Over heating

rc4mike · May 21, 2007

Just finished restoring my 65 vert. Now i am having engine cooling problems. Have an old 3 core radiator with a new elec. fan. Also have a new AC...not running yet. New water pump. Air temp was 85 this weekend and engine gets hot while siting idle for 5 minutes. Any suggestions? Alum. radiator with fan? Oil cooler with existing radiator?

thanks
mike

TOM B · May 21, 2007

STOCK ENGINE I assume, electric fan, is it installed as a pusher or puller, check to see if it is running the right way, does it have a shroud, Zirgo fans are way over rated and dont put out like they say. Fan should be installed as a puller mounted behind "engine side" the radiator and should come on about 175.
Check your timing also, on a stock 289-302 it should be around 8 deg with the vacuum advance pluged, also check that the advance is working but NOT at idle, if when you hook up the vacuum advance and the engine picks up RPM,s at idle then the advance line is hooked up at the wrong port connection.
Other things to check.
1) head gaskets on correct- stamped (FRONT) is on the front on both sides.
2) thermostat is in and working
3) water pump is correct and not a reverse rotation
4) pressure cap is correct pressure
I would be looking at the electric fan first, might be installed wrong or not big enough, then check timing.

jikelly · May 22, 2007

My brothers 86 GT with a 302 overheats too. He's got an electric fan and 3 row radiator, but the car still gets hot and overheats in traffic (stopping at lights and going the slow 35-40mph all the streets are posted at).

He's installing a new fan set up. I think the fan's out of a Mark 8. He was bugging me like crazy yesterday because the 30 amp fuse protecting the $80 fan controller he bought keeps blowing out. I told him I thought he was going to have to put a relay on the fan motor to isolate the controller from it so he could run a 75A fuse or something.

Sicarius428 · May 22, 2007

What efan are you running? Typically if everything else is in good working order, overheating at an idle is not enough fan. If your temp is fine at freeway speeds for example I would suspect the fan is the culprit... as long as the headgaskets are in the right direction, tstat is working fine. Oil cooler would not be a bad addition but don't put it in front of the radiator. Everything that you stack in front of the radiator takes away from the effectiveness of the it. Just keep that in mind. Another very nice additon to an electric fan is a dc controler. It dynamically ramps up the fan RPM as needed so your motor doesn't hit a preset temp, then kicks the efan on all the while the motor is on the bridge of overheating then kicks off when it finally brings the temp down. http://www.dccontrol.com/ can explain it better.
Kevin

Tubo(2-bo) · May 22, 2007

Junk the stock sized radiator, get a 22in or larger(Mine is 26in) aluminum CROSS FLOW, rad.
The stock non cross flow is too small & inefficent, even before you add A/C.
The only reason to keep a stock 65-66 radis for Show reasons.
You'll have to change water pumps or hoses to make the cross flow work , But its well worth it.

rc4mike · May 22, 2007

OK, good suggestions. My efan is a puller, mounted behind the rad. I noticed today that the fan was turning on after the engine temp was high, so i adjusted the thermostat so now it turns on at a much cooler temp. Seemed to really help. I am thinking it was waiting until temp was already way too high before turning on. I'll try it this way for a few days and see. I like the idea of the progressive fan speed. I might try that as well.

thanks
mike

Over heating

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