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*electric radiator fans

13K views 74 replies 20 participants last post by  sdcfish 
#1 ·
I'm going to install an 18" electric fan on my 55 (350). I'm not running a pulley driven fan blade. I've got the aluminum radiator located in front of the radiator support. Does anyone have a preference. Sucking -blowing-shroud or no shroud? Thanks
 
#40 ·
This is bullshit. New water pump, new thermostat and same shit! No change and the car is still overheating 240! I'm gonna take it for a pressurized flush and see if something gives. I had flushed it forwards and backwards with my garden hose under pressure and seemed fine.

If you've been following, I have replaced new radiator, water pump, hoses, fan, shroud.....someone please tell me what the heck this could be?

Regular rotation etc.....

And the car doesn't heat up right away either. Seemed like for 10 minutes, 3 miles all was so-so but she slowly creeps up and then there's no getting her back down. Fan is working the right direction. I'm freaking missing something!
 
#41 ·
I check your thread now and then to see what progress you have made. Hoping to see something positive.

It is time to make absolutely certain your timing curve is set correctly and the timing is set spot on. Spot on is as far advanced as it likes without detonation and starting grunts when heat saturated.

And make sure the engine is not running lean.

Maybe these two settings were OK before, but maybe they have been overlooked with all the focus on fans, radiators, pumps and water flow.

I would check/recheck/set them.

Don
 
#42 ·
if your going to 240 degrees and your not spilling water you might have a bad sending unit giving the wrong temp and i would check where the temp sending unit is mounted and one last thing with the radiator cap off with the engine running see if you have bubbles in the water you possible could have exhaust gas leaking into the water passages if so you will never get the temp down.
 
#45 ·
So, I went to the local Goodyear tire shop today to get a radiator flush. Some of my Hot Rod pals felt I could have some clogged water jackets near the heads.

$105 Quote to run the flush.

Spoke to the technician before he performed the flush and he wasn't agreeing with the flush. After I told him I had just replaced the water pump yesterday, he felt I hadn't burped the system well enough and had some air in there.....so we agreed before the flush he would just burp the system.

He mentioned that the machine that performs the flush runs at about 40 psi, but doesn't back flush.....just one direction. Also he mentioned that the water jacket ports in the heads are probably too large to clog, and most likely not the case....so the flush wouldn't solve any problems.

Ran the burping procedure by connecting a funnel to the top of the radiator, adding some fluid to the funnel, and allowing the engine to warm up.....

Well....that didn't work, and temp started to climb again as before.

This tech is an offroad car guy....has a lot of engine experience. He finally started to feel like my fan isn't strong enough to pull the heat from the radiator. He did ask me to my surprise, if the fan was rated for that size radiator, and I had never considered that. I just doubled the CFM volume from what was running on there previously, so went from a 1250 CFM fan 13", to a 14" 2250 CFM fan, along with the shroud, I figured that was more than enough of an improvement.

So.....now I am left with sending a message to Champion Radiator and asking them what CFM fan is rated for my new radiator. The tech did how me his personal fan he had off his engine, and he had paid $200 each for his, versus the $73.00 I paid for mine. I have to look again, but I am pretty sure I saw some 14" fans for double the price I paid for mine, in the 3000 CFM range.....off to the internet I go....send a few emails, and look up some other fan options.

Thanks everyone......can't believe this has been such a struggle.

Eric
 
#47 ·
That should be plenty of CFM, so I'm not buying the fan issue. I have a 16" electric that's pulls a little less and my car runs 180 all day long. I just recently added a 2 row griffin aluminum radiator also. Something is amiss for sure and I wish you luck in finding the problem. Sometimes it's just the simplest of things, so you may want to go back and start from scratch and re-evaluate each area of your cooling system.
 
#50 · (Edited)
After the system is full & hot put a condom over the rad fill neck if it blows up like a balloon you have a head gasket issue or a cracked head.

Edit: Plug the overflow for the above test

Check engine oil there may be water in the oil = head or head gasket issue, possible block issue.

Intake manifold been off lately? If you used later year intake gaskets they may be installed improperly front to rear.

Your heater core probably has the same scale in it that the radiator had. Flush it both ways with a garden hose.

