power Trac 3-Way Coolant Test Strips. Add SCA only if the nitrite concentration is below 900 PPM. Do not use SCA in OAT coolant, and do not use Power Trac 3-Way Coolant Test Strips to test OAT coolant.
Note : If the nitrite concentration exceeds 3200 PPM, the coolant must be drained and replaced with new coolant. A thorough cleaning of the cooling system may be required.
5.
Do not use another manufacturer's test kit to measure the SCA concentration of Detroit Diesel maintenance products.
6.
Pre-mix coolant makeup solutions to the proper concentration before adding to the cooling system.
7.
Do not mix OAT and other coolants in the same engine.
8.
Do not use automotive coolants.
9.
Where antifreeze/boil over protection is required, use only antifreeze that meets TMC RP-329 “Type A” EG  or TMC RP-330 “Type A” PG specifications. Always maintain coolant at the proper level.
10.
Do not use the following in Detroit Diesel engine cooling systems:
Soluble oil
High silicate, automotive-type antifreeze
Chromate SCAs
Methoxy propanol-base coolant
Methyl alcohol-base coolant
Sealer additives or coolant containing sealer additives.
HVAC coolant
Phosphated coolants

13.8.12.1 Coolant life of Glycol Coolant

A properly maintained cooling system, filled with phosphate-free coolant consisting of a 50/50 mix of antifreeze and water per TMC RP-329 “Type A” EG  or TMC RP-330 “Type A” PG specifications can be operated to the limits recommended. The proper maintenance involves periodic evaluation using Power Trac 3-Way Coolant Test Strips and the addition of SCA as needed, indicated by the strip test. To verify coolant acceptability, submit a sample for coolant analysis every 300,000 miles (480,000 km), three (3) years, or 5,000 operating hours, whichever comes first. Submit the sample in a DDC Power Trac Coolant Test Bottle. Required part numbers are in refer to "Power Cool Engine Products" .

13.8.12.2 Coolant Life of OAT Coolant

A properly maintained OAT coolant may be operated 600,000 miles (960,000 km), four (4) years, or until overhaul, whichever comes first. At this time the system must be completely drained, thoroughly cleaned, and refilled. OAT Coolants require the addition of an extender at 300,000 miles (480,000 km), two (2) years, or 5,000 hours, whichever comes first. Use 1 pint of extender for every 20 gallons of coolant.

13.8.12.3 Coolant Life of Other Coolants

Other properly maintained coolants may be operated up to 250,000 miles (480,000 km), two (2) years, or 4,000 operating hours, whichever comes first. At this time the system must be completely drained, thoroughly cleaned, and refilled.

13.8.13 Coolant Flushing and Changing

Flush and change the coolant as follows:
WARNING
HOT COOLANT
To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.
1.
Open the cap on the surge tank slowly, to allow excess pressure to escape. Set the cap aside.
2.
Open the water regulating valve for the heating system.
3.
Place a large receptacle underneath the coolant drain plug and open the coolant drain plug on the bottom of the radiator.
Note : Make sure the coolant can flow unobstructed into the receptacle.
NOTICE
Do not apply more than 140 kPa (20 psi) air pressure for a radiator flush; more pressure could damage the radiator or heater core.
4.
Start radiator flushing by attaching a flushing gun nozzle to the radiator outlet and run water in until the radiator is full.
WARNING
EYE INJURY
To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 276 kPa (40 psi) air pressure.
5.
Apply no more than 140 kPa (20 psi) air pressure intermittently to help dislodge sediment buildup in the core.
6.
Drain the radiator, and flush the radiator until clean water flows from the radiator. Remove the flushing gun.
7.
When the coolant has drained, install the coolant drain plug on the radiator.
8.
Add coolant in the specified concentration until the maximum mark on the surge tank is reached.
9.
Start the engine and run it for about one minute at varying speeds to release air pockets in the cooling system. Ensure the heater valve is still open. Check the coolant level and add more coolant if necessary.
10.
Shut down the engine, close and tighten the cap on the surge tank.

13.8.14 Cooling System Inspecting

Note : Before doing this inspection, do either "Coolant Concentration Checking," or "Coolant Flushing and Changing."
Inspect the cooling system as follows:
WARNING
HOT COOLANT
To avoid scalding from the expulsion of hot coolant, never remove the cooling system pressure cap while the engine is at operating temperature. Wear adequate protective clothing (face shield, rubber gloves, apron, and boots). Remove the cap slowly to relieve pressure.
1.
Inspect the radiator, condenser, water pump, engine oil cooler, freeze plugs, and heat exchanger for damage and leaks.
2.
Check all cooling system pipes and hoses for damage and leaks; ensure they are positioned to avoid chafing, and are securely fastened.
3.
Check the outside of the radiator and condenser for blockage. Check fins for damage; straighten them if necessary.