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7/25/09 8:32pm - Original Message: 'Over Heating'
ossw1
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Rocklin, CA - USA

Vette(s):
1970 T-Top350/350hp numbers matching 4 speed. It's a mess and 1970 Convertible 4 speed.

Joined: 4/2/2005
Posts: 484
Ok I have replaced the radiator the thermostat and the hoses. The car seems to run about 200 to  220 in city traffic. But it runs to 240 to 260 on the highway. Should it be the other way around if I have a heating problem? What would cause this?
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7/25/09 9:43pm - Reply: 'Over Heating'
williammoore2 Lifetime Member
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Mundelein, IL - USA

Vette(s):
1978 25 anniversary blue on blue with T-tops.

Joined: 6/9/2008
Posts: 411
Might be water pump. Did you check weephole and see if its leaking. do you have an electric fan or original? I replaced water pump last year and that did the trick for a while but now radiator is gettin put in.

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7/25/09 10:20pm - Reply: 'Over Heating'
ossw1
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Rocklin, CA - USA

Vette(s):
1970 T-Top350/350hp numbers matching 4 speed. It's a mess and 1970 Convertible 4 speed.

Joined: 4/2/2005
Posts: 484
No the water pump is not leaking. I have the fan clutch it has to be that sense it gets hotter at higher speeds? I could just replace the water punp for JP its not that hard.
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7/25/09 11:26pm - Reply: 'Over Heating'
williammoore2 Lifetime Member
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Mundelein, IL - USA

Vette(s):
1978 25 anniversary blue on blue with T-tops.

Joined: 6/9/2008
Posts: 411
not hard but can be a PITA removing the fan clutch. Auto parts do not always carry the studs either for the fan clutch. I had to reuse some of the old ones and they were no fun getting them off. 

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7/26/09 12:39am - Reply: 'Over Heating'
suncountry Lifetime Member
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Moses Lake, WA - USA

Vette(s):
1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II

Joined: 4/16/2005
Posts: 2134
Had the same problem with mine when I first got it. I live in the desert region so it was not surprising to have a cooling challenge. If I went above 70mph on the hwy the vette would over heat. If it cools in city traffic your fan and clutch are probably ok. Do you have the foam seals between the radiator and radiator mount (both sides, bottom and top). This will prevent the air from by pass the radiator. Also the seal between the top of the radiator mount and hood. Have you checked you engine timing? If your off a ways the engine will run hotter. Is you chin spoiler in place. It helps to deflect air up and into the radiator
My problem was I had a 3 row radiator core with the A/C. Went to the 4 row and it solved the problem but still ran a bit hot on hot days. When I put the new motor in I went with Diwitt Aluminum radiator and dual electric fans. It now stays nice and cool!


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C3VR Lifetime Member #110 We are all young at heart Glen
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7/26/09 8:16am - Reply: 'Over Heating'
Gunslinger
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Frederick, MD - USA

Vette(s):
1969 convertible L71 427/435 4-speed black interior

Joined: 9/8/2003
Posts: 3398
Check out your lower radiator hose.  It should have a spring inside it to prevent collapsing under vacuum.  What you're experiencing is classic symptoms of a collapsing lower hose...fine at low speed but as speed and rpm's rise, the hose collapses under vacuum, thus preventing coolant flow.  The spring will prevent that.  You could have a hose missing a spring.

Other possibilities...make sure all seals are in place around the radiator as already said, the shroud is in place, the air deflector under the front end is in place, you have a good radiator cap that holds pressure properly, the radiator and block cooling passages are clear of sludge, etc.

From your description, it sounds like the lower hose has no spring or the air deflector/seals aren't there or are improperly installed.


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Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, c o c k y and in general a malcontent.

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7/26/09 1:03pm - Reply: 'Over Heating'
Phill's Vette Lifetime Member
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Apache Junction, AZ - USA

Vette(s):
1982,150K,Renegade CFI,Hooker Side Pipes,85 fuel pump,Bilsteins,HD suspension, Aluminum radiator, SharkBar/w 5-Point Restraints. 3:73 gears coming soon.