Install a couple of cans of radiator flush & drive a week or so with it in the system then flush everything.

Put a flush tee in a heater hose, remove the block drain plugs & flush.

Car should run @ normal temp on the highway without a fan.

I'm not buying the fan size as it relates to radiator size opinion.


Good luck.
 
#53 ·
After the system is full & hot put a condom over the rad fill neck if it blows up like a balloon you have a head gasket issue or a cracked head.

Edit: Plug the overflow for the above test

Check engine oil there may be water in the oil = head or head gasket issue, possible block issue.

Intake manifold been off lately? If you used later year intake gaskets they may be installed improperly front to rear.

Your heater core probably has the same scale in it that the radiator had. Flush it both ways with a garden hose.

Your so darn smart, i woulda never thought of a condom, mmm, wished i used one once in a while in the past come to think on it. I have one of those mac screamers that smells the water for oil, if i can find it, jus like always. Thanks for the tip, jus dont want to have to splain what im doing with condoms to swmbo, mmm, leavem in the tool box me thinks :shakehands:
 
#51 · (Edited)
Well after soaking in vinegar and water overnight, I lifted the radiator cap and found a bunch of rust debris stuck to the underside of the cap....this is telling me that the vinegar is breaking down a ton of old crud left over from the previous rusted radiator......

Let's remember that this is a new radiator, and pump, and I did flush the system prior to removing the old radiator.

Im going to flush this vinegar and water, fill with water and drive over to get a pressurized back flush using a flushing chemical product and see if I can break loose any other sediment.....

See photo
 

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#54 ·
So freaking weird. Engine continues to run normal for 10-15 minutes.....4-5 miles driving down the boulevard and all seems to be holding at 200, and then all of a sudden, just when you think things are looking up, you see the temp start creeping.....creeping.....holding....creeping....creeping.....DAMN IT!

So.....Im soaking more Radiator flush in there with still some residual vinegar....

Spoke to the tech at the Valvoline center near me and he's got a pressurized flushing system and we went over, and I like the machine. It can, while under pressure, flush the system forwards, or backwards, and vacuums out all the fluids to new ones.

Gonna give that a try.
 
#57 ·
Well.....

Confirmed that my electric fan was no longer alive....going for a return. No idea how or what caused that sudden issue.

I replaced the electric fan with a bolt on blade fan....feels like it pulls more air than the electric...even at idle. No shroud for this at this time, so hoping it does the job.

Went for a pressure flush on the radiator and engine, as I didn't want to leave the CLR in the engine too long.

Maybe the shroud is gonna have to come next, or get the fan blades closer to the radiator....flush mount to the pulley leaves about 6 - 8 inches of gap between the fan and the radiator......and bottom line....left the thermastat off when taking the car to the flush, and ran it with this setup to see if it helped.....

Same old shit. Engine ran nice and cool for 10 minutes or so....under 160. Came up to 180, 190, 200......then I was hoping it would hold.....3 minutes....5 minutes....then boom....205, 210, 220......same old shit. Why does it run well for so long, and then just suddenly start to lose it and go off a cliff, climbing way too warm?

Im just stumped. Would a thermastat help keep the engine cool? Slow down the water flow so it can have more contact time in the radiator to cool?

Coolant looses its ability to absorb heat, and then just climbs quickly after it reaches a certain heat point and time?

I can go for the pressure test to see if I have a blown head gasket, but I have no water in my oil, no smoke, and a strong ass engine.....so hardly likely I have a blown head gasket.

What else could be causing this?

I did change the fuel filter, and all hoses...making sure I had no leaks whatsoever in the fuel lines.

Thanks for the continued ideas, and help.....Im really hoping this doesnt end up to a full tear down.

Eric
 
#61 ·
Im just stumped. Would a thermastat help keep the engine cool? Slow down the water flow so it can have more contact time in the radiator to cool?

Coolant looses its ability to absorb heat, and then just climbs quickly after it reaches a certain heat point and time?
Eric
Neither one of those is your problem. We have had this debate many times and you can not get more cooling by slowing the coolant down. If it is slow in the radiator to cool, it is also slow in the engine to get even hotter. I occasionally, have to design or size a heat exchanger at work and more flow = more heat transfer. Dirty fluid can lose a little of it's heat transfer ability, but yours must be clean with all of the flushes.

