Dart Running Hot?

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70orangeswinger

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I have a 70 340 4 speed Swinger that has a stock engine other than the intake and headers. Before I had the engine rebuilt the factory temp gauge ran about 3/4 of the way up. Since the rebuild, the gauge pegs when warmed up. I installed a manual temp gauge under the dash and it reads 210 degrees when warm. Is this too hot and if so, how can I fix it? I changed the sending unit on the stock gauge and installed a new 180 degree thermostat. I am afraid to run it on these hot days because I am afraid of hurting it. The temp stays right at 210 the whole time I drive it. Any help out there?
 
210 is pretty normal. That said, have you had the radiator checked out? When the engine was "rebuilt" was it sent to a shop to have it hot tanked and all the coolant passages cleaned?
 
RustyRatRod said:
210 is pretty normal. That said, have you had the radiator checked out? When the engine was "rebuilt" was it sent to a shop to have it hot tanked and all the coolant passages cleaned?
Click to expand...

Answering a question with a question may not be considered proper.
Regardless, I think questioning the radiators condition is the best response here.
With 3/4 of scale on the stock gauge, I would have questioned the radiator before the rebuild.
 
Did you put in a new thermostat? I had two. A 180, and a 160.the 180 was checked with a digital thermometer. It opened at 192. The 160 opened at 175. They need to be checked. I used the so called 160. Drilled 1/8 holes in it (4) to prevent trapped air. Put a hose spring in the bottom hose. Built a shroud, since none of the factory shrouds would work with my aluminum radiator. Runs 180 unless stopped for a while.
 
Checking the thermostat is always a good (first) idea to do.

But, unlike the rest of the 'info' above here... unless you want to risc blowing headgaskets or waterhoses, burn up the life of your oil quickly, yeah then running with 210F maybe fine...

For me it's not. 180-190 is the max I want to see on a gauge.

It's true a fresh engine can have tight clearances but these should not cause an engine to run 30 degrees hotter than normal.

Since the engine has been rebuild;
- Any chance the timing is off (too late)?
- Camshaft-timing installed wrong?
- Vacuum leak?
 
Believe it or not a higher temp T-stat can often help with a heating issue. Try the 195 and see what happens.
 
X2 on trying the 195 deg thermostat. Water doesn't have time to cool in the rad. My 340 ran hot when I first rebuilt it. I used a product called wetter water it helps the antifreeze to pull more heat out of the block. It worked for me the gauge never goes up to 1/2 anymore. Also the engine is broken in by now.
 
I have a 65 dart with a 360 in it and it always ran 210-212 with the old radiator and the new one i put in thinking the old one was shot. I tried several part store thermostats and water pumps to try and get the temp down with no luck at all. even tried water wetter and no change. I finally fixed it when I bought a flowcooler water pump and Mr gasket 180 thermostat from summit racing , the temp runs 173 on really really cold days otherwise it runs 180-185 highway, and might get up to 200 if i sit in traffic for a long time with out moving. Part store thermostats are junk, they don't flow enough volume.
 
I was having temp issues when running the A/C, I believe the culprit was the March Performance pulleys I have on the motor. Despite the claims from March Performance (they said they didn't ever make an underdrive setup for the LA) the water pump pulley was about an inch bigger than the crankshaft pulley, i.e. underdriven. So I bought a new water pump from FlowKooler and it runs just fine now. See if your pulleys are underdriven and whether you have the A/C or non-A/C waterpump.
 
Ditto on AC vs non-AC water pumps. The reason for the difference is that AC cars used different pulleys so the w.p. turns at a different speed. They actually have fewer blades (recall 6 vs 8 for non-AC car). Each is optimal for the speed they turn.

Installing a 180 F T-stat will not make it run cooler. A 195 F T-stat would be full-open at 210 F too. In winter, it may run cold w/ the 180 F T-stat, giving poorer mileage, more wear, and more emissions.
 
So what consists of your cooling system? i.e. stock radiator, what degree t-stat, water pump age/condition, fan (electric, flex, viscus) running AC. Also, what was done on the rebuild and what is the state of your tune i.e. timing, carb, ect.
 
What fan , rad and are you running a shroud ? Mine runs at 185 , stock rad clutch fan and shroud . Ran 185 yesterday in city traffic 100 degree heat . I was not running as cool as the car .
 
Pretty typical. A drive by poster.
 
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