I have a 1968 289 2v coupe. It sat for 8 years after being starting and running in a garage then not started again until a couple month ago. The car overheated very slowly (15-20 minutes at idle) but steady. I changed therostat, hoses all removed and good (no collapse), put a new 3 row radiator in last week and flushed the system. The temp gauge works, temp sender is new as well as the harness that goes to it. I bleed the sytem by removing the heater hose at the elbow on manifold until water comes out while filling the radiator at the neck.

Heres the symptoms: The car warms up normal, the thermostat opens as I see the antifreeze mixing with the water in radiator. The water starts to overflow out of radiator water neck but temp on gauge keeps rising. Before the gauge hits H I shut off the motor and can here the water/antifreeze slopping around inside the radiator. After is cool I have to put in also most another gallon of flud in radiator.

My questionis this....is it a water pump problem from sitting so long or do I have head gasket leak??? I checked other threads and I have NO chocolately oil, no white smoke out of exhaust, and and no oil in the raiator fluid. I am stumped. I hope someone has had this experience or mayhelp me with some insight. Oh yeah, could the heater core be clogged and have something to do with it??

I've been working on the puppy for years now and just got it done (so I thought) and want to drive it a couple months before the snow flies here.

68pony5

 

Sounds like you may need to burp it because you have air in the system. Start it and let it run with the cap off until the thermostat opens, then keep the water hose or extra mix handy and add fluid while the engine is running. You will probably see bubbles come out of the rad.....that's good. Just keep adding fluid until the bubbles stop and the rad is completely full. It is overheating because you don't have enough fluid in the system because the air is taking up that space. Keep your heater in the on position during this process.

 

Soaring,

The last time I tried this the water kept pouring out of the water neck of the rad (not bubbles) when running hot. The car got too hot so I shut if off so I would not damaged anything. Would air in the system still do this?? Shouldn't I see the water moving once the thermostat opens? Shouldn't I see a little movement cold due to the bypass hose?? I know a lot of this is basic but I have not work on the car in a while and forgot some of this stuff. Old age is creeping up on me.

68pony5

 

Well, I got it figured out today. It was a combo of things that built up to one big problem. I went from a 2 row to a 3 row radiator. The 2 row was clogged up with stuff from sitting for 10 years. I took off and replaced the water pump. Same thing....clogged from sitting for 10 years. An the final one that really burns me up (no pun intended)....I had the damn thermostat in backwards.

I took it for a nice ride to day after 10 years of restoration and it was SWEET............

I took my daughter to hockey practice in the Stang and people would look at us and smile and wave. My daughter turned to me and said "This car is awsome". On the way, I even had a 2006 Mustang GT pull up next to me on the road and rev it engine wanting to race. I just smiled and laughed. Kids.......

I'll try to get pics up tomorrow evening.

Thanks all again for the help and advice.