Fabio421

Mark, all of mine run that cool. The only thing I do thats "special" is use water wetter but I think you do too. As I mentioned to you before. You need to put an IR temp gun on that thing and see what the actuall temperature is that it's running. The gauges are known to be inacurate.

soupcan

The 86.5 is the only one of mine that runs any hotter than this one, and it is only slightly higher on the gauge. The 83 had a new radiator installed a month before I bought it and the 87 has been rodded and retanked.

I tilted the 87 radiator foward and use water wetter (thanks for the idea shawn) also.

Tampa 928s

What degree thermostat are you running? Any other mods on yours for cooling?

hacker-pschorr

IMO all 928's should have the colder thermostat. Only reason to keep the engine hotter is emissions.

My two cars do not run any hotter than the photo above. One exception with the supercharged car, stuck in Chicago traffic for about 30 minutes inching along on a 95+ degree day. The temp rose between the lower line and half way point.

My 79 will overheat if left at idle for a really, really long time. That's because the fan clutch needs an overhaul. Since it's a track car I've never worried about it.

Tampa 928s

Sounds like a new radiator, 75 C thermostat water wetter and a tilt is the ticket. I still want to replace the airbox and fans and not deal with this anymore.

I have a ton of time money and aggravation to make this a car I can just drive, up to now that has not been the case. I never got the lite throttle surge out of it new maf, honey comb air straightener, you name it I have done it. If I did not hear about other S/C owners having similar issues I would be feeling I am missing something. Seems like many are fine some are not.
I am at the point that I may pull it and move on. This car ran great before and it runs good now but not fluid like I would expect. Maybe I am expecting too much but if I drop any 1,200 into it is it worth it! So if I get the heat addressed what about the surge it is so aggravating. If anyone can suggest a direction to take please do, maybe I am missing something.
Sorry for the rant but this gets old especially when I jump in my Euro and it runs as good as my wifes Caddy.

dprantl

Earlier 928's with the mechanical fan that are healthy should always run 2.5-3bar hot oil pressure and temp in-between the 2nd and 3rd white line max, usually lower. S4 and newer with the stock dual fans are programmed to run a couple of needle widths below the 2nd white line and therefore have an oil pressure of 1.5-2bar instead. For a modified S4+ with fans controlled to run differently, you should be able to achieve the same running parameters as an earlier car, as soupcan has demonstrated. Soupcan also most definitely has the lower temp thermostat installed.

My car with the stock fans and lower temp thermostat will run just above the first white line in winter, but will be a couple of needle widths below the 2nd white line in the summer, solely because that's the way the stock '87+ fan controller is configured. On a side note, it would be nice to be able to modify the programming of the stock fan controller to increase the fan speed ramp up vs temperature increase relationship.

Dan
'91 928GT S/C 475hp/460lb.ft

Tampa 928s

I have my 75 C thermostat installed and new radiator coming from Roger.

I have a duel temperature sender installed now and wonder if a need a cooler switch, I have not been able to find anything on the net.

I am using one connection for the condenser fan the other for the 4-rear fans.
I would like to lower the turn on temperature for the rear fans the front will turn on when the air is activated so less of an issue.

So where can I get one and what would the ideal range be?

A25 S
FAE 37820
Shows
95-102C = 203-212 Degrees
85-92C=185-197 Degrees

jetrainor

Once the thermostat opens, what temperature should i be looking for if i 'shoot' the temp gun at the main front water housing?

dprantl

IMO around 185 deg F would be good to shoot for. That would put the temp needle just below the middle of the second and third white line.

Dan
'91 928GT S/C 475hp/460lb.ft

Imo000

Depands how long have the termostat been open, are the cooling fans on, has the engine been under load and so on. In every case, it should be higher than the rating of the thermostat.

Tampa 928s

I did the stove and hot water test with two meters, so I now know which pins connect at what temperature. I will use the 85-92 C for the rear fans and 95-102 C for the condenser fan. New thermostats opens at 75 C so will see if this brings my temps down.

Tampa 928s

New radiator, 75 c thermostat, sealing ring, flushed 50/50 G-05 with royal P water wetter. Temp in traffic now to just under second line when rear fans kick on drops to about 1/2 way fans turn off then temp goes up again. This is always at light, stop and go with air on.
Still waiting on my first white line reading!

I need to know what the temp range of my coolant sensor located in the radiator was from the factory.

I have a duel sensor 185-197 / 203-212 185 for rear fans 203 for front irrelevant when air is on.

It seems like I need a cooler turn on time, what sensor would work, any recommendations? I am going to bypass the switch for now to test if fans are on all the time if the temp stays in the normal range.

Imo000

The two S4 that I've worked on has the same fan kick in point as yours. I think your car is working as designed.

ramcram

Another new water pump, flushed the radiator, which increased the flow rate by 30%, changed the front fan to a 3630CFM and through out the 2 x 8" puller fans and replced them with a 10" [bigest I can fit in] puller, fitted to a custom shroud. This keeps it away from the core to allow better air flow without hub restritions and stops air just recirculating around the blades. The puller fan is triggered by a new temp sensor fitted into the top of the water bridge, next to the stock Porsche one and fed through a relay powered from the battery post under the bonet.
We get hot weather here about now, can hit mid 40C [114F] and stuck in traffic with the air on, my temp would rise passed the top white mark. Now it hasn't got passed horizontal and usually sits on the first white mark.