I can't keep it cool - Water Pump???
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 876
Likes: 1
From: Same as our leaders Out of my mind
I can't keep it cool - Water Pump???
I have a 79 Vette with a new 350 crate engine with a 9.5:1 compression ratio, a new 4 core radiator, new 190 degree thermostat and a new water pump. At highway speeds my temp gauge gets pegged at the maximum. I just checked the temp gauge for accuracy with an IR temp. gun and the gauge is on the money. At low speed or idle the temps are around 225 degrees. Do I need a high volume water pump to keep my cool at highway speeds? I am sure that someone else has solved this problem already.
Thanks in advance for all of your help!
Thanks in advance for all of your help!
Racer
Joined: Dec 2004
Posts: 379
Likes: 0
From: Fairfield Texas
How are the radiator too core support seals? The seals were
either missing or in bad shape on My 79 and a new seal kit helped
cool it down along with all the things You have done. My fan clutch
was also bad so replaced it too. Right now mine is running around
180 but it hasn't gotten real hot here yet.
either missing or in bad shape on My 79 and a new seal kit helped
cool it down along with all the things You have done. My fan clutch
was also bad so replaced it too. Right now mine is running around
180 but it hasn't gotten real hot here yet.
Racer
Joined: Apr 2005
Posts: 494
Likes: 0
From: Virginia
If the radiator and water pump are new, and the thermostat is working, it sounds like your fan clutch is most likely the problem. There's a quick way to check them, not sure, but something like if they spin easily they're bad.
Did your car originally come with an aluminum radiator? I once had a BMW that ran hot and couldn't figure out what was wrong. It was because I had replaced the aluminum radiator with a brass radiator.
Did your car originally come with an aluminum radiator? I once had a BMW that ran hot and couldn't figure out what was wrong. It was because I had replaced the aluminum radiator with a brass radiator.
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 876
Likes: 1
From: Same as our leaders Out of my mind
First, thank you all for your replies.
I do have a new seal kit for the radiator & fan shroud from Dr. Rebuild and it is installed. I also have a stock 7 blade fan backed by a good fan clutch. I also have a 16" 2500 cfm electric cooling fan installed.
Here's the deal. With an Infra Red Temperature Gun the readings are as follows.
At the temp sensor in the head - 225 degrees at idle
At the upper radiator tank - 155 deg.
If you increase the rpm's and put your hand in front of the radiator there is excellent suction - good air flow.
It seems like I am not getting enough coolant flow through the engine block.
Any Ideas???
I do have a new seal kit for the radiator & fan shroud from Dr. Rebuild and it is installed. I also have a stock 7 blade fan backed by a good fan clutch. I also have a 16" 2500 cfm electric cooling fan installed.
Here's the deal. With an Infra Red Temperature Gun the readings are as follows.
At the temp sensor in the head - 225 degrees at idle
At the upper radiator tank - 155 deg.
If you increase the rpm's and put your hand in front of the radiator there is excellent suction - good air flow.
It seems like I am not getting enough coolant flow through the engine block.
Any Ideas???
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
Safety Car
Joined: Feb 1999
Posts: 4,043
Likes: 342
From: Central NJ
Originally Posted by icanfixitforyou
First, thank you all for your replies.
I do have a new seal kit for the radiator & fan shroud from Dr. Rebuild and it is installed. I also have a stock 7 blade fan backed by a good fan clutch. I also have a 16" 2500 cfm electric cooling fan installed.
Here's the deal. With an Infra Red Temperature Gun the readings are as follows.
At the temp sensor in the head - 225 degrees at idle
At the upper radiator tank - 155 deg.
If you increase the rpm's and put your hand in front of the radiator there is excellent suction - good air flow.
It seems like I am not getting enough coolant flow through the engine block.
Any Ideas???
I do have a new seal kit for the radiator & fan shroud from Dr. Rebuild and it is installed. I also have a stock 7 blade fan backed by a good fan clutch. I also have a 16" 2500 cfm electric cooling fan installed.
Here's the deal. With an Infra Red Temperature Gun the readings are as follows.
At the temp sensor in the head - 225 degrees at idle
At the upper radiator tank - 155 deg.
If you increase the rpm's and put your hand in front of the radiator there is excellent suction - good air flow.
It seems like I am not getting enough coolant flow through the engine block.
