Hello everyone. I drive a 1993 Toyota Pickup. 22RE motor, 190,000 miles on it. I am having issues with it and I am having trouble pinpointing the source.

The truck begins to overheat when the Air Conditioner is on. This only happens when either idling or traveling between 0-35mph. When I am on the freeway, the issue isn't present unless it's about 100 degrees outside. I have replaced the following:
Radiator with a new cap, hoses and fluid.

1. OEM Fan clutch
2. Water pump
3. Belts
4. Spark plugs, wires, distributor cap and rotor
5. The entire AC. (Converted it from R12 to R134)
6. I replaced all the oils. Engine oil is 800 miles old, Transmission oil is roughly 10,000 miles old along with the differential fluid. (Worth noting, perhaps.)
7. New Temperature sensor for the gauge and ECU)
8. New thermostat (180f)

Now, I am missing a fan shroud entirely. The old one shattered and disintegrated, which I am aware can cause the overheating, but it's only when the AC is on. Sometimes, on a hot day, the temperatures will climb even if the AC is off. I've asked many people, but have yet to ask here.

My second issue is rough idle. But it doesn't always happen. At a cold start, there is no rough idle, it's fine. When the vehicle is at operating temperature and is hot outside, is when there is intermittent rough idle. It'll drop down to a low rough idle, causing the truck to shake and power steering becomes a lot weaker. A short bit later, it'll kick back up to its standard idle. When the engine and outside is both hot, sometimes the vehicle will stall after starting the engine. Sometimes, shifting it into reverse will cause it to stall. To remedy the stalling, I turn on the AC, which forces the truck to run at a higher idle. Here's my thoughts on what that could be:

1. Gunked up idle air control valve
2. Idle is simply set too low
3. Vacuum leak
4. Old dirty injectors

I would appreciate any additional ideas on any possible issues. Thanks for your time.

 

Why would the fan shroud only cause overheating when the AC is on? Go ahead and get that fixed before you start horsing around with the water pump, fan clutch, etc. https://www.ebay.com/itm/Fits-Toyota...-/282664972510 (be sure you get the part that is correct for YOUR vehicle)

 

Possibly due to the extra load that's put on the motor. And there was no horsing around. I've already replaced the fan clutch, radiator, and waterpump. Water pump was dead, so was the fan clutch. Old radiator was gunked up. My next step was to get a fan shroud. Probably will get one next week.

But that still wouldn't explain my rough idle issue. Any ideas?

Thanks.

 

When is the last time you took the Throttle Body off and gave it a good cleaning? Also, maybe time to get injectors serviced.

 

I haven't given the throttle body a good cleaning. When I replaced the radiator, there was a lot of build up, but I didn't have time to remove the throttle body. That's something I definitely need to do.
And I agree. 190,000 miles is a long time for injectors. I'll order some on LCE when I get a chance.

For now, I'm going to hunt for a fan shroud and see if that'll resolve my overheating issues when the air conditioning is on. But I would love more ideas.

Thanks.

 

Definitely go ahead and replace the fan shroud. Toyota spent millions of dollars designing certain things on those engines and that is one of the. Its going to direct more of that air flow to your engine instead of dispersing it all around the engine bay.
Secondly, Make sure you have properly bled that radiator and you don't have any air in the lines. Simply crank it in the driveway and let it get to operating temperature with the radiator cap off and continue to add water/coolant to the radiator until it just cant take anymore. You'll see once that thermostat opens up and starts sucking water because the level will drop but you may also see that level start bubbling a lot because you're pushing out whats been airlocked in your engine and causing hot spots.
Third, i would pull the thermostat and drop it in a hot pot of boiling water on the stove. if it opens up, that's not your issue. If it stays closed, you know you got a bad thermostat. Also, i've seen some people drill a 1/8" hole in their thermostat whenever they're having this issue and they claim it seems to help. I don't know the benefit of it but you may give it a shot. It cant hurt.
Regardless, i would start with the fan shroud and see where that leads you because that could very well be causing your issues.

Good luck!

 

I made sure to bleed the system when I installed the new radiator and coolant. I can definitely try again as it doesn't hurt to try. I do plan to flush out the green coolant (Thouroughly) and put in some Toyota Pink Coolant.

I could do that with the Thermostat. I am almost certain it works since it's brand new and the truck only overheats while idling when the AC is on. The thermostat already had a little hole in when I bought it. I do want to replace the thermostat with this: https://22reperformance.com/22re-coo...tat-dual-stage as I have read that could be an issue when dealing with the AC.

Thanks for your answer. Do you have any ideas on the rough idle?

Thanks again.

 

Try replacing the coolant temperature sensor. Whenever i had a similar problem in my previous toyota, the coolant temperature sensor quit working and the ECU didn't know what temperature the engine was and didn't know exactly how much fuel to provide it with.
Its only $15 or so as i recall.

In the winter time, it would cause the RPM's to surge up and down a few hundred RPM's but it may act differently in the summer time.
I always go with the cheapest options first..

How does it do under load/higher rpms? Does it skip or seem weak?

 

If it seems to lack power or skip, i would look into replacing the injectors. That was also an issue i had whenever it seemed to be idling on 3 cylinders and lacked some power.

 

Yeah the temp for the gauge and ECU are new. Just replaced them a couple months ago.

I do plan to replace the injectors. The ones on LCE go for 200$.

In the mean time, I'm i've place an order for the fan shroud. Should come here in a few days. I return to this thread whether or not it solves me issues. Thanks for you guys' time!

 

The fan shroud is pretty important for a properly working cooling system.

Toyota even added a small lower fan shroud piece to Trucks with A/C to help cooling even more.

I would start there and see how coolant temperatures look after the fan shroud is installed.

 

Thanks for the reply.

I have ordered a fan shroud. It should be here in a few days. I also am going to get the lower fan shroud when I can. 22RE performance sells one, so I'll grab that.

I'll come back if that solves my cooling issues. Thanks!