1991 ACURA NSX Service Repair Manual

Exhaust Pip e an d Muffle r
Replacemen t
NOTE: Us e ne w gasket s an d self-lockin g nut s whe n reassembling .
GASKETSReplace.
JOINT PIP E
REA R SECONDAR YHO2S
4 5 N- m (4. 5 kg-m , 3 3 Ib-ft )
• B e carefu l no t t o
damage .
• Us e th e specia l too l
fo r remova l an d
installation . SELF-LOCKIN
G NUT S
10 x 1.2 5 mm34 N- m (3. 4 kg-m , 2 5 Ib-ft )Replace .
MUFFLE R
SELF-LOCKIN G NU T8 x 1.2 5 mm22 N- m (2. 2 kg-m ,16 Ib-ft )Replace .Tighten th e flang e nut s
i n steps , alternatin g
side-to-side .
THRE E WA Y CATALYTI C
CONVERTER S (TWCs )
Inspect a s show nbelow.
GASKET SReplace.
FRONT EXHAUST -
PIP E A FRON
T SECONDAR Y
HO2 S
4 5 N- m (4. 5 kg-m , 3 3 Ib-ft )
• B e carefu l no t t o
damage .
• Us e th e specia l too l
fo r remova l an d
installation .
JOINTPIPE
SELF-LOCKIN G NUT S10 x 1.2 5 mm55 N- m (5. 5 kg-m , 4 0 Ib-ft )
Replace . SELF-LOCKIN
G NUT S
8 x 1.2 5 mm22 N- m (2. 2 kg-m , 1 6 Ib-ft )Replace .Tighten th e flang e nut s i n steps ,
alternatin g side-to-side .
GASKETSReplace.
SELF-LOCKIN G NU T8 x 1.2 5 mm22 N- m (2. 2 kg-m , 1 6 Ib-ft )Replace .Tighten th e flang e nut s i n steps ,
alternatin g side-to-side .
6 x 1. 0 m m10 N- m (1. 0 kg-m , 7 Ib-ft )
TWC Inspection :
Using a flashlight , mak e a visua l chec k fo r plugging , meltin g
or crackin g o f th e catalyst .
TWC
FLASHLIGH T
REA
R EXHAUS T
PIP E A
GASKE TReplace .
GASKETReplace .
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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
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EXPANSION TAN K
Refillin g an d bleeding , pag e 10- 5
Lea k Test , pag e 10- 8
ENGINE OI L
COOLE R PIP E
AUTOMATI C TRANSMISSIO N
FLUI D (ATF ) COOLE R
ENGINEOIL COOLE R
CAPTest , pag e 10- 8
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Radiator
Replacemen t
1. Remov e th e spar e tire .
2 . Drai n th e radiato r (se e pag e 10- 5 thr u 10-7 ).
3 . Disconnec t th e fa n moto r connecto r an d th e
resisto r connector .
4. Remov e th e uppe r an d lowe r hose s fro m th e
radiator .
5. Remov e th e bracke t an d th e radiator . Instal
l th e radiato r i n th e revers e orde r o f removal :
NOTE:
• Se t th e uppe r an d lowe r cushion s securely .
• Fil l th e radiato r an d blee d th e ai r (se e pag e 10- 5
thr u 10-7 ).
6 x 1. 0 m m10 N- m (1. 0 kg-m , 7 Ib-ft )
RADIATO R BRACKE T
UPPE R CUSHION S
RESISTO R CONNECTO R
FA N MOTO R
CONNECTO R
RESISTO R CONNECTO R
LOWER CUSHION S
FAN MOTO R
CONNECTO R
UPPE R HOS E
LOWER HOS E
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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

Radiator
Engine Coolan t Refillin g an d Bleedin g
6. Instal l rubbe r hose s o n th e drai n bolt s a t th e fron t
an d rea r of the engin e unde r th e cylinde r banks .
Loose n th e drai n bolt s t o drai n th e coolant .
• Drainin g ca n b e don e mor e quickl y i f al l th e blee d
bolt s an d plu g ar e als o opened . Befor e openin g
them , mak e sur e th e coolan t leve l i n th e expan -
sio n tan k ha s com e dow n completel y s o tha t th e
coolan t wil l no t pou r ou t o f th e blee d bolt s an d
plug .
7. Whe n th e coolan t stop s draining , tighte n th e
radiato r drai n plug , wate r pip e drai n bolt s an d
engin e drai n bolts .
• B e sur e t o replac e th e wate r pip e drai n bol t
washer s wit h ne w ones .
REAR ENGIN E DRAI N BOL T
3 0 N- m (3. 0 kg-m , 2 2 Ib-ft )
8. Ope n al l fou r bleeders .
1 ) Loose n th e radiato r blee d plug .
