Professor Fate
Push the button, Max...
Hmmm... that could have a little something to do with it!
How close should my fan be without a shroud?
- Thread starter Righty Tighty
- Start date
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I thought so, too, but then I started to wonder why an engine would overheat if coolant was constantly flowing — as in this case without a thermostat?
Professor Fate
Push the button, Max...
And if the coolant is flowing too quickly, it doesn't have time to shed it's heat in the radiator. It's a fine line.
My limited experience with cooing systems is.....and take with a grain of salt.....Its under pressure, I dont know how much pressure, but it will find the weakest point and then leak there. First its the water pump, then its the heater core, then its the rad....on and on until eventually you have replaced it all. So, when the system is pretty old and wore out....I just do it. I collect the best 'made in america' if possible parts and have at the whole deal. then fill with distilled and follow the instructions on all of it. good clamps, yad yada yada, but again......Im just a guy.
Thanks for the input. I took it for a test drive and it’s still running hot. That’s all the time I have for today, so maybe I’ll get back to it tomorrow.
My bet is there is some other issue and a PO thought removing the thermostat would help.
Do you ever smell molasses? yknow, the syrupey smell attributed to a coolant leak?
Take the cap off and start the engine cold. Let it sit there and let the thermostat fully open. Now, fill the radiator SLAM full. With the cap still off and you out of the way, rev the engine. If the coolant overflows even more, you have a stopped up radiator.
Post #29 is wrong, a common misconception. See tech tips link below, it explains it.
Missing stat can cause o'heating. The stat has two jobs: regulate temp & provide a restriction to flow. The restriction allows pressure build up in the coolant. Why? Because hot spots, such as near exh valves, can cause the water to boil, air in the water. Air is a very poor conductor of heat......
By adding pressure, the air bubbles are suppressed, improving heat transfer to the water. While I doubt this is the problem, it could be & a stat should be used.
www.stewartcomponents.com
Missing stat can cause o'heating. The stat has two jobs: regulate temp & provide a restriction to flow. The restriction allows pressure build up in the coolant. Why? Because hot spots, such as near exh valves, can cause the water to boil, air in the water. Air is a very poor conductor of heat......
By adding pressure, the air bubbles are suppressed, improving heat transfer to the water. While I doubt this is the problem, it could be & a stat should be used.
www.stewartcomponents.com
The heater core was leaking, but I have since replaced it and it's no longer leaking. There's no leak that I can see or smell.
I'll try that today.
Tried Rusty’s test. Cold start with the cap off, idled up to temp, topped off the radiator to the level of “SLAM full.” Blipped the throttle just a bit, and holy smokes! Immediate geyser.
Looking down into the radiator core, I can see quite a bit of gunk and chunks. I’m thinking if it’s bad enough to cause overheating, I may be best off taking it in to be re-cored.
Looking down into the radiator core, I can see quite a bit of gunk and chunks. I’m thinking if it’s bad enough to cause overheating, I may be best off taking it in to be re-cored.
Yup. Radiator is stopped up. The water has no place to go so out the top it comes. They'll all flow out the top a little, but when it does it like that, you know for sure the radiator is stopped up. At least now you know!
I will add that one thing I wasn’t prepared for was the mess it made…but if you’re gonna make an omelette, you’ve got to break some eggs.
That's why I added to get OUT of the way. You don't wanna get burned. I just bet you're fixin to have this thing runnin cool as a cucumber.
Yes sir, I knew exactly why you said that, so I made sure my face and other valuable parts I don't want burned were far away. But stupid me also didn't have the forethought to anticipate the coolant hitting the fan....haha. It was just a quick blip of the throttle, so it didn't make a terrible mess. Easily rinsed off.
I'm looking for a radiator shop, but my first 2 choices are booked 3-4 months out. Gotta say I'm eager to get her running cool so that it can be a daily. I love the sound of the engine -- she just purrs.
I'm looking for a radiator shop, but my first 2 choices are booked 3-4 months out. Gotta say I'm eager to get her running cool so that it can be a daily. I love the sound of the engine -- she just purrs.
BillGrissom
Well-Known Member
I've had 2 cars where changing the radiator or a good flushing fixed it. My 1985 M-B drove me crazy for 2 years, the temp creeping up at long stoplights. I removed the radiator and sat horizontal for a week in hot sun w/ citric acid, after backflushing. Tried swapping T-stats, clutch fans, used radiator, water pump, even removed T-stat housing looking for a plug (rag left in). Finally tried a new aluminum radiator after the prices dropped ($350 to $130) and solved it. The old radiator had orange coating partly covering the top tubes. I had even run a stainless grill brush over the top to clean such and tried a borescope view (looked OK in side view). The other was my 1996 Plymouth Voyager. A good in-car flush w/ citric acid and backflush fixed it (2nd radiator since new). I think having used Dexcool long ago was the main problem, though I still have rust stains on the driveway from the flush, so maybe the block passages needed cleaning too.
Don't run with no T-stat. If overheating, the T-stat is wide-open so won't restrict flow. A 190 F T-stat will give better mileage and less engine wear, with no added risk of overheating. Don't believe the absurd statements which are common on hobby sites (like here) about needing a restrictor (otherwise "flows too fast to cool down in radiator" is claim). That has no basis in engineering theory and if true then a T-stat would work backwards. More flowrate gives more cooling, which seems intuitive and obvious, but people prefer imagining mystical ideas. Other strange understandings are spread about cavitation and shock waves, but another topic.
Don't run with no T-stat. If overheating, the T-stat is wide-open so won't restrict flow. A 190 F T-stat will give better mileage and less engine wear, with no added risk of overheating. Don't believe the absurd statements which are common on hobby sites (like here) about needing a restrictor (otherwise "flows too fast to cool down in radiator" is claim). That has no basis in engineering theory and if true then a T-stat would work backwards. More flowrate gives more cooling, which seems intuitive and obvious, but people prefer imagining mystical ideas. Other strange understandings are spread about cavitation and shock waves, but another topic.
What car and what size radiator?
I detached the upper and lower hoses and added 1 bottle of CLR/topped off with water. Let it soak about an hour and flushed thoroughly, didn't make much of a change to the core from what I could see, but the car seems to be running just a little cooler (although still warm). By looking at the rate of how quickly (or slowly) the water was draining while flushing, I think the CLR didn't do much.
'68 Barracuda, 19" radiator.
Dartswinger70
Well-Known Member
Close...but not too close...
I cooked professionally for a while, and when new guys would ask how long to cook something, we’d just say, “Until it’s done.” 
If that's the same as a 64 Valiant, I have a nice aftermarket aluminum radiator.
Thanks Rusty, I'm wanting to keep it as close to factory as I can.
I understand. That's why I removed it. I installed a factory three row and it fits better.
Slantsix64
Well-Known Member
Radiator is clogged if your heating up on the highway,
if your heating up at a traffic light or while stopped its a fan pulling air issue.
if your heating up at a traffic light or while stopped its a fan pulling air issue.
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