Joined: 10/15/2006
Posts: 285
I agree on the seals, a lot of air flow is lost without them in place - all of them in place, also the hose collapsing.
Thumbs Up 
I also fought overheating for a good three years and installed a high flow pump, aluminum radiator, dual fans, new hoses and Water Wetter; STILL had problems until I connected the the dual fans up properly. Now my fans are receiving the correct amps and
blowing the rated CFM - FINALLY no more over heating. 180 to 210 even at 112 degrees in the shade with the AC on!

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LifeTime Member #154


Number 28 of 200 Made on July 28th, 1982
P E A C E !
Phill
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7/26/09 2:34pm - Reply: 'Over Heating'
anips
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 783
check the belts they might be loose,  belts don't always squeal when loose, when you have to push volumns of water at highway speed a loose belt may not be turning the waterpump fast enough.

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7/26/09 9:30pm - Reply: 'Over Heating'
BKVETTE
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Calhoun City, MS - USA

Vette(s):
1977 Black T-Top

Joined: 9/24/2005
Posts: 121
mines was running a high temperature  at one time until I replaced the  heads.  Mechanic  was going to put in valve seals  because it was  smoking  at startup  and running  idle,  discovered  i had a bad head, bought  a reworked pair,  lowered  the temperature .  Now  runs  from  180  to 200  max  on a 100 degree day.

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Kenny P   '77 L82 Black on Black Vette

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7/27/09 2:21pm - Reply: 'Over Heating'
dcherr Gold Member
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Elkhart, IN - USA

Vette(s):
1975 Red T-Top 1972 Red Convertible

Joined: 10/7/2007
Posts: 209
Do you have the air dam spoiler under the front lower grille panel. If it is missing it will not divert the air up into the radiator at hwy speed. Mine was missing and I had the same problem at hyw speed. I also keep the antifreeze to -10 only and use water weeter in the radiator and we stay nice an cool.


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7/27/09 8:38pm - Reply: 'Over Heating'
T-Mans70,73 Lifetime Member
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Elma, WA - USA

Vette(s):
Red 1973 Convertible. L-48 Auto #'s matching Red 1970 LT-1 Convertible #'s matching

Joined: 6/25/2007
Posts: 692
My 70 gets hot at highway speeds if the outside temp gets above 80+ degrees.
What I found out was I am missing some of the foam strips that surround the radiator and the bottom half of the shroud.
The way I understand it is without all foam seals and of course the bottom half the shroud the car doesnt force enough air through the radiator to cool it at speed. I guess it does make sense.

That would be where I would look first. (Its hard to know what you havent got!)


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7/27/09 8:49pm - Reply: 'Over Heating'
whtlitnin Lifetime Member
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VENTRESS, LA - USA

Vette(s):
1971 Blue Roadster, sb400, cam, electronic ignition,10 disc CD changer, 2.5" chambered exhaust, 3.36 rear,tremec 5 speed from Classic Chevy, fiberglass rear spring and vintage air.

Joined: 10/8/2003
Posts: 87
If you have a front liscense plate try  removing it and see if it makes any difference. Cured mine.

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RAY - Here for a good time, not a long time!


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7/27/09 9:54pm - Reply: 'Over Heating'
aceinthehole Lifetime Member
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Valley Springs, CA - USA

Vette(s):
1978,Metalic Money Green W/Gold emblems,TH350 w/gear splitter,black & grey interior.1978,two tone,Metalic Rootbeer & gold ,Doeskin interior,auto. trans. 1981, Silver w/mirrored T-Tops,4 spd, charcoal interior.

Joined: 11/20/2005
Posts: 3618
Dave, just say the word and I'll bring by my spare air dam. before you buy anything you don't need, it's worth a try.

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Jimmy B.
Just can't wait to get on the road again.

 
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7/29/09 9:16pm - Reply: 'Over Heating'
ossw1
Former Member
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Rocklin, CA - USA

Vette(s):
1970 T-Top350/350hp numbers matching 4 speed. It's a mess and 1970 Convertible 4 speed.

