383 water temp

Dave Baro

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I know this sounds ignorant (and there are many variables) but what would be a “normal” or acceptable water temp running at 70 mph at an outside air temp of 85-90 degrees? I’m running a 180 degree thermostat and I’m showing between 192 and 200 degrees. (With The AC on it kicks it up around 3 degrees). It gets hotter at stop lights (approaching boiling if it a real long light and hot outside) which I’m able to bring it down by putting it into neutral and increasing the rpm a little. Is all of this normal or indicative of a weak cooling system.
 

68NewportDDD

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My 68 Newport runs right at the same under similiar conditions if it is any help at all. Usuly it runs right at 190F.
 

Dave Baro

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Yes, it helps thanks. Just trying to figure out if running above the thermostat temp is normal for these motors.
 

Snotty

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Sounds normal, as well as warming up at a stop. If you had a dummy light instead of a gauge you would not know and would be blissfully ignorant.

Putting your transmission into neutral, if an automatic, at each stoplight puts unneeded wear on your transmission. I would not do that.
 

crazyboutwagons

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I had the cooling system in my 383hp equipped wagon cleaned out last year flushed/cleaned out and had radiator boiled/rodded out car new hoses.replaced the 180 degree thermostat with a 160 degree car never runs above 170 degrees now even with the A/C on.
 

Dave Baro

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I didn’t know that was hard on a transmission. Good to know. Why is that?I’ve got a replacement aluminum radiator, good hoses, new fan clutch, I’ll try cleaning out the radiator.
 

Snotty

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I didn’t know that was hard on a transmission. Good to know. Why is that?I’ve got a replacement aluminum radiator, good hoses, new fan clutch, I’ll try cleaning out the radiator.
It's been a subject of shows like "Car Talk" among others. Stopping and putting the car in neutral requires the transmission so shift out of gear. Then, back in drive is another shift. It's needless work on the internals of the transmission, as well as the driveshaft. Keeping it in gear is less wear than shifting at every stop.

A friend of mine did it because he was told by his dad that it saved gas. I asked him how when the RPM increases in neutral?
 

John Kirby

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I mentioned this on another thread recently. Try adding a bottle of CLR to the radiator and drive around town for an afternoon. Let it sit for a bit to eat up the lime & rust, then flush it out. Not drain and refill, FLUSH. Refill with antifreeze and use distilled water to keep the lime deposits under control. Make sure the radiator fins are not bent over and restricting air flow.

You can tell if your house water has lime in it by looking at your shower heads, are the water holes perfectly clean and open? Only cure is a water softener. Using unsoftened tap water causes the same deposits in a radiator over time. CLR dissolves that crud in a dishwasher, should do the same in a cooling system.
 

Dave Baro

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Thanks John. I never heard of using CLR in a cooling system before. Can we be reasonably certain that the CLR will not react in some nefarious way under heat and pressure? Is this similar to what is used when they “boil” out a radiator?
 

John Kirby

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Thanks John. I never heard of using CLR in a cooling system before. Can we be reasonably certain that the CLR will not react in some nefarious way under heat and pressure? Is this similar to what is used when they “boil” out a radiator?

I am not sure about pressure. I used it in dishwashers and they look like new. I wouldn't leave it in for an extended period. You could drain/refill/drive with water in the system a few times to make sure is is removed too.

A bottle of clr is cheap. If it doesn't do much you're not out a lot and a flush is always a good thing. An industrial grade cleaning would involve disassembling the radiator and using much more potent chemicals and running rods through all the passages. The clr is a poor mans method of buying some time before spending a lot on a radiator rebuild/recore.
 

Gerald Morris

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DO NOT USE CLR ON AN ALUMINUM RADIATOR!!! READ!

CLR® Calcium, Lime, & Rust Remover | Eliminate Hard Water & Stain Build-up

Bottom of the page:

"CLR may etch older sinks, tubs, and tiles. Avoid contact with wood, clothing, wallpaper, carpeting, natural stones, brass, copper, aluminum, galvanized metals, any painted, coated or sealed surfaces. Clean spills immediately."

