ACURA NSX 1991 Service Repair Manual

Heater-Evaporator Uni t
Overhau l
1. Remov e th e heate r cor e cover , remov e th e pip e clamp , the n pul l ou t th e heate r core .
2 . Remov e th e lowe r hal f o f th e housing , the n remov e th e evaporator .
3 . Remov e th e expansio n valv e i f necessary .
HEATER COR E PIPE CLAM P
AI R MI X DOO R
LOWE R HAL F
OF TH E HOUSIN G
CAPILLAR Y TUB E
SUCTIO N LIN E
*EVAPORATOR
The expansio n valv e capillar y tub emus t b e touchin g th e suctio n line .
New par t fo r R-134a .
4. Assembl e th e heater-evaporato r uni t i n th e revers e orde r o f disassembly . Hol d th e expansio n valv e capillar y tub e
dow n agains t th e suctio n line , an d wra p i t wit h tap e t o hol d i t there .
EXPANSIO N VALV E HEATE
R COR E
COVE R
TAPE
SUCTIO N LIN E
ProCarManuals.com

"DEF" Door Adjustment

Connect the control rod to

the clip.
Turn this lever all the way

clockwise and hold it there.

Turn this lever clockwise

and hold it against its stop.
"HEAT" Door Adjustment

Reposition gear 2 so this

mark lines up with the mark .

on gear 1 Loosen this screw in gear 2.

GEAR 1
GEAR 2ProCarManuals.com

Condenser
Descriptio n
Dual condenser s ar e mounte d behin d th e righ t an d lef t sid e o f th e fron t bumpe r a s shown . Th e coolin g efficienc y o f parallel -
dua l condenser s i s a s goo d a s o r bette r tha n a singl e condense r mounte d in fron t o f radiator .
LEFT CONDENSE R
Ne w part s (R-134a )
RECEIVER/DRYE RNew part s (R-134a )
RIGH T CONDENSO R
Ne w part s (R-134a )
ProCarManuals.com

Replacement
1. Disconnect the negative cable from the battery.
2. Remove the from bumper (see section 20).
3. Recover the refrigerant using a R-134a refrigerant Recover/Recycling/Charging System (see page

22-73).

4. Disconnect the discharge line C and the condenser lines from the condenser. Cap the open fittings

immediately to keep moisture and dirt out of the

system.

(Right Condenser)

CONDENSER
LINE A
DISCHARGE
LINE C

(Left Condenser)

CONDENSER
LINE C
CONDENSER
LINE A
5. Disconnect the connector from the condenser fan,
remove the two mounting bolts and nut, then
remove the condenser.

*: CORROSION RESISTANT BOLT

(Right Condenser)

NUT

CONNECTOR
RIGHT CONDENSER

* MOUNTING BOLTS
6 x 1,0 mm
10 N·m (1.0 kg-m, 7 Ib-ft)

(Left Condenser)
CONNECTOR
NUT

LEFT CONDENSER * MOUNTING BOLTS
6 x 1.0 mm
10 N·m (1.0 kg-m. 7 Ib-ft)
6. Install the condenser in the reverse order of removal; and:
If you're installing a new condenser, add
refrigerant oil (ND-OIL 8) (see page 22-69 ).
Replace 0-rings with new ones at each fitting,
and apply refrigerant oil to them.
NOTE: Be sure to use the right O-rings for
R-134a to avoid leakage. Charge the system (see page 22-91) and test its
performance (see page 22-70).
ProCarManuals.com

Condenser
Overhaul
1. Remov e th e fou r bolt s an d nuts . The n separat e th e condense r duc t fro m th e condense r shroud , an d remov e th e
condenser .
2 . Remov e th e thre e mountin g screws , the n remov e th e condense r fa n fro m th e condense r shroud .
CONDENSE R
Ne w part s (R-134a )
CONDENSE R
DUC T
NUTS6 x 1. 0 m m
1 0 N- m (1. 0 kg-m , 7 Ib-ft )
SPACE R
CONDENSE R FA N
SCRE W
CONDENSE RSHROUD
3. Assembl e th e condense r i n th e revers e orde r o f disassembly . B e carefu l no t t o damag e th e tab s o n th e condense r
shrou d whe n yo u attac h i t t o th e ai r intak e duct .
BOLT
ProCarManuals.com

Compressor

Description

This compressor is a Nippondenso piston type for R-134a. A revolving inclined disc drives the surrounding 10

reciprocating pistons. As the inclined disc revolved, it pushes the pistons, protected by a ceramic shoe, thus compress-

ing the refrigerant.

