Vintage Mustang Forums banner
21 - 24 of 24 Posts

·
Registered
Joined
·
2,834 Posts
How is a higher temperature thermostat going to make it run COOLER on the highway?
I don't know that it will in his case as I think there is something else going on within the cooling system. Might be timing but I would be more inclined to think a hose that's failing or a block full of rust. .

Since the only thing that has not been replaced on mine in the last 3 years is the heater core or a block flush I'm guessing.
Mine stays at a consistent temp slow or fast with a stock 4 blade fan& stock size radiator. I don't even know what the manual calls for in a stat only what got me where I needed to be with the Sniper

Then maybe mine disipates more heat running a split header over the cast iron restricted manifold,with the alumn carb heater sitting over the combined #3 & #4 exhaust port.
Again just a thought.

But if mine will run up the interstate 70 /80 mph with a 190 stat & not overheat his should also. My 66 with a stock everything 200 6 did years ago.
 

·
Premium Member
68 Mustang Coupe
Joined
·
6,748 Posts
At this point we're guessing if he has an issue. He needs a accurate way to read the temp at highway speeds. I'd install a temporary temp guage.
 

·
Registered
Joined
·
7,898 Posts
I had the same issue with my 68, 289. On the highway it would slowly get hotter and hotter until it overheated. The Radiator looked perfect. I took it to a radiator repair place and when they flow tested it, the radiator was only at 45% efficiency. The cost to record it was twice that of a new radiator so I bought one from NPD and it’s run nice and cool ever since.
 

·
Premium Member
1966 Convertible 6cyl 4sp
Joined
·
171 Posts
Discussion Starter · #24 ·
It could be. It could also be a partially plugged cooling system, water pump with a worn-out impeller, defective thermostat (failing to open all the way) or radiator with poor fin conductivity. Timing could also be an issue... improperly calibrated distributor advance, bad vacuum advance diaphragm or leaky supply, defective Spark Control Valve at the carburetor, vacuum leak somewhere, etc.
Well you can add really bad Rear Wheel Bearing to this list. I knew it was going (could hear it) but I didn't realize how bad it was until the axle was out. Could barely turn it by hand. I guess I've been dragging around my right rear tire/wheel for a while. The Mustang is running quite a bit cooler, quieter, and rolling better now too.
 
21 - 24 of 24 Posts
Top