Joined: 4/2/2005
Posts: 484
Hey Guy's thanks for the info. Well what I found out is the fan clutch is not working right. I ran the engine for awhile and found that I could move the fan. Should it lock up when the engine heats up. The hose does not have  a spring in it. Called Napa to ask if the hose I bought should have a spring and he said no? Told me to try a hardware store for a springAngry I know the hose I took out had one in it. All the seals seem to be good but it is missing the lower dam. I will get a after market fan and look for the right lower hose.
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7/29/09 11:35pm - Reply: 'Over Heating'
Phill's Vette Lifetime Member
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Apache Junction, AZ - USA

Vette(s):
1982,150K,Renegade CFI,Hooker Side Pipes,85 fuel pump,Bilsteins,HD suspension, Aluminum radiator, SharkBar/w 5-Point Restraints. 3:73 gears coming soon.

Joined: 10/15/2006
Posts: 285
I didn't reinstall the spring in my bottom hose, I was told the newer hoses do not need the spring as they are less likely to collapse. No problems since install and a good 800 miles later. I did save the spring though.
Geek 


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LifeTime Member #154


Number 28 of 200 Made on July 28th, 1982
P E A C E !
Phill
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7/29/09 11:37pm - Reply: 'Over Heating'
Phill's Vette Lifetime Member
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Apache Junction, AZ - USA

Vette(s):
1982,150K,Renegade CFI,Hooker Side Pipes,85 fuel pump,Bilsteins,HD suspension, Aluminum radiator, SharkBar/w 5-Point Restraints. 3:73 gears coming soon.

Joined: 10/15/2006
Posts: 285
Installing the missing lower dam will most likely take care of your problems.
Thumbs Up


____________________________________
LifeTime Member #154


Number 28 of 200 Made on July 28th, 1982
P E A C E !
Phill
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7/30/09 9:59am - Reply: 'Over Heating'
aceinthehole Lifetime Member
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Valley Springs, CA - USA

Vette(s):
1978,Metalic Money Green W/Gold emblems,TH350 w/gear splitter,black & grey interior.1978,two tone,Metalic Rootbeer & gold ,Doeskin interior,auto. trans. 1981, Silver w/mirrored T-Tops,4 spd, charcoal interior.

Joined: 11/20/2005
Posts: 3618
Dave, just to be clear on this. I don't think there is anything on the market that can beat the 7 blade fan that comes on these, so be sure to only change the clutch.

____________________________________
Jimmy B.
Just can't wait to get on the road again.

 
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8/12/09 8:26pm - Reply: 'Over Heating'
ossw1
Former Member
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Rocklin, CA - USA

Vette(s):
1970 T-Top350/350hp numbers matching 4 speed. It's a mess and 1970 Convertible 4 speed.

Joined: 4/2/2005
Posts: 484
Ok time for a update. I put a flex fan on and my over heating has gone away. The only problem with it is its noisier but I did get the over heating solved.
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8/12/09 9:36pm - Reply: 'Over Heating'
anips
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sonoma, CA - USA

Vette(s):
72 LT-1 AC coupe,69 l-36 coupe

Joined: 8/9/2002
Posts: 783
Great news, heres my story, Ive tryed to run flex fans on both of my cars, on the 69 I had side pipes and you could barely hear the fan, I drove the that lleh out of that car, I wanted another car so I put it up for sale, I take  a  propsect for a ride, I hammer it and I pick up a vibration, I get home lift the hood and a blade is sitting on top of the intake half under the air cleaner..phewno damage the guy buys the car, fast forward to the 72, the car doesn.t overheat but when I turn on the AC the temp would go to 220, so I try another flex fan, but this time I watch the fan, after about 3- 4 months I start to see stress cracks starting to appear on the SS blades where they attach to the hub, put the stock one back on, I didn't buy cheap on both occasions they were the highest rated Flex-a-lite's with the blue hub, maybe its the way I drive but I think its the constant flexing of the blades,be aware and good luck.

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8/14/09 9:13am - Reply: 'Over Heating'
ossw1
Former Member
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Rocklin, CA - USA

Vette(s):
1970 T-Top350/350hp numbers matching 4 speed. It's a mess and 1970 Convertible 4 speed.

Joined: 4/2/2005
Posts: 484
Yes good to know thanks.
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