I am having a bear of a time tracing down a cooling issue on my '66 Coupe with a 68 302 powerplant. I have put about 900 miles on the car since I purchased it second hand. Ran like a top, then started slowly overheating, but only under a load. Engine has the standard .30 rebuild and a mild cam, nothing crazy. Stock heads, some underdrive pulleys (which I read could be a problem) I have done the obvious:
New thermostat (Yes it's in correctly and working at an idle in the driveway)
Inspected Gano inline filter and replaced it (It was clogged with what looked like bits of liquid gasket and small pieces of metal. From what I have read, a product of electrolysis from the silica in the coolant and the aluminum radiator.
Removed the Northern Aluminum radiator and had it flow tested at a radiator shop. They say its flowing perfectly.
I tried to belch the system with the radiator cap off and didn't get anything.
Water pump is not leaking, but looks to be flowing when I have the radiator cap off from what I can tell.
Talked to a local Mustang shop and they are at a loss as well.
Please, anyone out there have the same issues? HELP!! I searched the forum with no relative results.
Yeah, sure did. Ran it with the cap off for about 10 minutes or so. Never saw any bubbles, nor did the coolant level drop at all. It only overheats when Its under a load which makes me think there may be some sort of blockage in the block somewhere. Coolant was clean, no scale and radiator was clear. Likelihood of the blockage in the engine? I was told to try to run a garden hose through the bottom hose before I put the radiator back on.. frustrating
I have a 69 with a built 302 and a 66 ranchero with new built 289. I have had similar problems. Mine with slow, hot cruises.
I suggest first jacking up the front of the car about a foot or two and then burping it with the heater on. It will surprise you how much more air will come out.
I recently used water wetter for the first time last summer. It did work great.
As always you should use a fan shroud, and you might want to upgrade your fan blade if haven't already.
Also carb could be running way too lean.
Joe in Detroit
1969 Mustang Sports Roof (SAG = Sports Appearance Group) 1 of only 5,729
1966 Ranchero Custom 1 of only 11,000 made.
1969 Mustang Grande (future unknown)
2014 Mustang V6 premium pony package
"It was a beautiful day, the sun beat down
I had the radio on, I was drivin'
Trees flew by, me and Del were singin' little Runaway
I was flyin'" Tom Petty, Runnin Down A Dream.
Last edited by 1969sag; 02-20-2013 at 01:07 AM.
I'm guessing the head gaskets were on correctly when he took custody
of the car. (drove it 900 miles apparently)
However, the head gaskets could be going "south." Maybe time for a
check for combustion gasses in the coolant. (block tester)
Another thought is the water pump impeller spinning on the shaft and
not connected solidly.
Head porting job where the exhaust port is now leaking into the water
As the drill sergeant said, "I taught you everything you know. I didn't teach you everything I know."
"Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so."
- Douglas Adams
Thanks for all of the replies, some great things to consider here.
A few things I will add...
When I say "Overheating" I am referring to running it down the road and back after the car is good and warmed up. Bouncing off of the thermostat at 180 degrees when sitting in the driveway down to 160-180 degrees. As soon as I run it about a mile down the road up to 60 MPH or so and back. Sitting at the stoplight and running through my neighborhood, the temp climbs up to the 200 degree mark on the gauge.
I inspected the lower radiator hoses in response to Wheelsup351 suggestion about a spring in the lower hose, I dont see one visible, but I didn't notice that the hose is more pliable when I squeeze it one way verses the other. As if the hose may have worked a crease in the rubber. Really wishing I would have paid attention to that hose when I was revving the car! I guess I should just replace the hose since I'm there and they're cheap.
Another note is, when I drained the remainder of the coolant out of the radiator, it was an orange or rust color, could this be the pinkish residue from the "water wetter"?
I noticed some metal looking particles in the hose as well. Normal?
Thanks again for all of your responses, best forum for info I have ever been on by far! A true wealth of knowledge...
Also, not too sure what the timing is set at, kinda curious why the previous owner ran "Water Wetter" in the car in the first place? Maybe there were some issues in cooling he tried to address.. Car seems to run perfect, no issues starting or anything leading me to believe timing is an issue.
Also would like to add that I am running a 180 Deg thermostat.
I have no heater box/core as it is blocked off at the waterpump. I am hoping there is air in the system and I can belch it as 1969sag mentioned, by jacking the car up in the front. Any other tips to burping the system without a heater system in place?
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