Golf IV / Jetta IV :: 2002 - Overheating In Traffic - Fans?
Apr 27, 2016
So i have a 2002 1.8t that i got in december. Everything has been great so far untill the other day the car overheated on me in traffic. It was a bit warm out maybe 75-80 degrees. I saw the needle start to climb and then the light went on so i through the heat on full blast and it dropped the needle a bit and turned the light off long enough to pull off the highway. I let it cool down and checked things out. I am not low on fluid, an the fluid was changed within the last year with the vw recommended stuff. The radiator hoses are pressurized so i believe that the pump and thermostat are working. I am thinking it could have something to do with my fans. I tested them in my driveway by supplying them with 12v and the spun perfectly. It only happens when the car is standing still for a period of time. Driving at any speed is fine. Is there some sort of switch that tells the fans to turn on?
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As the title says, car is overheating. Car gets to 190F within a couple miles drive. Temperature fluctuates between 190F and 225F.
Water pump was replaced ~2 months ago. Was not overheating prior. Temp reached 190F and stayed. Currently has the "black top" coolant temp sensor.
I noticed the coolant fans are not running after I turn the ignition off. This time of year they would usually be running after turning the engine off. If car is overheated and with AC off the fans do not run while engine is running.
I used the guide below to try diagnosing the cause: [URL] ....
Remember both fans should come on in slow speed any time the key is on and the AC is on - if the temperature is above about 32 F (0 C). Both fans run with key on and AC on
S180 (fuse 8, 30 amps, green plastic, above battery) must be good for slow speed operation.
Fuse and holder look good: no melting, no discoloration.
S164 (fuse 3, 40 amps, metal strip, above battery) must be good for fast speed operation.
fuse looks good: unbroken.
To ensure the AC circuits and the Fan Control Module has power check:
Fuse 5 on the cabin fuse panel.
Fuse 16 on the cabin fuse panel. When this fuse is blown the radiator fans will often run unexpectedly.
Fuse 25 on the cabin fuse panel.
All three fuses look good: unbroken
For the first test of the slow speed fans from the radiator thermoswitch have the key off.....Both fans should run in slow speed.
Passed test: both fans run slow
The second test is for the fast speed fans, key on, AC off.... Both fans should run in fast speed.
Passed test: both fans run fast
If the fans run in the tests above, then you should be good to go. No further tests are needed.
If you have been seeing high coolant temperatures and the fans have not been running, then you may need a new thermoswitch.
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So my friend, ignoring my advice that this generation seems to be riddled with electrical problems, decided to purchase a seemingly nice 99 Jetta, with a junkyard AEG swapped in(AEG is written on the intake and block like a JY would do). Sun roof doesn't slide back, gets jammed, evidence shows water has built up previously and run down the A-Pillar to the fuse box.
I just got the fans unplugged and verified that the fans with power applied, both have their low/high speeds. The fuses on top of the battery are in-tact, no visible melting, looks like the thing is in ok shape(haven't taken them off to inspect the contacts yet).
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My 2002 Jetta VR6 is overheating. The car only overheats when the car is not mobile. If I get stuck in straffic or just let it idle it will over heat. What could it be?
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I have a 2004 volkswagen jetta, and it has started overheating. At first my problem was the thermostat. After that was changed out the fans stopped working correctly. It kept blowing fuses in s180 slot.
I read somewhere in another post that this is due to the fact the resistor in the low speed fan go bad, and for your car's radiator fan to go from zero to high speed, causes the fuse to blow. Also I read that when the fans start up it draws the most current, and then after it's running the current is considerably less.
This is my solution, I went to napa, and got a circuit breaker for a car, and Yes, to my surprise they make them. I picked up several a 10amp, 15 amp, 20 amp, and a 30 amp. First, I tried the 30 amp circuit breaker and it didn't trip the circuit, but when I put a regular fuse in the slot, it did trip the circuit, when I did the fan test at the thermostat switch. Next, I put the 25 amp in there and neither did it trip the circuit. When I put the 10 amp in the s180 slot, it tripped the circuit, just as the regular 30 amp fuses do. So that confirmed that the amps that were being drawn from the fans were not enough to trip a 30 amp circuit breaker.
What I did next, is I took a 20 amp circuit breaker and put that in the s180 slot. Then I hooked up vag com on my laptop to check and see how it performed with the 20 amp circuit, and these are the results.
