Apparatus and method for repairing vehicle heater cores

An apparatus and method for repairing a leak in a vehicle heater core without requiring its removal from its vehicle mounted position. The apparatus comprises an airtight container having an immersible pump and heater element secured within the container and including inlet and outlet fluid lines for coupling with hose extensions from the heater core of a vehicle. Access to such hose lines may be accomplished by an intermediate cut on each of the inlet and outlet hoses to the heater core, joining the respective flowlines of the container into a closed fluid circuit. In this configuration, flushing solution, cleaning solution and sealing compound can be pumped through the heater core to repair any existing leaks. An inlet valve is provided for introducing air pressure to assist in delivery of the sealer compound through the closed circuit and confirming repair of any existing leaks.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
The present invention relates to devices and methods for repairing leaks in 
vehicle heater core structures. More particularly, the present invention 
relates to such devices and methods which do not require removal of the 
heater core from its attached position within the vehicle. 
2. Prior Art 
A conventional heating and cooling system in a combustion powered motor 
vehicle utilizes a heating core as a heat transfer element. This heating 
core comprises a coiled tube which is coupled into the fluid circulating 
network of the cooling system of the vehicle. As water/coolant within this 
cooling system is heated by the combustion engine, a water pump is 
activated and circulates the water between the radiator and the block of 
the engine. When the heating system for the vehicle passenger section is 
activated, the heated fluid is transferred through the heater core, which 
is usually positioned near the fire wall of the vehicle, considerably 
removed from the radiator and associated connect lines. The separated 
relationship of the heater core from the cooling system and its 
positioning within the vehicle structure create numerous problems upon 
occurrence of a leak in one or more of the coils of the heater core. 
Current procedure for repair of such a leak involves introduction of a 
fluid, sealing compound into the flow line near the radiator and pumping 
of this solution into the heater core. Ideally, the sealing solution flows 
through the heater core at the location of the leak, to form a bonded plug 
which blocks the leak opening. Unfortunately, various forms of deposits 
and residue accumulate within the heater core which may inhibit effective 
sealing by the stop-leak compound. Efforts to flush out this residue are 
often not effective because the heater core is so far removed from entry 
of the flush solution that effective turbulent action is lost and scaling 
off of the protective residue coating is minimal. 
If repair requires a thorough flushing and effective application of a leak 
sealing compound, removal of the heater core from the vehicle is typically 
required with direct flushing and treatment by a fluid pumping system. 
This service involves considerable expense, primarily because of the 
substantial labor required to access the heater core and remove it from 
its "buried" location within the vehicle structure. In fact, general 
consensus favors replacement of the heater core with a new heater core 
rather than repair in view of the referenced high cost of labor. 
Therefore, a vehicle owner who is faced with the problem of a leaking 
heater core has only two effective options. First, the owner can attempt 
to cure the leakage by pumping sealant compound through the coolant system 
by accessing tubing coupled near the radiator. This not only poses the 
difficulty of getting the sealing compound through the coolant system to 
the heater core in sufficient concentration, but also exposes the water 
pump and other areas within the coolant fluid circuit to possible 
detrimental effects of the sealing compound. The effectiveness of such 
repair has already been placed in question in view of the difficulty of 
developing an effective flush technique for reaching the heater core to 
expose core material to sealing action of the compound. 
The remaining option is to incur the high expense of removing the heater 
core so that direct repair can be effectively made. At this point of 
considerable expense, most repairmen would advise replacement of the core 
with a new core element because of likelihood of occurrence of new leak 
locations, with the renewed requirement of heavy labor expense to again 
pull the heater core element from its difficult location. 
Accordingly, what is needed is a method or apparatus for enabling effective 
and inexpensive repair of the heater core without the need of removing the 
structure from its location within the vehicle. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an apparatus and method 
for enabling an effective flush and cleansing operation of the heater core 
interior, as well as applying sealant compound in an effective manner. 
It is a further object of the present invention to provide an apparatus and 
method for repairing a heater core without removal from its vehicle in a 
manner which reduces labor cost and material expense. 
