Can someone please help. I just put in a brand new 350 turn key engine new radiator, rebuilt my transmission, new torque converter and all new hoses. However, my car is overheating. I checked the thermostat and it does open up. One thing I did realize is that if I turn on the car and keep it just at idle it doesn't overheat but as soon as I excelerate it overheats quickly. I tried changing the radiator cap and nothing. It over heats up to 240 250 then I just turn it off, I don't want to damage anything. I did all the work my self of putting in the engine and transmission so I am hoping I didn't do anything wrong. If you have Any idea of what it could be please advise. Thanks.

 

Did you check to make sure that the radiator hoses are not collapsing?

 

Could be a wide variety of things. Timing issues, air in the cooling system, clutch fan, water pump, vacuum leak(s), carb issues (lean), etc.

Give us more details to work with. Does it overheat and low speed, high speed, both. Lacking power, pinging, etc. I'll bet someone here can point you in the right direction.

Adam

 

I guess we will have to play 20 questions. That's OK, if he were an expert, he wouldn't be on this forum asking questions, he'd be answering them! Don't worry, we will try to get you up to speed. The thing to remember is that all we have to go on is your description, so give details. Even things that you think have nothing to do with anything might turn out to have some importance, so be Thoreau. (That's a little joke, don't mind me, I have a weird sense of humor.)

Can we assume that the car had no overheating issues before you re-built the engine?

So, it can sit at idle for a long period of time without overheating, but when you take it for a drive, it overheats quickly? Sounds like the lower radiator hose is collapsing, but it could be something else, I suppose. Does your lower radiator hose have a spring inside of it to keep it from collapsing? If not, that would be my primary suspect.

Tell us a little more about when it overheats. Can you putt around town without it overheating, like it just does it on the highway? Remember, we are just reading your description on the internet, we are not there to actually see the behavior of the car itself, so be specific, and include even mundane details.


Keep the shiny side up!
Scott

 

As above, there are many causes
Timing, what is it set at?
Radiator seals in place?
Is the fan clutch new? Is it loose?
Did you bleed all the air out of the cooling system?
Radiator hoses, both new?
Does the lower hose have a spring in it?

 

I will give all the info I know. My timing is at 12 degrees, my lower radiator hose does not have a spring in it, I did bleed the cooling system not sure if I did it correctly but I tried, the fans are two new electric fans they are always on since I have direct to turn on as soon the car turns on. Both radiator hoses are new. I am not so sure about my vacuum, it seems like its all connected. I have a valve on the exhaust passenger side the connects to the header that looks like a vacuum valve that is not connected because I don't know where it connects to. I thought it went to my transmission vacuum line because that is where it ends. However, I found out that I needed to have that line connected to my intake or else my tranny wouldn't shift. Nonetheless, I don't know if this valve needs a T so I can connect it to both places. Right now that valve is not connected.
The car overheats when I take it for a drive maybe right away. I can't go far maybe 50 yards and its overheating already. If I turn it on an leave it on idle its fine but if I rub the engine 2 or 3 times the temp gauge goes up immediately. Ok, we'll, thanks for your help and if you guys need more info let me know. I've been trying to get this car going for the past 3 years and now that I am close it overheats. It's really stressful specially because I am bearlly learning about cars. I've always dreamed of having a c3 corvette but never thought it would be this stressful.

 

It sounds as if it may be a timing issue but,
Have you looked at the plugs to check for a lean condition?
Be certain that you are moving water with the water pump. I have seen impellars come loose and cause symptoms similar to what you are seeing.

 

Pretty sure you need that spring in the lower radiator hose...good luck!

 

Its air in the system. If it heats up that fast its all it can be.
Drill a 1/8" hole in the thermostat, then with the engine idling and the rad cap off, fill it until the air stops.
Its gets hot so fast because there is air in the head right by the sensor, whick is between the combustion chamber tops on 3 and 5. When you run the motor up, it generates a lof of heat fast and with no water on it, it heats up quick.