Vandit

What are the symptoms of a bad oil ballast?

Did you do anything about the oily hardlines, softlines, and fittings?

911Jetta

Vandit,
Had to reread the thread to figure out what I did...that was a trip down memory lane. A big thanks to the RL members for there patience on that one! Big help.

What are the symptoms of a bad oil ballast? The front oil cooler fan doesn't turn on.

In this case I had a double whammy, both the oil thermostat and oil ballast went bad at the same time, so I was seeing 9 and 10 o'clock temps during in town driving.

I replaced the oil ballast (and tested the relays with a jumper), the fan started working but unfortunately the oil thermostat wasn't opening and pushing oil through the front cooler. It was a happy drive when I saw the oil temp drop after the thermostat opened and the fender fan came on.

Haven't done anything to the fittings...I should pull off lower corner sil cap and see what's lurking behind....

Vandit

Okay, I think my fan is working properly (i.e. probably not a bad resistor) but there's room for improvement. Driving around the temp will be at 8 o'clock, and it'll start creeping to 9 and almost 10 if I'm sitting in traffic for a while during the summer. What concerns me is that I was seeing 10 o'clock temps during a 5-6 min track session recently. I suspect my thermostat might be getting lazy and due for replacement.

911Jetta

As another data point:

I've only done a couple warm track days (easier to find cheap off-season, cooler days), but I've always been impressed that I never see anything over 9 on the track at the end of a 20 minute session. I've been much more worried about my brakes, so I drive around the paddock a bit to cool them down. I hope to get in another session on the track next Tuesday, will let you know what temps I see.

I've seen warmer temps sitting in traffic.

dutchcrunch

i tested my car and i can tell u that when the low speed fan kicks in , it is slow to bring down the temps.

Vandit

I think I'm taking the car off the road for a bit to investigate some oil leaks that showed up after my Time Trial, probably replace the thermostat, and probably finally do this resistor mod I've been considering since last year.

https://rennlist.com/rennforums/showthread.php?t=639980

John Rygg

I need to replace the thermostat also , where did you get your parts from and what were the part numbers ?

Thanks great write up.

Marc Shaw

Thermostats don't have to be replaced - they can be rebuilt for a great deal less money.

Marc

Vandit

Nice list of part #s. Thanks! That's what I meant, replace the guts, not the whole unit.

Vandit

My oil cooler fan is not running until the car starts approaching 10 o'clock then it kicks in at what I'm assuming is high speed.

Is this a sign my ballast resistor is not functioning properly?

Bluestar

Hi guys,

Need some expert advice here. I purchased an original AC Blower Relay part (811.951.253) on Ebay from a reputed seller and what arrived was a relay with part # (431.951.253)!

I am totally not familiar with relays and was wondering if the experts would know if I can use these two interchangeably or must I reorder the exact part (811.951.253)?

Thanks in advance for any advice!

HiWind

Udo/Vandit/Mark/Rob - thanks for the excellent thread ... sadly got the 9-10 o'çlock oil temp this weekend
on the way home after a hot 2 day track and hill event. Fender is cold when temps up.

Before I go in guns blazing re the thermostat, which of the two pipes can I feel to work out if its thermostat or the ballast resistor?
Re the thermostat inners replacement - does that work on all 964 therm housings or just later ones?
(as said on pg 1 of this thread)

Also Udo - what was the cause of the water in the oil? Fixed too?

thanks all!
Matt

HiWind

this is what I'm referring to in my post just above

Rocket Rob

Matt - Sorry to hear of your troubles. If you want to be more thorough than putting your hand on the fender, when the oil gauge is showing hot, jack up the car, remove the right front wheel and you will expose the two pipes that bring oil to the oil cooler. They both should be warm. If they are both cold then your thermostat is not opening.

HiWind

Thanks RR ... Not so bad .. Thanks for the pointer