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Discussion Starter #1
OK guys,

So I had my car for 8 years now (396ci), and it just seems to run hotter and hotter with the years. I used to always be able to keep under 190F in city driving and now it will just creep up and up and won't seem to ever be able to get down just with the fan, unless I get on the highway for some time and get some real airflow.

I had a pretty good Flex-A-Lite electric fan that was about 16in but the shroud was a 16in square too and so both sides of the radiator (50%) were not covered and had no airflow at idle. I recently decided to build a custom shroud and get dual fans from Amazon to help a bit. I also switched from a 180 thermostat to a 160. I have a copper radiator, 3 core. It has some scale build-up inside, nothing serious, I don't think it's clogged. I did put some Prestone radiator flush in it yesterday, I'll leave it in for 3 days and we'll see how it cleans up. Here's the new setup.






Those fans were supposed to be 13in 2000cfm, ended being a lot closer to 12in. I just ordered 15in 2500cfm to fit instead and I will try to cut some rubber flaps to aid airflow in closed shroud area when driving. The shroud is 2in thick and sealed all around. I have a thermostatic switch for the fan (180 On, 165 Off), it's located in the intake before the thermostat. Temp sending unit is there too and reads OK, I check it with infrared thermometer.

Went for a ride last evening to try it all out, it wasn't especially hot, about 24 Celsius. Well it didn't make a difference, and to be honest it might have been even worst. Would creep to 190, 200, 210 in mild city driving, didn't get stuck in traffic. It would not come down be itself. I would see a small decrease when going from a green light with airflow but it was pretty clear the temp was going up and not down.

I don't have my timing and jetting specs, I don't know if it could make a difference, but the car's been tuned this way for the last few years. Water pump is a no-name long model. I wonder if it could be the issue. I do not have the budget now for a aluminium radiator CAD to USD exchange is a real pain right now and I can't imagine spending 500$ on a rad.



Apart from waiting to get those 15in fans and see if it makes a difference, I'm thinking maybe getting a high-flow aluminum water pump. What else could I check next?
 

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Looks like your missing a water pump bolt. I think your going to be disappointed in your fan housing because in itself its cutting down on air flow.
 

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David see my Sticky at the top of this Forum
https://www.chevelles.com/forums/32-heating-cooling/968721-9-rules-improving-engine-cooling-system-capability-hi-perf-auto.html

Rule # 2 & 7 Efans work best on Alum 2 Row 1.25" Wide Tubes Core Rads
................... so your 3 Row Core Rad will be a Reduction in Air Flow for cheap Efans

Rule # 8 Flow Rate of Coolant

Rule # 9 Coolant mix % of Water / Antifreeze - you want just enough Antifreeze to Lube the water Pump only
as the more Water the better for Heat reduction

Some things I see from your Pics
1. Low Profile Efans are not the Best
2. Make of Efans - Cheap Efans are just that, not enough CFM to do a good job,
I have SPAL 11" Dual Efans on my Small 23.5" Wide X 16" Hi Alum 2 Row 1.25" Wide Tubes Core Rad
3. Size of your rad Core ?
as you could have bought a Unit with Good Efans/Shroud with Rubber Flaps from SPAL or Flex A Lite
4. I agree with Eric that a 2" Thick Shroud is not good
for allowing Air Flow going thru the Rad to Flow into the Engine Bay without Restriction
since it seems that you have room/space for a Thicker one
5. and yes Hwy Rubber Flaps are Good to have

I have a 160* Thermostat in my Housing and have no problems on the Hwy with one or none Efan on
or in the City with both Efans on

Anything in Front of the Rad Core that is also Restricting Air Flow ?? Pic please

Pics of my Small 23.5" Wide X 16" Hi Core Rad and Setup





SPAL Dual 11" Efans/Shroud Unit / you could like fit a Dual 12" or 13" on your Rad


I do not have as much Room/Space between my Engine and Rad as you do


 

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Discussion Starter #4
When you say 2in thick is bad, you mean I should have gone thicker?

No obstruction in front of the radiator apartt from hood lock and some bumper. No cooler. I have holes in the bumper.

Is there a way you could tell the water pump flows enough. I was looking at some aluminium high flow, nut sure if it would make a difference. I would like to get a smaller pulley but they all seem to be the same 6.xx in.
 

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When you say 2in thick is bad, you mean I should have gone thicker?

No obstruction in front of the radiator apartt from hood lock and some bumper. No cooler. I have holes in the bumper.

Is there a way you could tell the water pump flows enough. I was looking at some aluminium high flow, nut sure if it would make a difference. I would like to get a smaller pulley but they all seem to be the same 6.xx in.
Yes as some Efans/Shroud are 4" Thick
which would allow the Air Flowing thru the Rad Core some place to go before the Efans Pull it into the Engine Bay

Do you have a Short or Long Water Pump on your 396 ?



