My car has been overheating lately, and I'm not sure why. Last year my car overheated on Memorial Day weekend (2004) and I realized the motor in my radiator fan wasn't working. I tried wiring it directly to the battery and still didn't work. I went all summer without it ever overheating (didn't drive it much) and if it ever got hot, I'd turn on the A/C fan and it'd be an instant fix.

A few weeks ago I replaced the fan, fuse, and rewired everything. I figured I'd do it before the hot summer and lots of driving. New fan is in. Now my car is overheating everytime I come to a red light. If I sit there for a few seconds, the temp gauge starts to rise, and I turn on the heater and it cools down quickly. I got under my car yesterday looking at the fans (A/C and Radiator fans were both replaced). I realized that they weren't sitting flush against the radiator at the bottom (the screws weren't lined up to the holes that rest on them). So I fix that problem and hope that it was the reason for overheating.

Today:
I'm driving down the road... windows down, no A/C on, come to a brief red light and then resume driving. My car starts overheating, quickly... so I turn my heater on (not fun, especially today with 90ยบ+). It isn't helping. I'm only 5 minutes MAX from my girlfriend's house (my initial destination) but it's getting so hot that I pull over into a subdivision and let it sit for a few minutes. It cooled down, so I pull back on to the main road... cars are coming up fast, and for some reason my car is in no hurry to accelerate. I've got my gas pedal pushed in, but it feels as if I'm tapping on the gas then letting off. It would go, then coast, go then coast... about 1-2 seconds it would feel like I'm giving it gas, then for 1-2 seconds it'd feel like I just let off the gas. I don't know how to describe it. I pulled onto the next street, with the engine still doing this, and parked it under a tree. I let it cool down with hood propped for about 5 minutes. I get in my car and continue on to my girlfriend's house with no problem.

ONE HOUR LATER:
I'm on my way to work, not sure if I should take her car and have mine towed to dealership, or see if I can get to work... but I end up taking my car anyways. My trip is about 8-10 minutes away. As I'm driving normal at about 50MPH (flow of traffic) and my car starts doing it AGAIN. 1-2 seconds of acceleration, then it feels like I let off the gas for 1-2 seconds. This time, I don't have anywhere to pull off to. I take my foot off the gas pedal and just coast, and the problem stops. I accelerate and it comes right back, so I switch to the slow lane away from the cars and just coast for a little bit. About 20 seconds after it first started, I accelerate and everything seems fine. It only happened when I accelerated, and only those two instances.

Factors involved:
- Car was overheating the first time it happened
- I was on Empty. I filled up less than 1 mile from work after both times it happened, and put 13.3 Gallons in a 14.5 gallon tank.
- I drove home ~17-20 miles without a problem. I actually tried making it happen (accelerating fast, coasting, driving easy, interstate driving, etc.) because I had a friend following me. I've also got a new tank of gas.

Possible problems?
*I'm guessing it's not tranny related. Happened when I was taking off from a stop, and happened driving 50MPH.
*I don't think the overheating of the car is related, b/c it wasn't overheating the 2nd time it happened, and the car had been sitting under a shaded tree for an hour before the 2nd trip.
*possibly fuel related? injectors or bad gas?
*someone mentioned possibility of valves or TB having trouble opening/closing?

I have a NOPI Event to attend next Friday. If I tow my car to the dealership tomorrow, they probably won't look at it until Tuesday. That gives me all weekend to drive it and see if I can make the problem occur (easier to diagnose if I know under what circumstances it happens). I have 97,000 miles... is my engine covered under the 100,000 mile warranty?

Oh yeah... and why the hell is my car still overheating? I'm going to have a radiator flush done when I take it to the dealership, but I don't think it will fix it.

 

I think that problems with accelerations can be caused by allmost empty tank.

Does radiator fan working when engine overheats? If no check if there is voltage on radiator when engine hot. If no voltage - check thermo-switch. If there voltage is - something is wrong with radiator.

 

Yeah, I had a similar problem with my last car once. Similar symptoms. It ended-up just needing a new thermostat, if I'm not mistaken. Was pretty cheap to replace.

Either that... or maybe your Flux Capacitor??? wink1.gif

 

I am thinking the throttle problems are low fuel related. WHen I let my car get that low, my car will not accelerate beyond 40mph without it feeling like I am hitting the rev limiter.

As for your overheating problem.. what way are your fans hooked up? Make sure they are pulling air through the radiator into the engine compartment. You may laugh and think I am crazy, but with electric fans it is easy enough to wire them backwards so that they try and push air out the front of the car.

Also, how is your water pump and thermostat?

 

What oil weight are you using, how many miles on the car, and have you ever purged the anti-freeze?

 

Antifreeze was going to be my next question. I change mine every two years to keep the system from getting gummed up.

As he seems to be having trouble at idle and not when moving.. I am thinking this might be a low coolant issue. If he has a large air bubble blocking flow into the head or radiator, the speed of the waterpump at idle is not enough to force coolant through both the engine and radiator..

If it's the termostat, it is probably not opening all the way and causing a restriction.

I am pretty sure that the radiator on the tib is higher than the highest point on the engine. If it is, I would suggest waiting until the engine is cool and popping the radiator cap and then starting the car. Leave the cap off as the engine idles to see if you have flow through the radiator.

 

here is the answer:

 

If you think you need a thermostat I have a stock one from a 2001 Tiburon you can have (just pay shipping).

With the antifreeze levels what I usually do is once the radiator is drained pull the upper hose off of the radiator and hold it on so that just the top of the hose is not on all the way. This will allow the system to "burp" out a lot of the access air from the engine as you fill. Then once the level gets high enough that you are about to spill from the hose put it back on then top off the radiator. Also always make sure the coolant reservoir is filled to the full marker.

 

Just had this problem with my fiance's neon. As dumb as it sounds, check the spark plugs. She had a leak that was going directly on the spark plugs, and it wasn't igniting cleanly. New plugs and a little cleaning and it was as good as new.

 

The coolant levels are full, but the green is getting more of a brownish tint than normal.

The fans are pulling hot air into the engine bay. I rewired the new fans to use the same factory plugs. Green wire matches with Green, black with black wink1.gif

Could be thermostat or burp in line. I'm trying to find a place that will flush my tranny, but they either won't work on my car (liability) or still charge me full price when I bring my own fluid (nobody carries Hyundai ATF SPIII). If I'm spending $55 on ATF, they shouldn't charge me full price for the flush 02.gif I was already planning on flushing radiator when I changed ATF.

How do I know if it's a bad thermostat? Would a bad thermostat prevent the fan from activating? Fans come on fine.

Also, filling up with 13 gallons isn't rare for me. I still had at least 1 gallon left in the tank, and I drove about 10 miles after this started before filling up. I was running 93 octane (I use 93 about every other month)

I never have any electrical problems or any problem idling. Volts stay about 14.0-14.3