Overheating Mystery

[Tomm1468]

Don't recall if Tomm1468 installed a new Radiator or if this is an old\original Radiator?
If it's old\original, inspect front side for RoadDebris, could be clogged up fins blocking air flow?

I did not get a new radiator, but that was one of the first things I did, just making sure everything was clean and able to flow unobstructed.

 

[Tomm1468]

You can waste a lot of time and money relying on the factory temp gauge. I would get a second opinion from a infrared thermometer like someone else mentioned. Just to make sure the gauge is not lying to you.

yeah, Thats going to be my next step of investigating if the new clutch fan does nothing.

 

[alwaysFlOoReD]

I've taken apart a few old rads that were marginal at best. They flowed well but didnt cool all that great. Found the bottom third of the rad clogged with sediment, and that was after doing reverse flush and using aftermarket rad flush chemicals. Use the infrared to check the temp of the rad in several different spots. Or your hand after shutting off the engine.

 

[19Walt93]

If you decide to use flush chemicals, make sure you can get the block drains out so you can get rid of them afterwards.

 

[Tomm1468]

alrighty Bois, a new clutch fan came, and it its a bit quieter than the other so that one might have had issues, but all in all, still getting too hot. it likes to heat up a little and sit for about 5 mins, then heat up more and sit at one spot for about 5 min, and it will do this over and over as it creeps us the temp gauge.

One of the first things I did with the truck when I bought it is to buy a bunch of radiator flush chemicals, and flushed it out about 7 times until the water was coming out clear, then added in nice coolant, however the last time I took the engine apart, I drained all the coolant that would come out of the hole at the bottom of the radiator, I let it drain for probably an hour, then I turned my engine over and let it run for a second in an attempt to get all the coolant out then let it sit for probably another 3 or so hours, all in all, only about a gallon came out (though it takes just about 2. and when I went to add more in, it only took about a gallon in, even when I turned the engine over and let it burp out, only about a gallon. so maybe there is a huge blockage. at the bottom.

 

[Tomm1468]

thermal theromoeter is in the mail.

 

[Tomm1468]

 

[franklin2]

That picture above means nothing. Waiting to see what the thermal thermometer says. I haven't heard any stories about the radiator or the overflow bottle spewing over, no knocking from the engine, no burning oil smell, not down on power, no other signs of overheating except that gauge correct?

 

[Tomm1468]

That picture above means nothing. Waiting to see what the thermal thermometer says. I haven't heard any stories about the radiator or the overflow bottle spewing over, no knocking from the engine, no burning oil smell, not down on power, no other signs of overheating except that gauge correct?

yeah, you're right. and TBH when engines overheat you can generally feel it really just radiating heat, beside the fact that it's spewing coolant. My engine doesn't feel that hot, when it says it's this hot, and no spewing. but if it is a wiring problem, I'm wondering why just now it's having this problem since it was fine before I did the rebuild.

 

[RobbieD]

Long shot, but I'll throw it out just in case. I don't know on your '95, but assuming your gauge temp sending unit (noted as new Motorcraft) is a single-wire type, did you put a bunch of teflon tape on the threads to "seal it up good"? In other words, make sure that the sending unit is properly grounded to the engine. If it has to be taped, you should always leave some bare threads to ensure a good ground bond.

 

[Tomm1468]

Long shot, but I'll throw it out just in case. I don't know on your '95, but assuming your gauge temp sending unit (noted as new Motorcraft) is a single-wire type, did you put a bunch of teflon tape on the threads to "seal it up good"? In other words, make sure that the sending unit is properly grounded to the engine. If it has to be taped, you should always leave some bare threads to ensure a good ground bond.

Hey, thanks for the thought. Unfortunately, it is not a single wire type, the sender unit is, but the actual coolant temp sensor that reads to my gauge cluster is double wired and has a clip to hold it in place.

 

[bobbywalter]

Carefully check block with temp gun..as it may be sludged...need to actually drain it......and get a real gauge for testing purposes. A real gauge should have been the first thing bought...just as a temporary check...as it would have been an investment since you did not already have one to pop on for a look.

May have the head gaskets on wrong(not sure what brand used)...or like mentioned, pump running backwards....though...she would likely blow some steam in those scenarios.

There is a proper way to install a temp sending unit....

 

[RobbieD]

Hey, thanks for the thought. Unfortunately, it is not a single wire type, the sender unit is, but the actual coolant temp sensor that reads to my gauge cluster is double wired and has a clip to hold it in place.

OK, I'm used to the older stuff (OBD1), which uses a single-wire sending unit to the gauge, and a two-wire sensor to the PCM. Don't give up; you will figure it out, and good luck!

 

[Tomm1468]

OK, I'm used to the older stuff (OBD1), which uses a single-wire sending unit to the gauge, and a two-wire sensor to the PCM. Don't give up; you will figure it out, and good luck!

went out and looked at it, and im an idiot. i was mixing the sender and the ect. soooo yes it is a single wire that sends signal to my guages, but its tight down, really tight since its also new.

 

[RonD]

After it cools down remove rad cap, if there is any air in the rad then you have a problem with head gasket or a leak in the engine side of the system

The overflow type systems lets hot coolant flow OUT and over to the overflow tank when engine is warm
Happens every time you drive longer than say 20min at a time, that's what the COLD and HOT lines on the tank at for
Then after key off as the engine cools down the coolant is SUCKED back in from the overflow tank
So after engine is cold rad should be topped up completely, NO AIR at all

Any air in the engine side of the system will collect at the top of radiator and be PURGED out as engine warms up
This is why the hose from rad to overflow tank comes in at the BOTTOM of the overflow tank
Any air that comes out will bubble up to the top of the tank and be purged
When engine cools down only coolant would be sucked back in

If there is air at the top of rad after cool down then there can be a few things wrong
A leak in the engine side will allow AIR to be sucked back in as engine cools down, sucking in air is way easier than sucking in coolant from the tank

A leak in the overflow hose, it will allow air to be sucked back in

A head or head gasket issue, it pumps in "air" which pushes out too much coolant, so overflow tank gets too full
And it holds a higher pressure so coolant can't be SUCKED back in on cool down