Hey guys, I have a bit of an issue with my cooling system and a couple clues as well as guesses of my own. As some of you may know or have heard, I just recently (a year ago almost to the day) rebuilt my engine/transmission. Ford 302 and C4 transmission. (It's only been driven for about 5 days total though) Its been built into a mild street engine and sadly this problem seems to be intermittent.. The worst kind. Okay so put simply, the car will overheat under certain circumstances: 1) Sometimes at idle in traffic. If its a hotter day it seems to heat up a little more, but only sometimes will it heat up in traffic. It seems to heat up more often than not though. 2) Under heavy load if the engine starts to reach its power band. (Rev limiter is set around 5000 for now) so if i get too close to that or if I put the engine under a larger load while going slower it seems to get hot. I.E. I drove along a mountain road with a significantly steep incline. At about 55 miles per hour the engine was around.... 3000 lets say, and the gauge climbed from 180 to 215 before reaching the top of the mountain. But once I reached the summit, and started heading down the engine quickly cooled off and stayed at 160 for the next 40 miles. (even when I hit the 100mph mark on the way down it stayed that cool) The engine itself runs really good. It's quick to accelerate, and its smooth as silk at idle. I hear no pinging, knocking, or missing at all. No bog off the line, and no falling on its face at any point in the RPM band. It's just hot. Usually if I drive a little more reserved it will stay around 190 for the whole trip only venturing upwards in traffic or under more load. (thermostat at 160 with a flex fan) I am running the vacuum advance off of a manifold vacuum source. The last thing I'd like to add is a clue I found. I flushed out the radiator after the mountain drive hoping maybe if it was clogged I could fix my issue, but once I drained it, the coolant that came out looked like a swamp. Absolutely some of the rustiest stuff I've ever seen. The radiator walls are *caked* in this rusty stuff now, but it wouldn't come out when I flushed the system. I think it will only come out when the engine gets hot. So my guess is that this rusty caked stuff is preventing all the heat from being transferred from the radiator to the surrounding air, which is why when I go faster with less RPM it can transfer heat better but at higher rpm and when sitting at idle it can't cool itself. I guess when I cleaned out the radiator a long time ago, I never got all of the rust out from the old engine's cooling system.. Bummer.. Anyways, does anybody have anything they think I may be overlooking? I am completely open to any and all suggestions. I'm sure I cant possibly be thinking of everything. And surely it cant be this simple. P.S. It has the original bronze radiator from 1974 so it's definitely not in the absolute best condition as it stands, but I wanted to keep the original look since I really don't like the look of chrome/alluminium under the hood.
Any buildup in the cores are greatly hindering heat transfer(basically you have a insulated radiator), either have it cleaned or replace it, which unless almost new is best in long run... I bought a new one for mine just because...
you probably need to flush it several times to get rid of all the crud and use a flush additive I had to take my thermostat out to get all the crud out of my monarch then I replaced it with one that would stick open if it sticks plus I drilled a small hole in it to get rid of the air bubbles it is fine now no overheating
You are going need to take the radiator to a radiator shop and have it boiled out. The only to get the crud out . P.S. look in the filler neck If you can see any tube plunged you need the radiator boiled out . Where are you in socal are you going to Knott's '
I'm actually in the Temecula area. I really wanted to go to Knotts but sadly I'm stuck in Wyoming at the moment in school. haha. I may have somebody take it there for me, but I'm thinking it might actually be faster to just buy a new radiator if it's not too expensive.. I know they can get pricey. Anybody know what it costs to boil the radiator out? So then is that what were going to relate it to here? Everybody thinks it has to be something with the radiator and not the actual engine then right?
If I went thru the trouble of rebuilding and engine -- no way I wud use anything but a new radiator. I wud not do anything to a 40yr old rad but, scrap it. I wud not run all that crude and rust thru my new block. There are vendors who sell orig style radiators. If you ruin the engine - you still will have to replace the radiator. Get a new radiator. Also, if you don't have fan shroud -- think abt getting one. Finally, there was a member on this forum killed by one of those flex fans -- don't rev it while anyone is in close proximity.
Wow, that makes me seriously want to have nothing to do with this flex fan anymore lol.. Not too sure about that. I guess I'll just wish for the best and see if I can find another way to cool it (maybe when I get a better alternator I can use my electric fan..) I'm going to look into getting a new radiator though and flush everything out right after install. It seems like at the moment it will probably be the best alternative to anything. The look alike aluminum radiators look way out of my price range for now though, plus i like the look of the black so I'll definitely be hurting the cooling capacity if i paint it myself right? I have a bronze 3 core radiator now, so maybe I should just get a replacement for that and see if that doesn't fix the problem.. Does that sound logical? Also, there was no fan shroud at all. I'm thinking of fabricating one out of 20 gauge steel to fit around the 18 inch flex fan. Do you guys think that would help? Who was the one that died from a flex fan?
I think this is an exact post of mine from about 8 years ago. Did you cut and paste it? Just kidding, but seriously, I fought this battle for several years. The only true fix was tossing out the stock radiator and replacing it with a new modern aluminum one. I have had no problems since. Runs at 180 with the occasional 185 all the time, now. Couldn't keep it under 210-220 with bronze. I did the muriatic acid wash, taking it to the radiator guy to ream it out, used several different cleaning additives, but nothing really worked. I just needed a new radiator. I am sure I spent more money trying to "fix" the stock radiator than I did replacing it with a new aluminum one. WAY more...
You need a clean radiator with a shroud. Either totally clean yours out or get a new one. Even if you go the electric fan route you still need a shroud. Without it you will always run hotter. I think there is a member who knew of someone that was killed from a flex fan.
I got the story from two different guys in the same small town that "had a buddy". Small enough town that it could have been the same guy. One of the guys that told me that story was at the local pull-a-part type place, and that is where I grabbed my electric fans from. Burned one up, and went back for a second one which is still working after almost ten years. This is from 2006...Fan has its own shroud and covers nearly all of the radiator surface.
Not sure where I read it, or who posted it. It may have been the quality of the fan. I do believe any fan/rotating mass is subject to failure (bar none). The probability is rare but I don't stand in the direct path of any rotating mass. 71Gold posted a link above related to this subject. I have seen model aircraft props spin from the crank w/ tremendous force and if anyone had been in the path may/wud have been seriously injured. So, a automotive fan many times it mass and force wud also be leathal.
Flex Fan Fatality I knew the man personally. His name wasn't mentioned out of respect for his family. His wife still drives their Grabber here in the Deland, Florida area. She called me right after it happened and I was shocked also. I immediately removed the flex fan from my Maverick . All my cars have Electric Fans with shrouds I highly recommend anyone running a flex fan should replace it for obvious reasons. This was a young man in his late twenties with a future that was curtailed by a stupid FAN . Tragic . Cometized
