Hey,

I have a 1993 Toyota T-100 1-Ton with 150k miles. I have been having some problems that I am not sure how to troubleshoot. I have already checked for error codes, but there are none. Three different things have been happening:

1. When the engine is cold, it seems to hesitate when I try to accelerate. I especially notice it starting out in first gear, or when I shift into 2nd or 3rd. It hasn't stalled out, though sometimes it feels like it wants to stall out. It drives fine once warmed up, though.

2. If the engine gets hotter than usual, then shut off and rests for 20 or 30 minutes, it idles roughly for a second or two when restarted and then stalls. If I rev the engine for a few seconds, the rough idling goes away, and it then runs fine.

3. A few times, the engine has gotten rather hot. The first time I noticed it was Saturday, which was a relatively warm day (70s). It was even worse today as I drove up into the hills. By the time I got to my destination, the needle was almost to the red. Driving home this evening, the temperature was fine. I replaced the coolant last summer, though I simply drained and re-filled, I didn't flush the system.

I have no clue if these are three separate issues or all related somehow. There is a problem with the heater control cable. The cable is frozen, so I have to turn the heater on and off manually under the hood. On cold mornings, I start out with the heater on, and sometimes forget to turn it off under the hood. This was the case Saturday and today. Saturday, I left the heater valve on but turned the temperature knob in the cab all the way to cold and even turned on the AC. Today, I left the heater valve on but turned the temperature knob in the cab all the way to cold. I have heard before the heater can help remove heat from the engine (e.g. I've heard turning the heater on full can lower the engine temperature when it is starting to overheat). Could leaving the heater valve on have caused the hot engine?

Any idea where to start troubleshooting? Without an error code from the computer, my manual just gives a laundry list of possibilities, and I don't want to start shotgunning parts.

Thanks,
Tobyn

 

u might want to check and see if u have a head gasket going bad, or already bad with it getting that hot, items that can casue it to get hot is bad water pump, thermo stat stuck or not opening, radiator cap and radiator flow bad or plugged, yes running the heat inside would help lower the heat on the motor. as for other items when was the last time u did a tune up?

 

I would also pull your plugs and see how they look. It could be something as simple as plugs or wires.

 

I replaced the plugs last summer. They were horrible! I am amazed the truck ran, let alone pass smog in CA!

I haven't done a tune-up, though this engine isn't as old as the truck. Toyota rebuilt the engine under warranty around 2000 (75k miles ago). The valves don't make excessive noise yet, so I haven't had them adjusted yet.

Checking my plug wires is on my list to-do.

Is there a way to check the pump or thermostat without removing them? The thermostat isn't too bad to remove, but the pump requires removing the timing belt (according to the manual, at least).

I do have an oil leak in at least one of the head gaskets.

Thanks,
Tobyn

 

The imfamous 3.0 head gaskets surface again...How is that for internet diagnosis? Any significant coolant loss, smoke from the tailpipe, sweet burning smell, oily coolant, swelled coolant hoses, and/or watery oil? I'm only jumping right into the worst case scenario purely based on the fact that it's a 3.0...

 

Nope, none of that.

Tobyn

 

Well you said you have an oil leak in one of the headgaskets, that needs to be changed. You can't just let that go...

 

Is the oil leak from the head gasket, near the middle of the engine, or the valve cover gasket, near the top of the engine?

 

Snap a piccie of the leak and post it...

 

How much coolant oil does it use? U could do a compression and leak down test.

 

I have a 93 T100, my dad gave it too me when my car died. It was not running well at all, no power, and i found out the cataletic converter was gutted out. replaced that and the fuel filter and it has a bit mor power but once she is warm still has low power. thinking it is the fuel pump or the egr valve. the heads have been redone so i know its not that. truck has 216,000 miles, and sort of still going strong. thanks for the ideas.