Over heating
Thread Starter
Heel & Toe
Joined: May 2008
Posts: 21
Likes: 0
From: Barnhart MO
Over heating
I just replaced the radiator in my 77 and have problem with over heating. It actually blows the top hose off at the radiator. I replaced the thermostat too. In the owners manual it says the cooling system holds 21 quarts of fluid, but I can only get 12 qts in it. Any replies will be appreciated.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
If you only got 12 quarts in there you have a massive air bubble in the system. Take the t-stat out, drill a 1/8" hole in it and put it back together. Fill the system with 50 50 mix and fire it up. Look in the radiator and watch for movement inside and bubbles.
Keep an eye on the temp and refil as necessary
Keep an eye on the temp and refil as necessary
Safety Car
Joined: Jul 2005
Posts: 3,694
Likes: 833
From: WI
Corvette Enthusiast Magazine has a nice lengthy article about overcoming overheating problems in this month's issue. Some things outlined are straightforward, several strategies and potential problems I never really gave much thought about. It was interesting. May want to pick up a copy. I think it could offer some help/insight.
Personally, I've never had to drill a hole in the T-stat. Park it on an incline with the nose in the air. If you do drill out the T-stat, change it afterwards. You can't ever get all the coolant out unless you take out the motor and tip it over. So if you drain the system in the car and you only get in 12 qts, that's about right to fill the radiator and some of the engine. Look for bubbles in the antifreeze and smell in the overflow tank for exhaust gasses which might point to a potential gasket leak or other (cracked head - not likely but...).
Personally, I've never had to drill a hole in the T-stat. Park it on an incline with the nose in the air. If you do drill out the T-stat, change it afterwards. You can't ever get all the coolant out unless you take out the motor and tip it over. So if you drain the system in the car and you only get in 12 qts, that's about right to fill the radiator and some of the engine. Look for bubbles in the antifreeze and smell in the overflow tank for exhaust gasses which might point to a potential gasket leak or other (cracked head - not likely but...).
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
The purpose of drilling the T-Stat is to give it an air bypass, a way to get air out of the system. This is especially important with an empty system. The engine can overheat quickly since there is not enough coolant in the motor itself, the thermostat will block the air in the system until it gets hot enough to open, this may not happen until the engine is very hot. Drill the t-stat and then run it, no problem. I don't know why they don't come that way to start with.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Most do come that way 
Most of this style of thermostat already has the hole, though hard to see and it does take some time for the air to bleed out naturally.
The better type are full flow and prssure balanced, but do npt have the bleed holes.
It is better to put a less the 1/8" one in to solve fill up and air pocket problems. It realistically is not be noticeable at all and the good tstats are calibrated to run at +/- 2° from advertised. They are around 10 bucks, a good deal.
The better type are full flow and prssure balanced, but do npt have the bleed holes.
It is better to put a less the 1/8" one in to solve fill up and air pocket problems. It realistically is not be noticeable at all and the good tstats are calibrated to run at +/- 2° from advertised. They are around 10 bucks, a good deal.
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
possible that your heater core is clogged up...... that might have some play in the matter
or a collapsed hose?.....
might want to check all the hoses and see if the inner springs/coils did come out and create a blockage..............
b
or a collapsed hose?.....
might want to check all the hoses and see if the inner springs/coils did come out and create a blockage..............
b
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