1991 ACURA NSX heater

Engine Removal/Installation

Removal

20. Disconnect the engine wire harness connectors.

21. Remove the battery cable from the main fuse box.

ENGINE WIRE

HARNESS CONNECTORS

BATTERY

CABLE

6 x 1.0 mm

10 N-m
(1.0 kg-m,

7 Ib-ft)

22. Disconnect the throttle body 6P connector, and

remove the ground cable and starter cable.

STARTER CABLE
THROTTLE BODY

6P CONNECTOR

GROUND CABLE

CORROSION RESISTANT BOLT
23. Disconnect the two connectors from the emission

control box, then remove the control box.

• Do not disconnect the vacuum hoses.

6 x 1.0 mm

10 N-m (1.0 kg-m, 7 Ib-ft)

CONNECTORS

CONTROL BOX

24. Remove the radiator hoses and heater hose.

HEATER HOSE

RADIATOR

HOSESProCarManuals.com

10. Remove the engine cover stay from the strut brace,
then set the engine cover stay between the engine
cover and rear hatch latch (NSX-T open top),
CAUTION: Use a shop tower to avoid damaging

painted surfaces.

SHOP

TOWEL

11. Relieve fuel pressure by loosening the service bolt on the fuel filter about one turn (see section 11).
Do not smok* while working on fuel
system; Keep open flame or spark away from work

area. Drain fue1 only into an approved container.

12. Remove the fuel feed pipe and fuel return hose (see page 5-5 ('91-'93) or ('94-'96).

13. Remove the evaporative emission (EVAP) control
canister hose and brake booster vacuum hose (see
page 5-5 ('91-'93) or ('94-'96).
14. Disconnect the breather pipe and vacuum hose, then remove the air cleaner housing.

6 x 1.0 mm

10 N·m (1.0 kg-m, 7 lb-ftl

AIR CLEANER
HOUSING

BREATHER

PIPE

: CORROSION RESISTANT BOLT
15. Remove the Hoses, then remove the expansion tank
(see page 5-5 ('91-'93) or ('94-'96).
16. Removel the radiator hoses and heater hose (see
page 5-6 ('91-'93) or ('94-'96).

17. Disconnect the two connectors, then remove the
control box (see page 5-6 ('91-'93) or ('94-'96).

18. Remove the intake manifold plate and top cover.

INTAKE MANIFOLD

PLATE
6 x
1.0mm

12 N·m (12kg-m,

9 lb-ft)

TOP COVER

19. Remove the fuel injector covers.
6 x 1.0 mm
12 N·m (1-2 kg-m, 9 lb-ft)

FUEL INJECTOR

COVER

(cont'd)

ENGINE

COVER

STAYProCarManuals.com

Cooling
Illustrated Index
Syste m is unde r hig h pressur e whe n th e
engin e i s hot . T o avoi d dange r o f releasin g scaldin g
engin e coolant , remov e th e ca p onl y whe n th e engin e i s
cool .
Tota l Coolin g Syste m Capacity : Includin g expansio n
tank 2. 1 (2. 2 U S qt . 1. 8 Im p qt )
5 M/T : 16. 0 (17. 0 US qt , 14. 1 Imp qt )
4 A/T : 16. 5 (17. 4 US qt , 14. 5 Imp qt )
NOTE :
• Chec k al l coolin g syste m hose s fo r damage ,
leak s o r deterioratio n an d replac e i f necessary .
• Chec k al l hos e clamp s an d retighte n i f
necessary .
• Us e ne w O-ring s whe n reassembling .
Radiator, Wate r Pipe s an d Hoses :
BLEED BOL T10 N- m (1. 0 kg-m ,7 Ib-ft )
WASHE RReplace .
HEATER PIP E
RADIATO R
LOWE R HOS E
RADIATO R
UPPE R HOS E
RADIATO REngine coolan t refillin g an dbleeding , pag e 10- 5Leak test , pag e 10- 8Inspec t soldere d joint s an dseam s fo r leaks .Blow ou t dir t fro m betwee ncore fin s wit h compresse d air .If insects , etc. , ar e cloggin gradiator, was h the m of f wit hlow-pressur e water . BLEE
D PLU G
RESISTO R
RADIATO R DRAI N
PLU G
FRON T LOWE R
WATE R PIP E
FRON T UPPE R
WATE R PIP E FA
N SHROU D
5 x 0. 8 m m4.5 N- m (0.4 5 kg-m , 3. 3 Ib-ft )
Replace .
BLEED BOL T
10 N- m (1. 0 kg-m ,7 Ib-ft )
WASHER S
Replace .
WATER PIP E
DRAI N BOLT S
15 N- m (1. 5 kg-m , 1 1 Ib-ft )
WATE RPIPE ASSEMBL YWASHE
RReplace .
FAN MOTO R
ProCarManuals.com

Engine Coolant Refilling and Bleeding

CAUTION: When pouring engine coolant, be sure to

shut the relay box lid and not let coolant spill on the

electrical parts or the paint. If any coolant spills, rinse it

off immediately.

NOTE:

• Perform this maintenance when the engine is cool.

• Before replacing the coolant, turn the ignition ON,

slowly turn the climate control temperature knob to

90° and turn off the ignition. This will allow the

coolant in the heater to drain out with the rest of the

system.
1. Open the hood, the rear window and the engine

cover.

2. Remove the cover protecting the water pipes and

shift cables on the underside of the car.

3. Before removing the expansion tank cap, first

loosen the cap to lower pressure.

CAUTION: Do not remove the expansion tank cap

when engine is hot. The coolant is under pressure

and may blow out and scald you. Open the cap

slowly when the engine is cool.

4. Loosen the drain plug in the bottom of the radiator,

and drain the coolant.

