1995 F350 4x4 460 7.5L E4OD

Either I am overthinking things.....or I have a radiator problem.

About a week ago, I discovered a coolant leak. Went ahead and replaced the water pump and timing cover, as well as new hoses, radiator cap, and thermostat. Buttoned everything up, poured fresh coolant and turned the motor over. No leaks underneath.

My habit of keeping an eye on the water temp gauge for a week or so kicks in after a water pump replacement. My water temp reading is fine. Everything seems okay, right?

This morning I bought some firewood which filled my full length bed about halfway. The highway drive home was about 15 miles. I pull in, turn off the engine, and decide to make a quick visual inspection underneath the hood, underneath the truck.

Again, everything seems normal...except this: I place my hand on the radiator cap, and it is luke warm. The lower rad hose is cool to the touch.

The upper hose is extremely hot (I can keep my hand on it for no more than 4 or 5 seconds. The hoses to the heater core are extremely hot as well.

I'm wondering if my radiator is clogged? I mean, other than the cap and lower hose coolness, I don't see any other symptoms of a circulation problem.

What are your thoughts? Have you experienced anything similar to my situation? I want to go the route of "If it ain't broke, don't fix it", but I'm not entirely confident.

Any feedback would be much appreciated.

 

Get an infrared thermometer.

Start the truck cold and monitor the temps at the water neck and you should see the thermostat open at whatever temp stat you have.

Remember, once it opens it's going to go closed again as the cool water from the radiator (if it's not blocked) hits the thermostat and then it will open again. This will show on the gauge as well unless you have a failed sender.

A failed sender is entirely possible as I have a '95 also and before I replaced mine, it would never go above about 2/5ths scale at all. Pull the wire and ground it and the gauge should go full scale. If it doesn't you have a gauge problem. There's a chart lurking around here somewhere that shows what resistance you should see across the sender vs temp.

You should be able to watch the upper hose get warmer and see a temp gradient from the top to the bottom of the radiator and to the bottom hose.

If there are cold spots you may be able to see that you have some of the tubes blocked.

Where are you in the world? Ambient temp could be a factor. My truck is amazingly good at keeping cool even in the summer.

 

hot coolant comes out of the engine through the top hose. and is drawn into the engine through the bottom hose.
so the top should be hot, and the bottom should be cooler.

 

this one
Fuel Injection Technical Library » Engine Coolant Temperature Sensor (ECT)

 

Stonesg -

I live in Phoenix, AZ. Daytime temps this time of year hover in the mid 60s.

I was able to measure the temperature of the water neck and the intake just beneath the water neck with an infrared thermometer. The temp ranged from 200-210. The IR thermometer I used is the Klein IR5. On the gun I set the emissivity at 0.78. My experience with this gun is minimal, which is to say I'm not entirely sure the settings are "correct" in reading temps on a cast iron block, the water neck, intake, etc. From what I understand, temp values can vary with emissivity.

The gauge sensor is something I never thought to examine. It's a great idea. I'll ground the wire as you suggest and see if I've got a problem there.

 

No Sir.... That's the ECT for the fuel Injection. Has nothing to do with the gauge.

The coolant temp sender for the dash gauge is a single wire sender just back and to the right of the distributor.

 

Even if the values are not 100% accurate at this point, at least you'll be able to see if there are any cold spots on the radiator when the thermostat opens.

What temp thermostat did you install? Is it at all possible you put it in backwards?

 

Prior to installing a 195 degree thermostat, I drilled two small holes with a 1/8 drill bit in order for any air in the block to escape. I installed the 'stat with the thicker, "meatier", cylinder-shaped whatchmacallit facing the block. The smaller "tip" is inside the water neck. Did I make a rookie mistake and install this thing bass ackwards?

Reading temps on different spots of the radiator is going to be tricky. Is removing the shroud necessary to get good data? How many spots on the radiator would you recommend I test?

Thanks again for your help. Seriously.

 

this one, when you said chart I thought ECT, instead of looking,

temp sender for gauge in truck

 

You've got the thermostat in correctly.

I'd just monitor the water neck, the top hose, the top tank, as much of the rad as you can through the grill, the bottom and the bottom hose.

Do it from totally cool and since the tubes run vertically, before the whole rad warms up, you should be able to see if one side or the other is cooler when the coolant flows.

Don't forget that if the stat is operating properly, it's going to open and then close again at least once while warming up (if the coolant is flowing).

IIRC I had about a 20 or 30 degree gradiant between the top and the bottom hoses on mine.

If you REALLY want to see what's up and you suspect the rad is blocked, you could pull the top and bottom hoses and flush it run some water through it. I'd think it'd pool water in the top tank if it's really restricted. You could rig up some type of reducer and back flush it from the bottom and see how much crud comes out the top.

 

OOPS! You are correct. I just hit the link and saw the ECT and didn't scroll.

Mea Culpa.

 

Stonesg -

What's your take on aftermarket gauges, specifically, water temp & oil temp?

From what I understand, Ford stock gauges aren't the best in the business.

 

I'm a data geek and always put oil pressure and temp gauges in my vehicles if they don't have them.

Once I changed the faulty temp sender (It never went above the "o" in normal no matter how hot the engine got even in the depths of summer), and monitored the gauge while using the IR thermometer, I decided it's got fine enough resolution for me. It always goes up to the top of the "m" and then kicks down as the thermostat opens and then recovers.

The only thing I'd gain from another gauge is actual numbers so as long as it's working as well as it does, I'll stay with it. I plan on doing the oil pressure gauge mod too.

If you don't know about it, the OPG is just an idiot light in that the sender is just a switch and the gauge has a resister across it to give it about half scale reading when you have oil pressure. Apparently people who didn't understand that oil pressure will go up and down with RPM were pestering Ford about the moving needle so they gelded the gauges to stop the complaints instead of just telling them they were idiots.

Oil temp I wouldn't bother with as it's going to be close to coolant temp.

 

Steve83 posted a TSB on senders that came out, TSB 95-13-02 Erratic temperature senders(F1SZ10884A,DOWY10884A), and how to check resistance on it
1983 Ford Bronco TSBs & FSAs (Recalls) for '83-96 Broncos & F150s picture | SuperMotors.net

 

The moral of this story.....I've got a clogged radiator.

Spot scanned the temperature of the radiator after running the truck to normal operating temp. The upper half of the radiator was upwards of 190 degrees; the bottom half was 125 tops.

I decided to purchase an all aluminum 3 row replacement thru Radiator Express. Set me back $250 with shipping.

I want to thank everyone who chimed in to help. Because of your input, I'm a little wiser...and grateful.

Cheers!