Cooling Problem

[StephenEggo]

I have a 1991 Gti 8v Pb engine code. The other day I was sitting in traffic for around 20 minutes and a few things gave me a cause for concern. The water gauge moved across to the far right hand side of the scale and the oil temperature rose to 120 Deg. The exhaust seemed to be emitting more emissions than normal. Two weeks prior to this the water level warning light came on and I topped it up with a little water. The warning light came on around 10 months ago and I done the same thing and since then it has been fine even tough the car has done 7,000 miles. I can remember when I first got the car the coolent fan came while sitting in traffic and it didn't sound to healthy. I think it might not be working anymore and this could be a contributing factor. However when I got out of the traffic the water and oil temperatures returned to normal. The car has done 135,000 miles and the head gasket looks to be original
Any Suggestions?

[takethefifth]

You need to check if the fan is working first. Either sit with it running somewhere keeping a close eye on the temperatures, fan should kick in about 3/4 way up the gauge. I wouldn't expect oil to get to 120 without the fan coming on. Definately don't let it get any higher!

You can also check the fan by disconnecting the temp sensor connector at the bottom of the radiator and bridging the pins in the connector with a piece of wire or something.

[rubjonny]

Yup sounds like a fan failure to me, check by bridging the pins on the radiator temp sender plug as tt5th said.  Also you shouldn't have to keep topping it up, sounds like you have a coolant leak somewhere!

Replace the header tank cap first with a new blue one as these have a better seal/pressure valve design.  Next check the 2 plastic flanges on the front & right side of the block, common places for leaks.

If all that checks out, take the grill, rad fan & shroud off, and check the rad for white crusty deposits, especially on the end caps either side.