Car Temperature in celsius
at 111 degrees the gauge was moving past the halfway point
at 115 degrees the gauge was one notch past halfway going towards the red zone
at 120 degrees the gauge was two notches past halfway going towards the red zone
at 122 degrees the fans kicked on high speed for about 30 seconds, and knocked the
temperature down to 105 degrees.
In conclusion, if the high speed on the fans work, you don't have to take those out and go and buy an expensive new fan set. Just stick a 20 amp circuit breaker in the slot, and keep using the fans that you have.
Part no: 782-3154................ Name: Circuit Breaker, 20 Amp; Blade
Note: I take NO responsibility for any damage you do to your vehicle from any information you obtained from this post. Do this at your own risk! I am not a mechanical expert but this is my solution to the overheating problems.
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So I just got a 2002 1.8t, everything was fine until the fans and ac stopped working. After poking around the forums a bit I changed the following:
1. Fan Control Module. Result: nothing
2. Radiator Cooling Fan Switch Temperature Sensor. Result: nothing.
all fan components have the correct voltage going to them. Fuse 16 for the AC clutch is not blown and has power going to it. The AC compressor has power going to it. The fuses on the battery box have power going to them specifically S180.
My question is what am I missing? is it possible that the fans themselves could be bad? car is not overheating, the after run coolant pump kicks on. But the AC clutch is not spinning nor are the fans. btw AC clutch is not seized up.
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I bought a 2002 gti mk4 with about 127000 miles on it .I did not know the turbo fans were blown out , they were sitting in my down pipe next to my catalytic converter . So I replaced the turbo myself , and 2 hours later the fans fell out of the new turbo , what might be the problem ? why it keeps blowing.
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I have a 2002 1.8t with 90,000 miles on it. I have it serviced for new Timing belt and water pump (metal impeller, according to the shop) 3 months ago at this shop. The overheating problems never went away. The problem is that it overheating at heavy traffic or idle after a while or after heavily drive, but it cools off quickly when I rev up the engine a little bit, or after getting out of traffic again.
I have another shop diagnosed, they first told me the cooling system is leaking and may trapped air inside so they did replace thermostat, coolant housing assembly, flange seal, pipe sealing o-ring. they re-test and turn out there is no coolant flow and suggest that is it the water pump that fail and ask me to go back to the original shop for the Water Pump warranty. Additionally, they flow test radiator and its fine.
I did return the car back to the original shop and they tested and said the heater core is clogged with debris and that would cause the overheating. They asked me to replace the whole heater core that would cost $1500. But I know for the fact that I have heating in the car and it is hot!
Is there any other reason than what have been replaced or tested (thermostat, radiator, air trap, new coolant)? I think it could be the aux cooling fan since its never turn on when overheating, only when AC is turn on, is it supposed to work this way? Spent too much on this car and hopelessly the problems went away but it's not.
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So my 2002 Jetta 1.8t is overheating. The water pump was bad. Replaced. The thermostat. Replaced. Radiator. Replaced. Radiator cap. Replaced. We're running out of things to replace! I'm ready to go to a junk yard and get a new block! We've tried about 100 magical "ways to burp it" with no luck. We even tried running it without a thermostat. Without the heater core. EVERYTHING.
The car runs at operating temperature at 4 RPM. But when we take it for a drive, it overheats. There's no heat with the thermostat in unless you rev it at the high RPMs. As for the hoses, top is hot, bottom gets hot. As for the car, it runs beautifully. It gives no codes. No smoke either. Nothing in the oil, nothing in the coolant so I don't think it's the head. It just overheats. This has been FAR too long.
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My 2002 VW Jetta GLS 1.8T 5-Speed is over heating
Car is still over heating after replacing the following:
- Head gasket
- Coolant fan module
- Geba Metal Prop Water pump
- Full timing belt kit
- coolant fan switch in Radiator
- Bleed the system of all air blow hot air
So Driving the car around town is ok, doesn't over heat, but as soon as I take it on a highway it over heats. I drove it 50 kms out of the city and it over heated, let it cool down and added water. got it back home. Oil light flashed on as I pulled into driveway, turned it off right away. no external oil leaks. Checked coolant, Oil in coolant. also the coolant was boiling, the level was raising up and lowering. I have been reading the forums for a few hours and the oil in the coolant sounds like the oil cooler gasket. Ok so the fans are running and it still over heats. The old metal propeller water pump was very hard to turn so I replaced it with a Geba Metal water pump. no leaks at water pump. Could it be possible that the Oil cooler was causing air to leak into the cooling system causing the coolant to boil? And then when the oil cooler "o-ring" finally failed it dumped oil into the coolant?
