Originally Posted by cmk59
I notice overheating is a hot topic (bad pun) here, but I wanted to dive in with my woes and see if anyone can figure out what I haven't yet. The history:
1968 Impala Custom, 275/327, TH400, dual exhaust with 'h' pipe. New suspension, engine still stock save for water pump and t'stat. Still gets 15 mpg +/= city, so she's still doing ok there.
BUT, she has a cooling problem from Aitch Eee Double Hockey Sticks I can't figure out or fix. For 2 years, the idiot light came on intermittently, but could find no trouble. Added an Auto Meter gauge with probe inserted in lower center of radiator, but this showed actual NUMBERS that freaked me out...well over 290 degrees, w/o the A/C on!
SO, I did the following, in order (rather, my Goodyear guy did it):
1. Back flushed the coolant;
2. Put in a (tested first) 180 deg. thermostat;
3. Added an Impala Bob's 4-core Desert Cooler radiator, along with auxiliary external coolers for the engine oil and trans fluid;
4. Put dual 16" electric fans on said radiator, mounted 1/8" from the core (no shroud of any kind was provided with the fans..they mount on dual rails that span the radiator left to right).
STILL had high temps as described! Now, I added:
5. 160 degree thermostat;
6. 40 GPM hi-flow water pump;
7. All new hoses inside and out;
8. New heater core (thanks to the water pump);
9. Went broke converting the A/C to the new refrigerant.
And still the problem persists. It takes the car just 15 mins or so to get up to 180 when the ambient temp is 85, but after that it just climbs to about 205-210. If I use the A/C, the temp gauge pegs out and coolant spews out the overflow!
As we all know, the cavernous interior of a '68 Full-Size Chevy takes awhile to cool, but I can't risk using it anymore. I'm fed up and broke, and the only thing I HAVEN'T replaced is the condenser, which seems fine.
What's the normal op temp for my engine anyway?
Do I need to replace the condenser with something new anyhow?
Should I try to make a shroud of my own out of rubber, etc, to cover the inboard areas of the radiator not covered by the fans?
Please help me...I hate to sound pathetic, but I can't deal with this any more, and need a positive fix!