Greetings, my problem started a few weeks ago when the transmission lines blew atf all over the engine bay. I patched it to get to my friend's house while I was driving it, the electricity(lights, radio,etc) would shut off and come back in a couple of seconds and overheating while in gear or with the heater on. It was fine in park.

He replaced the lines and the problems went away, fast forward a bit and something hit my radiator while driving to work and coolant went everywhere. I replaced the radiator along with new coolant but now the overheating/electrical issue is back.

So to summarize, it overheats while in gear or the heater is on. Heat does come out. Along with that, if I drive it, the electricity will shut off and come back on. The top hose gets warm but not the bottom. No leaks as far as I can see and no coolant in the oil.

Things that I've tried: I replaced the alternator belt as it seemed to be stretched, possibly damaged from atf spewing all over. I don't know if maybe that's what was causing the electrical issue as I haven't been able to drive it to test it. I also replaced the hoses with the new radiator and I put in a tmeyer thermostat. I also thought maybe the carburetor needed adjustment as it has reached the 20s and last time I messed with it it was in the 70s.

It just seems weird to me and I can't figure it out, any help would be appreciated. Tomorrow my plan is to raise the front end and maybe see if its just trapped air. Is there a better way to bleed the air out without a mess other then just having the cap open?

Thank you for your time.

1978 f150, 400, no a/c just ps, mild cam.

 

To get the air out of the system park it on a nose up slope, or a set of car ramps. Sorry all I got this early.

 

That should work.

Ford had a TSB for air pockets in the cooling system at one time, when replacing a thermostat a piece of hard sugar candy ("boiled sweets" for our friends across the pond) jammed into the opening to keep it open on the initial start, allowing coolant flow to occur. The candy would soon dissolve and the thermostat would then work normally.

 

The alternator may be toast from the coolant shorting it out. Bottom hose needs a spring in it to keep it from collapsing.

 

Thank you all for the replies so far.

This was a theory I was having about the alternator. Could that also cause an overheating issue, maybe with misfiring? What else could the heater and it being in gear have in common.

The old one had a spring in it but the new one did not. Though it isn't collapsing, I could put the old one on. The new top hose came with a spring though.

 

I would say you are on the right track.
I would also check all grounds and connections in the engine bay to make sure they don't have ATF or coolant in them.
I would say it is electrical and not over heating.
Dave ----

 

"It isn't collapsing." Well ... how do you know this? The spring in the lower radiator hose (or lack of it) can sometimes cause a hard to diagnose temperature issue at highway speeds or when when the engine is under heavy load and trying to move a lot of coolant.

Like a lot of engine derangements it isn't going to show up at idle, but it can collapse under "suction" on the highway, enough to restrict coolant flow. "They" say the spring is not necessary, and therefore they no longer include them in replacement hoses, but if it's all the same, I use the spring in the lower radiator hose just like Henry did.

 

A bad alternator might cause bad gauge readings.

 

Because its overheating just it being in drive/reverse or with the heater on, so I'm able to see it. Visually it doesn't look like it, but I'm going to change it out anyways just to rule it out.

 

Ok, good feedback I gotcha. One thing that can cause trouble too, older engines start to build up lots of sediment and rust scale inside the engine cooling passages after so many years. Ordinary coolant flush won't get this removed. If a previous owner wasn't so good about coolant changes or it sat for a long time this might be an issue. In southern states people will sometimes run without coolant, usually a really bad idea.

Some have reported success by removing those square head pipe thread fittings usually found just above the oil pan line on either side of the engine. Snake a coat hanger in there and get it cleaned out. These pipe fittings are usually a real b&!tch to remove, but if I had an older engine with an overheating issue that would be something I'd want to look at.

It could of course be as simple as a defective thermostat. New doesn't mean "good", did you test it prior to installation? Worth doing these days with the quality of parts.

Jam a piece of a cough drop or something like that (hard candy) in the thermostat opening against the spring pressure holding it open temporarily. This will prevent air pockets at first startup. Keep adding 50/50 antifreeze concentrate and water at a fast idle till it reaches full, a couple inches below the neck. Top off as necessary.

 

Slipping belts will slow both the alternator and water pump. They both take horsepower. While they may keep up at idle, driving down the road at 2500 or more RPM, maybe not. ATF baths followed by coolant baths are a good way to create slipping belts.

No AC maybe means you have one belt from crank to water pump & alternator, and a second belt from crank to power steering?

I'm just guessing about the belts as mine has AC and while I have those two belts you have, I have a third belt from crank to water pump to AC so I'm not sure how yours is set up. ... and mine has no smog pump.

 

One belt from crank to alt, and another from crank, water pump, and power steering.

Thanks for the reply

Tomorrow I'll dig into the electrical system and I have a spare alternator on hand to change out and see. Hopefully this is it.

 

The electrical accessories dying should have nothing to do with the alternator. Even when the alt is completely dead everything else is running off of the battery and should for quite some time. And once things start dying, so should the ignition and engine stop running.
I think you have other electrical issues to find.

Just for reference though, the next time anything stops working (how long does that usually last?) use your multi-meter to check voltage at the battery. If it's 14v or more with the engine running then there is nothing wrong with the alternator.
Does your truck have full gauges by the way? Or does it have two gauges and two indicator lamps? When you say it's overheating, is the light coming on or does your gauge start to climb up? If a gauge, how far does it go? And how long in gear until it starts to show it's hot?

Paul

 

I would agree if the battery is a good battery.

 

Is the engine actually overheating and pushing coolant out, or the gauge just showing hot?

I had a Cleveland that started running hot and throwing coolant out at random times. No leaks or low coolant before running hot. It was the water pump, even though it gave no evidence of being bad, such as leaks or loose bearings, noise, ect.