Any Ideas???
1) The heat blew out cold most of the time
2) coolent overflowed from the overflow tank
3) The coolent flow in the rad was very very slow
4) my 160 degree thermo didn't actually open until the guage read 220.
Good luck,
Tony
Melting Slicks
Joined: Mar 2003
Posts: 2,512
Likes: 49
From: Franklin IN
Originally Posted by icanfixitforyou
I have a 79 Vette with a new 350 crate engine with a 9.5:1 compression ratio, a new 4 core radiator, new 190 degree thermostat and a new water pump. At highway speeds my temp gauge gets pegged at the maximum. I just checked the temp gauge for accuracy with an IR temp. gun and the gauge is on the money. At low speed or idle the temps are around 225 degrees. Do I need a high volume water pump to keep my cool at highway speeds? I am sure that someone else has solved this problem already.
Thanks in advance for all of your help!
Thanks in advance for all of your help!
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
...and check your total timing and how much vacuum advance you're pulling. Timing is critical to engine temp. You need 36 total plus 16 vacuum so you're runing close to 54 degrees at hiway cruise. If timing is retarded from this spec, the engine will run hot.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by 87bob
In addition to the other suggestions already here I have heard that if the timing that is too far advanced it can cause a engine to run hot.
Instructor
Joined: Sep 2005
Posts: 241
Likes: 0
From: St Louis Missouri
Are you sure you are getting circulation? You can check by running the car while looking into the radiator. It sounds like you may have air in the water pump that causes an air lock stopping the bump from pumping.
Melting Slicks
Joined: Mar 2003
Posts: 2,512
Likes: 49
From: Franklin IN
Originally Posted by lars
No, it's if the timing is retarded that the engine will run hot. Advancing it cools it down.
Sorry I defer to the Guru. Hey Lars do I get half credit I knew to check the timing?
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
I think I would go back to one of the first suggestions, and check the radiator to hood seals. If these seals are not in place then the air flow goes up and over the radiator instead of through the core to cool the fluids.
kdf
kdf
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Jack the front of the car and put stands under it. Take the t-stat out and drill a 1/4 inch hole it it. If it is an air lock this will let the coolant flow enough to keep the air lock from happening. Reinstall the t-stat and refil the radiator. Leave the cap off and start the car and watch for the coolant to start flowing thru the radiator. Add coolant until it just starts to overflow and install the cap. Cut off the car and lower it back to the ground; there should be no air lock in the system.
Check your timing as Lars suggests and if you do npt have a front spoiler/air dam install one for improved air flow at speed when your fan basically stops working. If everything is not right on our C3's, they will run hot. If this doesn't work try running it without a t-stat; several do and have no cooling problems.
Bernie
Check your timing as Lars suggests and if you do npt have a front spoiler/air dam install one for improved air flow at speed when your fan basically stops working. If everything is not right on our C3's, they will run hot. If this doesn't work try running it without a t-stat; several do and have no cooling problems.
Bernie
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 876
Likes: 1
From: Same as our leaders Out of my mind
[QUOTE]By the way which crate engine did you get? What is the horse power?[/QUOTE]
I got a 350 from Prestige High Performance, rated at about 390 HP, 390 TQ. I could have had 400 HP but they advertised it as having a "lumpy" cam and I wanted something a little smoother. In my opinion it is still somewhat lumpy.
I got a 350 from Prestige High Performance, rated at about 390 HP, 390 TQ. I could have had 400 HP but they advertised it as having a "lumpy" cam and I wanted something a little smoother. In my opinion it is still somewhat lumpy.
Racer
Joined: Mar 2006
Posts: 309
Likes: 0
From: Ocean City MD
I just went through the exact same thing on my 79. After installing my new crate motor it would run hot. As I drove it would peg then come back down. I installed a mechanical gauge to confirm the dash gauge. Sure enough it was the same. I replaced the radiator, all the seals around the radiator, tried various thermostats, and added an electric fan on a thermostat. It still ran just as hot. If I removed the t-stat it would run 180 and not overheat. It turned out to be low flow due to a defective water pump. I pulled the rear cover to find the impeller was not presses on all the way and one of the passages had an obstruction. I replace it with a better quality new pump and the problem fixed. I am running a 180 t-stat and that is where it stays.