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Should I be concerned?

1966Belvert

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Location
Mount Airy, MD
In early June, I purchased a 66 Belvedere II convertible. Over the last 2 months, it's been at my mechanics undergoing some maintenance to make it more road worthy. The car is an older restoration and hadn't been driven much by the previous owner, so it needed a bit of TLC. I got it back today and took it for a nice drive. While cruising, the temp gauge stayed steadily in the middle of the normal range. When idling at a stop light, the temp would creep up to the very edge of the danger zone, as the attached photo shows. Should I be concerned? If so, should I start with a fan shroud or jump right into a new radiator? I expect to use this car in a lot of parades, so it's crucial that it stays cool in stop and go situations!

My apologies for such a newbie question. I owned a 66 Belvedere II hardtop in high school and college, but I sold it in 1991 and I don't remember what "normal" is for these cars.

Thanks!

-Steve

IMG_0558[1].JPG
 
The FSM touches on this. (Paraphrasing) In slow traffic it may be necessary to put the car in neutral and raise the RPMs.
Secondly, if it does not have a fan shroud I would find one and install it. My ‘66 Belvedere always ran at ‘normal’ temps with a fan shroud. As I needed to address the radiator during my restoration I had it re-cored with a 3 core just to be sure.
Also, check to see what the thermostat is rated at.
I forgot to mention it’s an AC car with a 26” radiator
 
Driving in traffic is a LOT different today! My 318 with HD cooling factory can’t be driven in traffic and 100+ weather if I don’t want it over 200F. It will hit 220F. Turn the heater on and it drops to 190F. It is in the edge. This is a new OEM reproduction radiator from GlenRay. I have tried every little trick in the book and it only extended the inevitable a bit. An aluminum radiator would likely help but I decided I don’t want to drive it in traffic anyway. .
 
In early June, I purchased a 66 Belvedere II convertible. Over the last 2 months, it's been at my mechanics undergoing some maintenance to make it more road worthy. The car is an older restoration and hadn't been driven much by the previous owner, so it needed a bit of TLC. I got it back today and took it for a nice drive. While cruising, the temp gauge stayed steadily in the middle of the normal range. When idling at a stop light, the temp would creep up to the very edge of the danger zone, as the attached photo shows. Should I be concerned? If so, should I start with a fan shroud or jump right into a new radiator? I expect to use this car in a lot of parades, so it's crucial that it stays cool in stop and go situations!

My apologies for such a newbie question. I owned a 66 Belvedere II hardtop in high school and college, but I sold it in 1991 and I don't remember what "normal" is for these cars.
First check to see if the radiator is full of coolant.

Thanks!

-Steve

View attachment 1148540
 
Unless your gauge is wrong that seems hot to me.
My 69 Coronet with a 383 has a 22” radiator with 7 blade fan no clutch and no shroud and it has not gone above direct middle of the gauge.
Last week we had the heat advisory in North Florida 95 degrees- heat index 105-115 and it was fine sitting still idling in drive for 20 minutes at the Whataburger drive thru.
 
It would be a good Idea to install comp. gauges under dash. Have Oil pressure-water temp-voltmeter. It gives me a peace of mind.
 
In early June, I purchased a 66 Belvedere II convertible. Over the last 2 months, it's been at my mechanics undergoing some maintenance to make it more road worthy. The car is an older restoration and hadn't been driven much by the previous owner, so it needed a bit of TLC. I got it back today and took it for a nice drive. While cruising, the temp gauge stayed steadily in the middle of the normal range. When idling at a stop light, the temp would creep up to the very edge of the danger zone, as the attached photo shows. Should I be concerned? If so, should I start with a fan shroud or jump right into a new radiator? I expect to use this car in a lot of parades, so it's crucial that it stays cool in stop and go situations!

My apologies for such a newbie question. I owned a 66 Belvedere II hardtop in high school and college, but I sold it in 1991 and I don't remember what "normal" is for these cars.

Thanks!

-Steve

View attachment 1148540



let’s get a laser thermometer, check top of motor/ radiator
 
I've 'tested' a lot of factory gauges and found when the needle is over that far, it's at least or over 230! A temp gun helps tell you a lot but most of my tests were with the cap off the radiator and one of the old time thermometers in the neck. The only reason for a high pressure cap is to keep the water from boiling once over 212. Do some research on the effects of water over the boiling point and what PSI does for that. If you don't have a shroud, put one on it and make sure the fan is at least even with the edge. It's not that hard to run cool but there's a lot of variables why an engine runs hot. Has the engine been rebuilt? Were ALL the water jackets cleaned real well?? This includes not only the block but the heads also. What T-stat are you running? The list is long on this stuff....and welcome to the site!! :)
 
Assuming the engine isn’t some crazy race engine (and even then) a common reason for running hot I’ve found has been non-functional vacuum advance or some variation on incorrect advance.

What’s your distributor setup like? What port on the carb is the vac advance hooked up to? Does is work? Is the diaphragm good? Initial timing?
 
In early June, I purchased a 66 Belvedere II convertible. Over the last 2 months, it's been at my mechanics undergoing some maintenance to make it more road worthy. The car is an older restoration and hadn't been driven much by the previous owner, so it needed a bit of TLC. I got it back today and took it for a nice drive. While cruising, the temp gauge stayed steadily in the middle of the normal range. When idling at a stop light, the temp would creep up to the very edge of the danger zone, as the attached photo shows. Should I be concerned? If so, should I start with a fan shroud or jump right into a new radiator? I expect to use this car in a lot of parades, so it's crucial that it stays cool in stop and go situations!

My apologies for such a newbie question. I owned a 66 Belvedere II hardtop in high school and college, but I sold it in 1991 and I don't remember what "normal" is for these cars.

Thanks!

-Steve

View attachment 1148540
A shroud is a must for a Mopar with a clutch fan absolute must. Rmeber 2/3 of blade must be in the shroud, covering entire radiator and the edge of blades must be within 1/4 inch of diameter of Shroud. Shroud again must cover entire radiator.
 
Bingo !! Determine what the actual temp is, before throwing parts or doing this-or-that. Don't trust a factory cheap gauge.
Always a good idea but the factory gauges are usually good. Also if it’s in a “believeable” range while driving and on cooler days going really high probably means going really high.
 
I make a habit of carrying a temp gun because I don't trust the gauge. I've seen it go into the too hot zone and the gun tells me its at 180º and much of the time the gauge doesn't work at all.
 
Always a good idea but the factory gauges are usually good. Also if it’s in a “believeable” range while driving and on cooler days going really high probably means going really high.
Factory gauges are crap, nothing more than suggestion arrows.
 
Drain and flush it. See how much rust you get. You can install a shroud at the same time.
It appears to be within the normal range so I wouldn't get too worried.
 
Drain and flush it. See how much rust you get. You can install a shroud at the same time.
It appears to be within the normal range so I wouldn't get too worried.
I agree with Don about the flush. For some unknown reason the green coolant turns brown real quick. A good flush wouldn’t hurt. The FSM agrees.
 
Thanks for all the replies! I realized that I should have given more info on the car. It's a 273 2V auto. It had a rotisserie restoration almost 20 years ago and hasn't been driven much since. I will discuss all of these suggestions with my mechanic, but it seems like a radiator flush and a fan shroud might be a good place to start.
 
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