My car does not overheat when stopped at a traffic light. if a car does that it has a problem. Thermostats don't solve overheating problems. its not what they are for.
Here's an oddity: both my BJ8 and BN2 often run cooler than the thermostat set point at highway speeds. Every other car I've owned will warm up to the thermostat rating, then level off. The Healeys will run below the 180deg thermostat set points on all but the warmest days, and they'll go over the set point if I have to sit at idle for more than a couple minutes (both temp gauges have been rebuilt and calibrated). I can't explain this, unless the engines are able to dissipate enough heat without coolant flow through the radiator, but then why do they get warmer sitting at idle? I've tried several thermostats, and checked them against thermometers. The BJ8 has a 180deg Robertshaw with a BCS sleeve soldered to it, but the BN2 has a plain ol' 180deg Stant.
On another note, I don't think it's good for any engine to run too cool; I've read 190deg coolant temp is ideal--I think 'modern' cars usually run 190-200deg--but I prefer having the 10deg margin.
...Its hard to believe the huge lump of iron under the hood of a Healey could dissipate that much heat without coolant flow...
Here's an oddity: both my BJ8 and BN2 often run cooler than the thermostat set point at highway speeds. Every other car I've owned will warm up to the thermostat rating, then level off. The Healeys will run below the 180deg thermostat set points on all but the warmest days, and they'll go over the set point if I have to sit at idle for more than a couple minutes (both temp gauges have been rebuilt and calibrated). I can't explain this, unless the engines are able to dissipate enough heat without coolant flow through the radiator, but then why do they get warmer sitting at idle? I've tried several thermostats, and checked them against thermometers. The BJ8 has a 180deg Robertshaw with a BCS sleeve soldered to it, but the BN2 has a plain ol' 180deg Stant.
On another note, I don't think it's good for any engine to run too cool; I've read 190deg coolant temp is ideal--I think 'modern' cars usually run 190-200deg--but I prefer having the 10deg margin.[/QUOTE
]I wonder if the hotter running temp at idle is because the air under the hood is forced outwards to the front of the car and then rerouted back through the radiator? The Healeys do not have anything that really "masks off" the sides of the radiator and the wheel wells.
Seems like the easiest thing to do would be to temporarily remove the electric fan and drive the car over 50 mph. If you still have the problem, you've eliminated the fan as a possibility. If the problem goes away, proceed according to previous suggestions for either returning to stock or relocating fan.I just spent the last hour and a half pouring through all the posts about overheating. There where a few that had the same problem I have, overheating at highway speeds (210-220). I have a rebuilt engine and recored radiator. I took out the belt driven fan and put in an elecric pusher fan that turns on at 190 degrees. It does a fine job of keeping the temps at 190 degrees until the speed is above 50 MPH. I recently put in a thermostadt blanking sleeve to improve water flow, but it did not help. I read a few posts that reported problems with replacement water pump castings, not sure if this could be an issue. I hate to fix or replace things that aren't broke, any ideas where to begin? I have a 67 BJ8. Thanks for your help, Steve
Here's an oddity: both my BJ8 and BN2 often run cooler than the thermostat set point at highway speeds. Every other car I've owned will warm up to the thermostat rating, then level off. The Healeys will run below the 180deg thermostat set points on all but the warmest days, and they'll go over the set point if I have to sit at idle for more than a couple minutes (both temp gauges have been rebuilt and calibrated). I can't explain this, unless the engines are able to dissipate enough heat without coolant flow through the radiator, but then why do they get warmer sitting at idle? I've tried several thermostats, and checked them against thermometers. The BJ8 has a 180deg Robertshaw with a BCS sleeve soldered to it, but the BN2 has a plain ol' 180deg Stant.
On another note, I don't think it's good for any engine to run too cool; I've read 190deg coolant temp is ideal--I think 'modern' cars usually run 190-200deg--but I prefer having the 10deg margin.
One good thing I did to my exhaust manifolds was to have them sandblasted on the insides before I had them "coated". I read about doing that about 20/30 years ago in a Tech Tip for performance cars.The engine has to breathe. If your exhaust is plugged or restricted your engine cannot get rid of the burnt gases and will cause your engine to overheat. Disconnect the two front pipes at the front mufflers, take the car for a drive and see if that makes a difference. A plugged exhaust system is as inefficient as a plugged radiator. The exhaust system in an Austin Healey is very restrictive. I do understand the need for back pressure but the Healey exhaust system is excessive in that area.
Marty
Been away on vacation, Thought I would check to see if there were any new suggestions. You brought up an interesting point. When I rebuilt the engine, I noticed a significant difference in impellers between the replacement water pump and the original. Since I plan on taking the radiator out, any suggestions on where to buy a new pump?
Sorry, AFAIK all the new ones are County brand and they suck. If you have an original, you're better off getting it rebuilt. Michael Salter rebuilt one for me, but he's been having trouble getting parts:
https://www.netbug.net/blogmichael/