Is the Hemi too hot?

[Sixt8Chrgr]

I have a buddy that has a very sweet 69 R/T Hemi with an Arrozza built 472 with over 620 HP. The car is awesome in all ways.
The issue that he is having is what he perceives as an over heating problem. The car per the repro gauges reads 200 degrees in City traffic. He is very concerned about this and I have pleaded with him that the temperature is not too high based on the setup. He is considering adding two fans on the leading edge of the radiator to try and cool the motor down. I just dont think that it is an issue but could be wrong. We have the timing set correctly, the carbs are not too lean and he is running race gas. He plans on installing a nice after market temperature gauge to make sure he knows the real engine temp.

Do ya'll think 200 degrees is too hot for a Hemi in August heat in City traffic in North Carolina?

Thanks

[Ghoste]

Maybe not too hot but definitely getting into the not too comfortable zone.  I'd find out the accuracy of the guages first and then go from there.

[c00nhunterjoe]

big motors making bog power put off some serious heat, i'd be thrilled if all i got in nasty traffic was 200, it's still hot but not dangerous. if the gauge is accurate then i would look at his current radiator\ fan setup liek you said.

[68X426]

If the gauge is accurate, and 200 is the worst temp, then no problem if that's the worst it ever gets and then only occasionally. IMO

If you are always in traffic (like a taxi) then 200 is unacceptable.

Consider also the really obvious possibilities not mentioned: is there antifreeze in the rad (don't laugh, people do put in straight water), restricted block and/or radiator passages, restrictions in overflow tube, bad or weak pump, faulty thermostat, dragging brakes, faulty fan drive, erratic sending unit?

The service manual even mentions low engine oil level as a possibility, as well as a collapsed hose (but at high rpm, not low), belt loose or glazed, air leaks, and just plain low coolant level.

If all causes are eliminated, then it's time for better fan(s) or bigger radiator.

Hope you get it solved and stay cool. 

[Sixt8Chrgr]

Thanks guys I will keep you posted.

First thing is to confirm the temperature with a good quality gauge. Then check the coolant vs. water in the radiator.

[suntech]

If all causes are eliminated, then it's time for better fan(s) or bigger radiator.

Does this mean that there is not really been done any upgrading on rad/fan BEFORE he fired up the hemi??

Not bashing here, but with a powerplant like that, i would have made sure  that surrounding hardware was up to par 

[oldkimmer]

...............Check it with an infra red heat thermometer b 4 u do anything..........kim..........

[68X426]

If all causes are eliminated, then it's time for better fan(s) or bigger radiator.

Not bashing here, but with a powerplant like that, i would have made sure  that surrounding hardware was up to par 

You aren't bashing when you allude to the cutting of corners that people do on their vehicles. You are just being wise.    

Some dude might think that a free slant 6 radiator works on every Mopar.

[Sixt8Chrgr]

If all causes are eliminated, then it's time for better fan(s) or bigger radiator.

Does this mean that there is not really been done any upgrading on rad/fan BEFORE he fired up the hemi??

Not bashing here, but with a powerplant like that, i would have made sure  that surrounding hardware was up to par 

New B cool radiator,fan and fan clutch. All those parts are all new. Like I said the entire car is new and all is done right.

[Sixt8Chrgr]

If all causes are eliminated, then it's time for better fan(s) or bigger radiator.

Not bashing here, but with a powerplant like that, i would have made sure  that surrounding hardware was up to par 

You aren't bashing when you allude to the cutting of corners that people do on their vehicles. You are just being wise.    

Some dude might think that a free slant 6 radiator works on every Mopar.

Assume no corners cut here on this car........cause none were trust me. And no slant 6 radiators

[firefighter3931]

What waterpump and waterpump housing are you running on this engine ?   



Ron

[Ghoste]

I'd also dispute worrying about having straight water in the car from a cooling standpoint.  Antifreeze is added to prevent freezing obviously and the additive package in it lubricates pump seals and so forth but water is actually a better conductor of heat than antifreeze.  Running straight water brings in problems as far as rust and scaling in the block (unless you are using a distilled and demineralized water so I'm told) and the issue with the seals and the potential to freeze obviously.  But as far as causing an engine to overheat, straight water isn't going to be a problem.

All that said, you should still be running some antifreeze with the water for the benefits it supplies too.

[Sixt8Chrgr]

I'd also dispute worrying about having straight water in the car from a cooling standpoint.  Antifreeze is added to prevent freezing obviously and the additive package in it lubricates pump seals and so forth but water is actually a better conductor of heat than antifreeze.  Running straight water brings in problems as far as rust and scaling in the block (unless you are using a distilled and demineralized water so I'm told) and the issue with the seals and the potential to freeze obviously.  But as far as causing an engine to overheat, straight water isn't going to be a problem.

All that said, you should still be running some antifreeze with the water for the benefits it supplies too.

Great point, and I agree. We are running 100% distilled water. Probably will not put in any anti-freeze in the motor for awhile.

