After spending alot of money and time, frustratingly I just replaced my upper and lower intake manifold gaskets, throttle body and IAC gasket, exhaust manifold gaskets, valve cover gaskets, cap, rotor, plugs, wires, water pump, serpentine belt, and the thermosatat with a 160 degree instead of the OEM part(Thinking this would help). I put everything back together and started it up, it ran fine. I let it idle for a little and began to drive, but at stoplights and stop and go traffic it began to overheat, very fast. On the highway it runs great... temperature wise. My truck has no coolant leaks and holds pressure but runs SOOOOO HOT!!! I was talking to a car guy who I consider to know much more than I and he looked at it a said my radiator looked small, and could cause overheating. It looks OEM, where are the part numbers on radiators. Are there different radiators for each model? If I got a used radiator from a junkyard out of a 460ci F-series, WOULD IT FIT?? Would this work, what do ya'll think? Sorry for the legnth, oh and whats the best way to clean/flush a radiator? Thanks

(1991 Ford F-150, 5.0L, 5-speed, SWB, with 150,000 miles)

 

Please define 'overheating'.... temp gauge climbed up into the red accompanied by coolant bubbling out of the reservoir? Just one or the other?

If it's a hardware failure, the likey culprit is one of the two pieces you haven't replaced: The fan clutch or the radiator. If it cools fine on the freeway generating more power, but also getting more airflow over the radiator, it sounds to me like I'd be looking real hard at the fan clutch.

-Joe

 

Did this just start happening? What has changed? Could be a clogged radiator, air in the system or the pressure cap is no good.
Jes

 

"Overheating" in my case is defined as the gauge climbing into the red, no bubbling in the resevoir, everythings just really ****ing hot under the hood, no smoke, just lotsa heat. How would I find out if air is in the system? How do I find out if my fan clutch is bad????????

 

It's also quite possible that there's nothing wrong. If the radiator cap isn't spitting/steaming when it overheats, it's probably the engine coolant temp sensor. I believe it's on the driver's side of the block about halfway up near the front, but I could be mistaken (memory is fuzzy). It's just a little sensor with a pair of wires on it, and they do go bad occasionally. Without a direct-reading guage to connect, there's no way to know for sure what the actual temp of the coolant is.

What could be happening is that as the heat builds up under the hood, it further affects the resistance of the temp sending unit, and, therefore, the guage goes up. On top of that, it's a $10 part.

As for the fan clutch, get the engine up to temp, pop the hood, shut the engine off and watch the fan. It shouldn't freewheel and should stop spinning very quickly as the engine does. A revolution or two, maybe three topps is OK.... if it spins like a top, replace it.

Let us know what you find.

 

Fan clutch is in great shape, when I cut the engine the fan stops a quarter turn later, so I replaced my radiator cap and took it for a reasonably long drive, stopped at a gas station and then it wouldnt cut back on. I know parts of my radiator are clogged. Whats the best way to flush it? Thanks for ya'lls input.

 

Let a radiator shop do the job or replace it with a new one and have it over with.

 

If you can't find a reasonably priced radiator replacement, definately take it to a radiator shop.

They will pull the top off and cram a cleaning rod down all the passages, removing all the crud. Then they braze the top of the radiator back on. I have done this with a few vehicles over the years and it always worked great! Instant cool running motor.

BTW, those radiator flush in a can products do very little if any good. When your radiator passges are clogged bad, the chemical & water flush is not going to circulate to the clogged passages. You need to have someone get in there and scrape it out.

 

All right, I flushed my radiator with a hose earlier today, went for a drive and it still heated up extremely fast at lights and idling. My fan clutch is great, thermostats fine, belt and waterpump are new, hoses are fine and my temperature sending unit is fine. Having just flushed my radiator, What the **** is going on, how do I find out whats wrong???? How much do radiator shops usually charge and are they that much more thorough????? Thanks for ya'lls input thus far.

 

Last time I had a radiator rodded out at a shop, I think it was over $100 and that was more than 15 years ago. Probably alot more now. There is a fair amount of labor involved if you take the truck to them - they've got to wait for it to cool, drain the coolant, pull the top of the radiator, clean it out by pushing a cleaning rod through every passage, rinse the residue, reassemble by brazing the top of the radiator back on, replace the coolant, test for leaks, etc..

I'm telling you, those radator flushes will not effectively clear clogged passages, even though they will flush a lot of crud out of the system.

Ordering a replacment raditaor from someplace like Summit or JEGS (if they have one for your vehicle) might be the way to go. You can do it yourself at your convenience and not have to pay dealer prices. A new radiator may cost you a few hundred $, but its cheaper and easier to install than a new motor (which is where you are headed if you keep driving).

To help prevent problems in the future, use distilled water with the anti-freeze, especially if your area has hard water.

 

Well, ****, I just went a head and ordered a new radiator online at outlawradiator.com, Great deals, or are they too good to be true??? Anyone every used this site. I paid $112.oo shipping, taxes and all for a brand new 2 core radiator. Damn I hope this aint to good to be true. I figure if a shop flushed and cleaned my old one it'd just be cost efficient to replace it for this price, thanks for ya'lls input and hopefully this will end my cooling crisis saga. Thanks

 

I saw in another thread that an aftermarket radiator could be had for as low as $105, so your price sounds fair.

As long as it does not leak, you will be far better off than where you are now. Based on your descriptions and the things you have already replaced, I am almost certain the new radiator will cure your cooling problems.

Good luck!