Reader Question Dear Austin,
I have a 72 Chevy Truck with a rather obscure overheating problem. It’s a puzzle I hope you can crack. It takes about 5 min. driving to overheat and then the rochester 4 barrel carb percolates the fuel and the engine dies. The following is what has been checked and eliminated so far:
1. Faulty Thermostat – replaced
2. Faulty water pump – replaced
3. Faulty fan clutch – replaced
4. Bad Timing – same problem retared or advanced
5. Crushed water hose – checked
6. Blocked radiator – rodded out and checked
7. Radiator cap – replaced
8. Checked for exhaust impediance
9. Replaced Distributor vacuum advance
10. Checked Compression – All Cylinders within limits as to eliminate loose head or blown head gasket.
11. Checked radiator fluid for oil (cracked block) – none
12. Checked oil for radiator fluid (cracked block) – none
The 350 engine is a rebuild that’s been doing fine for about a year now. The distributor is the electronic type off a 74 chevy. What a nightmare. Any insight into this that you can provide would be GREATLY appreciated.
Many Thanks In Advance,
Hi there Ralph,
I saw something similar this that a few years ago and it was a stopped up intake manifold that was the problem. The intake manifold had tons of old oil sludge build up inside it which restricted exhaust, which overheated the intake, which boiled the fuel in the carb…which killed the engine. So, if you have a way to test the temperature of the intake manifold at the base of the carb…do so, if it is excessive…honestly I don’t know what that number would be, but probably not over 200 degrees.
If you suspect this is happening, remove the intake and see if you can manually remove as much of the oil sludge as you can. It MIGHT require a new intake manifold if you can not remove it all.
Let me know what you find out.
Austin C. Davis