shiners780

Just replaced the radiator, water pump, thermostat, lower temp radiator fan thermo switch, and hoses. I have only water in at the moment, no antifreeze/coolant. Bled the system several times, only getting water no air. The water is clean (no oil) and no loss of water, pressure tested fine.

The water temp gauge always stays between the second and third mark. The fans come on when the temp gets just over the second mark, and they stay on almost the whole time I'm driving.

Hoses 8, 9A, 11 are hot. Hoses 10, 32, and expansion tank are not hot.

Compared to my race car this seems like it's running too hot, and that the fans should not be running so much. I can't figure this out. Thoughts?

Mike C.

You have the lower temp switch in there already and it sounds like you covered everything else. Anti-Freeze may help the heat transfer coefficient but I wouldn't expect that much of an effect.

shiners780

Yeah I ran just water (and water wetter) in my 951, which was driven crazy hard on the track, and never had cooling issues. I'm kinda stumped on this one.

roman944

Hi Jim

Not sure if it has any effect, but my car had 2 6-blade fans on it, did your turbo have these too? What about your new N/A? Maybe that has some kind of effect on how cool the car runs?

shiners780

My 951 had double 6 blade fans, this one has double 3 blade fans. Is between second and third mark on the gauge normal operating temp???

roman944

My car operated at middle mark. But you probably remember that we were never able to bleed the system completely. I know why now - fans, bad coolant cap, hairline cracks in the coolant tank, and bad hoses in coolant and vacuum hoses. But getting the fans to work was a definite step in the right direction, as well as a new coolant cap. My car did run cooler during winter though.

I would think that its fine, so long as it stays below the middle mark. Doing the search, I kept reading at how cool some of the cars run, but that may vary by location + type of parts used in the cooling system, probably.

shiners780

No one else has suggestions?

What does everyone's temp gauge read during normal driving on a typical 65-70* day? (on an early gauge)

johnnykrand

You could go hardcore and install a heat exchanger if you arent satisfied with the problem :P

F18Rep

Both of mine run right at the lower mark and only occassionally stray a hair above it. But I run the lower temp thermostat for both the main tstat and the turbo tstat. Could it be maybe you have a bad oil cooler tstat (which I don't know squat about but supposedly can be removed and tested on the wife's stovetop)...Hey, you asked for ideas...Bruce

marky522

I would guess air trapped in the system. I always vacuum fill my cars and have had no cooling issues with any of them.

And FYI, straight water has the best heat transfer coefficient, coolant has less ability to transfer heat, so a straight water with water wetter would be the most efficient setup, but could freeze.

Mark

Van

I can't make sense of that diagram... it looks like it's missing about 15 hoses.

Was it running at the same temp before you changed all of those things? Do you have an infrared thermometer gun? how even is the head temp? Could there be some blockage somewhere?

shiners780

I suppose it's possible there's still air in there, though when pressurized all I'm getting is water. I have never ever had an issue with bleeding before.

As far as water heat transfer, that is what I have always understood as well.
Yes, many fewer hoses! I can't believe how much easier this car is to work on than my old 951.

I only drove the car a couple times before doing all this work, and didn't notice the temp being so high, so I am assuming it has something to do with what I did. Trapped air is really the only thing that makes any sense at this point.

I need to change a hose and put in a nice new white expansion tank so I'm going to drain the water again and start from scratch.

Thanks for the responses guys.

Van

I know a guy with a 924S - his car always ran "hot" until he changed the temp sensor...

shiners780

The one for the gauge?



Anyone have a diagram that shows the route coolant takes through the radiator and various hoses? Trying to figure out why 10 & 32 aren't getting hot like the other hoses.

Van

32 connects to the heater core return, no? That should only get hot when the heat is on (which you probably haven't had on...)

10 will only get hot after a long time - since there is no pumped "loop" through the reservoir. It will also get hot if, due to thermal expansion/contraction/air bubbles, etc., the system pulls water out of the tank, then spits it back out.