Vat Cleaning

WARNING

radiator with air gun before vat cleaning. This reduces

contamination of the vat solution.

If hot cleaning vat solution, muriatic acid or flux

enters the eyes, wash generously for 15 minutes

CAUTION

with clean water. Seek medical attention.

Aluminum radiators should not be cleaned with

WARNING

caustic base cleaning agents.

When working with the hot cleaning vat, safety

(d) Lower radiator in vat slowly until completely

goggles, rubber shoes, rubber apron and gloves

covered by solution. If violent boiling occurs when radiator

should be worn for protection against hot vat

first comes in contact with hot vat solution, immediately

solution.

withdraw radiator from vat and thoroughly wash and flush

with clean water. Violent boiling indicates that radiator or

CAUTION

some of its parts are made of aluminum.

c. Flushing and Washing

Adding large amounts of cleaning compound to a

(1) Thoroughly wash radiator externally and flush

hot vat will cause violent boiling. Add only small

internally immediately after removal from the hot cleaning

amounts slowly. Never add water to the dry

vat. This is necessary for removal of foreign matter that

compound but instead add the compound to the

has been loosened by the vat cleaning process and to

water.

prevent formation of trouble-some oxides which interfere

with soldering.

(a) The vat should contain a solution of water and

(2) After vat cleaning, flushing and washing, Flo-Test

radiator cleaning compound. It should be maintained at

radiator again (para 3-18). If GPM rate is not up to

the proper temperature when in use. Cleaning compound

specifications, repeat the vat cleaning and flushing

is used in a quantity of 5 to 8 ounces per gallon of water

The most effective operating temperature is 190F. to

procedure.

(3) If repeated cleaning is not satisfactory, remove

200F. The new vat solution becomes most effective after

tank for rodding. Flat steel cleaning rods are made for this

being maintained at operating temperature for a short

purpose.

period of time.

This enables the chemicals in the

compound to react and come Into balance.

3-10.

Drying

(b) To test solution strength, a simple test is

performed with hydrion paper. A small piece of hydrion

a. General

paper is dipped in vat solution and the color of the paper

(1) After a radiator has been vat cleaned and

changes in relationship to solution strength. The resultant

thoroughly flushed, complete drying before leak testing is

color change of paper is compared to a color chart

very important. If the radiator is not absolutely dry on the

included with the paper supply. The chart has three

inside, small leaks may be sealed and not be evident

colors, labeled PH-11, PH-12 and PH-13. The proper

during the air test. Small leaks are sealed by thin film

solution strength is indicated when the wet paper matches

surface tension of any moisture remaining in a radiator

the color of PH-13. To obtain a clean sample, be sure to

that is not completely dry.

blow any scum away from a small area before dipping

(2) The air test will not simulate operating conditions

paper.

which subject radiators to engine and road vibrations.

Heat expansion and contraction, mechanical stress and

gradually in small amounts to cold water, then heat and

other forces are exerted during operating conditions.

maintain the solution temperature to about 195F. To

(3) A dry radiator will show every leak, no matter how

bring a weak cleaning solution up to strength, start with the

small. If all leaks are exposed and repaired while on the

addition of one ounce per gallon of the existing vat

bench, the reliability of the radiator can be assured.

contents. A solution that is too strong, decreases cleaning

b. Drying Procedure

effectiveness. When adding small amounts of compound,

(1) Seal all openings on radiator except inlet and

the vat can be at operating temperature.

outlet neck with push on rubber test plugs (11, fig 2-1).

(3) Radiator vat cleaning procedure

(2) Using a hot air blower with suitable ducts, hoses,

(a) The length of time required to clean a

and adapters, connect forced warm air hose to inlet neck.

radiator will be governed by the condition of the radiator

(3) Allow warm air to circulate through the water

and the degree of plugging. The Flo-Tester will determine

passages and discharge from outlet neck until radiator is

this. The average cleaning time in the vat is approximately

completely dry internally.

one hour.

(b) Before cleaning, seal the oil cooler

openings.

3-5