I'm starting to think my Sportage might be running hotter than usual due to some problem with the engine.

What I mean is, maybe the problem is not the cooling system, maybe the engine is generating more heat than it should.

What could cause this?

Things I have already checked:

- Timing is correct
- Fuel filter and fuel pressure good (and not running lean)
- No blown head gasket
- No trouble codes and O2 sensors work fine

What else could make the engine run hotter than it should?

I'm getting really stumped here... Unless the Sportage just can not handle climbing hills at high RPM with the AC on in hot weather without heating up? Maybe that is just the limit of what this vehicle can handle?

The way I have been testing is I fire up my logging software that logs the temperature, and I turn the AC on and jump on the freeway. Then I drive at about 5k RPM in 3rd gear for about 3 miles, and in that time the engine has been heating up to 230 degrees and would keep rising if I let it. Then I turn around and head back home driving about 4k RPM in 4th gear home, and on this trip it will run around 220 degrees. Once I get off the freeway and the RPM lowers, it gradually cools back down.

I replaced the radiator and I also tried doing this test with:

RSG bumper
stock bumper
no bumper

The RSG bumper runs the hottest, followed by the stock bumper which runs a little cooler, and the best of all is no bumper, which runs a lot cooler.

I don't want to drive around with no bumper though <img src="/forums/images/graemlins/frown.gif" alt="" />

Post deleted by mpel787

Because the vehicle was overheating during NORMAL driving on the highway, which sometimes involves climbing hills or steep grades at high RPM (up to 4k or more at times). This is normal driving when you are traveling on the highway.

It happens a lot slower in real cases, the temperature creeps up. I don't have time to go drive on the highway for hours to see if it heats up so I do something I know will make the engine heat up, and compare the results to see if changing something makes the engine run hotter or cooler.

Ok got you, are you still using that new fan shroud the aluminum one.

Nope the latest tests I posted were all done with no shroud, the fan is just mounted directly to the radiator.

It's also a new radiator. The old one wasn't bad I guess, but it was 7 years old so I guess it's OK that I replaced it.

whoa, wait, have you been running the entire time with no shroud? that could be it right there...

also, no, 5k rpm is not normal, at 80 mph, the normal rpm is under 4k...

and are you sure you're not running lean? are you running a k&n & hi-flow exhaust? you might be running lean if you are...

also, is the fan sized right for this application? i've seen the size, but i mean cfm's...

the deal with the shroud is that it forces air to come in from all over the front of the radiator, helping to cool all the surface area... without one, you just suck air thru the center...

Ok, so you are not using any shroud at all, remember it needs one to force the air through the radiator to make a good heat exchange for it to work, if you can force more air through a specific spot (radiator) then you should get what you need, ok if i'm not mistaken you no longer have the factory shroud, you need one to maintain a constant air flow thought the engine, idling or driving the combination of the thermostat and fan clutch is essential to keep any engine cool, if I'm not mistaken you have a Spal fan-pwm to be honest have never used one how do you know when and how much to adjust it while driving, and from what I saw on the pictures I don't think you had enough back spacing on the aluminum fan shroud.

Guys, no I have not been running without a shroud the whole time, there is a long history to this issue and this is just the latest step. I just switched it to no shroud a couple days ago at the suggestion of some car buffs, they thought the aluminum shroud I was using was blocking too much airflow. I always had a shroud before.

In my road tests, shroud vs. no shroud has so far made almost no difference in heating up while moving. That's where the problem has been all along, heating up at speed. There was never an issue with idle or slow-speed heating up, and it doesn't overheat at idle or going slow now even with no shroud. The shroud is only there to help slow speed or idle cooling.

Dave, I looked into the possibility of running lean, the O2 sensors would seem to indicate that I'm not running lean, but I also changed the fuel filter in case it was clogged. Not sure what else to do for checking that, I could do a fuel pressure test but that is a PITA since there is no Schrader valve on the fuel rail (I thought my old one had one). To be honest, I would be really surprised if the engine would run lean enough to be this hot and NOT throw a code, this isn't an old carbureted engine, the computer is constantly monitoring the exhaust emissions to detect just such a thing and would throw a P0107 if it was lean.



The shroud doesn't create a venturi effect for the radiator, it's on the wrong side of the airflow to do that. Some cars do that with air scoops and such in the bumper or grill. The shroud is to help the fan work better and the fan is for idle and slow speed, nothing else.

If you don't believe me, start looking at the CFM ratings of some of the most powerful high-performance fans. Then do some simple math estimations, divide out the area of the fan blades from the CFM and get linear feet per minute, and convert to miles per hour. You'll find that you don't have to be driving very fast at all for the air hitting the front of the car to be much greater than what a fan would move.

2 things I would look at is the radiator and a clogged cat.
My 2000 seems to run warmer so I'm putting in a 180 thermostat and a new radiator.
Will let you know what I find out.
Everet

Yeah I thought about the cat, If the cat is clogged then it's not showing any of the normal signs such as low vacuum or unusual O2 sensor readings, but I suppose it's a possibility. I honestly don't know how to be sure, I may have the local muffler shop take a look, they say they can tell if it's clogged.

The radiator used in today's road tests is actually new, the old one was 7 years old and had some questionable deposits on the inside, so I went ahead and got a new one, even though it turns out the old one still works fine. I guess I have a spare now.

Everet I know you have a real temperature sensor, can you (and anyone else who has one) give me some examples of temperatures your Sporty runs at under normal driving conditions, or freeway, or going up a hill, etc? Anything, just to get an idea of what kind of temperatures are normal for a Sportage...