cooling problems

67coupe351w

New Member
Jan 31, 2004
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Portland, OR
Alright so I have a 351w in my 67 mustang. I just installed a Mildon Aluminum High Flow Water Pump, a Summit brand 2 core aluminum radiator (cross flow, 19" tall, 30" wide) and a summit brand "high flow" 160 degree thermostat.

With the engine idling in my garage on a 74 degree day and both electric fans running full blast the best it can do is hold the coolant to 230 degrees. What gives? Something is totally wrong here.

The engine is a 351w, 9:1 compression, windsor Sr. heads, performer RPM intake. Timing is set to about 13 degrees initial and I have a pertronix Ignitor II for ignition.

The engine wouldnt cool with the old brass 3 core radiator and stock pump either so I figured this upgrade would set me straight. Guess not.

Any help would be GREATLY apperciated.
 
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here's a pic if that helps...

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You need a shroud. At the very least a single large fan that moves a lot of cfm. The ford torus fan is a good and cheap one.

this would help a ton. That being said my 351w doese not have a highflow pump but a oem piece and i have a 3 core aluminum rad and a black magic electric fan. If you override the electric fan while the car idles it will stay at 180 degrees forever. I was wondering if your moroso water pump maybe a reverse flow pump and you are spinning it the wrong way.
 
you need minimally 3000 cfm on a 3 core radiator those 8 iners are not enough to pull the air flow you need. I agree with 86 bluecobra check the rotation of the pump too. my 68 has the stock radiator and with a/c blowing and in stopp and go traffic, or parker and idling it never gets 2 needles abof C. IT barly reaches 1/4 of temp sweep.
 
You need more fan or a shroud. You have at least 50% of you radiator that is not flowing air in an idle condition. Install a shroud with a large single fan, stop all air leaks to force all air through the radiator and you should be good.

Nice setup on the radiator by the way.
 
Those two fans aren't NEARLY enough. I've got twin 10 inchers on the radiator in my V8 Ranger with a mild 5.0 and it'll heat up to 235 sitting and idling with a 160* T-Stat. Only other thing to check is the head gaskets to make sure they're not backwards. At the front, there should be a portion of the lower corner sticking out from the head if they're on correctly.
 
You need more fan or a shroud. You have at least 50% of you radiator that is not flowing air in an idle condition. Install a shroud with a large single fan, stop all air leaks to force all air through the radiator and you should be good.

Nice setup on the radiator by the way.

I verified the Waterpump is correct flow direction, It is for a 70 to 78 351w which is the range my block is from. It also externally looked identical to the stock pump. Good idea to check though.

I went out and bit the bullet and got a shrouded electric fan that is supposed to move 3300 CFM.

I looked into the cfm ratings on my other fans and they are only about 800 CFM'ers each. I originally used those fans on the brass radiator because of space but I took some measurements and I think this huge (and expensive) new fan may work. I'll let you all know how it goes. Thanks for the input!
 
I bet it will work fine now. my fan is 2500 cfm i think. I wouldn't mind bumping up to a 3300 cfm fan. Which one did you get?

I got the Flex-a-lite #180...it was $309..ouch...at least it comes with the thermostat control and a sticker. :p

I started with the install and it is going to involve surgury on the radiator support...I just dont have enough room between the radiator and water pump pulley. I've began trimming the radiator support and modifying the mounting brackets I had fabed up. The radiator support trimmed quick and easy but my frame notches are a job better left for tommorow (don't worry I have MII).

I had 3.5 inches between the rad and pully, the fan unit takes somewhere between 4 and 4.5 inches. I'm shooting for as much clearance as I can get but I think im only gonna end up with about 3/8ths of an inch between the fan and the waterpump pully....
 
I had the same problem until I realized I needed a relay to ensure my electic fan was getting the true 12 volts. Try hard wiring your fans to the battery if the fans kick in like mad then your current setup needs a relay.