Go Back   Corvette Forum > C3 Corvettes, 1968 - 1982 > C3 General
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
C3 General
General C3 Corvette Discussion not covered in Tech Sponsored by
Corvette America

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 08-01-2005, 09:36 PM   #1
BKbroiler
CF Senior Member
 
BKbroiler's Avatar
 
Member Since: May 2002
Location: Lebanon Township New Jersey
Default What happens when a thermostat goes bad?

Can they just open partially? My car, with new radiator, all shrouds and seals in place, and clutch fan that spins half a turn by hand, gets up to 230 or higher. The radiator gets hot all the way across and the lower hose does not collapse. A partially open thermostat might explain this. Right?
__________________

383, 9.7:1CR, forged pistons, Vortec heads, 225/232 .535/.550 hyd roller cam, Lars Qjet, headers, 2.5" duals, 3000 stall converter, TH350, 3.73:1 rear, 12.15 sec, 110.33 mph, 1.69 sec 60 ft, (drag radials) best so far. 2004 coupe, 6 speed .
BKbroiler is offline   Reply With Quote
Old 08-01-2005, 09:53 PM   #2
MYBAD79
CF Senior Member
St. Jude Donor '05
 
MYBAD79's Avatar
 
Member Since: Oct 2004
Location: Orlando Florida
Default

No, with a partially open thermostat (that is stuck in it's position) the water in the engine would get very hot (not enough flow), the water in the radiator would have all the time in the world to cool down.
I may be wrong but my guess is that you don't have enough air flow across the radiator.
MYBAD79 is offline   Reply With Quote
Old 08-01-2005, 10:23 PM   #3
rihwoods
CF Senior Member
 
rihwoods's Avatar
 
Member Since: Feb 2005
Default

Put a new thermostat in.Cheap and easy to do...you have alot invested in the rad..at least you will have eliminated that as an issue...
rihwoods is offline   Reply With Quote
Old 08-01-2005, 11:36 PM   #4
BKbroiler
CF Senior Member
 
BKbroiler's Avatar
 
Member Since: May 2002
Location: Lebanon Township New Jersey
Default

I will change the t-stat. Just wondering if anybody thinks that is really the problem.
BKbroiler is offline   Reply With Quote
Old 08-02-2005, 12:26 AM   #5
71SoCal
CF Senior Member
 
71SoCal's Avatar
 
Member Since: Apr 2005
Location: San Diego CA
Default

Quote:
Originally Posted by BKbroiler
I will change the t-stat. Just wondering if anybody thinks that is really the problem.
It's hard to say. If the t-stat is stuck mostly open, then the car will take a long time to warm up. If it's mostly closed, it's more likely to start overheating.

They're cheap. Get a new one and eliminate that question.
71SoCal is offline   Reply With Quote
Old 08-02-2005, 12:28 AM   #6
carbster09
CF Senior Member
 
carbster09's Avatar
 
Member Since: Oct 2002
Location: Aberdeen
Default Air in the system ..

I have a similar problem. I replaced my water pump and now the car runs at 230! I really did not have a BIG problem before, however in my quest for the perfect cooling system I added a high flow pump. Now I have this issue of it running at 230. I think I have not purged all of the air out. I am going to replace the T-stat and purge it yet again.

carbster
carbster09 is offline   Reply With Quote
Old 08-02-2005, 02:28 AM   #7
rihwoods
CF Senior Member
 
rihwoods's Avatar
 
Member Since: Feb 2005
Default

In my opinion,no...if your thermostat was restricting flow,you would heat up fast....and overheat above 230...(but put a new one in anyway)..personally,I'd check that fan clutch again...rotate it slowly by hand,and if you feel resistance in one spot and it feels "free" in another,it is toast...I learned the hard way...install a thermo clutch..they operate on underhood temps...
Rich

