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View Full Version : V5 Overheating & Cooling.


wellful
10-09-2008, 11:23 AM
Hi all,

I have a Mark IV '99 Golf V5 and it overheated the other day, causing the coolant to boil over.

I think it was caused by the fans not working as they weren't on but the temp gauge was reading 135 and the warning indicator had sounded. I've checked the fuse but it seems OK however.

I've read a similar thread on here, if anyone else had a similar problem, does this sound like the likely cause?

Also, before I head off to my nearest VW dealer, the handbook says I MUST replace the lost coolant with G12 A8D, is this correct?

Thanks in advance, all help appreciated!
Issac Hunt
10-09-2008, 11:35 AM
Even without the fans on, it shouldnt get upto 135 during normal driving. You sure the waterpump is working OK?

I'd use the correct coolant. Mixing the wrong stuff can cause problems.
wellful
10-09-2008, 11:48 AM
Even without the fans on, it shouldnt get upto 135 during normal driving. You sure the waterpump is working OK?

I'd use the correct coolant. Mixing the wrong stuff can cause problems.

Waterpump was my other thought actually but I paid for a full service recently so was hoping it would be something cheaper like a fuse :biglaugh:

It was quite a muggy day and I was doing a lot of stop-start driving around town, but yeah I was surprised it reached that high. Having said that, it only happened the minute I got home and parked on the drive, having been driving for 45 minutes, which I thought was strange. As far as I can remember the fans weren't on, which I also thought didn't seem right.

Thanks, I will definitely use that coolant.
v6dub
11-09-2008, 03:51 PM
the coolent system in a car is very easy to understand, you have a temp sensor just next to the termostat and that detects the water temp as it comes off of the head, it sends a signal to the dash and to the thermo switch which controls the fans, the termostat is wax operated, when the water in side the head heats up to 86oC it will start to open and allow water to flow and return from the rad pumped by the water pump, what it sounds like to me is that your termostat has broken, and is stuck shut, i had a problem with my v6 4mo where the thermostat was stuck open and the engine would not heat up, the bad news it that it costs about £200 to change the thermostat. if that is what the problem is.