I currently have a '75 with the original 350 SB in it. It had some modifications done in the late 80's but it appears to still have the stock radiator and fan. It runs pretty hot especially at high speeds, even when it's cool outside.

I know I want to switch to an electric fan, but haven't decided which type yet (either dual fans or the Lincoln Mark VIII). Used electric fans make me nervous from my experience with smaller DC fans. The Lincoln fan seems like a lot of work because you have to find a suitable controller/wiring and then figure out mounting. So I'll probably just get the new dual fan kit... We'll see.

Anyway, what I need advice on is the actual radiator. I want to upgrade it to an aluminum radiator. I was hoping to get some good suggestions on good ones... Been looking at the Be Cool, but is it really that much better than some of the cheaper aluminum radiators?

Also, my vette is an automatic. Would adding a transmission cooler be worth while (they're not that expensive)? With a transmissions cooler, could I get the manual trans radiator and use just a good external transmission oil cooler? I've been reading that people use internal transmission coolers in series with an external. Any opinions on internal, external, or dual transmission coolers as well?

 

I would stay with a clutch fan setup.
Just look on ebay and fins an aluminum 4 core for about $244.
Don't buy a $500, your just wasting money for the name.

 

You say it gets hot at high speeds...do you have a front spoiler? The front spoiler forces air up through the radiator as you are driving so if you don't have one that could be causing the higher temps when driving at higher speeds.

 

I'm going to get the 3 piece pace car front spoiler. Currently have the stock black plastic spoiler.

 

Go with a Dewitt radiator, and they have electric fan set ups too. It's worth the extra money to go with quality like theirs.

 

If that's the original radiator from 75' can almost guarantee it's mostly plugged, hardly transfering any heat at all. If your mods are mostly resonable, then agree staying with the stock set up and clutch fan. Of course with a new stock rad or re-core, keeping the tranny cooler set up. An external tranny cooler really isn't needed, unless running a high stall torque converter with lots of slippage.

 

I personally would fix the overheating problem before purchasing any upgrades. For sure, something is amiss with your cooling system as there's nothing wrong with that of the factory.

 

When I restored my '69 I had the original rad. cleaned and checked for leaks... no problems.
I installed a Spal dual fan set-up with their controller and use it at the factory settings and it has never ran hotter than 180 degrees even in mid-summer in bumper to bumper traffic.(Woodward Dream Cruise)
No additional air dams or scoops other than what it had when it came with from the factory.
180 degree standard part store t-stat with a 1/8th hole drilled as a slight bypass for some flow till the stat opens.
Block is bored .030 however I have a T-5 5 speed but I doubt if I had a auto. it would run any hotter.
These cars did not run hot from the factory and I feel if you use OE and all is in good working order you should have no problems.
I went with an electric fan only cause the car did not have a shroud when I bought it and I like to play with the eng. running and not have to worry about being bittin by a spinning fan.
Good luck with whatever you decide is best for you.

 

I know that this car has always had cooling issues in the past... I took a look at that front of the radiator and it's pretty clogged with debris. Will clean it out tonight and hopefully that gets the temp down if it gets hot here again. It's been great temp around here for the convertible.

Anyway, I really appreciate the suggestions. I think I've decided to go with a integrated transmission cooler. Should be sufficient for my use of the car. I looked into Dewitt radiators. They look good... Are they the same ones that Eckler's carries? They have the same price and specs, so it seems like they might be.

Hearing that cooling was that good without a front spoiler is reassuring. But I like the look of the pace car spoiler and being even cooler couldn't hurt...

 

I just found a 4 core aluminum radiator on ebay for a REALLY good price. It has plastic tanks on the side. Talking with a friend of mine he says most new radiators are like that...

Is it OK to change the type of coolant used?

 

A number of comments:

I have owned my 78 L-82 4 Speed since 1983 and can tell you by my experience that the 78 L-82's and the 79 L-82's for certain ran VERY hot from the factory with a perfectly functioning cooling system so much so that the 12 O'Clock position of the temp gauge was changed by GM from 78 to 79 model years from 200 degrees at that position to 220 degrees due to customer compliants about the cars running hot. These cars routinely ran at 225 degrees and higher.

