I've searched through this forum and read many posts about similar issues, but I want to make sure I'm going in the right direction before I drop more cash.

I've got a 390 and it's been running hot in traffic. I started having these issues during the summer and replaced a few things: water pump, upper hose, switched to a 180° thermostat, and I flushed the system pretty well.

I've got a stock fan/shroud and a stock radiator. After replacing the aforementioned parts things were much cooler, but the weather also started getting cooler, so that may have been the biggest help. At highway speeds everything's fine. A little city driving isn't a problem either, but if I have to sit in stop and go traffic for more than 10 minutes the temperature starts rising. Turning the heater on doesn't help. Shifting into neutral when I'm stopped does help a bit. It hasn't overheated, but that's because I get out of traffic as soon as I can and pull over for a while. If I don't pull over the heat under the hood starts wreaking havoc on the carb (I guess), because the engine will start to miss and shake a little.

I just put on a new cap tonight since I haven't changed that yet, so we'll see if there's any improvement. The next step I think is replacing the radiator, though I don't really know if that's necessary. My other thought was switching to an electric fan. Seem's like a lot of people go that route. As far as I know the radiator is original, so I'm leaning towards doing that first.

Any advice or experience would be appreciated.

 

What are you using for a temp gauge? The stock guage is notoriously inaccurate.

 

if you have the stock 5 blade fan, get rid of it and go with a 7 blade clutch fan..(found mine in a 70's ford fan with a 460) I had a 78 RV with a ford 460.. always ran hot..after I dumped the 5 blade fan and installed the 7 blade clutch fan, it didn't run hot anymore. the 5 blade stock fans stink..the 7 blade should bolt on easily..

 

Yes I'm using a stock gauge, so I'm not certain exactly what the temps are. But that seems like a moot point, really. Regardless of what the actual temperature is when things start "running hot", it's obvious by the affect on my engine idle that it's excessive.

 

Ok, so this is a good option too. Looks like I can pick up a fan and the required spacer for $65. Does it matter whether I get a thermal fan clutch or non-thermal? The non thermal is $16 and the thermal is $32, so my thought is to get the thermal fan. My truck's stock fan is a 5 blade fixed fan, no clutch. Any idea if the new fan/spacer/clutch will fit with my stock shroud, or will I need to find something else? I'm thinking that the spacer and clutch it might affect the north/south position of the fan.

 

There is a link in the tech thread sticky on clutch fans with PNs too.

Add a bottle of Redline water wetter or Royal Purple's purple ice.

Correctly flushing an FE requires pulling the pipe plugs on each side of the block. Ya did that, right?

Install a real water temp gauge instead of the oem 'kentucky windage' gauge.

 

Thermal Clutch allows the fan to free-spin when it's cool enough to not be needed, and spin when it's hot.

 

Great. I'll check out that sticky. I did not pull the freeze plugs. I understand that's the proper way to flush the system, but if I got all the rust out of from the block, flushing and reverse flushing, and got all the rust out of the radiator and the heater core, AND it's cooling fine while moving, will doing that again with the plugs out really change anything?

I'm not clear on what gets missed when flushing without pulling those plugs. I was thinking that if there is debris left behind because I didn't pull them, then I'd see consistent cooling problems rather than just in traffic jams.

I should reiterate that it's only in traffic jams that there are issues. Normal stop and go traffic is fine, as of course is highway driving. And again, when it does get hot, shifting into neutral and letting it idle up helps.

As to your comment about the temperature gauge, yes, I do plan on installing a real gauge sometime in the future. But at this point do I really care what temperature it is? I know its getting hotter than it should, and it would be nice to know exactly what that temperature is, but, being that I am experiencing heat related problems (not just a rise on the gauge), it's not like there is a question.

 

As to the temp spike, that might be the new normal. But is there an anti-collapse spring in the bottom radiator hose?

The tips above were to help make the cooling system as efficient as possible.

Btw, it's not the freeze (core) plugs to pull... there is one pipe plug on each side of the engine... crawl under and look directly below cylinders 3 and 7, about two inches above the pan rail. The head of the pipe plug is visible in the pic below...

Cooling system sediment settles at the bottom. When I pulled the plugs below nothing came out... then I poked it with a screwdriver and a torrent of scale and yuck spewed out. The block musta still had about a quart or so of remnant coolant.

 

Clutch fan from a 78 Bronco... Bolts right on. Got it from pick n pull. Normal price is $25. This is half off weekend.

It was on a 351m or a 400; not sure...

 

Yeah no cooling issues even w/o shroud.

Not to hijack but... Silver... Are you referring to the pipe threaded plugs that take a 1/4 in allen wrench? Since my radiator is out, now is the time to drain the crud. Gonna have to buy a 1/2 drive bit so I can use my breaker bar... Those things don't like coming out.

Also can that anti-collapse spring be purchased separately or does it only come with a new hose?

 

Thanks for the clarification. While I was under the truck I loosened both of mine but left them in. Just wanted to make sure they weren't going to break off. Mine are 9/16 bolts. I'll flush the system again with them out, it can only help. So, I should get in there with a coat hanger or something and just go to town? Will I risk damaging anything? I'll get a new lower hose too. There isn't a spring in mine.

 

Yep... it differs widely and can be an outie pipe plug, an allen-headed (innie) pipe plug, or even petocks.

Every good tool box should have a set of 3/8-drive allen sockets. Get a set from HD or HF for like $12.

Or use a 1/2-inch headed bolt and locking pliers.

You're welcome.

Yeah you can go to town... use some engine(rifle) brushes if ya got 'em. Stay out from under it because coolant will come out regardless if the cooling system seems fully drained.

The spring is from NPD, Mac's, and other vendors.... But don't just look for it in their truck catalog. Try other Ford models too catalog too.

Here is an article with a snippet on that spring below pic #13.: https://www.ford-trucks.com/forums/n...e=1&p=14850150

 

Thanks for the advice in this thread. The pipe plugs were so gummed up they didn't even leak when I pulled them out. Really had to jam a screwdriver up in there to get junk out and water flowing. Seems like flushing this time everything eventually came out cleaner than before so it definitely helped remove more rust. The redline water wetter's directions suggested using as little as 15% coolant in the mixture. I didn't go that far, I have 33% coolant to distilled water, and put in a 12oz bottle of redline.

I drove around at rush hour until it was up to temp, then came home and left in gear with the parking brake on for about 15 - 20 minutes. No variation in temp, and no heat related idle issues. So far so good. I'll report back if there are any more problems, or once I'm certain this exercise solved my problem.

Thanks again.

 

'Glad to help. We likes happy trucks with happy owners.