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#21
03-08-2020, 09:04 PM
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It has a wide 4 core brass/copper radiator, with a pair of electric fans that are made to a shroud that completely covers the core...
At first look, it doesnt look like it has the plate between the pump and timing cover...It is an aftermarket cover, so i'll have to figure that out first... I would think the first statement is the issue. The fan asm's are probably restricting air flow at highway speeds. I would also want the A/C cover's as B-man referenced. just my wag. If it didn't have the divider plates I would think it would overheat in the staging lanes...
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72 Luxury Lemans nicely optioned 
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#22
03-08-2020, 09:09 PM
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My 69 is a 400 AND A/C, so I had them.
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- Mike  '69 Firebird 400 - Goldenrod Yellow, 455 +.060, '6s-7' heads, Comp Cam 276AH-10 (51-309-4), TH400, Ford 9-inch w/3.08, 800cfm Q-jet, Stock Intake, Hooker Headers, Flowmasters '68 Coronet 500 Convertible - Medium Gold Metallic, stock 318 +100,000 miles |
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#23
03-08-2020, 09:11 PM
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Quote:
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
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#24
03-08-2020, 09:37 PM
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Someone else on this site had the same problem. The fans pushed enough air at slow speeds. But, at higher rpm, there wasn't enough air pushed through the radiator to cool. They did away with that style pusher fan to open the front up, problem solved. I believe they went back to a clutch fan with shroud.
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#25
03-09-2020, 12:00 PM
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#26
03-09-2020, 12:25 PM
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Yes, the fan shrouds do need a relief to allow air to pass when on the highway, but another thing I've seen is where the fans and shroud are too close to the core, and the shroud is completely flat. When it's like that, the fans only draw across the core the diameter of the fans. It's like bolting them right to the core and blocking the rest of the rad.
I've also seen some that have louvers on the sheet metal shrouds, completely open. All that does is draw air from the engine compartment, and not across the core. Those crappy wiz-bang sheet metal rad/fan/shroud combos you get cheap on eGay are notorious for that. .
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#27
03-09-2020, 12:36 PM
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Yeah, I tried cutting reliefs in the shroud didn't help mine so I went back to the factory setup with the alum radiator.
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#28
03-09-2020, 01:33 PM
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Highway overheat
I design and build refrigeration equipment and have looked at many radiator/electric fan combinations and thought the shrouds look like they would do a good job of getting enough air through at idle but would tend to block the air-flow through the portions of the radiator that are not directly in line with the fan(s).
OE shrouds have sufficient space between the fan and the back of the radiator coil bundle. This space combined with a nice shape/taper that permits air to pass through the full radiator surface then be routed to the fan makes the OE shroud work properly. |
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#29
03-11-2020, 11:35 AM
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water pump must have cast impeller and gap at separator ..035 to 050 not .250
__________________
 BOB SLUSSER 937-286-4343 |
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#30
03-11-2020, 11:56 AM
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GM, when first building shroud technology put holes in the shroud and had 20+ Vacuum gauges all over them to test the airflow Pull at ALL parts of the radiator. Its easy to have a cooling "fail" even when the radiator is covered by a "metal shroud" You would be surprised to see how well a stock fan shroud and a clutch fan would work for POWER and Cooling. Highway driving burns MORE calories= More heat, and guess what?, the air flow in that set up does NOT increase... = heat build up.. Good luck. |
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#31
03-11-2020, 12:47 PM
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Fins are coming loose from the tubes in the radiator core . I would try a new aluminum radiator.
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#32
03-11-2020, 04:48 PM
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The water pump separator plate will normally cause overheating in traffic driving at lower speeds. Two things come to my mind that haven't been mentioned, the first and I'm sure it has been checked by one of the shops, is make sure the fans are wired correctly and are directing air across the radiator instead of pusing it forward. The next thing that hasn't been mentioned is, if the car has an automatic transmission, the trans could be overheating causing excessive heat in the engine cooling system from trans. cooler in radiator.
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#33
03-11-2020, 08:08 PM
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Fans are running correctly...
I jetted the carb up...No help Advanced timing...No help... Swapped the T-stat and will test in the morning... If that doesnt help, i'm going to pulled the electric fans, and install a factory shroud and 7 blade fan... I did notice that the car has a bunch of gear, and it turning 3500RPM to go 65mph... |
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#34
03-11-2020, 08:45 PM
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So one condition I had with a similar setup, where a car with gear at highway speeds, say 3500-4500 RPM, at part throttle/low load, would pull the vacuum advance enough to where it would start running hotter. Try running it with no vacuum advance and see if it still does it.
That won't help at lower speed driving & idle obviously, but the only way to get around that is to go to a electronic controller advance, such as the MSD programmable 6-AL with a MAP sensor or EFI ECU. .
__________________
. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#35
03-11-2020, 10:10 PM
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#36
03-12-2020, 10:02 AM
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So how much timing are you seeing at 3500 RPM's? With centrifugal and with vacuum advance. Clay |
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#37
03-12-2020, 10:35 AM
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Post a pic of the rad/shroud/fan combo.
.
__________________
. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#38
03-12-2020, 11:51 AM
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#39
03-12-2020, 11:53 AM
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It currently has the twin Flexalite kit on it, and in my opinion, they do not draw enough air, and they create a restriction when on the highway. |
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#40
03-12-2020, 11:58 AM
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I fought with cooling on my Firebird and tried many different fans, shrouds, radiators, A/C / 400 baffles on the top & bottom, etc... What I ended up with was a Cold Case radiator & Spal extreme duty fans, but the biggest difference was when I removed the thermostat so the water could FLOW. Even the "high flow" thermostat caused too much restriction. Faster flow = cooler water. After that, temps stayed at, or below, 195*-200*. The only time the temps creeped over 200* was extended highway driving around 3500 rpm.
I'd be curious what the oil temps are. With the large mains in a 455, mine would climb at the higher rpm driving and would push the water temps up with it. There's a lot of good suggestions above, but I would remove the t-stat & see if that helps. Faster flow = cooler temps. My checklist (From Least $ to More $$$: Timing Spring in lower hose Remove T-stat Diver plate clearance Seal around radiator - Black foam water pipe insulation works good & is easy to seal the gap. Good/big enough radiator Proper/enough fan(s) Upper & lower baffles
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No! Do not try! Do! Or do not. There is no try. - Yoda 1967 Firebird Restoration 2005 - 1/25/2017 
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