[crwindy]

My 968 Cab had always run at the 1/3 up the temp gauge. It is now up to 2/3 and the light came on briefly. I turned on some heat and blew it off, but I was wondering whatit might be. My thought is a stuck thermostat. The electric fan does operate properly, and coolant level is normal. If it is the thermostat, where might I find it, and how tough is it to replace?

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[Mark]

I thnk you are on the right track with the thermostat, same symptoms I had after replacing the water pump and thermostat.. The thermostat is at the waterpump and apparently is held on by a monstrous snap ring that is a bear to get out.





I highly recommend you test the new thermostat on the stove before you put it in, my replacement was bad. <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />

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[rustech]

You will have to remove the lower hose where it connects to the waterpump on the block. The thermostat resides inside the pump. You will need some small snapring plyers with a fine tip, and either bent (90deg) or short handles.

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[orphanowner]

[quote name='rustech' date='Jul 1 2006, 08:55 AM']You will have to remove the lower hose where it connects to the waterpump on the block.  The thermostat resides inside the pump.  You will need some small snapring plyers with a fine tip, and either bent (90deg) or short handles.

[right][post="23555"]<{POST_SNAPBACK}>[/post][/right][/quote]



I'll chime in that I highly recommend that anyone installing a thermostat in their 968/944’s, make a small modification to the new thermostat to prevent initial overheating while bleeding the system. I recommend that you drill a small, 1/8" hole in the movable plate of the new thermostat. This will prevent the inevitable mini-overheat from occurring when the thermostat base is not exposed to hot coolant upon initial start up. It is not uncommon for the coolant temp gauge to move to the red zone or for the engine to overheat and not indicate such on the gauge because it is not exposed to hot coolant due to an airlock in the block.



Position the drilled hole at the 12 O'clock position in the water pump housing to facilitate bleeding coolant and air to the "business side” of the thermostat. This prevents an airlock between the block and the thermostat.



Instead of the drilling a hole, some folks take two aspirins (I'm not kidding) and use them between the movable blade and the fixed part of the thermostat housing to hold the T stat open during this initial startup. The thinking is that the aspirins will dissolve after they are exposed to coolant and allow normal operation of the thermostat. The small hole will not affect the ability of the thermostat to maintain coolant temperature.

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[flash]

nice write up - something everyone should know - very cool



i have always drilled a 1/8" hole in my thermostats - very old race trick, showed me by a very seasoned veteran - one of the best tips i ever picked up

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[rustech]

A tip on the initial bleed.



When filling the car with water and coolant, make sure the bleed screw is open to allow the air to escape while fluid is entering. To work the air out of the system, and make sure the thermostat is surrounded by fluid, squeeze the lower hose and hold with the bleed screw open, and then close the bleed screw and release. It will draw in fluid from the reservoir to replace the air, repeat this step until only fluid comes out. 95% of the air will be removed. Drive and heat up the car for 3-5 minutes, turn off and wait a minute, then do the final bleed.

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[Cloud9...68]

Just as an alternative, much simpler thought, check to make sure both your fans are coming on. In the course of doing some work on my balance shaft belt, I forgot to re-connect the right fan. It was a medium-hot day, and it was amazing how much hotter the car ran, particularly when stopped. I hustled home, re-connected the fan, and found that this made the difference between running at the 10:00 oclock line, versus just a hair above the 8:00 oclock line.

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[PorscheDude]

I usually prssurize the system using compressed air in overflow tank, with the engine running and the bleed valve open.



Thats great tip drilling the small hole in the t-stat. I will try that on my next service.

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