barnett468

ok, if your rad is chinese, the tubes hold at least 25% less water than a US made rad . If you still have the previous rad, you can fill both with water and compare them . Also, count the number of tubes on both.

99.9% of the electric fans out there are total crap and don't flow anywhere near what they claim . Holding your hand behind the fan to see how hard it blows won't tell you anything other than it is flowing in the right direction . Some of the most powerful fans on the planet are the factory Lincoln, Taurus, Contour and big Spal and Derale has some decent ones.

fastbackford351

The Mark VIII fans are incredible.

BKKSW

I ordered and returned 3 aftermarket fans for my 99 Cobra and returned every one of them. Compared to what I was taking off they were very lightweight and the plastic more brittle. I ended up at the junkyard looking at fans that seemed high quality (more weight, more windings and heavier capacitors/switches/plastics) and I brought along my power probe and a 12v battery from my cordless drill.. and tested a bunch. It was educational. BMW's, Volkswagon, and Audi's.. especially off their V8/V10's.. were awesome. One on a GT500 was in the same class but the guy wouldn't sell it. Anyway, there is definitely a difference in fans and in the electronics.

panelguy

We did a good flush and checked temp with a digital temp gun and it's cooling just fine .
Thanks for all your suggestions

Mustangs of Illinois

I have the same problem with the electric fan on my 351W I just put in. Going back the the mechanical flex fan, as I never had a overheating problem with it ! !

BKKSW

Something some don't understand. An electric fan by itself isn't the answer. Not only do they need to pass enough air (CFM cubic feet per minute) when the car is likely to run it's hottest (idling during hot temp days with the A/C on or after making/using a lot of horsepower), but the fans need to cut on/off at the right times.. like before it gets too hot. This means sensors in several places, being tied into the computer so other sensors can be used and systems adjusted, and if you have an electric variable speed water pump that needs to be controlled as well.

So it's not a simple on/off situation. It can be, but usually when the system (cooling) isn't being taxed even close to capacity for the current weather and use conditions. A smart cooling system lets you get away wiht less hardware.. This is why one person with a like system to another can have very different results.

The motto of this verbosity.. is if you're going to use an electric fan try to understand the entire system and get as many components as possible to work together.

jwog666

its really not complicated at all, as long as the radiator, pump, and the rest of the cooling system are in good working order an electric fan will add cooling ability when an engine needs it the most (traffic on a hot day/ low speed) which also is when a belt driven fan is the least efficient. no fancy computers or multiple sensors needed, just a simple kit that utilizes a thermostatic switch>>>>>>>>>http://www.jegs.com/i/JEGS/555/10560...FVc1aQoduAwOeA

BKKSW

Thihs is exactly the sort of thing I was talking about. I suppose it's not complicated if you keep it simple. But simple has it's issues. Complicated has it's issues.

Most don't understand that the gauge really isn't reading a "now" temp. It's reading a temp assigned to a given set of temp parameters. Connect your computer to a OBDII port via a dongle or whatever.. and watch the temp rise/fall in real time. Most are surprised to see the temp rising/falling quickly just sitting there, or rise/fall in reaction to different driving conditions. While I car gauges mostly stay right in the middle, the OBDII temp is changing all the time. Sensors in modern cars, my 99 Cobra included (but not nearly as complex as my BMW) allow the computer to react immediately to a temp not within spec. Virtually all newer cars use such systems because they cool better with less hardware capacity which means lighter weight.

I'll be building my 351w for my 66 soon.. I'm not yet sure how I'll cool it. Much will depend on if I efi or not. And if it's going to be a daily driver.

Just to mention.. on my 99' I improved the cooling system.. high capacity pump, 3 row radiator, etc, etc.. but also a thermostat which opens 10-11 degrees. It was cooling nearly 50% more power with a stock cooling system, but the OBDII port showed it wasn't able to react to changes in higher heat nearly as fast as the stock engine. After I changed everything it really didn't improve much.. but a few weeks later I remembered, probably read something which triggered the memory.. to lower the temp the fan comes on in the ECU.. so now the fan comes on 10-12 degrees before it did before which allows it to cool before the temp climbed.. not after.

jwog666

you are overthinking almost all of your statement......first the OP had an issue with a 1969 so no computers or inaccurate gauges there, just a simple sender that reads the temp from the engine and a belt driven fan with wildly varying efficiency, an electric fan will be far more consistent. next on newer cars (your 99) the temp sender is in the water crossover and reads the exact same info, coolant temp, but it doesnt read it after cooling, it reads it on the way out to the radiator, so yes it will always vary and spike depending on what you are doing while driving. there is no way for a cooling system to prevent these variations, they also are a characteristic and arent an issue at all, its how every water cooled engine has worked since day one. the 10 deg window switch for fan operation does the job perfectly as has been proven by just about everybody who has swapped to an electric fan.

Mustangs of Illinois

I tested my trigger point. And it does kick on at the correct temperature. But the amount of airflow from the electric fan itself is the culprit. It just doesn't flow enough air through the radiator. Before with my other flex fan, I never had a over heating problem at all.