QuestionQUESTION: Hi Kevin,
Facts: '68 AMX, 390 4sp., stock engine (except for mod. cam), total timing of 38 deg. or so, engine does not detonate, engine was overhauled 10k miles ago, radiator re-cored with 3-row 3k miles ago, new thermostat (180 deg. according to machinist), new hoses, and amc hi flow water pump, stock fan shroud and fan (not clutch), live in Calif. and use 91 octane fuel with 10% ethanol--no choice about that. Today, while driving around at low speed for 1/2 hour, temp gauge went in the middle of range, approx. 200-210. Normally, at cruising speed, temp is approx. 165 deg. (changed the temp. sending unit, btw, b4 this occurred). When I stopped and shut off the engine, radiator fluid came out (no overflow tank--engine is stock) for about a min. I have used 50/50 antifreeze/water; currently, I use "Water Wetter" product and water. Have had similar issues in the past. What do you suggest I do to prevent future occurrences?
Thanks,
Steve
ANSWER: The easiest thing to try is an auxillary electric fan. You might mount it in front of your radiator and let it push air through. They come with a thermostat you install in the upper hose. This will at least assure good air flow. If nothing is restricted, this should help. Let me know how it turns out.
Good luck
---------- FOLLOW-UP ----------
QUESTION: My car is extremely stock, so I don't want to add a fan to the radiator. Any other suggestions? I'd like to know what the underlying problem is here, so if you could help me with that, I'd appreciate it.
ANSWER: Did the overheating occur after the engine was rebuilt, or before?
If you have a lazer temperature gun, measure the temperature of the radiator at various locations with the engine running to check for any restrictions.
Make sure the thermostat is not installed upside down. I know, but it happens. With it running and the radiator cap off, check for strong circulation when the engine has reached operating temperature.
You might have to install an overflow tank. When you shut the engine off and the coolant stops circulating, the hot spots inside the engine will continue to heat the coolant.
Install a higher pressure radiator cap, i.e. 15#.
What heat range spark plugs are you running?
---------- FOLLOW-UP ----------
QUESTION: I wanted to ask your opinion about using Redline's Water Wetter product (a pint of that stuff and the rest is distilled water into the radiator) vs. using the old school prestone yellow coolant, 50/50, vs. using the latest coolant product that may be pink, green, or whatever color, in 50/50. Which product(s) in order of effectiveness, do you think would do the best job in cooling the engine faster? Oh, btw, I blocked off the exhaust crossover passages in the intake manif. to keep the hot exhaust gases away from the carb and therefore to keep fuel percolation down during the hot months. So far, this change has seemed to work, as my engine stumbled much less yesterday during the 1/2 hour low speed cruise than ever before. The unfortunate side effect of the blockage is that my fast idle choke won't work.
Steve
AnswerAll the coolants mixed 50/50 will do about the same job in cooling your engine. The basic ingredient is the same. The difference is the additives each manufactuer uses for anti-rust, foaming, lubrication, etc.
You can always install a manual choke cable.
Good luck with your AMX.
