keep losing coolant
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,387
Likes: 2
From: Meriden CT
keep losing coolant
I recently thought I had all of my cooling issues worked out. After the new 383 went in, I was having some overheating problems. Put in a set of Spals, problems went away.... for a little while. I got very fed up with what was going on, it would run fine on the highway, but got real hot on in town. I was convinced I needed to go spend $500 on a DeWitts radiator, but on a whim I went and bought a new radiator cap, and topped off the collant..... problem solved again.. temporarally. Now I just keep losing coolang out the overflow. The cap is a 16 lb radiator cap, and its brand new. I am thinking that after topping if off so many times, maybe there is too much water? If there is more water than coolant, my speculation is that it begins to boil, therfore building excess pressure, and blowing it out of my overflow. Its definatley coming out the overflow, because I topped it off again today, took it out for a spin, and once warm, when I step on the bad boy, I can see it in the rearview. Any ideas? Should I drain a bunch and put in strait coolant?
Thanks
Joe
Thanks
Joe
Safety Car
Joined: Jan 2004
Posts: 4,776
Likes: 142
From: North of Atlanta GA
St. Jude Donor '05
Don't use straight coolant, the engine needs water to cool it, coolant only conditions the water to prevent freezing, boiling and rust. Is your water pump new? How about thermostat? Sometimes a fairly new thermostat can go bad. What is your temp reading on the highway? What is it on the street?
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,387
Likes: 2
From: Meriden CT
water pump is new, thermostat is new, radiator was flushed not too long ago. On the highway, it will run 180-185. Around town, the temp climbs past 200, and creeps to 220. Go strait home, let it cool, and my coolant is low. Top it off, it runs beautifully, right at 180. Drive around for a while, and it starts creepin again. Again, let it cool, the the coolant is low. I just have a feeling that my ratio is off, and there is more water than coolant, causing it to boil over. What else could it be?
Thanks
Thanks
Drifting
Joined: Feb 2003
Posts: 1,461
Likes: 2
From: Allen TX
Water is a better at cooling than antifreeze. Antifreeze does raise your boiling point, but your overheating problems most likely don't have much to do with the ratio you are using. Lack of cooling at low speeds is caused by not enough water circulation, overheating at high speeds is due to lack of air.
I would do a compression check on all cylinders. You might be sucking air in somewhere causing the cooling system to fill with air and making it overflow. Just an idea.
I would do a compression check on all cylinders. You might be sucking air in somewhere causing the cooling system to fill with air and making it overflow. Just an idea.
Safety Car
Joined: Jan 2004
Posts: 4,776
Likes: 142
From: North of Atlanta GA
St. Jude Donor '05
Coolant/antifreeze mix should be 50/50, are you SURE it's coming out of the overflow??? Other possibilities are leaking intake manifold gasket or head gasket, OR (I pray this isn't the case) cracked head(s).
Drifting
Joined: Feb 2003
Posts: 1,461
Likes: 2
From: Allen TX
Ratio usually depends on your climate or what works for your car. In the winter I run 70% water and 30% coolant because it barely ever dips below freezing here in Texas. In the summer I run just water and Water Wetter.
Safety Car
Joined: Jan 2004
Posts: 3,529
Likes: 1
From: Sherwood Park Alberta
Make sure you clutch fan is working properly and not giving signs of quitting. It could be working periodically now and that's why the car is ok for a couple of days. Make sure that it is not the problem before thinking of changing your rad.
Safety Car
Joined: Jan 2004
Posts: 4,776
Likes: 142
From: North of Atlanta GA
St. Jude Donor '05
Originally Posted by vttedrm
Make sure you clutch fan is working properly and not giving signs of quitting. It could be working periodically now and that's why the car is ok for a couple of days. Make sure that it is not the problem before thinking of changing your rad.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Melting Slicks
Joined: May 2003
Posts: 2,387
Likes: 2
From: Meriden CT
I've got dual Spals, so the fan clutch is not the problem. As for checking the compression on all cylinders, I'll give it a try, but this engine has less than 2000 miles on it and runs beautifully, no smoke, just pure *****. The coolant is DEFINATLEY coming from the overflow, and only the overflow. It wont leak at all until I get on the sucker hard. I can even look in the rearview sometimes during hard acceleration and see the start of a trail right under the overflow tube. Thats the only time it leaks. Im stumped, and I dont know what to do.
Thanks for the input guys.
Joe
Thanks for the input guys.
Joe
Race Director
Joined: Oct 2000
Posts: 15,048
Likes: 79
From: central FL, near the beach.
