Engine Running Hot - Team Camaro Tech
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post #1 of 13 (permalink) Old Jun 14th, 02, 06:20 AM Thread Starter
 
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I recently bought a 67 Camaro with a rebuilt 327. It has an Edelbrock intake manifold. The previous owner installed a new 4 core radiator, thermostat and fan clutch. The car still runs hot. The needle on the temp gauge approaches max temp at idle, but goes lower as soon as you begin to drive and air flows onto the radiator. The belts are tight and the fan seems to be spinning correctly. The car does not have headers or any other non-stock parts that are increasing the temperature in or around the engine. Any ideas on why it runs hot? Could it be a bad water pump? Anything I can try to make it run cooler? Help!
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post #2 of 13 (permalink) Old Jun 14th, 02, 07:34 AM
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make sure the fan is spinning the right way!!!

its suposed to suck cold air through the radiator into the engine compartment.

and not blowing hot air from the engine to the radiator!
if you look at birdseye at your fan ,and you see the fan-blades look like this \ then it should rotate counterclokwise.

if it looks like this / then it should rotate clockwise.


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post #3 of 13 (permalink) Old Jun 14th, 02, 09:04 AM Thread Starter
 
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The fan is spinning in the correct direction. With the hood closed, I can feel air being sucked in through the grill. Here are some more details, which might be helpful in figuring out my problem.

The radiator is 4 core, it has a new fan clutch and a new 7 blade fan. The fan is installed correctly with one-half of the blade inside the shroud and one-half of the blade outside the shroud. The thermostat (also new) is 160 degree. An overflow tank has been installed by a previous owner. The radiator cap has a release point of 16 pounds. It generally starts to release water into the overflow tank within a few minutes after warming up the car.

The temp gauge climbs more rapidly when running the a/c.
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post #4 of 13 (permalink) Old Jun 14th, 02, 10:29 AM
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Check the cap pressure, make sure it "popps" at the right pressure.
when cold, if the hoses get rock hard within the first 25 seconds or so of running, you may have a bad headgasket or a crack in the head
Good luck
John
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post #5 of 13 (permalink) Old Jun 14th, 02, 11:56 AM
 
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check to see what your timming is set at idle.it should be somewhere between 12-16
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post #6 of 13 (permalink) Old Jun 14th, 02, 12:12 PM
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Your engine shouldn't be poping up a 16 psi rad cap so early. IMO there got to be something else, bad water pump, clogged rad, soft hoses getting sucked, too much compression (extremelly shaved cyl. heads) or even clogged water engine passages. The first thing I'll do is take your car to a rad shop and ask for cooling system pressure test. That way you'll know if you have a bad cyl gasket, or else. Good luck and please keep us up to date on your findings. Remember, we're all in the same boat here.

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post #7 of 13 (permalink) Old Jun 14th, 02, 02:44 PM
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Since your temperature comes down with airflow due to speed, the problem is airflow at idle. Even tho the fan displaces some air at idle, this is not absolutely indicative of a fully working clutch system. I do not suspect the water pump or radiator, even tho your premature lose of coolant indicates either hotspot formation, which is a flow issue, and or as one previous poster pointed out a possible head gasket (but if it runs down the road cool without these symptoms..rule out the head gasket and water pump). If that was the problem, it would have a perpensity to exaggerate the problem as more waste heat was added.

If the seven bladed fan fits the shroud, and is a high pitched original OEM style fan, then the clutch can not be functioning correctly. I would check that carefully. I do not run clutched fans anymore, especially since the aftermarket manufacturers of the clutch units have very poor quality and is a crap shoot in my opinion.

I run the new generation of flex fans that have the newer "entrapment" attachment technology, and higher grades of stainless steel to allow more pitch at idle, which means more airflow, and thinner blades which means it gives up faster as RPMs rise.

I have a 69Camaro ragtop with a 400+hp small block with air in Atlanta, and the new Derale flex does the job. I will admit to having an aluminum crossflow tho, which is a higher efficiency radiator. The engineering is such that it's a much better product that any other flex in the market. Even some OEMs are considering flex technology these days.

I would make sure that the fan you have has enough pitch and the clutch is functioning.

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STEVE JACK
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[This message has been edited by HOTRODSRJ (edited 06-14-2002).]
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post #8 of 13 (permalink) Old Jun 17th, 02, 03:46 PM
 
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I took it to a rad shop today. The pressure test was fine...no leaks.

I also checked the timing...its also fine.

I drove the car alot this weekend, without running the a/c and it never overheated and basically ran in the middle of the temp gauge, although it would rise slightly above that at stop lights.

The guy at the rad shop agreed that its an airflow issue. The shroud could be attached a little tighter against the rad it seems.

He also said that the a/c condensor is mounted a little too far from the rad. He said it should be no more than an inch, and mine is about an inch and a half. He said this would cause additional heat build-up when running the a/c.

I think I'll fix the shroud and see what happens. I don't feel like messing with the condensor...its a ragtop anyway...who needs air.