I don't recommend this product for copper tubed radiators either. It does fine on the water jackets of cast iron blocks, but that's it.

CLR is based on a mixture of organic acids which react primarily with calcium salts, ferrous and ferric oxides in a RELATIVELY safe fashion.

Aluminum is a Group IIIA metalloid, just below Boron in the group, and can be surprisingly reactive to those who didn't attend to their valence electronic sums in kindergarten. One can use single organic acids like acetic, ascorbic or tartaric acid to flush the cooling jacket with an aluminum radiator. Since acetic acid can be had dirt cheap as "cleaning vinegar" I'd recommend that for the flushing agent. One can pour a couple gallons in. run the engine up to temperature for 15-60 minutes, drain, FLUSH WITH PRESSURIZED WATER (no more than 16 psi), then refill with whichever coolant solution is most appropriate for one's driving locale. Avoid any ionized water solution, using only distilled water with the non-polar antifreeze of choice.
 

Big_John

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I know this sounds ignorant (and there are many variables) but what would be a “normal” or acceptable water temp running at 70 mph at an outside air temp of 85-90 degrees? I’m running a 180 degree thermostat and I’m showing between 192 and 200 degrees. (With The AC on it kicks it up around 3 degrees). It gets hotter at stop lights (approaching boiling if it a real long light and hot outside) which I’m able to bring it down by putting it into neutral and increasing the rpm a little. Is all of this normal or indicative of a weak cooling system.

That's a pretty normal temperature. With 50/50 antifreeze mix, you're at 223 degrees for a boiling point. With a good working pressurized system, boiling is up around 250 degrees.

Yes, it helps thanks. Just trying to figure out if running above the thermostat temp is normal for these motors.

There's a lot of factors that determine engine temperature. A lower temperature thermostat might drop the engine temp a little, but when really all it does is let the coolant run through your engine a little sooner. Most of the time, it isn't going to affect the engine temperature. You could switch to a 160 and see what happens. Might help, might not.

There's a ton of other factors though. A lean carb can cause high temps, so can engine timing. Things like the "splash guards" under the car help channel the air through the radiator and they are often missing in older cars. The spring that's often missing in the lower hose (keeps it from collapsing) is another factor. I know you said you've replaced the fan clutch and that's good, but they aren't all the same. The Hayden 2747 clutch has been my weapon of choice with better results than the Advance Auto supplied version I tried first. You haven't said anything about a fan shroud either, and I would expect an A/C equipped car to have a fan shroud.

One other factor that guys never think about is the accuracy of the temperature gauge. It doesn't matter what type or brand, the truth is that they can be reading incorrectly.

It comes down to the fact that your car is really running about normal temperatures and you could just leave it alone and be fine. As was said, if you didn't have the gauge, you'd be blissfully ignorant of the engine temperature.

Thanks John. I never heard of using CLR in a cooling system before. Can we be reasonably certain that the CLR will not react in some nefarious way under heat and pressure? Is this similar to what is used when they “boil” out a radiator?

This is just a bad idea. I've seen it done with cars that are having problems and that's great. Doing it with a car that's not? No... Just no.

Any kind of coolant flush, and it doesn't matter what kind, is tough on the components. As stated above, CLR shouldn't be used on copper or aluminum. All the engine flushes are going to clean out the crud, but at what expense? I've seen where suddenly heater cores and soft plugs start leaking after flushes. Maybe they would eventually, but why make things worse now.

Again, your car is really running about normal. If you want, look at some of the things I mentioned (like the "splash shields" for example) and fine tune on those. You could just leave it alone too, especially if you aren't having any real overheating issues.
 