2 ) Remov e th e heate r pip e blee d bolt .
3 ) Loose n th e wate r pip e blee d bolt .
4 ) Loose n th e engin e blee d bol t o n th e therm o
cover.
9. Mi x th e recommende d antifreeze/coolan t wit h a n
equa l amoun t o f wate r i n a clea n container .
NOTE:
• Us e onl y Honda-recommende d anti-freeze /
coolant.
• Fo r bes t corrosio n protection , th e coolan t con -
centration s mus t b e maintaine d year-roun d a t
50 % minimum . Coolan t concentration s les s tha n
50 % ma y no t provid e sufficien t protectio n
agains t corrosio n o r freezing .
• Coolan t concentration s greate r tha n 60 % wil l
impai r coolin g efficienc y an d ar e no t recom -
mended.
CAUTION :
• D o no t mi x differen t brand s o f anti -
freeze/coolant .
• D o no t us e additiona l rus t inhibitor s o r anti-rus t
products ; the y ma y no t b e compatibl e wit h th e
recommende d coolant .
Engin e Coolan t Refil l Capacity : Includin g expansio n
tank 2. 1 (2. 2 U S qt , 1. 8 Im p qt )
Manual : 12. 0 (12. 7 U S qt , 10. 6 Im p qt )
Automatic : 12. 0 (12. 7 U S qt , 10. 6 Im p qt )
FRON T ENGIN E DRAI N BOL T30 N- m (3. 0 kg-m , 2 2 Ib-ft )
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10. Fil l th e expansio n tan k wit h engin e coolant . A s
coolan t start s t o ru n ou t i n a stead y strea m withou t
bubbles , tighte n th e bleeder s i n sequence : therm o
cove r blee d bolt , radiato r blee d plug , heate r pip e
blee d an d wate r pip e blee d bolt .
11 . Afte r tightenin g al l th e bleedin g bolt s an d plug , fil l
th e expansio n tan k wit h coolan t u p t o th e MA X line .
12. Loose n th e therm o cove r blee d bol t t o remov e an y
remainin g air .
13 . Whe n bleedin g i s completed , retighte n th e therm o
cove r blee d bol t an d fill the expansio n tan k u p t o
0. 5 (0.5 3 US qt , 0.4 4 Imp qt ) o r 3 0 m m (1. 2 in)
ove r th e MA X line . 14
. Instal l th e expansio n tan k cap , an d tur n it 6 0 degree s
(wher e it engage s th e firs t loc k ta b o f fille r neck) .
1 5 . Star t th e engine , an d le t i t ru n unti l warme d u p (unti l
th e thermosta t open s an d th e radiato r coolin g fa n
runs) .
16. Tur n of f th e engine . Chec k th e expansio n tan k and ,
i f needed , ad d engin e coolan t t o brin g i t u p t o th e
MA X line .
17. Tighte n th e expansio n tan k ca p securely .
18 . Reinstal l th e cove r o n th e car' s underside .
THERMO COVE R
BLEE
D PLU G
RADIATO
R UPPE R
TAN K HEATE
R PIP E
BLEED BOL T
10 N- m (1. 0 kg-m ,7 Ib-ft )
BLEE
D BOL T
10 N- m (1. 0 kg-m ,7 Ib-ft )
BLEE
D BOL T
10 N- m (1. 0 kg-m ,7 Ib-ft )
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Expansion Tan k
Cap Testin g
1. Remov e th e expansio n tan k cap , we t it s sea l wit h
engin e coolant , the n instal l i t o n th e pressur e
tester.
2. Appl y a pressur e o f 95-12 5 kP a (0.95-1.2 5
kg/cm2, 14-1 8 psi) .
3 . Chec k fo r a dro p i n pressure .
PRESSUR E TESTE R
ADAPTO R(for 3 2 m m neck )
EXPANSIO N TAN K
CAP
Testin g
1. Wai t unti l th e engin e is cool , the n carefull y remov e
the expansio n tan k ca p an d fil l th e expansio n tan k
with engin e coolan t t o th e to p o f th e fille r neck .
2. Attac h th e pressur e teste r t o th e expansio n tank ,
an d appl y a pressur e o f 9 5 - 12 5 kP a (0.9 5 - 1.2 5
kg/cm
2, 14 - 1 8 psi) .
3 . Inspec t fo r coolan t leak s an d a dro p i n pressure .
4 . Remov e th e tester , an d reinstal l th e expansio n tan k
cap.
NOTE : Chec k fo r engin e oi l i n th e coolan t and/o r
coolan t i n th e engin e oil .
PRESSUR E TESTE R
EXPANSION TAN K
ADAPTO R(for 3 2 m m neck )
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