A still further object of this invention is to provide a method and 
apparatus for repairing a heater core which facilitates convenient use 
with respect to vehicles of differing manufacture. 
These and other objects are realized in a device disclosed herein which 
comprises an airtight container having a container volume capable of 
holding liquid coolant and sealing compound wherein the container includes 
an inlet port for receiving fluid from the heater core and an outlet port 
for delivering fluid from the container to the heater core. An immersible 
pump is positioned within the container. This pump operates to take fluid 
at its intake opening from within the container and deliver it to an 
outlet opening which is coupled to the outlet port of the container for 
return to the heater core. An intake connector line is coupled at one end 
to the inlet port of the container, with the remaining end being coupled 
in line with a fluid entry point to the heater core. An output connector 
line is attached at one end to the outlet port of the container, with the 
remaining end being attached to the remaining fluid access point of the 
heater core. This creates a closed fluid circuit between the container and 
heater core which has been retained at its vehicle mounted location. Means 
are provided in the container for pressurizing fluid within the circuit 
during operation of the apparatus. An access opening is also provided for 
introducing sealant compound into the container for circulation through 
the closed circuit into the heater core. The apparatus may also include a 
submersible heater element to enhance cleaning and sealant operation 
within the fluid circuit. 
Also disclosed is a method for using this apparatus as part of a repair 
technique on heater core structures which comprises the following steps. 
First, the heater core is isolated from its coolant flow circuit with the 
vehicle radiator system by clamping input and output lines from the heater 
core to block fluid movement therefrom. Input and output flow lines from 
the heater core are then cut beyond the clamp portion to provide access to 
the heater core through exposed flowline openings. Flow connector lines 
from the airtight container are then attached at these exposed heat core 
flowline openings to form the referenced closed flow circuit between the 
container and the heater core. Leak sealant compound is introduced into 
the container and may be heated and pressurized to more effectively 
perform its sealing function. In addition, a prior cleansing flush can be 
performed using the same pumping hardware and closed circuit with heating 
element to raise the temperature of the cleaning solution. Upon completion 
of the sealant application, the system is flushed and the heater core 
flowlines are reconnected to the cooling system of the vehicle. 
Utilizing this method and apparatus enables direct access to the heater 
core without its removal from the vehicle. This saves substantial cost in 
labor, as well as enhancing the effectiveness of the repair services. 
Other objects and features of the present invention will be apparent to 
those skilled in the art in view of the following detailed description, 
taken in combination with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings: 
FIG. 1 discloses an apparatus which is adapted for flushing and repairing a 
leak in a vehicle heater core without requiring its removal from its 
vehicle mounted position. This apparatus includes an airtight container 10 
which has an interior container volume capable of holding liquid coolant 
and/or sealing compound in solution. The introduction of such coolant 
material and sealing compound is discussed hereafter in connection with 
the method of use. The container includes an inlet port 11 for receiving 
fluid 12 from the heater core and within the container volume. This inlet 
port 11 is coupled to an intake connector line 13 which is joined at its 
remaining end 14 with a coupler tube 15 (shown in greater detail in FIG. 
2). The construction of this coupler tube 15 with its multiple diameter 
sizes 16, 17 and 18 will be discussed hereafter in connection with use 
directly with differing hose sizes of vehicles of various manufacture. 
An outlet port 20 is also provided in the container 10 for delivering fluid 
from the container to the heater core through an output connector line 21 
attached at the outlet port 20. A two-way valve 24 is coupled inline with 
the connector line 21 and provides selectable output flowlines 22 and 25. 
Where as line 22 provides a return path for fluid to the heater core, line 
25 is a flush line to discard fluid 26 in accordance with procedures which 
are outlined hereafter. This valve 24 includes a control lever 27 which 
can be selectively adjusted to alternate fluid flow between the respective 
flowlines 22 and 25. 
Fluid transfer is controlled by an immersible pump 30 which is positioned 
within the container volume. Fluid flow occurs through an intake opening 
31 and an outlet line 32 which connects in line with the outlet port 20. 