Here is what I have on my BBC
Weiand Alum Short-Action+ http://www.jegs.com/i/Weiand/925/9212/10002/-1

What do you mean by a Smaller Pulley ?? Longer or Smaller in Diameter

The 4th Pic above in my Post Shows my Short Water Pump & Main Pulley
 

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The clue is on the sticker on the fans 12 V and 80 W or 80 watts. That is like 7 amps which is not enough power for the fans. So for both fans you have 160 watts or 14 amps total. You need to be twice that. The fans that Kurt runs above there are 30 amps for the two so say 350 watts. Do not go by CFM go by watts as that is what pulls it through the radiator. You 80 watt fans say 2000 cfm but at end of day through radiator its like to pull 600-800 cfm with that watt rating. Think of it like a big block and torque (watts) you can put a bunch of 200 pound guys (radiator resistance) in the car and it will still run good.
 

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Discussion Starter #7 (Edited)
I have a long water pump. About pulleys, I mean smaller diameter so the pump would turn faster. I remember talking about this in another thread, but when I replace the gasket on my water pump last year I realized that a big block pump gasket would not fit, I ended up getting a small block gasket, which is smaller and it fitted perfectly. Could this mean I have a small impeller than some other water pump?
 

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So you do not know what kind of a water Pump you have now

I do not think you need the different Sized Pulley

Buy a new Water Pump with the correct Gasket

https://www.jegs.com/i/Weiand/925/9243/10002/-1

Just check to make sure the Bolt Holes look like they match the one on your Engine now
 

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How did you come to the conclusion that the mechanical fan was your problem? Reduced cooling over time is not a result of the mechanical fan. Did you have a clutch on it go bonkers?
 

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Discussion Starter #10
Never had a mechanical fan, bought it with a 15-16in Flex-A-Lite that came with his own molded shroud. Problem was it was a square shroud so 50% of my rectangle radiator was not covered by it so was not cooled when the car was not moving.
 

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my bad on missing it was electric.

the fan either worked (turned on and ran when it was supposed to) or it didn't. it and the poor fitting shroud are not the reason for your temps creeping up and up over the years. your new fans and shroud are bound to improve things, but are only compensating for another issue you have.

you could have saved a bunch of money by skipping the new fans with shroud and just addressed the issue with your radiator or h20 pump. this would have put you back to the cooling you had 9 years ago, which must have been fine, for much less cost.

good luck.
 

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David what is the size of your Rad Core Width x Height ?

Does the Efans/Shroud you have now cover all of it ??

Having the Rubber Flaps is good for Cooling on the Hwy

Looking at your Post # 1 Pics again the Rad like needs a good Clean out
maybe even the Engine
 

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Discussion Starter #13
The core is 28x16. The shroud cover 100% of it. I did a clean up with radiator flush, 2 bottles, it did help a bit with the calcium but did not take it all off. Will end up getting bigger fan from the same company, these will be rated 120w instead of the smaller 80w in my pictures. I've test fitted the size for the 120w fans and is it the biggest I can fit on the shroud.
 

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If the 120 watt fans do not work then go to Durale fans website look at Shrouded Power Packs (nice all-in-one kit) they got lots of fan/shroud options. Their fans run from 200-300 watts each. If you do go this route make sure you got a good high output alternator.
 

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Hi
Unknown condition of rad core ,,probably partially blocked
Cooling system cleaners often clean the scale off every part and send it to rad core . Then it partially blocks cooling tubes .

*******HAVE THE RADIATOR RODDED OUT ******************
remove thermostat and reverse flush block

Factory 3-4 1/2" copper cores NEVER cool as well as an aluminium rad of 2x 1.25 cores

Look into SPAL HP range
2500cfm or less is borderline
13amps absolute minimum
ALWAYS ALWAYS compare blade sizes some makers use housing size

verify quality of water pump
verify pulley sizes
 

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I would send all those fans you bought back and put the biggest baddest Spals in place. By the amperage draw alone, you can tell those fans won't move much once placed against the resistance of the radiator. The CFM quoted is surely a no load cfm and you are asking too much from them with your old school 3-4 core rad.

Rodding out the rad or replacing with a newer large tube aluminum radiator will probably solve your issue. If you want to run electric fans, large tube aluminum radiators are the way to go because the have less air flow resistance.

If you need a water pump. Flow Cooler is one of the best for the price.
 

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Discussion Starter #18
Man is my head spinning with fans. I was looking at Flex-a-lite Flex wave series. The 14in is a bit to big to fit duals on my 28x16 core. The 13in Spal 30102044 would fit like a glove but two of these would pull 39 amps....I don’t know if my CS130 105amp alternator is going to survive. The 12in Flex-a-lite Flex Wave pulls 8 amp and in a dual setup would pull around 2700 cfm.
 

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Forget the flexalite 12 that pulls 8 amps each you need something twice that. The spal dual 11 and dual 12 are nice you may have to do some fabricating. Or look at the durale dual 12s they have a nice kit. You need at least 28-30 amps total to start.
 
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