Pyzik

Pump is from 928 motorsports/new

Pyzik

Is the radiator fan supposed to be on as the ignition is on or is it on only when it needs to be on ? Because in my car it turns on as soon as the ignition is on even when the car is cold . I wish I knew somebody with another 928 to see how things are supposed to be.

Randy V

No


Fan comes on only when it is hot. The fans should not come on when the engine is cold and you first start the car.

Tip - click on the User CP link at the top left of this page then add your car model info into the Signature area.

Imo000

Saw the same exact thing 2 years ago on an S4. End tank was leaking, radiator hose to the thermostat housing was cold and it overheated just from iddling in 5 min. It was a failed thermostat and it always stayed closed. Mechanic diagnosed it as a failed head gasket.........it was just a $25 themrostat.

Also, just because the thermostat was changed, don't assume the rear seal was too.

Pull the t-stat and put in in a boiling cup off water. Try it 3 times, it shoud always fully open.

Pyzik

I warmed up the car today and the upper hose got nice and hot while the lower one was freezing cold also no heat inside the car just cold air blowing , so I I will check the receipt as I think the pump still might be under warranty from 928 motorsposrts .

Pyzik

I had the thermostat out since I put new one so I put it in boiling water and it opened each time .

littleball_s4

My car is currently in a similar problem.

Some things I've learnt in the past: Leak does not produce heat. Heat produce leaks (more pressure than normal) and then leak removes pressure. Heat + no pressure = water boils = massive amount of water coming out leak and cap. So I'll bet you have a lack of cooling, so: Tsat, pump, fans, cooler. Then you can fix the leaks and all will be ok.

Mu suggestion with the cooler is: take it out, take it to a rad shop, have it fixed. It's cheap. Buy an end cap or have a custom-made alu. They are used to that job. Clean the internals: it will rule out the cooler.

To rule out pump: open the cap, top it, start, revvit. level goes up and down with a working pump. Pumps are mostly digital.

I've been adviced to open the temp sensor just above the tstat to be sure it's coolant in there, not air. Tstat can be mounted backwards. It has 2 seals, the one that comes out when you don't want it to, and the one that doesn't come out when you want it to. Both are said to be vital.

Good luck!

Barry Chan

when i did the whole cooling system last year, the first two was too high, temp at the second white mark when warmed up, the third thermostat finally settle at a little pass the first white line and it's still good now.

Pyzik

I removed the temp sensor that is above the t housing and when the engine was cOld so when I unscrewed it I saw some air bubbles escaping from the thread and then all coolant so I scewed it back filled up the reservoir tank and started the car , reved it and nothing happened , didn't go up or down as I was revinig the engine , then I let the car run for about 5 min because my uncle called me from Poland as he had some. Questions regarding this problem also suggested flushing the radiator. What you think about that? After 5/6 min of ideling I shut it down , temp was at 3rd bar out of 5 bars ,so not really overheating yet . After the upper hose cooled down little i was holdin the upper hose in left hand and lower in right hand and I was squeezing them and I think that would tell that radiator isn't clogged? I felt the coolant move but not sure If thru the radiator or engine? Would a broken water pump just stop spinning and not couse any damage to the engine ?Could you suggest a water pump ? I only had the car for about 2 weeks and it's really hard for me to decide what to do , man this sucks I wanna drive it already

Pyzik

That's where the temp sits , is that normal?

Barry Chan

funny looking gauges and headlights?

Pyzik

Haha yea headlights are funny and I'm putting stock back on tomorrow but unfortunately I don't have stock guage background

Carl Fausett

Give me a call tomorrow, I may be able to help.

I especially want to be sure that the water pump is not defective. We have seen cases where the pump impeller is loose on the pump shaft. Search the forum here and you will see whole threads about it. I'd like to rule that out for you.

Pyzik

The instructions from you on how to rule out the pump , are those 100% accurate all the time ? I fallowed it and didn't the get results your talking about up/down movements, can I rely. On that and have the pump changed?

blown 87

No, but then again very few things are 100%.
I think what Carl is trying do determine is if the impeller has failed, which happens some times.

From what you have said, that one hose stays cold and one gets really hot, my guess is on a bad water pump.
This can and does happen.
I would also want to do a chem check for a blown head gasket.