I have a 69 with a new rebuilt 400(with 20 driven miles on it) and it keeps overheating to 210+ within 10 minutes of driving. Its got almost new/rebiult everything but waterpump and fan. I am thinking now it might be the clutch fan since the speed does not vary. The fan has no wobble or free spin or oil on it and does make any weird noises so hum. Any thoughts?
Pontiac water pumps are notorious for excess clearance at the backing plate, which reduces water flow dramatically. Easy to fix: http://www.youtube.com/watch?v=UdyAo5546JQ
Also you want tight clearance between the edges of your fan and your fan shroud. This is to ensure ALL of the air moved by your fan is actually pulling thru the radiator, and not just getting sucked from behind the shroud and bypassing the radiator.
If I were you I'd check these 2 items first. And certainly you want to verify your fan clutch is working properly also.
Also have you had anything done to the radiator? Original? how many rows? If original has it been hot tanked and cleaned up? Are the fins on the radiator in good shape? If new how many rows? Not to mention what exactly did you do to your motor? What year motor? What type of heads on it? What kind of fan you running? I could keep going.... To many variables and not enought info....
arg, there is no shroud, bad, bad...any tips on where to order one? I'll check out the link you posted for the water pump. I was also thinking of getting an aftermarket one with more water flow?? Not sure how to check the clutch fan except put one on that for sure works from my friends gto.I saw one that was messed up and freely spinned and mine doesn't.
I was also thinking of getting an aftermarket one with more water flow??
It's been said on this site many times, Just use stock waterpump with a cast iron impeller with the proper clearances between the cast vanes and divider plate.
arg, there is no shroud, bad, bad...any tips on where to order one?
Betcha dollars to donuts this is 80% to 100% of your problem. You absolutely NEED a shroud, without it, your radiator gets air only at highway speeds if you're lucky.
All the restoration warehouses have them if you want a repro. Classic Industries, NPD, Year One, etc...
You could also fab up your own custom if you want out of sheetmetal if originality is not a concern. You just need one.
Welcome to the site. Hate to do this to you right off the bat but wow, drive a brand new motor with no shroud? OUCH! As stated, Pontiacs are NOTORIOUS for running hot (210-220), then a new motor when built tight and everything fresh will run even hotter yet. Therefore, EVERY original part and piece that was on these cars when new that were there to help cool the car, absolutely need to be in place now more than ever as we add more HP and aftermarket parts etc. There are several things that make up the entire cooling system on these cars, lower filler panel/baffle (almost always missing), upper filler (X-fillers), rubber seals in front of the radiator core support etc. etc. and the list goes on...
Also how many rows in your stock radiator? 400's originally had a 4 core radiator. The 350 cars had 3 core. If you are going to get a new one, buy the 4 core or an aftermarket that can handle the heat.
......actually its not been driven but at little excursions ( 1 mile )AFTER we put on the gauges for oil, battery and engine temp. We were also dealing with a leak in the intake manifold and figured out the guy who put the motor anad tranny together put the WRONG gasket on it.
Actually at highway speed it didn't make a difference. We are getting a schoud, fixing the plate in the water pump (great video on "routy") and getting a 4 core radiator. Can't wait!!
also, remember they tend to run hotter at first after re build....but , dont drive too much until you have all the equipment, radiator shroud, water pump, fillers etc.
Just to help explain further, this link has some more comprehensive explanation, and comparative photos, of the water pump mod. It costs only about $5 for gaskets available at any auto parts store, plus a bit of antifreeze and a couple hours of time, depending on your skills:
Also the testing that was done by High Performance Pontiac that absolutely proved that a stock 4-row radiator was more efficient than any of the aluminum rads on the market. I remember when I bought my $600 aluminum radiator for my bird expecting miracles. When it arrived it installed it and found that it made absolutely no difference whatsoever.
Then I searched and searched until I found the lower baffle, installed it and bingo, problem solved. Then I couldn't wait to get that big not so nice looking, ill fitting aluminum radiator out from under the hood!
Tossed together 2 yrs ago to go race 1 wkend. 455 w/RAIV cam and only 10.0 cr 3500 stall cnvtr No baffles or shroud Didnt ck plate to vane clearence Non A/C pulleys 3 tube aluminum rad Big trany cooler in fnt of rad 19.5" flex fan 170* stat Didnt get ovr 195* in the staging lane in 90* heat. By 2nd gear was back down to 180* Apart for body work & paint now, gona put shroud on for safty when finished. Those blades are RAZOR SHARP! Hopefully be next yr. Oh ya, ran 12.0's @ 114mph like clockwrk. 3.42 grs and tires to big for combo
Thank you guys for all the GREAT tips and tricks...
I read about the info on wallace racing website.Where do I order a new Spacer plate?
So stick with the stock water pump huh?
