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Discussion Starter · #1 ·
I've been curious about one thing on these cars that I haven't noticed being mentioned. Does anyone have (engine) cooling system troubles after making the HX huge and overdriving the SC? It would logically add tremendous heat load to the radiator to cover the whole thing with a hot-assed HX and dump all those extra BTUs into the radiator's air stream. But I don't see any mention of overheating...
Are there overheating issues? Are there overheating 'fixes'? Four-core custom radiators? aux water pumps? extra-duty fans?
OR
is the cooling system robust enough to handle these extra demands without upgrading?
 

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I think the engine cooling system is robust enough. Here in southeast NM, June through August is well over 100f and I've never had an issue running the WeaponX in front of the radiator.
 

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Discussion Starter · #3 ·
a related anecdotal follow-on note. Ages ago (1977) my cousin bought a brand new Olds Cutlass Supreme, 350 Rocket V8 (yes, the real rocket and this was his fourth new cutlass through the years) and, as all of were motorheads/hotrodders etc, we immediately installed two mechanical Stewart-Warner gauges, because...idiot lights. Oil Pressure and water temp, of course. We all proceeded to freak out because the damn thing was running 210_218* all the time. Tested the gauge in boiling water, it's correct. BRAND NEW CAR! Dealer said not a problem, within spec. We called BS and changed the t-stat to 180 and then 160... and the car cooled down. Cousin was happy, all was right with the world... but.
It was quickly apparent that this new car which had amazed us all with 18~21 MPG right outta the box (from a huge cutlass 350(!) suddenly dropped to 12~14 MPG with no other changes. It takes a while for a shop full of gearheads to admit they are wrong. We all respect real data, though, and replaced the t-stat with the spec'ed 210* and the MPG came right back. Emissions demands what they were at the time, the mfr's had retarded the cams, leaned out the carbs and cranked up the heat. Power was down, but MPGs were better. Fast forward to these modern times: computers/efi/ totally different emissions demands and design goals and better tools to work with. Does dropping tho a 160 t-stat noticeably kill mileage, now?
 

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I run the stock tstat. Sure the 160 stat opens sooner but it doesn't change the systems ability to cool the engine.
 
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Discussion Starter · #5 ·
As relates to the lengthy anecdotal post above: I'm wondering if running these engines at lower temps hurts the (already atrocious) MPG even more.
 

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If you were to log a stock tstat against a 160 stat, you'll most likely see that it takes 5 minutes longer to get to full operating temp with the 160 so I doubt that there's any difference in mpg.

Gotta remember that these cars are for spg, not mpg.
 

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Discussion Starter · #7 ·
Are you saying that he ultimate operating temp is the same with either stat?

Yes I very well understand the SPG (or SPM)
But the question about temp and efficiency is merely a matter of curiosity.
 

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Some guys went with the CSF or weaponx radiator, but these setups comes with a few caveats. The upgraded radiators are double wide, so some cold air intakes will have an interference issue. They also make changing a lower pulley a juggling act and PITA.

Most of them were originally replaced because the stocker was leaking. I’ve had a CSF in the car for 6 years and have had zero issues.







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Discussion Starter · #10 ·
Most of them were originally replaced because the stocker was leaking.
Very interesting. I wonder if there have been people upgrading because the stocker couldn’t keep up btu-wise.
It seems that the stock unit must be pretty capable just based on how little mention of engine cooling I’ve found around the forum and the web at large.


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I highly doubt any of the coolant going through the heat exchanger ever reaches the temp of the coolant in the radiator, so I'd guess that's why no one has issues. The airflow across the radiator difference is probably minimal compared to stock hx, especially since the radiator was designed with 5 other coolers in front of it to begin with.
 

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With a C&R HX, BMR reservoir and a 160 degree thermostat my car has never ran hot even, during the most brutal Houston summers in stop and go traffic. You can tune the car the so fans come on sooner but the lowest temperature setting (which I can't recall) that you can program them for is still higher than 160.

Now a long time ago when I had an 87 Buick Grand National I did experience cooling after after I added a humongous aftermarket intercooler that sat in front of the radiator. But on the V even with all the coolers it has in front of the radiator the car stays cool.

Btw, make sure both of your fans are operating. If one goes out your hot rod caddy will overheat, especially in stop and go summer traffic. Ask me how I know.
 

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I run the stock tstat. Sure the 160 stat opens sooner but it doesn't change the systems ability to cool the engine.
This!
 

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Engine coolant not an issue, IAT2 is the issue when upgrading


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