My bet is on an exhaust leak into the coolant that is a small leak that is sealed when cool but as engine warms and expands, the crack opens up. Do the cheap condom test. This is an interesting, but frustrating I'm sure, problem.
 
#58 ·
Carbed engine with dual exhaust?
If no H or X exhaust pipes:
Run the engine @ fast idle & check the exhaust pressure @ the tailpipes. If one side is weak there is a restriction in the weak side which causes exhaust to transfer to the other side via the intake manifold = Engine heat.

Or drop the exhaust head pipes & test with an open exhaust.

If it still heats up with open exhaust pull the heads & have them checked for cracks + have them surfaced (milled)

You have eliminated the cooling system as the problem area there is a different problem.

Good luck
 
#64 ·
At high idle when the engine was cold, choke on, I did notice a slight difference on the left pipe being a bit less pressure...but not more than 15% difference. I did not rev, or wait for the engine to warm up.

Now that Im thinking about it, I have noticed one time, that some water came spit out of the left tail pipe when I started it up a few days ago....I noticed it and just discounted it to condensation, but now that we are talking about a crack or gasket leak, it would make sense that it's on the left side where the water came out, and shows very slight less pressure. Crack in the block/head or just a gasket? That's a big question, but sure as shit, stop leak was put in there at some point to seal that problem. They just fogot to drain the stop leak at some point when they should have. Will be interesting to figure out when I finally do.
 
#69 ·
Had some more time to work on Bella.....checked the timing, and it was about 8. Moved it to 10. Changed the radiator cap that had a small leak, added a new radiator overflow tube...the old one had melted a bit and was pinched. Added a 3" spacer to the water pump pulley to bring the fan 3" closer to the radiator, and that greatly increased the flow, and got some paper sticking to the frontside of the radiator. Took the car for a drive on the freeway this time, and it was a cool 65 degrees outside....nice late afternoon for a cruise. No thermastat and car ran super cool on the freeway....8 miles North, up a nice 2 mile grade, and never got over 160. Got off the freeway, turned around, came home 8 miles and exited at 160 as well. Hmmm.....well that is sweet. Maybe the head gasket isn't cracked after all? Maybe the temp just never got hot enough to open the crack and start letting exhaust into the cooling system? Came to the exit on the freeway and caught the red light....well that was good I though and could test some idle time after having driven 16 miles and all was good. Yup....after about a minute and a half, she started to climb. But only to 170. Then I putted home 1/4 a mile, and by the time I backed her in, she was 175. So definitely going up at slow speed. I didn't wait to see if she would continue to climb as before, and just quit while I was ahead. From what I have read, I can almost be sure that I just need more air coming through the radiator. So if this is the case, I will build a fan shroud this weekend, and can also add two smaller pusher fans to the front of the radiator for extra support. I actually don't mind leaving the thermastat out....Sunny California/Los Angeles, Im not worried too much about the cold weather coming
 
#72 ·
Added a fan shroud today and tested it in about 90 degree temp. Held at 170 on the freeway, and 200 on the streets.....back on the freeway and it came back down to 170. I think I am going in the right direction, but not saying "fixed" until I drive it some more......but feeling better about it for sure!

Had fun making the fan shroud from a piece of flat aluminum bought at Home Depot......$21 and about 2 hours of sketching/tin snipping, and she's in and looking good.

Thanks everyone....keep ya'll posted if things change. I sure am feeling better that I don't have to rip the thing apart.....yet!

E
 
#73 ·
Blown Head Gasket

After testing and testing, the car was still over-heating in traffic. I broke down and did the compustion leak detection test for $49.99 at Pep Boys, and within a half a second, the dark blue liquid turned yellow. FAIL! That means the head gasket is blown somewhere......

So there ya go.....had a blown head gasket the whole time. Time to tear it down and see what the heck happened.....this is a relatively new build by my cousin's builder......I'll know more when I pull the heads Im sure.

Just hoping that this isn't a cracked head, or block!
 
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