[68X426]

I have limited knowledge about hydrothermodynamics (cool word). 

But I do know that Prestone reports that antifreeze used in a 70-30 mix raises the boilover point to 276 degrees. I don't believe that this is just hype. 276 is way more than 212. I like my odds better at 276, plus lubrication, anticorrosion, and antifreze values.

I will continue to use antifreeze for its comprehensive heat management properties, especially because I have 22k tied up in just my Hemi motor. So now we are back to suntech's point: a component is not up to par (corner cut by using water, not antifreeze). The value of the motor is well worth $10 from a yellow jug; straight water is just not worth it. 

I submit it's time for a test: the friend's sweet Hemi is hot, so flush the water, fill with 70-30 and then find some real bad traffic on a 95 degree day. Is it cooler?

Hope you can get to the bottom of your heat issue. Dan.

[SeattleCharger]

 

[Ghoste]

Well I have limited to no knowledge of hydrothermodynamics (you're right, it is a cool word  ) but if running straight water is cutting a corner than I have to say that my own real world experience is that my car runs much cooler with that particular corner cutting than any of the antifreeze/water mixes I have ever tried.  And I've tried just about everything from 100% to where I am now.  I do add an additive package to help with pump lube and antiscale but I don't add any antifreeze until the fall.  At that time I typically drain some water and add a 50/50 mix.  Come spring I flush the system and fill it with distilled and the additive.  Right or wrong (and it's probably wrong) it has been working for me.
This year I did use about 25% antifreeze because when I filled it in the spring I didn't have enough distilled water on hand to top the system up.  I'd like to say it's running hotter but the limited amount I've used the car lately has only been under extreme conditions so it falls even further into that "anecdotal evidence" category.

[Rolling_Thunder]

200* is fine for sitting in traffic   

[68X426]

Geography, local conditions, altitude and weather certainly all matter. I think most of all that compnents matter.

Hey Ghoste, since I grew up in Cleveland, that tells me that your location puts you somewhere out on the lake. Now that is an interesting real world experience.

My location dictates antifreeze for heat management. It's an easy 102-104 all summer in Sacramento-Modesto and traffic is murder. No one runs with straight water. (I know, what most people do doesn't prove anything). I can't even imagine life in Arizona and Vegas.

In the meantime, the sweet Hemi should run a test with antifreeze as a fast way to know if that is a contibutor to their hot issue.

For my real world, I have to run Prestone for the real and perceived advantages.

So, can the moderators set up a poll? What do the members run = water, 50-50, 70-30, additives? And, then, based on real world experience, do you think that it matters? 

[yeahitsgotahemi!]

No deep discussion of thermofluids needed here. This little article should answer questions regarding antifreeze.

http://en.wikipedia.org/wiki/Antifreeze

To summarize, the main purpose of antifreeze is to lower the freezing point of water. Coincedentally, it also raises the boiling point, making the coolant more effective by preventing a gaseous phase change (which would significantly reduce the thermal conductivity of the cooling medium). Note however that anti-freeze by itself is NOT an effective cooling agent and is no better than straight water. Indeed, water needs to added. 50/50 is generally the recommended ratio. As previosuly mentioned, other additives are present that help prevent corrosion.

[Ghoste]

There is a shore on the other side of that lake too ya know.  (ever watch the Ghoul?)
I should probably add that in a case like this, what works best is what works best.  Or as a buddy of mine often says, "these cars have a way of telling you what they need" (typically spoken when something that should work doesn't).

[Sixt8Chrgr]

I will check and see, but I do believe he was running coolant prior to the latest flush. However, I dont know what ratio he was using.

I have had no heat issues running 100% distilled water in my 69 Z/28, 68 Charger, or 67 Vette. The climate here in Charlotte may have a lot to do with that as compared to Modesto CA. I have to agree with Ghoste that not running coolant is hardly an example of cutting corners.....just personal preference. But, like I said it is worth checking into to see if the temperature can be reduced some 10*.

68X426 what type of engine temperatures do you experience?

Thanks!

[68X426]

180 nearly all the time, saw a 190 once in real bad traffic in Sacramento at 105 degrees (leaving the Capital City Mopar show). The gauge is new and I assume accurate. Run with 50-50 mix. Maybe I'm just lucky and overly cautious.

[acelondon]

Id say electric water pump and a big electric fan.

Actually, start with the electric fan, Should drop idle temps hugely, because it isn't RPM dependent.

are you running a fan shroud? how much clearance does you fan have from the rad and shroud?

It should be a tight fit in the shroud and also be deep in it. If its hanging out of the shroud, you might need a spacer to get proper air flow.

[Ghoste]

I don't think so (saying that without seeing you drive of course), I think it's a case of what works-works.  I had a 69 Charger years and years ago that ran best when it was hot.  How accurate was the guage, who knows?  But I do know it ran fantastic right at the top of the range.  

[c00nhunterjoe]

i would stay away from electric water pumps on street cars, seen plenty of street cars overheat with them and run fine when goign back to stock style water pumps.