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Topic: c4- 85 thermostat replacement

in Forum: All Vettes Discussion


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c4- 85 thermostat replacement (1/7)
 4/6/14 12:02pm
68vet427
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macedon, NY - USA

Vette(s):
68 COUPE 454 HAS MOTION HOOD SCOOP, REVERSED GILLS ZL-1 FENDER FLARES AND MOTION REAR SPOILER, LEMAN'S GAS CAP, BUCKET HEADLIGHTS. CAN-AM FRONT RACING SPOILER. CHROME HOOKER HEADERS AND SIDE PIPES! 4 SPEED M20, LOOKS FAST STANDING STILL !!


Joined: 7/20/2006
Posts: 364

Hi all.
I have a buddy that has a 85 vette, He wants to know what is needed to replace the thermostat on it.
Does the throttle body have to be removed?
Any other parts on the block , hoses, brackets ect...
Draining coolant required?

I tried finding a video. No luck.
I told him i could help him, but not sure myself what to do.
I have no experience with the C4's so any help is appreciated.
Thanks in advance.
Joe

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Re: c4- 85 thermostat replacement (2/7)
 4/6/14 12:17pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20128

Taking the throttle body loose from the plenum would give ya more room, but I don't think ya HAVE to remove it. Could be wrong, tho. Just drain the radiator....that will lower the coolant level enough that you don't make a huge mess. The throttle body also has coolant running thru it, so you will loose some there IF you take the hoses loose. If you remove the throttle body, you'll need the gasket that goes on there, between the TB and the plenum.
You'll need the t-stat, and gasket for it, too, of course. To make it easier to fill the system, and burb the air bubbles, the new t-stat will usually have a small hole in the edge, with a little chunk of metal in it to act as an orifice. Take some side cutter pliers(dikes), and cut that little piece off, so you have JUST the hole in the edge. This will give the coolant a small amount of full-time flow, and keep air from getting trapped. Thumbs Up

In this pic, I drilled several 1/8" holes along the edge of the t-stat, but you really only need the one. If the t-stat you get does not have the orificed hole built in, drill at least one 1/8" hole in the edge.....it'll be much easier to fill the system...




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Joel Adams
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Re: c4- 85 thermostat replacement (3/7)
 4/6/14 8:04pm
68vet427
Former Member

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macedon, NY - USA

Vette(s):
68 COUPE 454 HAS MOTION HOOD SCOOP, REVERSED GILLS ZL-1 FENDER FLARES AND MOTION REAR SPOILER, LEMAN'S GAS CAP, BUCKET HEADLIGHTS. CAN-AM FRONT RACING SPOILER. CHROME HOOKER HEADERS AND SIDE PIPES! 4 SPEED M20, LOOKS FAST STANDING STILL !!


Joined: 7/20/2006
Posts: 364

Joel,
thanks for getting back.
Should this have been under the cooling forum?
Hope this will help.
Thanks again.
Joe
Re: c4- 85 thermostat replacement (4/7)
 4/7/14 9:17am
Adams' AppleLifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20128

Naw...it's in the correct forum, since it is a Non-C3 issue. Yer good. Thumbs Up



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Joel Adams
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             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: c4- 85 thermostat replacement (5/7)
 4/14/14 10:00am
68vet427
Former Member

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macedon, NY - USA

Vette(s):
68 COUPE 454 HAS MOTION HOOD SCOOP, REVERSED GILLS ZL-1 FENDER FLARES AND MOTION REAR SPOILER, LEMAN'S GAS CAP, BUCKET HEADLIGHTS. CAN-AM FRONT RACING SPOILER. CHROME HOOKER HEADERS AND SIDE PIPES! 4 SPEED M20, LOOKS FAST STANDING STILL !!


Joined: 7/20/2006
Posts: 364

One other question came up.

He wants to put a lower degree thermostat in it, ( 195 degree I think he said) . Will this screw up his computer readings and or performance of the engine since it normally runs at a higher temp?


Re: c4- 85 thermostat replacement (6/7)
 4/14/14 1:02pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
Posts: 20128

68vet427 said:

One other question came up.

He wants to put a lower degree thermostat in it, ( 195 degree I think he said) . Will this screw up his computer readings and or performance of the engine since it normally runs at a higher temp?


No, not really. Unless you go down into the 160* range, that is. A t-stat that is rated far lower than OE will allow the stat to open sooner than "normal". It can also sometimes cause a lot more condensation to form inside the engine if the engine is allowed to idle for long periods of time, or if you just start it and let it run, without actually driving it.
These L98 engines were designed to run in the 225*-230* range. Putting a lower rating stat in will not change that....it might just take it longer to get to that temp, but it will eventually get there. The thermostat doesn't control the actual engine temp....it simply control when the coolant starts to flow. The rest of the system components(w pump, radiator, fans, etc) are what controls the actual running temps. Well.....that, and the driver's foot....LOL
180*, or 195* stat is perfectly fine. Thumbs Up

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Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: c4- 85 thermostat replacement (7/7)
 4/14/14 6:24pm
68vet427
Former Member

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macedon, NY - USA

Vette(s):
68 COUPE 454 HAS MOTION HOOD SCOOP, REVERSED GILLS ZL-1 FENDER FLARES AND MOTION REAR SPOILER, LEMAN'S GAS CAP, BUCKET HEADLIGHTS. CAN-AM FRONT RACING SPOILER. CHROME HOOKER HEADERS AND SIDE PIPES! 4 SPEED M20, LOOKS FAST STANDING STILL !!


Joined: 7/20/2006
Posts: 364

Joel,
thanks again for the info!!!!
Joe
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