My 78 also would get hotter on the highway like yours. I believe that primary culprit on the smog cars is the 882 smog heads that makes them run so hot on the L-82's, not sure on the L-48 cars. Over the years, I made sure the timing was perfect, replaced the 4 core OEM copper radiator with another 4 core copper radiator, replaced the OEM water pump with another OEM water pump, and added the rubber spoiler extension from the 79's with heavy duty cooling to my 78-ALL to NO AVAIL! I also replaced the factory fan clutch with a GM factory L-82 fan clutch-no Change! Note-that the L-48 fan clutch is thermostatically controlled to fully engage the mechanical fan at 180 degrees versus the L-82's clutch which engages at 195 degrees. I still have the 195 degree clutch and it works perfectly. I have run a 160, 180 and 195 Robertshaw thermostats-no go!

Solution: About 3 years ago I again replaced the radiator with a Dewitts aluminum one and also replaced the OEM type water pump with a Stewart stage 2 aluminum water pump (expensive) and a modified 180 Robertshaw thermostat that MUST be used with the Stewart pump. The engine now borderline runs too cool! Around town on a 90 degree day about 160 degrees and on the highway NEVER more than 180. My L-82 has never run those temperatures in 28 years I have owned the car.

If the car is unmodified, I would suggest a new 4 core brass/copper radiator running a 180 thermostat and a Stewart stage 2 water pump OR a Dewitts aluminum radiator with an OEM water pump but I don't think you need both. I would also go for a 180 degree thermostatic clutch if you do not have one now.

As for the tranny cooler: Definitely remove the tranny lines from the radiator and buy a Double stack cooler (the biggest GVW rating you can fit in the grille), not a tube and fin cooler which are NOT nearly as efficient. I have been running coolers outside of the radiator on many of my automatic cars since 1978 and have never had a tranny failure: 73 Nova SS, currently 94 Mustang GT and a 2001 Pontiac Grand Prix! The mechanical fan in the C3 is ideal for this setup since air is always being pulled through the cooler! The tranny fluid gets VERY hot running on the highway and will heat the radiator coolant unnecessarily. The 94 mustang GT used to run hot with the trans lines in the radiator and now it NEVER does with the Long Double Stack 28,000 GVW cooler outside of the radiator.

Hope that helps!

 

jb78L-82 - I own a 78 L-82 with a 4 speed as well. I've owned mine since 97. It has always run hot just as you state. My car is a 43,000 survivor. I am going to follow your recommendations. Thank you!!

 

12+ years ago I had my stock '76 sbc radiator repaired due to a leak. The rad shop told me they could install a 4? tube core from a big block vs the 3 tube stock core.

I took them up on their offer. I also installed a Permacool 16" electric fan and a 180* thermostat.

With this set up on my stroker, I have never had a cooling problem. Temperature gauge does not go over 200* even when sitting and idleing. All rad seals, must be in place and the front under bumper spoiler must be installed and intact.

When and if I never need a new rad, it will be a Dewitts.

 

This is one of the least expensive and first things I would make sure is correct. These Vettes are bottom suckers having to pull the cooling air up into the radiator unlike most vehicles where the air rams right into it. The front lower spoiler helps the air up and creates a low pressure area behind it pulling air through. The shroud, hood and core support seals will make sure the air goes through the radiator and not around it. It may be all you need.

I made a few mods to my motor and needed more radiator. I bought an aluminum Champion off ebay and I am very pleased. The price was great. Fitting it in was not exact but the modifications to get it in were not too bad. There are a lot of threads on fitting these in.

-Rick

 

X 2 on the radiator seals.

specifically, top, bottom, sides between the radiator and the radiator support. also, between the top of the radiator support and the hood. very important.


i have dual electric fans, flexalite 490. lesson learned: i wired each of the fan motors up to individual relays & individual 20A circuit breakers, but shared water temp switch. previously, i had a flexalite 412 (dual fans) on a single 30A ckt bkr. one of the earlier fan motors started going bad, sucked more current, tripped the ckt bkr and shut off both fans, motor got hot.

running electric fans did require upgrading the alternator.