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My son has a 2002 Jetta, we just changed the water pump and the thermostat. The car will sit at idle and the temperature will stay around 190. When you drive down the road the temerature will rise and when you let off teh gas the temperature goes back down. What this could be, I have tried everything I can think of to fix this car.
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So i replaced everything, Crack pipe, thermostat, greentop CTS, water pump... still getting 1 or 1.5 bars past the vertical in traffic after about 10 minutes...
The fans work... atleast they are both on when i shut off the car...
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A couple weeks ago, I noticed the a/c air warming up while I was in traffic. Later the car started overheating while the a/c was on in traffic, but cooled back to normal as the a/c was switched to econ. As of a few days ago my a/c air is not cold at all anymore, in traffic or moving. And now today, my car overheated in traffic without the a/c on, but returned to normal after I waited out the freeway blockage and drove home when the traffic speed was higher.
I've been reading threads on here for about three hours now and going out to run tests. It appears that neither fan runs on low or high speed. I want to check the fuses, but the fusecard is like reading hieroglyphics. It appears that slot 25 (with a picture of a fan) might be the right one, and after checking it appears intact. Questions:
- Is there a fan fuse? Is it #25? Are there more than one?
- If the fuses aren't the issue, is there something else to rule out before removing the fans for inspection and cleaning or replacement? (controller module, thermostat, relays, etc.?)
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I have a 2002 jetta 1.8t that overheated on me out of no where i have read some post and couldn't really find what i need it never overheated on me before and this was the first time and when ever i open the reservoir where you put in coolant everything spills out its my first time owning a volkswagen, it happens as soon as i start driving like 30 secs and temperature starts to rise.
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So recently my car has been starting to over heat. not to the extreme but the temp needle is going past the middle. only happens when stuck in traffic but as soon as I start going it goes back down.
As far as iv noticed only thing getting me puzzled is my fans are not running when running and starting to overheat. they run when I shut the car off though. The radiator is less then a year old. fresh oil change and the coolant is fine
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I was slightly overheating in traffic, watching the gauge creep up a little. So i bought a new fan, swapped it in this morning, and still no Big Fan.
Fuses on top of the battery are all good. Does this mean my FCM is gone?
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Today is the first day I noticed this problem !! driving regular hit traffic I notice my fans come on so I look down at my cluster and my temp gauge is a quarter pass 190 ?? Happen 3 times with in 10 minutes of each other no air condition or heat fans on ??? Get to my destination stay there for 2 hours then drive home but no temp issues ??? 74000 miles I hit today on the car completely stock ?? Thermostat , housing ??
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So I noticed my temp gauge was starting to rise when I was on the freeway. I figured my fans were out but I just opened my hood and both fans were spinning. When I turned the car off both fans turned off but the temp gauge was almost into the red.
In the morning I turned on my AC and only the passenger side fan was working.
So I am not really sure what my next diagnostic step should be. The engine was not radiating any heat so I am not sure that it is even actually running that hot. Could it possibly be the temperature gauge? If I got a vagcom would I be able to check the actual temperature from there?
I am also concerned on how to find out if the fans are running at both speeds at the appropriate times.
Not sure if this is related but my cruise control stopped working a few weeks ago also.
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As it was such a matter of time, my fans on my 24v gave up during winter, no big deal as it was a pretty cold winter but now that spring is around the corner, I gotta fix this issue. To they change for the same OEM unit that will die in the next 30k miles.
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I have a 1.6 8v mk4 Golf, and my fans started staying on all the time. There are 2 coolant sensors on this model, one is the green one, and the other is the black one which seems to be hardwired into the thermostat housing. Anyway, I changed the green one, and that didn't solve it, so changed the whole thermostat, which obviously came with a new sensor build on....Hey, it worked, for 2 weeks, and then the fans started coming on again as soon as you turned the ignition key...and the temp needle doesn't move much, as before.
My suspicions have moved to the sensor wiring loom, that was fiddled with, while changing the thermostat...I hear they can become brittle over time, and so behave as if the sensor is unplugged, i guess.... Do these wires unplug anywhere in there so I can test the loom properly?
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Compressor does not engage, and my fans do not come on when I turn on the A/C. They do come on low speed when I jumper pins 1 and 2 on the temp switch plug, but they do not come on high speed when I jumper pins 2 and 3.
I have replaced the FCM with a new one, as well as a guaranteed working used one; neither one changed anything. I assumed right away that it was the fcm because my original one has a hole eaten through it from battery acid.
Compressor clutch ohms out within spec, and it will engage if jumpered.
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