An acceptable pumping device for use in accordance with this invention is 
a conventional 12-volt hermetically sealed pump. The pump is activated by 
toggle switch 33 which couples the pump through wires 34 and 35 to the 
grounded outlet plug 36. 
A submersible heater element 40 is secured within the volume of the 
container 10 and is powered by a second toggle switch 41 which couples 
into control circuitry 42 and thence through wires 43 and 44 to the actual 
heater element 40. This circuitry draws electrical power from the same 
external power source used for the pump 30 via plug 36. Various heater 
core elements may be used for this application; however, they should at 
least have the capacity of generating sufficient resistive heat to raise 
the temperature of contained fluid to at least 150 degrees F., and more 
typically 180 degrees F. A suitable heater element for this application is 
a conventional liquid immersion heater. 
This airtight container is also adapted with a air pressure feed line 47 
with valve stem to enable use with a conventional air hose 48 with a 
charging head 49 for engaging the pressure valve 47 in a manner similar to 
that which is used to inflate vehicle tires. The function of increasing 
air pressure within the sealed container 10 will be more apparent from 
discussion relating to pressurizing the fluid circuit to enhance sealant 
action within the heat core. 
Additional fluids such as sealant compound and cleaning solution may be 
added to the container volume through an opening 50 positioned at the top 
of the container. A pressure cap 51 similar to a conventional radiator cap 
may be engaged at the opening 50 to retain pressure within safety limits 
within the container. This cap 51 also operates as a safety valve in the 
event that pressure from the air hose 48 exceeds preset levels. 
The method of repair enabled by the disclosed apparatus is more 
specifically represented in the following steps. Initially, the heater 
element mounted within the vehicle must be isolated from fluid flow with 
the remaining parts of the cooling system. This may be accomplished by 
clamping hose extensions which couple to the two inlets supplying fluid to 
the heater core. Although the actual heater core has not been disclosed in 
the drawings, the hose elements are represented by items 60 and 61. 
Extensions of these respective hoses 60 and 61 would be connected at the 
respective inlets to the heater core. In their normal configuration, these 
hose lines 60 and 61 would form part of the fluid circuit carrying coolant 
to and from the heater core from the remaining portions of the cooling 
system. 
FIG. 1 shows clamps 62 and 63 applied to the respective hoses 60 and 61 to 
block fluid flow with respect to the heater core. Such flow isolation of 
the heater core is necessary in view of the second step of this procedure 
which involves cutting these respective flowlines 60 and 61 to form 
flowline openings 64 and 65. To prevent coolant from leaking out of the 
radiator/coolant system, similar clamps are applied prior to cutting the 
referenced flowlines 60 and 61. Accordingly, the flowline cuts are applied 
between each pair of clamps to effectively seal off the cut ends which 
isolate the heater core from the remaining portion of the cooling system. 
Obviously, if fluid loss within the heater core is not of concern, clamps 
62 and 63 may be deleted from this procedure. 
The next step to set up the present apparatus involves establishing a 
closed fluid circuit between the sealed container 10 and heater core 
through its respective flowlines 60 and 61. This is accomplished by use of 
the coupling tubes 15 and 23 which remain affixed to the respective 
connector lines 13 and 22. 
The particular coupler tube includes a step-up diameter configuration 
represented by consecutively larger diameters shown as 18, 17, and 16. 
This structure enables versatile use with differing hose sizes as may be 
encountered on different vehicles. For example, smaller cars having lesser 
flow rates may be adapted with smaller diameter tubing which would fit 
tightly over diameter size 18, at the and of the coupler tube 15. This 
smaller diameter 18 might be 1/2 inch O.d. The intermediate tube diameter 
17 could be dimensioned at 5/8 inch O.D., with the largest diameter 16 
being approximately 3/4 inch. A tube clamp 66 is positioned around the 
contacting diameter and secured to prevent inadvertent release of the 
heater core flowlines 60 and 61 from the attached flowlines 13 and 21 of 
the present inventive apparatus. The coaxial orientation of the respective 
tube diameters 18, 17 and 16 around a common tube axis 67 facilitates 
attachment of most flowline hoses on the coupler tube by simply inserting 
the hose end over the coupler until it develops a snug fit. The 
convenience of having such coupling means attached directly to the present 
apparatus is particularly suited to commercial businesses who may service 
many different vehicles within a single day period. This feature avoids 
the need of constant sizing of hose couplings which might thereby encumber 
an otherwise streamlined process of heater core repair. 