RELIFE VALVE

PISTONS

FIELD COILProCarManuals.com

Compressor
Illustrated Inde x
RELIE F VALV E
Replacement , pag e 22-8 7
O-RING
Replace .
SUCTIO N SERVIC E VALV E
2 6 N- m (2. 6 kg-m , 1 9 Ib-ft ) CENTE
R BOL T
PRESSUR E PLAT E
SHIM(S )
SNAP RIN G B
Replace .
PULLEY
CLUTC H SE TInspection ,page 22-8 5
SNAP RIN G A
Replace .
FIEL D COI L
Inspection , pag e 22-8 5
COMPRESSO R
(D o no t disassembly )
ProCarManuals.com

Replacement
1. I f th e compresso r stil l works , ru n th e engin e a t idl e
for a fe w minute s wit h th e A/ C on , the n shu t th e
engin e of f an d disconnec t th e negativ e cabl e fro m
th e battery .
2 . Recove r th e refrigeran t usin g a R-134 a refrigeran t
Recovery/Recycling/Chargin g System . (se e pag e
22-73 ).
3 . Disconnec t th e compresso r connector .
COMPRESSO RCONNECTOR
4. Rais e th e ca r o n a hoist . Mak e sur e it' s properl y
supporte d (se e sectio n 1 ).
5 . Remov e th e fron t bea m (se e sectio n 5 ).
6 . Disconnec t th e suctio n an d discharg e hose s fro m th e
compressor . Ca p th e ope n fitting s immediatel y t o
kee p moistur e an d dir t ou t o f th e system .
DISCHARG E HOS E
SUCTIO NHOSE
8 x 1.2 5 mm30 N- m(3.0 kg-m ,22 Ib-ft )
7. Loose n th e idle r pulle y cente r nu t an d adjustin g bolt ,
the n remov e th e bel t fro m compressor .
ADJUSTING BOL T12 N- m (1. 2 kg-m ,9 Ib-ft )
IDLE R PULLE Y CENTE R
NUT45 N- m (4. 5 kg-m ,33 Ib-ft )
8. Remov e th e fou r mountin g bolt s an d compressor .
COMPRESSO R
MOUNTING BOLT S
8 x 1.2 5 mm25 N- m (2. 5 kg-m ,18 Ib-ft )
ProCarManuals.com

Compressor

Replacement (cont'd)

9, If necessary, remove the one bolt from the idler pulley bracket, then remove the four mounting
bolts and the compressor bracket.

10 x
1,25
mm

50 N·m
(5.0 kg-m,
36 Ib-ft)

IDLER PULLEY

BRACKET BOLT
COMPRESSOR

BRACKET
10 x
1.25
mm

50 N·m
(5.0 kg-m,
36 Ib-ft)
10. If necessary, remove the two other bolts in the idler pulley assembly.
IDLER PULLEY

ASSEMBLY
Check the idler pulley bearing for play and drag.
Replace it with a new one if it's noisy or has ex-
cessive play or drag.

46 N·m
(4.5 kg-m.
33 Ib-ft)

11. Install the compressor in the reverse order of removal; and:If you're installing a new compressor, drain all
the refrigerant oil out of the old compressor and
measure its volume. Subtract the volume of old
Oil from 140 CC (4-2/3 floz); the result is the
amount of oil you should drain from the new

compressor (through the section fitting).

Replace 0-rings with new ones at each fitting,
and apply refrigerant oil to them.
NOTE: Be sure to use the right 0-rings for
R-134a to avoid leakage.
Use (ND-OIL 8) oil for R - 134a Nippondenso

piston type compressors only.

Do not return the oil to the container once
dispensed and never mix with other refrigerant

oils to avoid contamination.
Immediately after using the oil, replace the cap
on the container and seal it to avoid moisture
absorption. Do not spill the refrigerant oil on the car; it may
damage the paint; if the refrigerant oil contacts

the paint, wash it off immediately.

12. Adjust the compressor belt (see page 22-88). After adjusting the belt, tighten the idler pulley
center nut.
Then tighten the adjusting bolt securely,
13. Charge the system (see page 22-91).
14. Test system performance (see page 22-70).
ProCarManuals.com

Clutch Inspectio n
• Chec k th e plate d part s o f th e pressur e plat e fo r colo r
changes , peelin g o r othe r damage . I f ther e i s dam -
age , replac e th e clutc h set .
, • Chec k th e pulle y bearin g pla y an d dra g b y rotatin g
th e pulle y b y hand . Replac e th e clutc h se t wit h a ne w
on e if i t i s nois y o r ha s excessiv e play/drag .
PULLEY
Measur e th e clearanc e betwee n th e pulle y an d th e
pressur e plat e al l th e wa y around . I f th e clearanc e i s
no t withi n specifie d limits , th e pressur e plat e mus t b e
remove d an d shim s adde d o r remove d a s required ,
followin g th e procedur e o n pag e 22-40 .
Clearance : 0. 5 ± 0.1 5 m m (0.02 0 ± 0.00 6 in )
NOTE : Th e shim s ar e availabl e i n thre e thicknesses :
0.1 mm , 0. 3 m m an d 0. 5 mm .
Chec k resistanc e o f th e fiel d coil .
Fiel d Coi l Resistance : 3. 6 ± 0. 2 ohm s a t 6 8 F (2 0 C )
I f resistanc e i s no t withi n specifications , replac e th e
fiel d coil .
ProCarManuals.com