My temps during the hotter months will go past 230 if I don't keep moving, 180-190 with ac on while driving.. I've used 2 different temp gauges to rule out a bad gauge. I've had the fan all the way in the shroud, 50/50, 60/40 and on and on with no success. The radiator is sealed between the support and core and when the shroud was installed, it was sealed pretty well as well.
Thanks for your help.

John

I'm with John,  What temp is it running??  My 289 used to get so hot it would boil the gas out of the carb after I shut the car off!  I changed to an Aluminum 2 core radiator and I'm running a 6 blade flex fan and a stockish fan shroud.  I am now running a 302 HO with same radiator, fan and shroud.  The highest temp I have reached was this summer while sitting in traffic and it got to 200.  Normally in the summer it runs right at 185 to 190 and this time of year it struggles to open the thermostat

What width radiator are you running?  Have you opened up the radiator support for a wider radiator?  I know you have been through a variety of pumps but what pump are you running now?  Is the water pump inlet on the driver or passenger side? Do you have a reverse rotation pump on it from a late model?  I assume that the fan is for normal rotation?  What year/engine is it for?

With that 306 you should have no problems with what you have done, and all the advice has been good.  I have one additional suggestion.  Change your front valence to a Shelby with the scoop below the bumper.  That will unshroud the bottom 1/3'rd of the radiator for much better airflow and cooling.    It worked for me.

I have a 351w with a 4 core stock size radiator, 5 blade cut down 351 flex fan, 180 thermo, and no shroud.  I'm good to 95 deg before the temp starts going up.

MS is right about pitch.  Maybe the fan you ordered wasn't the one you ended up with. Hornman makes a good point about the clutch if it has one.

Can you post pics of the fan/shroud relationship?  I wonder if the opening in the shroud is too large allowing air to circulate backwards around the fan blade, particularly since you mentioned that it doesn't seem to pull air through the radiator.

John
 

I had the same problem on my 65. Had the northern aluminum radiator. I saw MS tech on installing a stock 24 inch radiator with stock shroud- did the swap. It is one of best and easiest changes I ever made. As long as you have no other major motor - tune issues I suggest this change. Happy Motoring!

Hello again and thanks again for all the replies. MS and someone else made the point that maybe I don't have the right pitch on my fan. What would the correct fan pitch be? I haven't seen pitch listed on any of the fans that I've been looking at.

Thanks.

John

Posting a photo is pretty straight forward.
Click on the "Upload" box.  A Tinypic box comes up.
Click on "Browse" and procede to find your image.
Click on "Open".  The Tinypic box returns with your file location
There is a 'resize' box.  change it to 'message board'
Click on "upload now!"
Click on "add to your post"
That should do it. 
Your photos are jpeg's aren't they?

 

Just a FYI on my cooling issues in the past. For 15 years I drove around with a stuck partway  open thermostat and didn't know it until last year.  On my 70 trans am ( yes I had one of those) the top of the air cleaner  hit the choke butter fly and stuck it open a little, this made car over heat.  Just another FYI good luck.  

65fastback wrote:

Ok.. There must be a post min for me to be able to post pictures. I can get my picture loaded, but it won't post. Hopefully a few more posts by me will do the trick.

John

Here's another post to reply to!

Anyway, I reread your post and it seems like you covered everything (2 engines, 3 radiators etc.), but I only see one fan.  I think MS may have nailed it.  A fan needs two things to move air; rotation speed and pitch.  If the car runs, we know the first is good .

My mom's family room has an overhead fan, and that thing cranks along at a pretty good clip but moved almost no air.  So when I selected overhead fans for my bedrooms and family rooms, I looked at CFM specs.  The fans I bought will blow the toupe off Willard Scott.  The difference is pitch.  Back at mom's, I ended up getting a handful of washers and putting two under the screw on the leading edge of each blade and it made a big improvement although I think the increased pitch slowed the motor down a bit, something that won't happen in your car.

John

I use a stock Ford 17" flex fan on my car, similar to the one in lowercasesteve's picture.  It has stainless steel blades.  After my wreck, I thought the fan might have gotten damaged, so I ordered a new one from Summit.  It was almost identical to the factory flex fan EXCEPT the blades did not go as far towards the center of the fan.  It was like there was 2" less fan blade on the entire fan, which made for one heck of a "hole" in the middle of the fan that moved zero air.  Needless to say, I put the Ford fan back on.

When describing fan pitch, what you need to measure is the width of the blade (distance across the blade) and the "thickness of the fan.  Visualize the fan sitting flat on a table and take a ruler and measure how thick the fan is.  From those two dimensions you can calculate the angle of the blades, but there is no real reason to know the angle as long as you know thickness and blade width.  Then we can compare to other fans known to work.  The thicker the fan, the higher the pitch, but the blade width figures into the equation.  Blade LENGTH also, as mentioned about the fan I bought from Summit.  This may or may not be the way PITCH is actually measured, but having the dimensions will let us compare to other fans.

Also, I have seen reverse rotation fans sold incorrectly when a std fan is ordered, so be sure to verify.  That is one of the reasons I want to see a picture.  Your previous statement about a piece of paper not staying attached to the front of the radiator at idle is cause for concern, making me think the fan is not doing the job.

How many thermostats have you tried?

I just went back and looked at my notes on overheating engines and the fixes.  One came to mind on a forum member's car that was overheating terribly even though it had all new parts on everything.  It turned out that whoever installed the water pump had used excessive amounts of RTV on the gasket where it attached to the timing cover and the RTV had oozed into the timing cover's water passages, completely blocking the driver side passage and blocking the passenger size about 50%.  Simply cleaning out the goo and reinstalling the pump cured the problem.

We always tend to think of the usual parts going bad, or the wrong parts being installed, but it can also be caused by the improper installation of parts, or something really weird like the extra gallon of RTV used to install that water pump.  I try to think of the unusual problems that have come up in the past when helping to diagnose.