Hi all, Ok originally I thought I had overheating due to oil problems as I was getting "Stop Engine, Oil Pressure" coming up all the time which the garage advised me was a faulty sensor. I drove the car about 5 miles and the message flashed up but soon went off again, then whilst driving back the same message again but it didn't clear this time and the car over heated to the point steam was pouring out of the bonnet. The car has been to the garage and been checked over but they say the oil pump and water pump are working fine and that it is not the oil giving me the problem. They changed the sensor for me and they reported that it was still doing it.. The car had a diagnostic and all that came up was a crankshaft speed sensor?? Nothing else... So I drove the car about 4 miles back home it was running fun and felt fine but just as I pulled up on the drive the temperature was starting to go over 90 and there was steam coming out from the bonnet... After inspection I noticed the coolant reservoir cap was loose... After doing some research I noticed people had problems with their fans causing over heating so thought I had better test them and the result is that I have no low speed at all from either fan and only full speed from the smaller fan? Do I need a new set of fans or does this sound like the resistor problem? Any help is much appreciated
The contacts under the 30A fuse- S180 are known to corrode This would stop the electrical supply to the cooling fan and I also believe the SAI pump. I had to replace this fuse holder on our Bora V5 after having similar issues.
The fuse will be fine but the terminals deep in the holder tend to corrode until the fuse starts arcing and burning as shown in those examples. It is fault that can affect most MK4 based vehicles. Our car had 45K miles when that started happening.
I suppose the other thing to look at if Toyo's problem looks clean is the fan control module. Some of these also have fuses in so thats one to check.
Ok no corrosion and removing the fuse there appears to be no corrosion in there, I took the tray off and tried to look underneath the fuse holder but couldn't get it off.. While I was out there I noticed that there was something completely undone and when I started the engine it rattled and moved about..
That's the serpentine belt tensioner. Which part is loose and the 2 pieces spin under spring tention. It runs your aircon, Waterpump and power steering pump.
Both fan's were siezed on my mk4 and i had the burnt out fuse problem. I got 2 new fan from a local factor and a second hand fuse pack from a breakers. Touch wood its been ok since. The auxillery belt tensioners do fail as well. Can you see if the belt has any tension on it? If not the tensioner will need to be changed
Thats the Auxillery belt tensioner. You can get them on the aftermarket for around 40 quid or so. The INA part number is 531053610
Yes, check if the belt has any tension. If not then there is your problem but I'm sure you would have noticed heavy steering if it had failed. It's not expensive and quite an easy fix.
Where you see that bolt hole in your photo, theres not supposed to be a bolt in there all the time. That is only used when changing the belt or tensioner. When a bolt is screwed in there it takes up the tension from the belt to allow enough slack to remove it. Once your done and all is assembled again take the bolt out slowly and you will see it go tight again. Theres a bit of movement on the tensioner when engine is running but impossible to tell if yours is excessive enough to warrant replacement without seeing it. Wee tip....(if you need to change belt or tensioner on a mk4 golf the bolt that holds the lower battery clamp on is the correct thread and is long enough to take the tension off. just take the bolt out and carefully screw into that hole. A wee bit copper slip helps it in and out) Also check the tensioner has all its securing bolts and there tight.
