Cooling system Question
#1
Cooling system Question
Car: 68 442, all stock , 4 core OEM rad(original), New fan Clutch, rebuilt motor Etc.
Driving in traffic/ around town/ On highway up to 60MPH it will stay at 180 all day long no matter how hot it is outside, PERFECT. However if on highway going 70-80 up is starts to creep up to 200. Not sure how high it will get as i don't normally drive at 80 in an old car for long periods
Question: What are possible causes?
Driving in traffic/ around town/ On highway up to 60MPH it will stay at 180 all day long no matter how hot it is outside, PERFECT. However if on highway going 70-80 up is starts to creep up to 200. Not sure how high it will get as i don't normally drive at 80 in an old car for long periods
Question: What are possible causes?
#2
What RPM is the engine turning at 70+ MPH?
Mine is the same way, stays at 180-190 all the time EXCEPT it starts creeping up to 210-220 at 70+ MPH (during the 110+ summer with the AC on), but that's because the RPM is in the 3400+ range. If I slow down to below 3000 RPM the temp comes down below 200 and stays there. More RPM = more heat. For the temp to stay at 180 you (and I) would need more cooling capacity to dissipate the extra heat.
Mine is the same way, stays at 180-190 all the time EXCEPT it starts creeping up to 210-220 at 70+ MPH (during the 110+ summer with the AC on), but that's because the RPM is in the 3400+ range. If I slow down to below 3000 RPM the temp comes down below 200 and stays there. More RPM = more heat. For the temp to stay at 180 you (and I) would need more cooling capacity to dissipate the extra heat.
Last edited by Fun71; September 19th, 2016 at 05:50 PM.
#3
My Olds and even my modern Challenger do what Kenneth describes--coolant temp rises with engine rpm. In the Challenger, five minutes over 3500 rpm sends the coolant temp to 240 and oil temp to 260°.
Most people who race their OEM cars (that is, they want to run consistently at high rpm) need more capable radiators for the same reason.
I always thought my Olds built heat at higher rpm because of the drag on those wide, old-school rings. Obviously there's more nuance to the explanation because modern Hemis use low-tension, narrow rings.
Most people who race their OEM cars (that is, they want to run consistently at high rpm) need more capable radiators for the same reason.
I always thought my Olds built heat at higher rpm because of the drag on those wide, old-school rings. Obviously there's more nuance to the explanation because modern Hemis use low-tension, narrow rings.
#4
Car: 68 442, all stock , 4 core OEM rad(original), New fan Clutch, rebuilt motor Etc.
Driving in traffic/ around town/ On highway up to 60MPH it will stay at 180 all day long no matter how hot it is outside, PERFECT. However if on highway going 70-80 up is starts to creep up to 200. Not sure how high it will get as i don't normally drive at 80 in an old car for long periods
Question: What are possible causes?
Driving in traffic/ around town/ On highway up to 60MPH it will stay at 180 all day long no matter how hot it is outside, PERFECT. However if on highway going 70-80 up is starts to creep up to 200. Not sure how high it will get as i don't normally drive at 80 in an old car for long periods
Question: What are possible causes?
#5
Same, Same
I experienced the same trouble in my '68 442 with A/C. I wound up having the "OEM" 3-row radiator re-cored. The original core fell to pieces when attempting to "rod" it in the acid bath. I suspect the radiator was replaced at some point along the way, due to an accident. My upper support is clearly for a four-row rad, but the lower support has three-row rubber and steel channels. There is other evidence of body/frame/wheel hub repair work in the front left, along with other hints, so I suspect the three-row rad is not original to the car.
No longer an issue after having the radiator re-cored.
No longer an issue after having the radiator re-cored.
#7
A coworker recently had a similar issue with overheating only on the highway with the AC on. He found there was a bunch of leaves blocking the air flow in the lower corner of the radiator. Same effect of reducing the radiator area.
#8
Thanks guys for all the info.
I will push it to see what it may climb to.
Just finished a two hour trip over the weekend to a show(Each way) And noticed at 70MPH it kind of stays at 200+-, If i slow to 60-65 it comes back down.
I guess with nothing else to occupy my time for 2 hours(driving) i became fixated on what the temps were doing.
With this being the orig. Harrison 4 core it is more than likely it is a little restricted inside due to age.
Maybe a recore is in it's future.
I will push it to see what it may climb to.
Just finished a two hour trip over the weekend to a show(Each way) And noticed at 70MPH it kind of stays at 200+-, If i slow to 60-65 it comes back down.
I guess with nothing else to occupy my time for 2 hours(driving) i became fixated on what the temps were doing.
With this being the orig. Harrison 4 core it is more than likely it is a little restricted inside due to age.
Maybe a recore is in it's future.
Last edited by 68442; September 20th, 2016 at 10:23 AM.
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