I have a needle guage not an idiot light

 

How would I tell if it were a blown head gasket?

 

Great, be sure to get the sender for the guage.

 

Blown head gasket can put oil in the coolant and or coolant in the oil. If you have oily film in the radiator under the cap, or milky oil or sometimes overflowing reservoir bottle. Usually has white smoke in the exhaust, poor engine performance etc. You'll know.

 

I go away for a few days and what do you all do? You scare the poor guy to death! Blown head gasket? Clogged radiator? Bad water pump? Thermostat? Failed gauge? How about some basic troubleshooting first, before entering FullPanicMode™?

Has the most basic question been answered yet? Is this an actual overheat, or simply an indication issue? Before trying anything else, get thee a paper grocery bag. Cut two eye holes. Drive to your nearest Harbor Freight. Put the paper bag over your head, so nobody sees you shopping there. Spend $25 and make yourself the proud owner of an infrared thermometer.

Bring the engine to normal operating temperature. Point your spiffy new thermometer at the thermostat housing. If all is good, you should see about 180F. Make sure the gauge on the dash is pointing somewhere in the Normal range, typically around the O or R. Before being told the stock gauges are trash and must be replaced with an aftermarket unit (of unknown accuracy), simply be aware the stock gauges performs adequately and you just need to know where the needle normally points when the engine is warmed up. That's your normal reference point.

For the coolant loss past the cap, read this amusing thread:

https://www.ford-trucks.com/forums/1...lant-leak.html

If still concerned about a bad head gasket, get yourself a combustion leak detector. I think HF sells one, and you already have the paper bag for shopping there. The tool looks like a turkey baster with some inner compartments. You fill the tester with a special fluid. With the engine cold, remove the radiator cap and then run the engine to normal operating temperature. Put the tool over the radiator neck and draw in a sample of air. If combustion byproducts are getting into the cooling system, the test fluid changes color.

You can also do a pressure test of the cooling system, as shown at the link above. You pump up the system with the engine off. If the gauge drops back down, you've got a leak somewhere that needs attention. If the pressure holds for at least 15 minutes, you're good there.

There are more steps we can do based on what you find, but don't listen to these cotton-headed ninny muggins. They'll have you replacing every last component under the hood and dash just to be sure. I'm willing to bet we can narrow things down just a tad to make it easier on your wallet.

 

Thank you for taking the time and explaining a few things to this non-mechanic. I don’t mind spending a few bucks to simply replace the water pump, heat sensor, fan clutch, thermostat and radiator. Worst case scenario it’s something way less serious at least I know my cooling system is new…peace of mind. Would you replace the radiator with stock or upgrade to an all aluminum? If aluminum which manufacturer do u suggest?
larry

 

You have a money tree? I wish I had one. I tried planting one but it withered and died.

Ah, but there's one important factor you may not have considered. The quality of new parts can be iffy at best. Personally, I'd trust most functioning OEM parts over Fling Dung brand Chinese replacement parts.

​​​​​​​See my previous comment about replacing perfectly good parts. And then see my personal motto in my signature. I'm a firm opponent of making more work for one's self, even in pursuit of the elusive peace of mind.

​​​​​​​With that said, I did replace my radiator. I found a problem preventing the cap from sealing properly. Please see the previous link in post #50 for details.

 

I just replaced my STANT cap(maybe 2 years old) with one that has the red lever. For the first few drives it seemed to fix my problem, but then noticed it was overflowing again.
My Rad has 2x ports on the neck. One below the cap which goes to the tank, and one above the cap that drains to the street.
It shouldn't be "over pressurized" like this, right?

 

I have worried a lot about my head gasket.
Cold, hot, dry or with a few drops of oil in the cylinders, all 8 of my combustion chambers fall within(close enough) a 10% variance. (110-125psi)
I WANT(not really) the head gasket to fail, because I know how to fix that.
No overheating issues(because the hot fluids are leaving the truck).
I can watch my thermostat open while driving. It climbs and climbs and suddenly drops.
The Rad is aftermarket, though only an OEM replacement. If I block the lower port and move the overflow to the upper port, then it will only flow to the tank when the cap is compressed due to heat. But then the tank won't be able to fill the Rad either.

 

Larry and RYan, can you guy's post pictures of what your radiator, cap and overflow tank look like ? Here's mine in my 86' 302EFI. This with the engine cold. Notice the level in the overflow tank. Radiator is a OEM style replacement .



It's a 13lbs cap.

 

Extraordinary times call for extraordinary measures.The moderators have given me permission to break out the tranquilizer gun. Here's a quick video showing what you can expect. Trust me, it's for your own good. Don't pull out the dart:


After a few hours, the drugs will wear off and you will (hopefully) regain consciousness. At that point, do some actual troubleshooting as previously detailed.

 

Note to all
A full radiator is not to the vary top but down a few inches from the opening.
So if you checked the level and "topped it off" to the top when it heats up it will push out coolant as it expands.
If you have a "over flow" container it will push it into it and you are now back to the lower level in the radiator and that is fine.

Now also note our truck only have a over flow tank not a recover tank.
If you look at the hose that goes to the tank it goes in the top but dose not go to the bottom of the tank into the liquid.
Because of this the cooling system can not pull fluid from the tank back into the cooling system like modern cars & trucks.

You can try and put a longer hose on that will reach the bottom of the tank and see if that will work.
That is how I have mine and it worked as I had a leaking heater core and it sucked the coolant from the tank into the system.
I have since replaced the core.
I can also tell you I "topped off" and when it got up to temp it pushed the coolant to the tank and because I added some to it it over flowed.
This was last weekend and have not had the truck back out or checked anything (yet)
Dave ----

 

Max it looks like you have a recover tank and not a over flow like I have.
I guess some did have recover tanks?
Dave ----

 

My Rad is the same. I have my overflow connected the the lower port. Yours is capped.
my upper port is just a hose to the ground. It stays pretty dry....because coolant comes out of the overflow tank.
It seems like I should try your setup.

Dave mentioned that our overflow tanks are not recovery tanks. My tank - the hose from the RAD goes in the bottom of the tank, not the top. Like the pic above. *how important is it to cap the overflow tank? Mine is open. I know I should be careful of debris, but it's not a pressurized tank.
​​​​​​

 

I would hook the recover tank up like Max has it.

As for over flow or recover I did not know the tanks came with the hose to the bottom like yours & Max that wold be a recover tank as the hose is in fluid all the time and can be pulled back into the cooling system when it cools off.
There is no need to cap the tank but if you want to measure the opening and look for a cap to fit.

I need to get a picture of mine but it dose not have a cap or any way to clean or fill it.
I had to use a small funnel to fill it where the hose goes in at the top.
The full blck top on mine is also glued to the bottom so no way to pull it off for cleaning
Dave ----