The car: 1966 Porsche 911 with a 1980 Buick Turbo 3.8L V6, engine mounted in the rear with radiator up front, hoses go to the engine under the car and the stock waterpump is being used, fairly new waterpump with ~3K miles on it. The radiator has (2) 13" electronic fans (one on top, one on bottom, the radiator is mounted horizontally) that turn on when the temperature of the radiator goes over 180F.
The problem: overheating... This is a problem that has been getting worse in the last month or so, and I am worried if I just 'get by' with the car something major will break. I have spent way too much cash on the project and I am looking to sell soon, but it is something I would prefer to fix for my resale value (I have about $20K into the car).
Basically the car will start up and drive fine, but it seems the fans have stopped working. At streetlights it will get hotter and hotter until it starts to overheat - the overflow will boil (large bubbles), and coolant will leak out of the car causing it to overheat even more - this is using about 80% water, with antifreeze 50/50 it takes longer to boil. Until this last week driving the car would cool it back down, so I figured my fans were the problem (as they haven't been turning on). Today the car overheated BAD, and this was after driving less than a mile. The car overheated this morning on my way to school, a trip of around 4 miles, and I left it there for around 4 hours. I tried to fill it with water, but it only took about 0.5 gallons - I started it back up, and started going home when it overheated again going out of the parking lot of my school. There is a long road with a 50mph speed limit right outside, so I made the turn and brought it up to 50mph expecting the temp to go down - it didn't. The car started to steam, and I kept it at 50mph hoping to cool the rad down. When it became apparent this wasn't going to work I parked it. When I turned it off lots of vapor came off of the engine, and the overflow hose made a 'whistling noise' for a good 2 minutes - the overflow was empty, the plastic overflow tank was hot and flexible, and the overflow hose was letting out steam. I let the car cool down for about 2 hours and put water in it, this time it too 1 gallon of water, and tried to limp home. I made it about 0.25 miles when the car started to overheat again, but I kept on it to get home - the car got VERY hot and started to lose power, so I turned it off on the side of the road and left it there. I opened the hood and checked the radiator up front, and it was cool to the touch. The overflow was again empty, and the car was letting off steam. I used a thick towel and took off the rad cap, and lots of steam came out - I was able to put in 2 gallons of water, but the car would not start back up (now about a block from my house).
It sounded to me like there was a problem with the electronic fans on the car, but today there really wasn't enough time for this to cause the car to overheat. The front radiator was also cool to the touch, where as the engine was HOT. Does anyone have an idea what I should check? This project, which started off quite interesting, has been nothing but a series of little things breaking, and I have paid way too much for a car that cannot even take me 4 miles back and forth to school reliably - I would prefer not to put any more cash into this car. I am going to try and get the car the last block home after dinner tonight (a couple of hours) - what items should I check? If the waterpump was the problem I would hear it making noises, no? The electric fans don't seem to be the problem, as the front radiator doesn't get hot. Might it be my 80/20 mixture? Water has a lower boiling temp than antifreeze, but I didn't think it was that dramatic? The thermostat in this car is kind of buried under the distributer, so it is hard to check, but this seems like something I should also look into?
The problem: overheating... This is a problem that has been getting worse in the last month or so, and I am worried if I just 'get by' with the car something major will break. I have spent way too much cash on the project and I am looking to sell soon, but it is something I would prefer to fix for my resale value (I have about $20K into the car).
Basically the car will start up and drive fine, but it seems the fans have stopped working. At streetlights it will get hotter and hotter until it starts to overheat - the overflow will boil (large bubbles), and coolant will leak out of the car causing it to overheat even more - this is using about 80% water, with antifreeze 50/50 it takes longer to boil. Until this last week driving the car would cool it back down, so I figured my fans were the problem (as they haven't been turning on). Today the car overheated BAD, and this was after driving less than a mile. The car overheated this morning on my way to school, a trip of around 4 miles, and I left it there for around 4 hours. I tried to fill it with water, but it only took about 0.5 gallons - I started it back up, and started going home when it overheated again going out of the parking lot of my school. There is a long road with a 50mph speed limit right outside, so I made the turn and brought it up to 50mph expecting the temp to go down - it didn't. The car started to steam, and I kept it at 50mph hoping to cool the rad down. When it became apparent this wasn't going to work I parked it. When I turned it off lots of vapor came off of the engine, and the overflow hose made a 'whistling noise' for a good 2 minutes - the overflow was empty, the plastic overflow tank was hot and flexible, and the overflow hose was letting out steam. I let the car cool down for about 2 hours and put water in it, this time it too 1 gallon of water, and tried to limp home. I made it about 0.25 miles when the car started to overheat again, but I kept on it to get home - the car got VERY hot and started to lose power, so I turned it off on the side of the road and left it there. I opened the hood and checked the radiator up front, and it was cool to the touch. The overflow was again empty, and the car was letting off steam. I used a thick towel and took off the rad cap, and lots of steam came out - I was able to put in 2 gallons of water, but the car would not start back up (now about a block from my house).
It sounded to me like there was a problem with the electronic fans on the car, but today there really wasn't enough time for this to cause the car to overheat. The front radiator was also cool to the touch, where as the engine was HOT. Does anyone have an idea what I should check? This project, which started off quite interesting, has been nothing but a series of little things breaking, and I have paid way too much for a car that cannot even take me 4 miles back and forth to school reliably - I would prefer not to put any more cash into this car. I am going to try and get the car the last block home after dinner tonight (a couple of hours) - what items should I check? If the waterpump was the problem I would hear it making noises, no? The electric fans don't seem to be the problem, as the front radiator doesn't get hot. Might it be my 80/20 mixture? Water has a lower boiling temp than antifreeze, but I didn't think it was that dramatic? The thermostat in this car is kind of buried under the distributer, so it is hard to check, but this seems like something I should also look into?