Pro
Joined: Dec 2004
Posts: 570
Likes: 0
From: glace bay nova scotia
add an overflow tank??
isn't that the exact reason all cars now have an overflow tank?i am assuming you don't have one as you said the water was right under the tube.the water must go somewhere when it expands or gets pushed by the pump,reasonably it should be contained within the rad, but if you have it exit into the tank,it will be sucked up when the engine needs it. just my thoughts,mike
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Although straight water is better at transferring the heat, a mixture with antifreeze would be recommended. No only does it lower the freezing point, but also increases the boiling point.
How old is the radiator? It may be wise to have it checked to see how well it flows. The downside to that is that if it checks out bad, you could have put that money towards the new radiator. The cooling system should have an overflow tank as mentioned. It allows the coolant to go some where during expansion. It should be sucked back in when the engine cools off as long as it is just normal expansion. With a 16 lb. cap and a 50-50 mixture, your temperature is probably above 250*. This problem will not go away by itself and will get worse as the hot summer is approaching.
Although the thermostat is new, you could try changing that. Easy and cheap to do, but will eliminate one of the possibilities.
How old is the radiator? It may be wise to have it checked to see how well it flows. The downside to that is that if it checks out bad, you could have put that money towards the new radiator. The cooling system should have an overflow tank as mentioned. It allows the coolant to go some where during expansion. It should be sucked back in when the engine cools off as long as it is just normal expansion. With a 16 lb. cap and a 50-50 mixture, your temperature is probably above 250*. This problem will not go away by itself and will get worse as the hot summer is approaching.
Although the thermostat is new, you could try changing that. Easy and cheap to do, but will eliminate one of the possibilities.
Race Director
Joined: Oct 2002
Posts: 12,065
Likes: 2
From: Smalltownville Michigan
Cruise-In 5, 6 & 10 Veteran
St. Jude Donor '09
when I got my car, the idiot before me took the tank off.. i would lose coolant too.. put a new one on it and no issues to speak of now...
Racer
Joined: Apr 2004
Posts: 370
Likes: 0
New England Events Coordinator
Sounds Farmiliar
I too have the same scenario, not quite reaching 220 too often. My last thread received recommendations to up my rad cap from the 13 psi to a 15psi cap. Higher pressure raise the boiling point. What cap psi are you running?
Safety Car
Joined: Dec 2004
Posts: 4,876
Likes: 1
From: Jersey Shore Exit 98
Fan Clutch
I was reading about the overheating problem and hope someone could answer this question. My fan clutch on my 79 is starting to make noise and a friend told me its on its way out. We talked about replacing it and this guy who is an old time Corvette mechanic and a motor head suggested replacing the clutch fan with a light weight aluminium fan.
What do you guys think??
What do you guys think??
Advanced
Joined: Apr 2005
Posts: 82
Likes: 0
coolant
It could be that the thermostat isnt opening/closing. Try replacing that and and drain all the coolant and start with a perfect 50/50 mix of coolant an easy 20 dollars and a hour in the garage and see what that does.
Originally Posted by JoeRags
I recently thought I had all of my cooling issues worked out. After the new 383 went in, I was having some overheating problems. Put in a set of Spals, problems went away.... for a little while. I got very fed up with what was going on, it would run fine on the highway, but got real hot on in town. I was convinced I needed to go spend $500 on a DeWitts radiator, but on a whim I went and bought a new radiator cap, and topped off the collant..... problem solved again.. temporarally. Now I just keep losing coolang out the overflow. The cap is a 16 lb radiator cap, and its brand new. I am thinking that after topping if off so many times, maybe there is too much water? If there is more water than coolant, my speculation is that it begins to boil, therfore building excess pressure, and blowing it out of my overflow. Its definatley coming out the overflow, because I topped it off again today, took it out for a spin, and once warm, when I step on the bad boy, I can see it in the rearview. Any ideas? Should I drain a bunch and put in strait coolant?
Thanks
Joe
Thanks
Joe
Safety Car
Joined: Jan 2004
Posts: 3,529
Likes: 1
From: Sherwood Park Alberta
Originally Posted by Jims79
I was reading about the overheating problem and hope someone could answer this question. My fan clutch on my 79 is starting to make noise and a friend told me its on its way out. We talked about replacing it and this guy who is an old time Corvette mechanic and a motor head suggested replacing the clutch fan with a light weight aluminium fan.
What do you guys think??
What do you guys think??
Pop the hood. let the engine run then shut it off. If the fan keeps spinning change it. If it stops after a couple of spins then look for the problem elsewhere.
