Overheating question

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lisapenn62

lisapenn62

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I have a 72 Dodge Demon with a 340 bored 30 over with 10.5/1 pistons. I'm having trouble with it overheating. It goes up to 200 degrees when I drive it for over a 1/2 hour. It has a new fan shroud, new fan, new electric push fan on the front that I can kick on and off but I've been having to leave it on due to the heating situation. The question is, could it be the radiator, blown head gasket (not seeing compression in to the coolant system though). Any thoughts??
 
could be the water pump getting weak, dirt in the cooling system/bad radiator/low coolent level
 
200 degrees ain't overheatin..
 
depending on a few things, how old is the radiator,,,if old could be plugged. you can take it out and run a garden hose through it, and it might look fine but could be plugged just enough.
thermostat if it's a 165 stat and your reaching 200 you have to look into is the stat opening up all the way. check it out in a pan with a thermometer. If you have a 185 or higher stat then 200 ain't bad.

is the rad sized for the v8, i'm assuming it is.

Could be the pump but unless there was no antifreeze and the impellers have corroded away I doubt seriously that it's the pump. but anything could happen

I'd look into the stat and radiator as being the prime suspects

I had the exact same issue with my 305 chevy truck, that why i say what i say and I found the radiator to be the culprit.

good luck
 
200 isn't overheating but getting close. My engine runs cooler with NO t-stat. So in the summer I just remove mine and the engine runs 10 degrees cooler.

Yes the rad could be getting plug, too bad new ones aren't cheap.
 
Try removing the pusher fan. In SOME cases, it may block more airflow than it makes. I've seen it happen.
 
200 almost overheatin? What planet did yall come from? First, 212* is the boiling point of plain water. Secondly, coolant has an even higher boiling point. Thirdly, for every one pound the cooling system is under, you raise the boiling point somethin like 3 degrees. All that together usually puts the boiling point up in the 260 degree range. Most modern electric fans in new cars don't get the juice until 220 degrees. Some 230. The hotter an engine runs (to a point of course) the more efficient it is. The more fuel it burns because it burns more completely. 200 degrees ain't overheatin. It ain't even close.
 
When your driving it does it get hotter or cooler? What does it do sitting at idle or at a red light?
 
StrokerScamp said:
200 almost overheatin? What planet did yall come from? First, 212* is the boiling point of plain water. Secondly, coolant has an even higher boiling point. Thirdly, for every one pound the cooling system is under, you raise the boiling point somethin like 3 degrees. All that together usually puts the boiling point up in the 260 degree range. Most modern electric fans in new cars don't get the juice until 220 degrees. Some 230. The hotter an engine runs (to a point of course) the more efficient it is. The more fuel it burns because it burns more completely. 200 degrees ain't overheatin. It ain't even close.
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sorry I know nothing
 
StrokerScamp said:
200 almost overheatin? What planet did yall come from? First, 212* is the boiling point of plain water. Secondly, coolant has an even higher boiling point. Thirdly, for every one pound the cooling system is under, you raise the boiling point somethin like 3 degrees. All that together usually puts the boiling point up in the 260 degree range. Most modern electric fans in new cars don't get the juice until 220 degrees. Some 230. The hotter an engine runs (to a point of course) the more efficient it is. The more fuel it burns because it burns more completely. 200 degrees ain't overheatin. It ain't even close.
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200 is a little higher then most are meant to run, 185-195 is ideal. 200 is not terrible on a hot day, but not on a cool day
 
If, besides your temp gauge going to 200º, the car is showing no symptoms of overheating, like steam, or overflow, it could be something as simple as a bad sending unit.



In my 71 and 72, I run a 165º thermostat during the summer months, and occasionally I'll change to a 180º T-stat in the winter (even though I'm quite sure the 180 would be fine all year round). I mention this because so many of the 15 day know-it-alls at the little box auto parts chain stores will tell you that you need to run a 195º t-stat in your classic, and that's BS, IMO.
 
66plyValiant said:
200 is a little higher then most are meant to run, 185-195 is ideal. 200 is not terrible on a hot day, but not on a cool day
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What everyone seems to forget when discussing engine temps is unless the oil temperature is 220* or better, it will not burn off contaminants such as moisture and the like. In order for that to happen, Coolant temp needs to be in the 195-210 degree range. Of course, if you want to change your oil more frequently, then certainly you can get by with a cooler engine temp. By and large, the industry standard was 195* for a long time. Look at modern cars. Hotter is the norm. I have routinely seen 225* on a heat gun aimed at the thermostat housin of a newer car and the temp gauge is always right in the middle.....in fact, a tad on the "C" side. ....and most of these cars have aluminum heads. There's a lot more to how "hot" an engine really is than coolant temp. There's oil temp, ambient air temp, incoming air temp....it ALL plays different roles in the real engine temp. I don't know how many millions of these were made, but if 200* was too hot, you can bet your *** 200* would not have been in the middle of the gauge. I wouldn't even be afraid of 225* on a hot day idling in traffic with the A/C on...as long as it dropped at least 10* back out on the road.
 

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It's pretty easy to check rad, a little harder with the pusher fan. With the engine running and at temp, just use the back of your knuckles, and feel across the front of the rad, about halfway down(prob good idea to disconnect elec. fan). any cool areas are plugged tubes. With cross-flow rads, feel up and down.. Hope it helps..
 
Could also be lower rad hose is missing the wire coil inside lower rad hose (this helps keep hose open for the coolant to flow........rather than being shut closed by water pump)..........get coat hanger wire and wind it up in a long spiral shape (put small loops on the ends so wire doesn't poke hole in rad hose), stick wire inside lower rad hose.........see if this might help
 
We ended up taking the old radiator out and putting in a new aluminum radiator. The old one was mostly plugged. Took off the mechanical pusher fan too. Also put on a 160 thermostat, now she runs as good as new, never gets over 160 when running. Got up to 190 once when stuck in traffic for a long time but didn't think that was too bad since it runs so hot anyway.

Thanks everyone!!
 
Aluminum radiator solved my problem in my Duster.
 
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