Dave Baro

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Thanks Big John. I just put the hayden clutch in because I couldn’t tell the difference in rotating resistance hot or cold. It’s the heavy duty one I believe (which is the same as putting in a lower temp thermostat I believe. It just starts working a little earlier). I have the fan shroud and don’t think i’m missing any splash shields up front. Although my wheel shields are getting a little ratty. With respect to all ideas I think you and 70 big block are correct. I was not taking into account the boiling point corrected for a anti freeze/boil and 16lbs of pressure at about three degrees per lb. My paranoia started with the installation of a temp gauge...
C33CE008-BB15-454E-B932-B315F46A525C.jpeg
 

Joseph James

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I run OE copper and brass radiator. Gauge sits center and will run to high end of normal if I sit a long time, like road construction or something. Never has overheated. Owner’s manual says it can dump coolant in heavy traffic and to only fill 1 1/4” below bottom of neck as I recall. I did add an overflow bottle that someone gifted me.

I agree on being careful with aluminum. I deal with a lot of aluminum oxidation in the electrical business which is why I didn’t want an aluminum radiator.
 

Gerald Morris

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I run OE copper and brass radiator. ....
I agree on being careful with aluminum. I deal with a lot of aluminum oxidation in the electrical business which is why I didn’t want an aluminum radiator.

I run a good aluminum radiator and extol its merits, but I exercise due care with it. I run a nice big #10 copper bonding jumper all around the engine compartment, from the right headlights, picking up the cooling fan and left headlights, horns et al on the front and straight to the negative battery post, to avoid any extraneous current passing through that aluminum radiator too. If I had about twice the bread I dropped on that Cold Case radiator, I would have had the old one re-cored at my favorite local shop, but shop time HAS become pricey. I don't bond copper directly to that radiator either, but rather the steel bolts securing it to the radiator mount.

I never would have retired my old radiator had it not started leaking in a few too many places. I ran it the first summer we had Mathilda to good result with the straight 6 blade fan Ma Par put on that engine, but wanted something which would optimize the power used for cooling a little more adroitly, and went to first a BIG 7 blade Mopar fan off a truck, then the 6 blade DeRale fan I now use with the Hayden 2747 clutch. This does well and if temperatures goes over 200F, I run a 16 inch electric pusher from the front to bring it back down. Even with a 16 psi system, I just don't like my coolant going over 200 F down here. It can happen too easily during the summer, and thermal run-away CAN occur. I thank the Lord it hasn't ever on Mathilda, nor should it, as I WILL shut her down should I see any such start.
 

Big_John

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Thanks Big John. I just put the hayden clutch in because I couldn’t tell the difference in rotating resistance hot or cold. It’s the heavy duty one I believe (which is the same as putting in a lower temp thermostat I believe. It just starts working a little earlier). I have the fan shroud and don’t think i’m missing any splash shields up front. Although my wheel shields are getting a little ratty. With respect to all ideas I think you and 70 big block are correct. I was not taking into account the boiling point corrected for a anti freeze/boil and 16lbs of pressure at about three degrees per lb. My paranoia started with the installation of a temp gauge...View attachment 412316
OK, you have me curious about that gauge setup. Details??
 

Dave Baro

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Well, I wanted something beyond the idiot lights and ammeter but there’s no good spot on my dash to hang a set of gauges. It just would have ruined the look of the dash. So I found this cheap but effective setup online. I like the hidden mounting. ( I guess this would would work well under the dash also as it’s mounted on a hinge so you could fold it back when you wanted to preserve the look) It works great but you’ve got to get used to Celsius for temp and pascals for oil pressure. It’s got a voltmeter also. It was all of twenty-five bucks plus another few bucks for the fitting to mount the water temp sender. (36mm) Going to put some tape over the foreign lettering. It was so cheap and effective that I bought two for a backup in case it fails.
 

Gerald Morris

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Its a cheap bang for the buck, but I don't like electronic data sources, as I've seen too many fail with detrimental consequences, especially cheap stuff. I admit putting a gauge pod o the bottom of the dash does detract a little from the aesthetic, but not so much as a smoking, steaming, dead engine. I go with Made in the U.S.A. gauges only now. Try Clark Brothers if you're on a budget, as I am. You can sometimes find NOS Stewart Warner stuff surprisingly cheap too, but you DO have to look.

I probably would have used what you got 4 yrs ago, when I first got Tilly and wanted SOME GAUGES IMMEDIATELY. Good Luck and Happy Moparing.
 
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