Edit.... http://www.haydenauto.com/fce2.htm
rihwoods is offline   Reply With Quote
Old 08-02-2005, 03:35 AM   #8
DMONSVETTE
CF Senior Member
 
DMONSVETTE's Avatar
 
Member Since: Mar 2002
Location: On an island surrounded by sharks Hawaii
Default

Pretty sure it's the clutch fan. That is where my problem was about a month ago after replacing the radiator, water pump, t-stat and all hoses. Run the car for awhile then turn it off while someone watches the fan if it continues to spin for 3 or more rotations the clutch is out.
I was able to hold my fan with my hand to keep it from spinning.
Put on a flex fan and spacer and Vette runs very cool now.
DMONSVETTE is offline   Reply With Quote
Old 08-02-2005, 09:34 AM   #9
GDaina
CF Senior Member
Support Corvetteforum!
 
GDaina's Avatar
 
Member Since: Feb 1999
Location: In Dreams There Is Truth Ohio
Send a message via Yahoo to GDaina
Default

as others have mentioned, 'stats are dirt cheap. If you want to eliminate sthe 'stat as a problem...take it out, and observe if it's cold...place it in a pot of boiling water...if the 'stat opens, it's good, if not, get a new one...oh yea...use some pliers to take the stat out...
GDaina is offline   Reply With Quote
Old 08-02-2005, 10:31 AM   #10
Pete76Shark
CF Senior Member
Support Corvetteforum!
 
Pete76Shark's Avatar
 
Member Since: Jan 2003
Location: Columbia SC
Default

Sometimes it helps just to get it out of the circuit and test.

suggest you remove the thermostat completly and run the car, on the road, see what she does. It is either going to get better or stay the same. If it gets better then go down to your local Chevy parts place and but a new thermostat. I learned the hard way to never buy this part from anybody except the dealer.

If it stays the same temp then you have another issue.

FYI.....
I have others that replaced a stock water pump with a "high flow" water pump and have had high temp problems as a result. Nothing else was changed just the water pump. I think the high flow pump creates cavitation and as such slows down the water flow.

With no thermostat in your car (for testing only) the engine will stay as cool as possible. So if you still have high temps then something else is causing it. Like air finding an easier path around the radiator, or a radiator problem, or a fan clutch that feels ok by hand but does not lock up completly.
__________________
Custom Pearl White 76 Coupe, L48 350/201rwhp & 258 rwtq, auto, Comp 260H Cam, Lars Recurve kit, Dynomax ceramic coated headers and true duals (no cats, no X, no H) to Borlas. Stock Rochester Q-Jet with secondary fuel tube mod. Flame thrower ignition module and coil. Taylor 8mm spiral wires. 3.55 rear gear. Hydroboost Braking System. LED tail lights. GE4537 aircraft landing light. Alpine 9820XM Receiver. R12 A/C.
Pete76Shark is offline   Reply With Quote
Old 08-02-2005, 10:36 AM   #11
jonny4523
CF Senior Member
St. Jude Donor '05-'08
 
jonny4523's Avatar
 
Member Since: Nov 2000
Location: Lafayette Indiana
Send a message via AIM to jonny4523
Default

Here is a different suggestion. Do you have the air dam on? Underneath your front bumper? From the picture, it looks like you do, but I didn't know if you took it off or not. I had replaced everything and I was still running hot. Then I found out that you are supposed to have that air dam on there and I didn't. Put one on and the problem went away. It was all a matter of bringing enough air across the radiator.
__________________
1977 Corvette L-48 (mid restoration)



jonny4523 is offline   Reply With Quote
Old 08-02-2005, 10:46 AM   #12
tigers123
CF Senior Member
 
