Originally Posted by 64Joker
Engine: 327 CUI
Tran: 350 Auto
I located what appears to be a coolant leak on the right front top corner portion of the intake manifold (see attached pic).
I used photoshop to circle the leak in the color yellow, the leak drains around and down a small intake pocket near the front corner bolt! It leaks a very very small amount of fluid, not enough to drain the coolant!
The leak does not appear to be coming from the digital temperature sensor right above the leak!
What are the symptoms I should see or hear!? The cars seems to be running fine, idles fine at 185 temperature, but has begun to heat up to 225+ when driving.
The leak is probably not the problem though it should be fixed before it does become a problem. The key piece of info here is that it holds temp at idle and gains it when driving. This is a pretty good indicator that the higher rate of coolant flow when driving cannot get through the radiator fast enough. This usually indicates that the radiator's tubes are plugging up. If this is an older copper brass radiator they suffer from corrosion around the soldered joints. All radiators collect the debris that sloughs off the inside walls of the engine's cooling jackets. Plus you get debris from chemical reactants and breakdown of the coolant itself. All this stuff tends to "filter" out in the radiator core tubes.
Other problem makers are the thermostat itself, collapsing of the pump intake hose, and trapped bubbles that obstruct or reduce coolant flow. You can add ignition problems that result in retarding the spark, fuel mixture problems that cause the mixture to become too lean, and certainly with a high mileage engine wear of the timing gears and chain that drives the cam which usually result in the cam timing become retarded to the crankshaft and this takes the ignition timing with it. If you constantly need to reset more advance to the distributor position to keep the proper base timing, this is a pretty good indicator that the timing gears and chain are wearing/worn out.