[Chris65LeMans]

You say the car is "constantly going over 190 degrees." How far over? You may not have a problem.

[Pepi]

Originally Posted by pfilean

Saying that the water moves to fast and won't cool is like saying blowing across your hot coffee won't cool it. But everyone does it anyway.

At first thought the idea that water can move to fast seems to make sense. But on the other hand the water is also moving fast through the block so it should not have time to pick up any heat either.

I fell better having gotten that off my chest.

Not to start an argument, but some of your examples don't make sense. Your hot coffee one...If you blow across your hot coffee while moving left to right, it won't cool as quick as blowing across it at the same place.

Water moving fast through a block won't have time to pick up heat...water flowing through anything like that causes friction which will heat the water.

I have seen tests being done flowing water through 2.5" hoses that had too tight of a bend and the water got so hot it burned through the rubber and nylon hose because of the friction.

So I do see how flowing too fast through a radiator could cause overheating, although I have never seen or heard of it actually happening.

I know, I'l submit it to Myth Busters.

Karl

[My64GTO]

Uh oh, now you've done it. Can we still have polls on these bulletin boards?

You say move it away from the radiator. Someone will respond soon and say move it right up to the radiator. And others will say the fan should be 50% into the shroud.

Right now its 1/4 of the way into the shroud (what's that about 2" away from the radiator I guess?), but when I get the new fan I plan to move it closer to the radiator. If I don't see any results, I will order the divider plates from inline tube, remove the pump (again) and clearance the pump to the plate.

Originally Posted by rexs73gto

How far is your fan from the rad.? Also do you have a shroud?? You divider plate should be clearanced so it's no farther away then 30 ths. . the closer you can get the plate to the impeller , the better it will cool. If you fan is to close to the rad. it will stay hot & keep getting hotter. Get the fan back as far as you can from the rad. & it will cool better.

[My64GTO]

It depends where you want it to go. If I let it sit an idle, it will climb continuously past 210 if I let it, but that is past my comfort zone. And I know the gauge is accurate. I have observed it going to 230+ after the car is shut off.

Originally Posted by Chris65LeMans

You say the car is "constantly going over 190 degrees." How far over? You may not have a problem.

[Chris65LeMans]

My '65 owner's manual has one sentence on heat that says something like "if it hits 245; shut down and diagnose." 230 isn't too bad - especially if you're not running. When you start the engine, the temp drops rapidly; right?

If your temp goes up with long periods of idling and drops when you start moving, it sounds ok to me. You could throw handfulls of money and time at it (like I've seen guys on here do - often unsuccessfully), but you don't have to.

[torqjunki]

My64GTO.....This something I did yesterday to help determine if problem was air or water flow. Driving the car it did not want to heat up to the 180 thermostat temp. However when stopped, it would go to 185. Drove back to the shop, opened the hood and put a big powerful fan in front of the car and the temp only came down a few degrees. Raising the rpm from idle of 1000 to 2000 or so, the temp would immediately go down to 165. I know the mech fan pulls more at 2000 but I think the open hood and big shop fan would have cooled it down more if a air flow problem. So I'm certain my issue is coolant flow. Also checked again and the coolant just dribbles out of radiator veins at idle.

[rexs73gto]

The reason I say move it back as far as you can from the rad. is I have tried it in several ways, I had the fan as close to the rad. as I could get it & where it is now as far away from the rad as I can get it. I also tried it in between those spots to. When it was as close as possible to the rad. it would overheat in just a few miles & didn't matter at what speed, slow or fast. I then moved it back to about the middle & it helped a little bit. But still not good enough. I then moved it back away from the rad as far as i could get it & POOF like magic it ran cool & stayed at about 170 degrees all the time. In hot weather & cooler weather. I drove it on the highway & in town Both at hot & cool temp. It stayed right about 170 degrees & no longer over heats. Thats why I say move it back, it works.

[scorpio ps]

Where do you purchase a 3/4 in fan spacer. Seems like they are 1/2, 1 or 2 inch

[72LuxuryLeMansLa.]

Originally Posted by scorpio ps

Where do you purchase a 3/4 in fan spacer. Seems like they are 1/2, 1 or 2 inch

A one inch spacer that meets up with a band saw is less than a one inch spacer!