tigers123's Avatar
 
Member Since: May 2004
Location: belle plaine ks
Default correct

Quote:
Originally Posted by GDaina
as others have mentioned, 'stats are dirt cheap. If you want to eliminate sthe 'stat as a problem...take it out, and observe if it's cold...place it in a pot of boiling water...if the 'stat opens, it's good, if not, get a new one...oh yea...use some pliers to take the stat out...
This quote is right, but have it hanging from a thread through the opening. [just push it open cold and drop thread through] and a thermometer in the water to see when it opens. You would be surprised to see how many don't open when they are supposed to. I learned this from an old GM line mechanic at a dealership I worked at a few years back. He said he got burnt on a service call one time because of a new 'bad' thermostat and decided he would check them from then on.
tigers123 is offline   Reply With Quote
Old 08-02-2005, 12:10 PM   #13
BKbroiler
CF Senior Member
 
BKbroiler's Avatar
 
Member Since: May 2002
Location: Lebanon Township New Jersey
Default

Quote:
Originally Posted by jonny4523
Here is a different suggestion. Do you have the air dam on? Underneath your front bumper? From the picture, it looks like you do, but I didn't know if you took it off or not. I had replaced everything and I was still running hot. Then I found out that you are supposed to have that air dam on there and I didn't. Put one on and the problem went away. It was all a matter of bringing enough air across the radiator.
I do still have the air dam in place, with all seals.
I think I will try it without the stat to see what happens.
Thanks guys.
BKbroiler is offline   Reply With Quote
Old 08-02-2005, 12:26 PM   #14
rihwoods
CF Senior Member
 
rihwoods's Avatar
 
Member Since: Feb 2005
Default

Question to anyone here...re testing without thermostat...agree engine would run cooler...but would this "mask" an issue with the clutch fan ? Just wondering...these clutch fans are not easy to check when they are going out...I got lucky as I felt resistance then it would feel free...turned out the bearings were gone...another I had on my Trooper was "wobbly",and that was obvious..
Rich
rihwoods is offline   Reply With Quote
Old 08-02-2005, 01:49 PM   #15
Pete76Shark
CF Senior Member
Support Corvetteforum!
 
Pete76Shark's Avatar
 
Member Since: Jan 2003
Location: Columbia SC
Default

On a hot summers day the stat opens up and stays open so removing it for testing will not change the engine temp at all. I have a 180 stat and my engine runs at 210 or a little under all the time in the summer.

This does not apply to a winter day of course as the stat will maintain the engine temp at whatever it should be.

Also I had a bad clutch and it was very difficult (for me anyway) to tell that is was not working. I replaced it on a guess and sure enough the new one works alot better then the old one.
Pete76Shark is offline   Reply With Quote
Old 08-02-2005, 02:44 PM   #16
rihwoods
CF Senior Member
 
rihwoods's Avatar
 
Member Since: Feb 2005
Default

Good point on stat staying open on real hot days...and in my case that occurs mostly at highway speeds with temps at 200....in traffic it modulates cause the fan kicks in more often...I have a 180,as well...
rihwoods is offline   Reply With Quote
Old 08-02-2005, 02:44 PM
 
Go Back   Corvette Forum > C3 Corvettes, 1968 - 1982 > C3 General
Reload this Page What happens when a thermostat goes bad?
 
 
 
Reply

Tags
bad, car, changed, corvette, dies, eliminate, fan, fuel, happen, open, partially, pump, stays, thermastate, thermostat


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
where to measure radiator out temp myronf C1 & C2 Corvettes 7 09-08-2013 10:42 AM
New Coolant = Thermostat & Cap? Gearhead Jim C6 Corvette General Discussion 6 09-25-2012 08:28 AM
How does a fail safe thermostat work? bweaver999 C1 & C2 Corvettes 3 10-13-2008 05:38 PM
Correct thermostat 327 motor please? Kensmith C1 & C2 Corvettes 23 06-04-2007 06:42 PM
Coolant gauge acting crazy after replacing radiator, water pump and thermostat. FL87Z52 C4 Tech/Performance 9 09-27-2006 07:54 PM


All times are GMT -4. The time now is 09:49 PM.


Emails & Password Backup