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1994 Toyota Truck- The Mysterious Shut Down... Who Knows The Answer?

I have a 1994 Toyota truck that overheats and dies after 2-3 hours of driving. Once it cools, it starts back up until it gets hot again. It has been taken to many different professionals and no one can find anything wrong with this truck. One shop changed the fuel filter and checked the catalytic converter. Another checked the radiator. One said it could be the fuel pump, but found nothing wrong. The problem still exists! The truck is used for work (delivering mail in rural areas) so there is a lot of stop and go. Anyone…help!!!

First thing I’d address is why it’s over heating. That’s your biggest problem.

Has that been analyzed??? Water pump, Radiator, Thermostat???

Once that’s figured out then it’ll be easier to find out why the engine is shutting down. In fact if you fix the overheating problem then it may fix the engine shutting down.

I assume the engine coolant is getting too hot when you say it over heats after time. I also assume the cooling fan has been checked for a problem there. It may be time to replace the radiator. It is most likely partially clogged.

It would be nice to know if the ignition system is the cause of the shut down or if it is a fuel delivery problem. Try spraying some starter fluid into the intake the next time this happens. If it is a fuel problem then the engine should restart for a bit.

If by overheating you mean the temp gauge is pegging out and you’re continuing to drive it then it could be anything. Is that how you’re defining overheating or are you assuming that operating it a few hours and it dying is the definition of that.

Your complaint is very murky based on a fuel filter/converter replacement and a radiator/fuel pump diagnosis.
If someone is changing a fuel filter based on a random dying then maybe you need to find another mechanic.

You mention it gets hot after an 2 to 3 hours. Do you mean the coolant temp is high, or just after the truck has been ‘working’ but not necessarily ‘overheated?’ Need more clarification as to what exactly is ‘overheating.’

A coolant issue would not let you drive that long, and would probably have killed your engine completely by now. I would be looking at ignition or electronic controls.

Let me clarify… the truck runs for 2-3 hours fine. Then it starts to whine (sound comes from the under carriage, driver side, in between the two tires), and when you push the gas, there is a sputter, then it quits. The temp gauge never goes into the red, however. After the truck sits for 20-30 mins, it will start again and run for a few more hours-sometimes with the whining sound. The radiator has been checked-o.k, the thermostat-o.k. I think it may be fuel delivery/pump or the fan belt? The truck has approx.123k miles. It has been to three mechanics, however, it never “act ups” for anyone and no one can find anything wrong with it?. I think the stop and go is a key factor in diagnosing the problem? In addition, I live in the Deep South, very hot!!!

That sounds like a failing fuel pump. Fuel pumps can quit in a variety of ways and what you describe is one of those ways.

I will replace and hope that fixes the problem, but why does it take so long for it to quit if in fact that is the problem??? there must be something more to it??

In some of those cases a pump may work fine for week, month, or even 6 months and then out the blue hiccup and cause the engine to die. There is no timetable on something like this.

A few years back my daughter had a Mitsubishi that was prone to dying. No codes, no obvious problems, etc so I suggested she leave the car with me until I was dead certain of the cause.
I drove that car daily for a week with not a hiccup and one weekend decided to drive it to my youngest son’s house. (130 miles round trip)
So as per the usual, about halfway home on a 100+ degree day it died on me on a deserted back highway.

A little diagnosis showed it was indeed a failed fuel pump and I was stuck. About 20 minutes later it started right up, ran fine, and got me home with no problems.
What made this particular problem a bit stickier was that I had replaced the pump about a year before and one would not think a 10k miles pump would have gone belly-up already.

(Most fuel pump problems are caused by rough commutator surfaces on the armatures. The pump may be like new in every respect but that one area will cause them to go stupid.) Hope that helps.

Thank you! I will let you know the outcome:)