[torqjunki]

How much of fan in shroud Rex?

[rexs73gto]

As i said in the original post , The fan blades are even with the back edge of the shroud & the hub of the fan is just barley in the shroud. In fact when I finally got it to where I wanted & it worked best for me I had to trim the tips of the fan , which is a flex fan by about a 1/4 inch off the tips so it didn't hit the nut on the power steering pump. My flex fan is the biggest one I could get at the time which is the 18 inch flex fan. When I put the power steering pump & alt. on I used a couple of miss matched brackets that why my power steering pump is so close to the fan. When I would rev. up the engine the fan wouldn't hit the nut on it but when it came down to an idle & the fan would relax the very tips of the fan would hit the nut on the power steering pump. By trimming the ends off the fan blades worked perfect for me. Also I think if I could back up the fan even more I would do it. But the fan with the spacer I have behind it right now is as far as it can go back. I'd have to remeasure the spacer again to know for sure but I think it is a 3/4 inch spacer but it might be a 1 inch, but it was kinda hard to get an exact measurement with the way it's mounted. I can try if you need an exact size. ?? I tried to post a pic but it wouldn't let me so i could show you exactly where the fan sits in relation the the shroud.

[Sirrotica]

Originally Posted by Pepi

Water moving fast through a block won't have time to pick up heat...water flowing through anything like that causes friction which will heat the water.

I have seen tests being done flowing water through 2.5" hoses that had too tight of a bend and the water got so hot it burned through the rubber and nylon hose because of the friction.

So I do see how flowing too fast through a radiator could cause overheating, although I have never seen or heard of it actually happening.

I know, I'l submit it to Myth Busters.

Karl

My stepson is a volunteer fireman and they commonly use hoses of 2 1/2 inches. Even with a huge capacity pump running off of the trucks diesel engine at 1800 RPM he has never seen a hose overheat or rupture due to internal friction. I believe it's safe to say no waterpump in an automotive application is going to move water fast enough or under enough pressure to melt or rupture the vessels which the water is contained in.

You must be talking of thousands of pounds of pressure flowing into a restriction to cause that kind of carnage. City water pressure is usually under 80 PSI (which no automotive system even approaches, even under full throttle, the pressure relief cap limits it) and I have never seen a garden hose melt no matter how restricted the hose is. Pinching off a garden hose to control it's flow also does not heat up the water. In my 62 years I've yet to see a pinched off garden hose spew hot water.

Again, heat is transferred by electrons, the water never exceeds the speed of electricity in an automotive system. The phenomenon your talking about is running very high pressure water through a restriction. Trying to compress a liquid moving at very high speed will cause heat. This unusual situation is never going to show up in any automotive cooling system, is it?

No need to even mention this extreme scenario in this instance. Do some research on automotive cooling systems. No one that has any credentials in this field, is under the opinion that water needs to be slowed down to accept or reject heat. This is based on the fact that electrons are the vehicle that heat moves through, and the speed of the coolant will never exceed the speed of the electrons.

There is only so much area in the coolant system to accept and reject heat, it is a constant. Speeding up the coolant and raising the pressure and adding air flow as it is moved through the system is the only variable that can make the system more efficient. Slowing coolant flow DOES NOT make the system more efficient, Pontiac engineers knew this and made a smaller pump pulley to overdrive the pump and fan in extremely taxing conditions, (A/C, HD cooling for taxis and police cars, towing packages, etc.)

No need to submit it to Mythbusters, physics and common sense easily bust this myth.

[torqjunki]

Rex.....so as I understand it, the actual fan is all the way in the shroud and the hub is just barely in the shroud. It will most definately cool better if you can get at least half the fan outside the shroud. You must have the wrong shroud on there. When I purchased a new reproduction shroud for the Bird, it had a large section cut out on the bottom of the shroud. Not sure if it helps get the hot air out or???

[72LuxuryLeMansLa.]

Originally Posted by torqjunki

Rex.....so as I understand it, the actual fan is all the way in the shroud and the hub is just barely in the shroud. It will most definately cool better if you can get at least half the fan outside the shroud. You must have the wrong shroud on there. When I purchased a new reproduction shroud for the Bird, it had a large section cut out on the bottom of the shroud. Not sure if it helps get the hot air out or???

