How hot can I push her?

-
sargentrs

sargentrs

Well-Known Member
Joined
Aug 9, 2014
Messages
436
Reaction score
31
Location
Jasper,GA
'74 Dart with 225 /6 and A904 trans. Started overheating a day or two ago. Only had her a couple of weeks. Been running around 180*-190* up to now. Day before yesterday she got up to 205*-210* before I got home. Yesterday, I pulled over when she hit 220* and as she sat got up to 230*. Going down a long hill, put it in neutral and coast and she drops back down to 190 ish. Back in drive going up the next hill back up to 220+. Got it home, flushed the radiator and added fresh antifreeze. On the morning commute to work, always before, ran about 165*-180*. Now, this morning after the flush/fill, she runs about 190*-205*. Looks like the lower radiator hose may be collapsing, kinda flat in the middle and a little soft, and I don't know what kind of shape the thermostat's in. Picking up a new hose and thermostat on the way home but wondering how hot I can push her. Thanks to all for your help!
 
Make sure the new bottom hose has a support spring.
 
My slant hit 220 all the time and then climbed substantially to 280* while sitting on the side of the freeway. Only when I replaced the electronic temp gauge with a mechanical one did I realize the car was only at 180-190. I've hit 200 on the freeway while really pushing but it's never gone over that.

Also if you have a radiator cap at all, I'd assume the rad wouldn't boil at 230, but other stuff will get damaged I'm sure.
 
I'm running a Sun pro temp gauge in the port next to the upper radiator hose. Tried to put it in the hole in the water jacket close to the dizzy but, even though it was smaller than the plug, it wouldn't go in. Maybe gunk plugged the hole? Haven't gotten to trying to fix the stock gauges, I've only had her less than 2 weeks, but needed a temp gauge asap just in case. Might not be getting an accurate reading where its at but she's definitely running hot. Pulled over when she hit 230* today and it cooled down to 190* in 15 minutes. Another 5 miles home and it was back to pushing 220*. Replacing the lower radiator hose and thermostat tomorrow. Radiator core looks good through the cap opening. Flow seems a little odd though. It'll flow like a fire hose then stop, drain down a little, fill back up, then whoosh! flow again. Anybody seen that before?
 
Have you changed the theromostat ,if it worked fine then went bad that's where I would start ?
 
That rushing and stopping of coolant you are seeing is probably the thermostat opening and closing, and what I would change next. As others have said, the lower hose should have a spring in it to prevent it collapsing closed.
 
I'll be changing the thermostat tomorrow along with the lower hose. The old hose doesn't have a spring in it that I can feel, is kinda soft and no longer round. The new one I bought doesn't have a spring either but is a lot firmer and stiffer. It'll have to do for now. Thanks everybody!
 
IS it a mechanical gauge though? I had a sunpro electric gauge and I noticed the exact same conditions, seemed when the alternator charged the gauge went up, and when the it went to idle, it gradually cooled back down. Also when the turn signals were flashing, the gauge would tick back and forth like a metronome. lol.

I'd replace the thermostat anyway, since it's cheap and easy to get to. I drilled a small 1/16" hole in mine to prevent air bubbles while I was chasing a heat issue myself.
 
Make a spring for the bottom hose.
 
Yes, it is a mechanical gauge. That infrared thermometer sounds like a good idea. How would you go about making a suitable spring? Coat hanger wrapped around a pipe? Thanks for the input guys!
 
"Boiling over" is going to depend on atmospheric pressure (altitude) and temperature. Atmospheric pressure in the case of a an automobile is going to be determined by the radiator cap. A 15 psi radiator cap should be able to allow 250º F coolant temp without boiling. This assumes that the rest of the cooling system is up to snuff for this sort of thing.
 
You must log in or register to reply here.
-

Back
Top