Lack of Power when hot.

[leandro]

Hi everyone.
I searched the forums several times looking for this problem but couldn't find anything.

I live in a subtropical weather, very hot in summer, mildly cold in winter.

In winter my X runs perfectly, absolutely no problems. The temp gauges is about 1/4 of the scale.

In summer, it gets hotter, the needle of the temp gauge reaches the water picture with the AC on, with the AC off, a little lower.
When it first start, it runs fine, but when it warms up it looses power, like if you are towing an entire house. It doesn't react, takes too much to gain speed.

I tried several things (spark plugs, injectors, fuel pump, fuel filter, cleaned the MAF, colder thermostat, replaced oil and filter for the transmission and don't remember what else), nothing worked and as summer is coming here at the southern hemisphere I started to worry again.
After a lot of reading and investigation, I think that could be the transmission, as it shares the radiator with the coolant, the transmission oil gets hot and gets too liquid. I cannot find any other possible solution, no error codes, all sensors seems right.

Any help would be very appreciated.

 

[yavapaires]

I would install an auxiliary transmission cooler. I put one on my 96, in the same location as the factory cooler. On the right side just behind the grille.

 

[leandro]

I would install an auxiliary transmission cooler. I put one on my 96, in the same location as the factory cooler. On the right side just behind the grille.

That is one of my options, but first, as the AT are not common here, there is no specialized people to do it. Second, I'm not sure yet that the problem is the transmission, it's just a guess.

Thanks for your response.

 

[RomeovilleIL]

I would suspect that it is not the transmission unless you feel like it is slipping when you have no power. Your description does sound like what happens when an engine is overheating - slow reaction, weak power. Just wondering, what happens to the idle when you are in this condition? Is it high (like 1000 RPM stopped in gear), or normal to low?

Since you are seeing the temp rise but not redline, I would check 2 items: radiator fluid mix (50/50) and airflow through the radiator.

I suspect you have a bad clutch fan or missing/damaged shroud given the other parts you already replaced and the fact that the truck works properly when temps are mild. Also, do you have any aftermarket parts on the front of the truck that could impede airflow? A lot of offroaders get issues when they install front skid plates or custom mount large winches that block the air getting to the radiator. Try taking a hose to spray out the radiator fins from the engine side towards the front. An amazing amount of dirt & bugs can get clogged in the fins and reduce the cooling function.

 

[leandro]

I would suspect that it is not the transmission unless you feel like it is slipping when you have no power. Your description does sound like what happens when an engine is overheating - slow reaction, weak power. Just wondering, what happens to the idle when you are in this condition? Is it high (like 1000 RPM stopped in gear), or normal to low?

Since you are seeing the temp rise but not redline, I would check 2 items: radiator fluid mix (50/50) and airflow through the radiator.

I suspect you have a bad clutch fan or missing/damaged shroud given the other parts you already replaced and the fact that the truck works properly when temps are mild. Also, do you have any aftermarket parts on the front of the truck that could impede airflow? A lot of offroaders get issues when they install front skid plates or custom mount large winches that block the air getting to the radiator. Try taking a hose to spray out the radiator fins from the engine side towards the front. An amazing amount of dirt & bugs can get clogged in the fins and reduce the cooling function.

The transmission doesn't slip. The idle is fine when hot, around 700 rpm and stable.

i took my radiator to flush and clean about 6 months ago. They told me that the fan clutch was OK, but my mechanic says it is soft, I don't know any other way to test it but moving it by hand when hot and cold. When hot is harder than cold, but I can't tell if it is hard enough.
I have a custom bumper, with a winch.
The temp never goes further the thermometer image on the gauge.

 

[RomeovilleIL]

It's the lights and winch blocking air to the front of the radiator. You will need to find a way to get more air flow through the radiator. Cluch fan might be somewhat weak as well. Check with the guys who runs lots of offroad mods to see how they overcome the airflow blocks. Maybe a dual electic fan?

 

[leandro]

It's the lights and winch blocking air to the front of the radiator. You will need to find a way to get more air flow through the radiator. Cluch fan might be somewhat weak as well. Check with the guys who runs lots of offroad mods to see how they overcome the airflow blocks. Maybe a dual electic fan?

I see we are on the same page, because I was looking for electric fans this morning on the web.....

So the problem is the fact that the engine is running too hot and I have to lower the temp....