Just as a discussion point, not an argument, my 1972 Luxury LeMans has the stock radiator,shroud, fan, engine and the fan fits inside the shroud. I bought Jim Hand's book almost as soon as I joined this site when I bought my car and read the whole fan half in/out deal.......Also every GM truck I've ever worked on had the fan all the way in to the shroud. I would really love to talk to an engineer about the efficacy of fan placement halfway at the edge of the shroud vs. all the way in.

[torqjunki]

I would be willing to try the fan further in, but the fan would be hanging sooo far off the water pump. Hard to believe it could pull any more air than it does. Since I'm using a flex fan, when the blades flatten out, the fan is actually in the shroud now that I think of it.

[indymanjoe]

Originally Posted by 72LuxuryLeMansLa.

Just as a discussion point, not an argument, my 1972 Luxury LeMans has the stock radiator,shroud, fan, engine and the fan fits inside the shroud. I bought Jim Hand's book almost as soon as I joined this site when I bought my car and read the whole fan half in/out deal.......Also every GM truck I've ever worked on had the fan all the way in to the shroud. I would really love to talk to an engineer about the efficacy of fan placement halfway at the edge of the shroud vs. all the way in.

Yea but you drive a Luxury Lemans...

[Willshire]

Originally Posted by Chris65LeMans

My '65 owner's manual has one sentence on heat that says something like "if it hits 245; shut down and diagnose." 230 isn't too bad - especially if you're not running. When you start the engine, the temp drops rapidly; right?

If your temp goes up with long periods of idling and drops when you start moving, it sounds ok to me. You could throw handfulls of money and time at it (like I've seen guys on here do - often unsuccessfully), but you don't have to.

I agree with this sentiment. 245 puts you at, or close to the boil over point,of a 50/50 mix. As Chris said if it drops quickly after you accelerate i think you are without issue. There isn't likely enough water flow or air flow at 500 rpm to prevent a block that has 550* (roughly) at the exhaust ports from trying to heat up the rest of the engine. As someone else said, "too much iron holding heat". Same as when you shut it off, no circulation, hot iron, higher temp.

[72LuxuryLeMansLa.]

Originally Posted by indymanjoe

Yea but you drive a Luxury Lemans...

Touche'

[rexs73gto]

torqujunki, The fan blade on my car is right EVEN with the edge of the shroud & the face of the fan hub , the part that hold the blades is just in the shroud by maybe 1/4 inch. When the fan blade flexs the fan proberly is just inside the shroud by that 1/4 inch. But as I said in one of my posts I di try the fan at different spots with 3 different spacers until I got to the last one that is as i measure it is about 3/4's to 7/8's of an inch. it is porberly a 1 inch spacer but it doesn't measure at a full 1 inch. That is the spot that it works the best. My car can now set & idle for an extened length of time , I tired it for about 20 min's with it sitting in my driveway facing the garage with no air flow into the front of the car other then the air it was pulling. It stays at about 170 degrees the entire time. When I drive it going down the road at 70 + mph it runs right on the the 170 mark & after driving for a while it goes up to about 185 when I stop but then come down after I sit for a min's or so. Before it would go to 240 + if I drove it faster then 55 mph or got in traffic for ANY length of time 3-4 min's tops. Now with my fan at this point is best for me. I have a friend that was having a problem with his Camaro BB car. It would over heat if it sat for any time to. He had the 2 1/2 spacer on his car. We when to a show yester day & he had swapped out that one for a 1 inch spacer which brought his out so the fan was just inside the shroud & it ran coller & he even tried it before he came out with it sitting facing his garage to & it took about 25 min's to get up to 200 degrees but came back down to the 180 mark as soon as he started to drive it, maybe a couple of min's or so. So having it out by the edge of the shroud does work for 2 car s now.

[72LuxuryLeMansLa.]

Originally Posted by torqjunki

I would be willing to try the fan further in, but the fan would be hanging sooo far off the water pump. Hard to believe it could pull any more air than it does. Since I'm using a flex fan, when the blades flatten out, the fan is actually in the shroud now that I think of it.

There's the difference. My car has the OE seven blade clutch fan not a flex type.