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Only difference is he pulled his pump and found a rusted metal impeller (mine is plastic). I am still reading through the thread to see what the final diagnosis was. Mark Kibort suggested a possible sticking thermostat though. If I remember correctly, his Euro car suffered a head gasket failure. I have noticed no mixing in mine (oil pan and coolant reservoir)
Don't waste too much time speculating and scaring yourself..... eliminate the simple cheap option by doing the thermostat and rear seal. If that does NOT fix it then you can start sweating.
I don't think this an HG issue anyways. I have never noticed any coolant loss. Given I had a 944 that suffered an HG failure, the loss was very noticeable through pressurization of the cooling system. The reservoir was basically pushing coolant out on its own when the car ran. Also 2 spark plugs were squeaky clean. That headgasket failed at the fire rings near the water jacket.
Randy, I haven't tried that. One quick way I heard to bleed air was to park it on the driveway and open the small radiator hose on the driver side radiator by the driver side intake tube. When I did this, it was a solid stream of coolant. No air there.
No complaints when in motion, the temp needle behaves like it should at speed between half-way and just above the first white mark. Sit at a light at idle, and the sucker climbs real fast to the top hash mark.
I found this thread. He had no heat as well, but blamed it on a stuck open thermostat. Changing the thermostat fixed it. I wonder if mine just isn't opening enough and/or the seal behind it took a dump and is floating somewhere in the cooling system.
One more thing... For those of you who have cooling flaps cross your mind. I pulled that fuse back in 2005. There was a 3-page thread of me bitching about it too.
Now here is a pic where you can sort of see the angle of the needle pointed at the first white mark on the temp gauge in the left corner.
The car ran at this temperature 1 year ago today, or 200 miles ago
That is also 30 minutes into stop and go traffic. Dunno about you guys, but within that time span, that temperature is a hell of a difference. Something ain't right. I hope this clarifies what is going on now.
Normal temp is between the two centerlines. Porsche says it may show higher temps under high-speed, but should not go above the upper mark, and should go back to normal when speed is reduced. Normally, the amount of heat removed is controlled by the volume of coolant flowing (engine speed and water pump), the amount of coolant flowing through the radiator (engine speed and thermostat) and the volume and temp of the air through the radiator (speed and fans). If the gauge shows a high temp, but there are no signs of high engine temp, it may be a gauge problem. If the engine overheats only at low speeds, or only with the AC operating, it’s often an airflow problem. If the engine overheats at highway speeds, it’s often coolant flow. Lugging can cause overheating, as can stop and go traffic in high ambient temps and AC. A lower temp thermostat may mask the problem but won’t fix it. A lower temp thermostat decreases engine life, economy, and increases emissions. They fail in any position. Signs of a failed closed thermostat are overheating under normal driving conditions. Signs of a failed partially open thermostat are very slow warm-up and overheating under highway speed/high load conditions, but not at low speed/low load conditions. Signs of a failed open thermostat are no warm-up and poor economy. It should not overheat with the normal temp fan switch. A lower temp switch will often prevent problems in a marginal system by increasing airflow before the engine coolant gets too hot. A lower temp switch will often improve AC performance slightly. It’s possible, but unusual, for a water pump failure to cause slight or intermittent overheating. The most common causes of that type failure would be slippage of the impeller on the shaft or erosion of the impeller. The most common water pump problem is failure of the bearings, often caused by failure of the shaft seal allowing coolant into the bearing. All water pump leakage on a 928 is critical, and must be dealt with immediately. If the water pump fails, it will destroy the engine, by causing timing belt failure, with subsequent valve/piston crashing, or by eating the block with the impeller. A bad radiator pressure cap can cause overheating through loss of coolant, and allow coolant to boil at a lower temp. The flaps and variable speed fans on the late cars must function properly. A lean fuel air mixture (caused by vacuum leaks) can cause overheating. High temps and thin air can cause overheating, especially at WOT. There are things you should check to be sure your cooling system is functioning optimally. 1) Make sure the louvers are wide open. 2) Check that the fans are working. 3) Do not run without the belly pan, at speed, it helps in cooling. 4) Clean out all debris from the radiator and AC condenser. 5) Use clean water with the correct 50/50 mix of distilled water and a phosphate-free anti-freeze. A good choice is Dex-Cool. 6) Add a bottle of Water Wetter. 7) Make sure the coolant system holds pressure.
Since your needle is still between the two white marks it's still okay. Could just be a deteriorating system. All of the advice above is good. The best thing is to drive it.
Jim, in my case, it is low speed/low load. anything under 35 mph and that gauge is at the top white mark. Smack the dash pod, and it drops down a tad to around the middle. It also jiggles like crazy after that.
Jim, in my case, it is low speed/low load. anything under 35 mph and that gauge is at the top white mark. Smack the dash pod, and it drops down a tad to around the middle. It also jiggles like crazy after that.
You realize that thing where Fonzie got the jukebox playing was just a TV show right? It didn't really work that way.
02-13-2017, 02:26 PM
If that does NOT fix it then you can start sweating.
