I have the 3rd radiator, what is the normal operating temp for the coolant gauge, when in traffic? If I'm not stopping and going, then the needle normally stays ay 180 or below, but when in traffic it goes up about 3/4 of the way to the line just after the 180 line.

 

Mine stays at just a mm above 180 once warm, traffic, stop and go or not.

 

The in-dash coolant gage is really not accurate/sensitive enough to use for anything other than to tell if engine coolant cold, warm, or hot (up to operating temperature hot).

After driving through 116F temps in desert I was worried about overheating cause gage needle climbed quite high. I related the various temps: coolant 226F (steady....), intake air temp: 135F; ambient temp: 116F; and service manager passed these on to Porsche. The word back was as long the coolant light was not flashing there was no overheating.

My experience with several Porsches (no Tip just manuals), is in traffic on mild day (mid-60s) and with A/C off (if on this turns on radiator fans which tends to moderate coolant temps considerably) the coolant temp will climb to the point (212F or thereabouts) the radiator fans come on. These stay on until coolant temp drops to 205F.

If the coolant temp climbs above 212F, like is possible on a hotter day (80s, 90s, and beyond, and if the A/C is still not on) the coolant temp of around 216F will cause the fans to go to high speed mode.

I have captured coolant temps on various days and have found the coolant climbs to the point the fans come on then drops to 205F and of course the fans turn off. This cycle repeats for as long as I continue to drive the car in whatever conditions are present. Traffic, stop/go. Once out of the freeway and at sustained steady speeds at the speed limit, the coolant temp will drop to under 200F and may drop as far as to 190F.

Some in-dash gages react differently than others. Also, some T-stats open a bit sooner or a bit later than the 190F temp they're spec'd to open at. This can cause the in-dash temp gage needle to varying its position by some seeming large and significant amount that is really meaningless.

As long as the coolant warning light not on/flashing, temps are ok.

Since we are coming up on warmer weather, might be a good time to point this out: Even if the light not on, though, if the cooling system loses water, there is a leak and the system may not be pressure tight and this can lead to localized overheating as it is mainly the present of pressure that keeps the coolant from boiling at the hotter areas of the engine. If the coolant boils, flashes to steam, this steam acts just like an air pocket and blocks coolant flow. Thus the area heats up even though the system has plenty of coolant and the water pump is working just fine.

Sincerely,

Macster.

 

search on 'cleaning radiator'

unless you have cleaned the side radiators recently they are probably all jammed up

 

has anyone used the thermostat upgrade from LN?