1979 overheating
Thread Starter
Racer
Joined: May 2009
Posts: 286
Likes: 11
From: LA CA
1979 overheating
I already did a search on this and I found nothing useful thas why I am posting it... I had the car seating in my driveway for about 6 months
I would start it up atleast once a week.. Two weeks ago I finished the interior and started driving it. Right off the bat it heated to about 130after only 15 minutes driving it... Came back home parked it waited for it to cool down and changed thermostat to a 180 d's unit and flushed the system.. Drove it and worked fine for around 25 miles and then it started heating up to around 140 gave me a chance to return home,atleast, I checked everything and the only thing that I can see wrong at this point is that the coolant does not seem to circulate that fast there is movement when I accelerate but I can't see coolant circulation althoug the coolant level in the rad goes up and down when I accelerate.. Any help is appreciated
Thanks in advance
I would start it up atleast once a week.. Two weeks ago I finished the interior and started driving it. Right off the bat it heated to about 130after only 15 minutes driving it... Came back home parked it waited for it to cool down and changed thermostat to a 180 d's unit and flushed the system.. Drove it and worked fine for around 25 miles and then it started heating up to around 140 gave me a chance to return home,atleast, I checked everything and the only thing that I can see wrong at this point is that the coolant does not seem to circulate that fast there is movement when I accelerate but I can't see coolant circulation althoug the coolant level in the rad goes up and down when I accelerate.. Any help is appreciated
Thanks in advance
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Pro
Joined: Aug 2007
Posts: 707
Likes: 31
From: Pitman NJ
Could there be air in system still? How much colant did you add to it when you flushed it? Are you losing coolant on the driveway?
The level shouldn't go down when it's running. If it does, it has to be going somewhere.
On my '79, I was losing coolant from my overflow tank, but not enough to make it overheat.
Running with the cap open will cause it to boil over. The pressure that the cap maintains raises the boiling point of the coolant.
Just for referance, when fully warmed up, my temp gauge is almost pointing straight up.
The level shouldn't go down when it's running. If it does, it has to be going somewhere.
On my '79, I was losing coolant from my overflow tank, but not enough to make it overheat.
Running with the cap open will cause it to boil over. The pressure that the cap maintains raises the boiling point of the coolant.
Just for referance, when fully warmed up, my temp gauge is almost pointing straight up.
Pro
Joined: Jul 2008
Posts: 699
Likes: 3
From: Millersville, MD
OK. So, it's not the thermostat. Check the obvious like air in the system and for binding/caved in hoses. Get an IR Gun an determine true temp first. Gauge or Temp Sender could be the problem. Use a 15psi rad cap. Fan Clutch assembly could be bad as well. There are plenty of threads on Heating and Cooling to search for answers.
Thread Starter
Racer
Joined: May 2009
Posts: 286
Likes: 11
From: LA CA
I added 1 gallon of coolant. No I am not. The level goes down when I accelarate and then goes back to normal. The water is not boiling when i run it with no cap. I am more concerned about the fact that I do not see the water circulate and while the motor is hot the radiator is not as hot.... I am thinking about replacing the water pump. What do You think?
Thread Starter
Racer
Joined: May 2009
Posts: 286
Likes: 11
From: LA CA
I went trough a whole bunch of trheads and I did not find any that relates to what I am seen in my car.. Maybe I missed it. but any how I am going to change the water pump and see what happens. Thanks...
Race Director
Joined: Oct 2000
Posts: 17,102
Likes: 7
From: Fair Oaks, OK
Before changing the water pump, pull your thermostat then put the water neck and hose back together. Run it and see if coolant circulates without a thermostat. If not, then I would change the pump. If it does circulate without a thermostat, get an IR gun and check to see if your temp gauge is working properly. It's been a while since I've messed with a Chevrolet thermostat... is it possible to put it in upside down?
Thread Starter
Racer
Joined: May 2009
Posts: 286
Likes: 11
From: LA CA
Thanks for the advise, I took the thermostat out of the equation and what do You know coolant circulates fine.. Goes to show me not to trust the product even if it is new.. On the other hand with no thermostat the car is running "According to my gauge at around 150.. Impossible..Right, I took the IR gun and at idle the switch is from 194 to 198...Does anyone know how to fix this...By the way I changed that switch about a month ago...
Thank You guys for the help You are lifesavers....
Thank You guys for the help You are lifesavers....
Pro
Joined: Jul 2008
Posts: 699
Likes: 3
From: Millersville, MD
Thanks for the advise, I took the thermostat out of the equation and what do You know coolant circulates fine.. Goes to show me not to trust the product even if it is new.. On the other hand with no thermostat the car is running "According to my gauge at around 150.. Impossible..Right, I took the IR gun and at idle the switch is from 194 to 198...Does anyone know how to fix this...By the way I changed that switch about a month ago...
Thank You guys for the help You are lifesavers....
Thank You guys for the help You are lifesavers....
Thread Starter
Racer
Joined: May 2009
Posts: 286
Likes: 11
From: LA CA
Can I ask You where You got your sendig unit from? I tried my local auto parts, 2 of them already and neither of the parts was the right one.. I checked the resistance and they were both off...
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
Try the Corvette vendors, they will have what you need. I just looked at the Paragon catalog, they list one for your car - it is kind of pricey, but sounds like you need so what are you gonna do... That's the way it is with these cars. Part of the fun of owning them is these little puzzles or obstacles we must overcome to get them working correctly. Matching the temp sending unit to the gauge is a very common problem that has had a lot of scratching our heads. But the solution is simple, find the correct ones for your car.