Thanks for your help.
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post #9 of 13 (permalink) Old Jun 17th, 02, 05:10 PM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by HOTRODSRJ:
I run the new generation of flex fans that have the newer "entrapment" attachment technology, and higher grades of stainless steel to allow more pitch at idle, which means more airflow, and thinner blades which means it gives up faster as RPMs rise.
<HR></BLOCKQUOTE>

Steve,

Would you care to comment on the negative "rap" flex fans have regarding thier propensity to throw blades?

I would consider putting a flex fan on the '67 but do want to turn it into a cheese grater.

-Funk

P.S. That 69 for sale yet?
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post #10 of 13 (permalink) Old Jun 18th, 02, 02:01 AM
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Chris.....the flex fans of yesteryear were poor performers at moving air AND had a perpensidy to throw blades off due to the poor mechanical design. Usually the blades were attached with just a few cheap rivots (soft) and when the rivots got some miles on them they hollowed out their mounting holes (sometimes the blades were made of aluminum...another no-no because of the soft materials) and then castrophically failed when the mechanical action of the force of the blades actually cut the rivot...and off came the blade. The blades also gave it up due to metal fatigue of the loading point and usually cracked, then departed the scene. I have seen pictures of blades sticking thru hoods, not good to say the least. Another point, the hubs were made of inferior materials too allowing for poor attachment bases.

The combination of low airflow performance, mechanical design or the lack thereof, makes the old flex fans a good canoe anchor. I used to NEVER consider a flex fan. But times are changing and even OEMs are considering this newer technology.

The newer technology that uses a much higher grade of stainless steel typically used in aircraft applications can be bent to produce more air at slow engine speeds, yet will not metal fatigue like the poorer grade blades. In essence, the blades really load up at idle, and because they can be designed to flatten more at higher speeds. The attachment methods are much better with the "entrapment" design which not only holds the blades in place with high grade rivots, but utilises a companion plate which also supports alot of the entire leading edge of the blade to put more force on the blade to hold it on, disperse the force of the attachment compression and reduce the metal fatigue issue to nil. Just a better design all over. The hub materials are as good as or better than OEM style fixed bladed fans.

I researched this subject a few years ago when I was building my 69 and ran across a Derale fan engineer at the SEMA show in LVegas. I was studying the new line of Derale flex fans they claimed to be far superior and started with my usual dribble and soap box speech about flex fans. He agreed with my past analysis and assured me of the new line performance with all kinds of empiricle proof, including some pretty hefty cycling hours and rpms. He offered me one for free (since we were both engineers and in the business) as long as I would write a report to him at the end of two years which is coming up in the fall. The model that I am using is this one


Initially we put in on a racing engine on a dyno that turns in excess of 8800 rpms to give it a welcoming test and make sure that everything was what they said it was. Derale claims to guaranty these things to 10000 rpms even tho the data on testing goes to over 20000! I have already used it for going on two summers and just recently pulled if off to Xray for cracks at my favorite aircraft facility (I do airplanes too). I have found absolutely no material degradation and back on it went. The amazing thing about this fan is that it will cool my Camaro with the air a blowin' and I still can't hear the thing at 6500rpms? This tells me that the fan is really efficient.

Anyway Chris, I would recommend it now for certain applications and certainly for your 67. I am going to write an article in the Northern/Southern Rodder magazine coming before the end of the year after the full testing period is up.

Chris....if ya want the 69 you will have to see the wifey....it's her ride and now she has been driving it by herself to cruises etc.

Michael67....your radiator guy is right about the air condensing coil. The coil acts as an air block in that air rolling off the coil in front of the radiator will eddy current in the void space setting up unproductive flow and degradate the airflow pattern. Keeping the coil up against the radiator is the trick to keeping airflow moving smoothly and productively thru the system. I would look to change that situation immediately.

That's my story and I'm stickin' to it!

------------------
STEVE JACK
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[This message has been edited by HOTRODSRJ (edited 06-18-2002).]
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post #11 of 13 (permalink) Old Jun 18th, 02, 05:00 AM
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Steve the use of the word "yesteryear" in describing flex fans may mislead some in thinking all new flex fans are created equal and as good as the product you indorse. As I understand there are many brands on the market that are inferior and still fall under the heading "best to be avoided" Do you concure?
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post #12 of 13 (permalink) Old Jun 18th, 02, 05:14 AM
 
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I had the same problem with my 79. If I had the AC on it would overheat 230 and up, but when I would have the AC off and on the freeway it would tend to over heat going 70-75 for long distance. I switched the Radiator out and it solved the problem. I think the old Rad might have had some lines pluged or something.
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post #13 of 13 (permalink) Old Jun 18th, 02, 07:42 AM
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Dennis.....you are absolutely correct-a-mundo, as the Fonz would put it!

Even Derale, the brand lable that I have experience with and recommend the heavy duty product in the previous post, has a line that I still think is faulty by design.



This in an example of one that has very little air production, aluminum blades (yuk), not alot of front edge support, and only four rivots per blade. I would NOT want this on my 6500+rpm turning engine. Would not cool it anywho!

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STEVE JACK
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[This message has been edited by HOTRODSRJ (edited 06-18-2002).]
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