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#1
03-07-2020, 11:38 AM
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Over heating while driving on freeway.
I know this subject has probably been beat to death, but i'm ready to beat it some more...
I have a customer bringing me a 68 firebird with a fresh 455...He says the car never overheats during city driving, but will immediately overheat on the highway...Says he can pull over and it will cool right back down... Its been to several other shops, with no luck...They have supposedly done all of the normal things, water pump swaps, new separator plate, thermostats, etc... I'm leaning towards it being a timing/carb issue... |
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#2
03-07-2020, 11:55 AM
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Quote:
Timing could be set too low if the engine pings on pump gas. If it has factory type exhaust, with heat riser valve for the cross-over, make sure it's open. Clay Last edited by "QUICK-SILVER"; 03-07-2020 at 12:01 PM. Reason: little more |
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#3
03-07-2020, 12:13 PM
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does the lower hose have a reinforcement spring inside?
it may be collapsing... |
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#4
03-07-2020, 02:58 PM
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Quote:
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#5
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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#6
03-15-2020, 11:01 AM
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No idea what brand the radiator is...
At this point, it looks like its going to be manageable now. |
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#7
03-08-2020, 08:58 AM
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Quote:
Bingo
__________________
🧩 Burds Parts, Finding those Hard to Find PCs, no Fisher Price Toys Here Southern Hamtramck Institute of Technology , Alumni Put some 8” flakes and BFG’s on dude!, like everyone does🙄 Burds Literature, nOS factory Brochures, Glovebox literature, & black & blue freedom toppers. 1978 YEE 1995 Q45 #whoremembers |
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#8
03-07-2020, 12:15 PM
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Are both cover plates installed at the top of the radiator support?
Here’s a ‘68 I recently sold, both plates are missing in this picture.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/3.08 2002 WS6 Convertible LS1/4L60E/3.23 1966 VW Type 2 Single Cab Pickup 140hp 2276 1956 VW Type 2 Panel Van 36hp 1200 1957 VW Type 1 Beetle 180hp 2276 |
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#9
03-08-2020, 08:44 PM
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Quote:
__________________
- 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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#10
03-08-2020, 09:01 PM
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Quote:
Used on 400 cars as well from what I’ve read. Main point being is get some plates if it’s not originally equipped with them, they’re definitely needed for a car with a 455.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/3.08 2002 WS6 Convertible LS1/4L60E/3.23 1966 VW Type 2 Single Cab Pickup 140hp 2276 1956 VW Type 2 Panel Van 36hp 1200 1957 VW Type 1 Beetle 180hp 2276 |
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#11
03-08-2020, 09:09 PM
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Quote:
My 69 is a 400 AND A/C, so I had them.
__________________
- 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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#12
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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#13
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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#14
03-09-2020, 12:00 PM
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Quote:
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#15
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. .
__________________
. 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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#16
03-13-2020, 08:21 PM
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Put a factory shroud on(its about 3" too narrow for this radiator), a 6 blade fan, swapped the 160 stat for a 180 stat, and it stays on the thermostat at 4000rpm on the freeway for extended runs...
I started off with the timing through the roof today(where I ended while testing with the electric fan setup), lowered it twice and it never changed the temp... Going to swap the fan with a derale 6 blade on Monday, and add a little more spacer to put the fan where i want it in the shroud, and will try it again on Tuesday when its warmer... At this point, I know its going in the right direction...It was climbing continuously after about a mile at 3500rpm on the freeway...You had to pull off to let it come back down, or it would climb till no mans land... |
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#17
03-07-2020, 12:24 PM
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Those are some great ideas guys...It'll be here tomorrow, so i'll let you know what I find...
Thanks for taking the time to post. |
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#18
03-07-2020, 12:55 PM
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As always, the first thing to do is get an infrared thermometer and check the temp gauge.
__________________
 1965 Pontiac LeMans. M21, 3.73 in a 12 bolt, Kauffman 461.
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#19
03-07-2020, 08:11 PM
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Quote:
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#20
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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