I have my 69 firebird built to around 400 hp with aluminum heads and intake. Runs on 93 octane. I have an aluminum radiator (3 core) with 16" electric fan (1700 cfm). Stock water pump. 180 degree thermostat. Ran hotter w/o thermostat. On the highway, it runs 200-210 degrees. In town, it will get up to 220-230. At 225, coolant will run out the overflow tank. I was thinking of upgrading to 3000 cfm fan first, then if that didnt work, maybe a better radiator. HELP!
Check all your Vacuum fittings and Carb for a leak, mine was running hot til I found the fittings on the manifold for the PCV connections were leaking, I replaced them with the proper sized fittings and it has dropped to normal. I also changed my water pump and closed up the gap between the water pump back plate and impeller to less then a 1/4".
I have my 69 67 firebird built to around 400 500 hp with aluminum heads and intake. Runs on 93 octane. I have an aluminum radiator (3 core) with 16" electric fan (1700 cfm). an OEM 19.5 inch HD 7 blade fan and clutch and a stock fan shroud. Stock water pump. 180 190 degree thermostat. Ran hotter w/o thermostat. On the highway, it runs 200-210 190 degrees. In town, it will get up to 220-230 190. At 225, coolant never will runs out the overflow tank. I was thinking of upgrading to 3000 cfm fan first, then if that didnt work, maybe a better radiator. HELP!
I took your story and put in the specs from my car. You can see what the differences are.
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
It's a Fact jose, they do work that's why it was a feature. I don't understand why someone would trust an electric motor fan over a mechinical fan, if some quits it's all over, Mech. fan both belts have to break and the power gains aren't that much but somewhere he's not pumping water like it's suppose to and or has something simple that is causing it as pci has discribed.
Here is an article about how to do it. It is critical to get the impeller and the divider plate as close as possible. Too large a gap greatly reduces the efficiency of the pump.
OK. Took water pump off. Divider plate in bad shape - getting new one. Gap between fins and divider plate at least 1/8". Will remedy that if necessary when new one comes. Thanks everyone for all the advice.
While you're in there, REPLACE the two sleeves...their rubber seal against the divider plate is usually rock hard and brittle on old ones, and it's supposed to be pliable to make a good seal.
GM Part number 9796347 gets you a pair of sleeves for $20-ish. Any GM dealer, Amazon, Ebay...still in production and easy to find.
So many people seem to skip this step, and I'll never understand why...
Yep, Water Wetter, or a similar product, will lower your temp about 10 degrees. I've been touting this stuff for years now. However, the main problem is your fan. Run the stock clutch fan, or an HD thermal clutch unit, and a stock fan shroud.
When in doubt, stick with what the factory did. Pontiac had brilliant engineers that created parts that work for 100,000 miles or more, and their goal was make these engines run efficiently under extreme heat and extreme cold, and to keep GM from having warranty problems. They knew what they were doing.
Another thing I would recommend would be a change to a later style closed radiator system, like those on 1971-up Pontiacs. You need an overflow bottle, and a 1971-up radiator cap. This setup adds additional cooling capacity, allows you to run less pressure (always a good thing, less stress on your hoses), and prevents your system from leaving those embarrassing green puddles when you park it at a cruise night.
PROBLEM SOLVED! (I think) New divider plate, set to .030" or less clearance. I used the stainless steel plate. I think the regular steel plate would have been easier to work with. This was pretty stubborn.
It was a cooler day today, but it ran at 190 on the highway and 195 in town. I just hope I ran it long enough that my result is accurate.
Thanks to all who offered their knowledge and advice!