5. Remove the two drain bolts from the water pipes,

and drain the coolant.

WASHERS

Replace.

DRAIN BOLTS

15 N-m (1.5 kg-m, 11 Ib-ft)
DRAIN HOLE
DRAIN PLUGProCarManuals.com

Carpet

Replacement

SRS components are located in this area. Review the SRS component locations, precautions, and procedures in the SRS
section (24) before performing repairs or service.

DASHBOARD

INSIDE SCREW
CARPET

HOOK

(3)

AIR VENT
AM VENT

AIR DUCT
CUPS

FLOOR

CARPET

CONSOLE

CARPET

CONSOLE CARPET

SRS UNIT
SCREW

(cont'd)

1. Remove:
Seats (see page 20-39('93-'96), 38('91-'92)

Footrest

Under-dash fuse box lid (see page 20-38('93-'96),37('91-'92)

Side sill trim (see page 20-38 ('93-'96), 37('91-'92)

Side sill pad (see page 20-38('93-'96), 37('91-'92)
Rear side trim panel (see page 20-38('93-'96), 37('91-'92)

Center armrest (see page 20-49('94-'96)('91-'93)

Center console panel (see page 20-52('94-'96)('91-'93)


2. Detach the clips at The front edge (passenger's).
3. Remove the console carpet attaching screw from the heater unit (passenger's).
4. Disconnect the air duct (driver's) and air vent, then remove the carpet hooks from the dashboard inside screws.ProCarManuals.com

('93-'96), 86 ('91-'92 Models)
MODE CONTROL MOTOR
Replacement, page 22-57
('93-'96), 69 ('91-'92 Models)
Test, page 22-58
('93-'96), 91 ('91-'92 Models)
"DEF" DOOR
Adjustment, page 22-77
('92-'96), 72 ('91Models)

"HEAT" DOOR

Adjustment, page 22-77
('92-'96), 72 ('91Models)

RECIRCULATION

CONTROL MOTOR

Replacement, page 22-59 ('93-'96), 64 ('91-'92)
Test, page 22-59 ('93-'96), 64 ('91-'92 Models)

BLOWER UNIT

Replacement, page 22-67 ('93-'96), 63 ('91-'92)Overhaul, page 22-68 ('93-'96), 62 ('91-'92)


RECEIVER/DRYER

Serves as a reservoir which filters and
removes moisture from the refrigerant.
OUTSIDE AIR TEMPERATURE SENSOR

Removal, page 22-62 ('93-'96), 86 ('91-'92 Models)

Test, page 22-62


DUAL CONDENSER

Dissipates the heat which was

absorbed by the refrigerant.

Replacement, page 22-79 ('93-'96), 74 ('91Models)Overhaul, page 22-80 ('93-'96), 75 ('91Models)

HEATER CORE

TEMPERATURE SENSOR
Removal, page 22-64

Test, page 22-64
AIR MIX CONTROL

MOTOR

Replacement, page 22-56 ('93-'96), 70 ('91-'92 Models)
Test, page 22-57 ('93-'96), 69 ('91-'92 Models)

HEATER-EVAPORATORUNIT
Replacement, page 22-74('93-'96), 66 ('91-'92 Models)
Overhaul, page 22-76 ('93-'96), ('92), 71 ('91 Models) IN-CAR TEMPERATURE SENSOR
Removal, page 22-61('93-'96), 69 ('91-'92 Models)
Test, page 22-61 ('93-'96), 69 ('91-'92 Models)
COMPRESSOR (NIPPONDENSO)
Compresses the refrigerant and

then forces it through the condenser.

CLIMATE CONTROL UNIT
Replacement, page 22-54
Adjustment, page 22-55
SUNLIGHT SENSOR

Removal, page 22-63 ('93-'96), 87 ('91-'92 Models)Test, page 22-63 ('93-'96), 87 ('91-'92 Models)

EVAPORATOR

TEMPERATURE

SENSOR

Removal, page 22-65 ('93-'96), 88 ('91-'92 Models)
Test, page 22-65 ('93-'96), 88 ('91-'92 Models)

HEATER VALVE CABLE

Adjustment, page 22-58 ('93-'96),
91 ('91-'92), 75 ('93-'96), 66 ('91-'92)

VENT DOOR CONTROL MOTOR
Replacement, page 22-60

('93-'96)
, 69 ('91-'92 Models)
Test, page 22-60 ('93-'96),
69 ('91-'92 Models)

A/C TRIPLE
PRESSURE SWITCHProCarManuals.com

Heater-Evaporator Doo r Positio n
ProCarManuals.com

SRS components are located in this area. Review the SRS component locations, precautions, and procedures in the SRS

section 24 before performing repairs or service.

POWER TRANSISTORBLOWER MOTOR

RECIRCULATION

CONTROL
MOTOR

CONDENSER
FAN MOTOR UNDER-HOOD RELAY BOX A
(CONDENSER FAN RELAY, COMPRESSOR CLUTCH RELAY,
BLOWER MOTOR HIGH RELAY, BLOWER MOTOR RELAY)
UNDER-HOOD

FUSE/RELAY

BOX

HEATER CORE TEMPERATURE SENSOR
CLIMATE CONTROL UNIT VENT DOOR
CONTROL MOTOR
OUTSIDE AIR
TEMPERATURE SENSOR ENGINE COMPARTMENT

FUSE/RELAY BOX
A/C TRIPLE PRESSURE SWITCH
FAN CONTROL UNIT (Fan radiator and con-

denser fans inside car,

behind seats)
EVAPORATOR

TEMPERATURE

SENSOR

IN-CAR

TEMPERATURE
SENSOR
MODE CONTROL

MOTOR

AIR MIX CONTROL MOTOR
SUNLIGHT

SENSORProCarManuals.com