Once the apparatus is coupled on line with the respective flowlines of 60 
and 61 on the heater core, clamps 62 and 63 may be removed. The container 
10 is then filled with fresh water which is pumped through the heater core 
by means of immersible pump 30. The illustrated flow shows incoming fluid 
12 forced from the heater core by pump fluid 69 drawn into the pump 30 and 
forced through the flowline toward the heater core as illustrated by arrow 
70. By adjusting the valve lever 27 to the water entrained within the 
heater core can then be flushed as indicated at arrow 26 and discarded. 
This procedure can be repeated as often as necessary. 
The container is then filled with a cleanser solution through opening 50. 
For enhanced cleaning action, the immersible heater element 40 can be 
activated by the use of toggle switch 41. As the heater element raises the 
temperature of the cleaning solution, slime and other residual matter 
retained at the interior surfaces of the heater core is cleared and 
subsequently flushed free by the same procedures as previously outlined. 
Following use of the cleanser solution, a final flush with clean water may 
be applied, in preparation for sealing any leaks within the core coils. 
The sealing step is accomplished by introducing sealant compound through 
opening 50 into the container and by heating such solution to at least 150 
degrees, and preferably 180 degrees F. Such sealer compounds are well 
known and are applied for sealing radiator, as well as heating heater 
cores. In order to enhance flow of the sealant compound through any 
possible leaks within the heater core, the closed fluid circuit is 
pressurized. This is accomplished by applying air pressure through air 
hose 48 at air valve 47. The sealant solution is then pumped through the 
core with the applied pressure until leakage is believed to have been 
stopped. This condition can be confirmed by checking air pressure within 
the closed line. Any drop in air pressure would be indicative of a 
retained leak, requiring further sealing compound. Once the air pressure 
is maintained within the closed system, the sealing solution is flushed 
free, with clean water then being pumped through the system to clean the 
heater core prior to removal of the inventive apparatus. 
Once the operation has been completed, the respective coupler tubes 15 and 
23 are removed from the hose flowline 60 and 61. These hoses 60 and 61 are 
then reattached to the cut locations within the coolant system. This 
attachment can be simply accomplished utilizing a small sleeve dimensioned 
to fit tightly within each end of the joining hoses. Remaining clamps are 
then removed from the engine side of the coolant system, placing the 
heater core on line in its repaired condition. 
The advantage of applying the present inventive apparatus and method to 
repair a heater core will now be apparent, based on the foregoing 
description of prior art techniques. Specifically, the principle advantage 
is the elimination of extensive labor costs which would otherwise be 
required if the heater core was removed from its mounted position in the 
vehicle. The present system allows access to the heater core in most 
vehicles by accessing interconnecting hoses located near the top of the 
engine compartment. These hoses are easily accessible and allow the 
apparatus to be positioned in a convenient location under the hood while 
running the process in accordance with the predefined steps. In addition, 
utilizing the present apparatus and method does not require the vehicle 
engine to be running, because it does not rely on the water pump or other 
circulating system typically applied when the flushing and sealing 
operations are introduced through the coolant fluid circuit. Finally, the 
present invention allows direct access to the heater core with the 
advantages of improved flushing, cleaning and sealing contact without 
intervening components such as radiator, engine block, etc. which impede 
fluid flow to the heater core. 
It will be apparent from those skilled in the art that the foregoing 
examples are merely illustrative of the inventive principles identified 
herein. Accordingly, these examples are not to be construed as limiting, 
except as provided under the following claims.