FlowKooler claims: "FlowKooler water pumps solve low-speed heating problems by doubling the water flow rate at low rpm and idle. At 3,500 rpm, the flow rate returns to normal, to prevent too much water flow at high speeds. These pumps also last longer than a stock replacement. They use a specially designed steel plate on the impeller that traps water, eliminates cavitation, increases flow, and reduces engine temperatures."
Tossed together 2 yrs ago to go race 1 wkend. 455 w/RAIV cam and only 10.0 cr 3500 stall cnvtr No baffles or shroud Didnt ck plate to vane clearence Non A/C pulleys 3 tube aluminum rad Big trany cooler in fnt of rad 19.5" flex fan 170* stat Didnt get ovr 195* in the staging lane in 90* heat. By 2nd gear was back down to 180* Apart for body work & paint now, gona put shroud on for safty when finished. Those blades are RAZOR SHARP! Hopefully be next yr. Oh ya, ran 12.0's @ 114mph like clockwrk. 3.42 grs and tires to big for combo
I can echo a lot of this on my car: 490 hp 455, stock OEM replacement water pump with cast impellor (Ames), Rodney Red aluminum radiator, 50/50 mix antifreeze, Factory recommended thermostat (185 or 195?)19.5 inch 7-blade flex fan with clutch, and with the upper and lower 400 cooling block off plates left off until after final body work and paint.
Runs in the OK summer heat all day long and idles without any cooling issues.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
.......but the aluminum radiators look so cool.;-)
Especially to those aluminum recycler guys.
I used to be indecisive. Now I'm not sure. I feel like I am diagonally parked in a parallel universe. 1968 400 convertible (Scarlet) 1976 T/A - 455 LE (No Burt) 1976 T/A New baby, starting full restoration. 1968 350 - 4 speed 'vert - 400 clone (the Beast!) 1968 350 convertible - Wife's car now- 400 clone (Aleutian Blue) (Blue Angel) 2008 Durango - DD 2008 GXP - New one from NH is AWESOME! 2017 Durango Citadel - Modern is nice! HEMI is amazing! 1998 Silverado Z71 - Father-daughter project 1968 400 coupe - R/A clone (Blue Pearl) (sold) 1967 326 convertible - Sold 1980 T/A SE Bandit - Sold
.......but the aluminum radiators look so cool.;-)
I have to agree.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
I couldn't wait to get rid of mine and go back to a stock 4-core so that everything else fit properly and correctly etc. Once I realized the alum rad didn't make any difference and the tests came out in HPP I was thrilled to go back to my stock set up. The 19.5" 7-blade clutch fan is a KEY piece to the puzzle when cooling these old Pontiacs!
I'm with you hokie! I hated mine and was really ticked when it didn't cool the car one degree lower than the stock 4-core. IMO way over rated, over priced and I just don't like the look myself but then again being more of a purist no surprise there...
We fixed the cooling problem!!!!!!!!!!! We ran it last night and it didn't go over 165 wow!!!!!!! We put in the new 3 inch wide 2 tube aluminum radiator from "Be Cool"(only $330) , new OE water pump from "A1 Carpone", regular 165 thermostat, new thermal clutch fan and 2 inch extension on the fan. All parts from Summit Racing. The stock shroud didn't fit this rad so its going back. Any company out there make schrouds for Be cool rads or comp? Maybe a half schroud?
Region Warrior and Salmon brag of not having cooling problems, which is well and good, but not entirely unexpected. I just want to make sure all readers noticed they are both running 455's. The 455 was not introduced 'till 1970, which means they all have the newer style 11 bolt cooling pump, which is a better design than the original 400 pumps were.
Those cars that still have their original 400 blocks from 67 and 68 have an older style 8 bolt pump that is less efficient, and therefore by their very design are often more difficult to cool than the later models.
'69 was the first year they introduced the better 11 bolt pump design for the 400's. Pontiac even press released it in 1968 when they introduced the 1969's, the more efficient water pump is mentioned toward the end of this newspaper article:
Region Warrior and Salmon brag of not having cooling problems, which is well and good, but not entirely unexpected. I just want to make sure all readers noticed they are both running 455's. The 455 was not introduced 'till 1970, which means they all have the newer style 11 bolt cooling pump, which is a better design than the original 400 pumps were.
Those cars that still have their original 400 blocks from 67 and 68 have an older style 8 bolt pump that is less efficient, and therefore by their very design are often more difficult to cool than the later models.
'69 was the first year they introduced the better 11 bolt pump design for the 400's. Pontiac even press released it in 1968 when they introduced the 1969's, the more efficient water pump is mentioned toward the end of this newspaper article:
Goes to show you even Pontiac acknowledged they had a cooling system design problem on the early 400's...
Sorry, I put my entire OEM '67 setup back on my 455 - meaning I have an 8 bolt water pump. It's the one from Ames with the cast impeller.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
My 455 came to me as just the bare block, not a transplant I pulled from a later car that would have had all the accessories, pulleys, etc.
Thus the straight swap for my original 400 motor, which is hibernating in a corner of the garage.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
