thermostat types
04-30-2003, 02:49 PM
#1
Drifting
Thread Starter
thermostat types
the local garage is changing out the thermostat for me and they have a replacement part only it dosent look quite the same as the original.
the original has a much larger flat section projecting from the block/engine side. can the new thermostat with a smaller flat section be used?
thanks,
nick.
the original has a much larger flat section projecting from the block/engine side. can the new thermostat with a smaller flat section be used?
thanks,
nick.
04-30-2003, 03:54 PM
#2
Burning Brakes
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Nick,
Be careful with the thermostat - Only install the original, and on newer models from 1984 (incl) also change the rubber seat behind the thermostat
On a 928 the thermostat works 'in the opposite way' - I.e. when it open it close a bypass (internal circulation in the engine) and force the cooling water via the radiator
On older models (up to 1983) the thermostat close against a alu-seat, check this for corrosion.
Use the Rennlist search facility and find more info - See also <a href="http://nichols.nu/tips.htm" target="_blank">http://nichols.nu/tips.htm</a>
Be careful with the thermostat - Only install the original, and on newer models from 1984 (incl) also change the rubber seat behind the thermostat
On a 928 the thermostat works 'in the opposite way' - I.e. when it open it close a bypass (internal circulation in the engine) and force the cooling water via the radiator
On older models (up to 1983) the thermostat close against a alu-seat, check this for corrosion.
Use the Rennlist search facility and find more info - See also <a href="http://nichols.nu/tips.htm" target="_blank">http://nichols.nu/tips.htm</a>
04-30-2003, 05:03 PM
#3
Burning Brakes
Join Date: Dec 2002
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Hi Nick,
In the earlier post about the DEVEK RADIATOR I raised this point;
"....along the same lines I read in a DEVEK advert for a 75C thermostat, something that I cannot come to grips with.
It says "..and allows refilling of the cylinder heads with coolant before the first thermostat cycle, thus avoiding cylinder head stress on initial start."
Can somebody explain this ????
I think I must be losing the plot - well I'm 64!
Regards...."
Perhaps Marc from DEVEK can explain what is meant as my humble knowledge of the 928's cooling system aligned with these comments have given me untold sleepness nights in wonder.
And at my age sleep - or driving my 928 - are two of the four great pleasures in life - I'm missing out on 50% at the moment due to the unanswered question!
I agree with Eric however - use a standard OEM thermostat and the correct Nitrite/Phosphate free coolant.
Regards
In the earlier post about the DEVEK RADIATOR I raised this point;
"....along the same lines I read in a DEVEK advert for a 75C thermostat, something that I cannot come to grips with.
It says "..and allows refilling of the cylinder heads with coolant before the first thermostat cycle, thus avoiding cylinder head stress on initial start."
Can somebody explain this ????
I think I must be losing the plot - well I'm 64!
Regards...."
Perhaps Marc from DEVEK can explain what is meant as my humble knowledge of the 928's cooling system aligned with these comments have given me untold sleepness nights in wonder.
And at my age sleep - or driving my 928 - are two of the four great pleasures in life - I'm missing out on 50% at the moment due to the unanswered question!
I agree with Eric however - use a standard OEM thermostat and the correct Nitrite/Phosphate free coolant.
Regards
05-01-2003, 01:06 AM
#4
Banned
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I installed that 75 degree thermostat along with a low temperature fan switch- they both work great.
I can also remember puzzling over the fact that they were indeed slightly different. It didn't seem to matter- just make sure the little vent hole is at the top when you mount it.
-I don't think I completely understand why a thermostat makes the engine run cooler. I guess I was always of the opinion that in general, the thermostat starts to open at 75 degrees C [instead of 90 c for the factory unit], so it opens sooner...but does that mean that it regulates the temperature to a cooler level? I was of the opinion that the thermostat runs pretty much wide open above 75 c...
N!
'85 S2 5 Speed
I can also remember puzzling over the fact that they were indeed slightly different. It didn't seem to matter- just make sure the little vent hole is at the top when you mount it.
-I don't think I completely understand why a thermostat makes the engine run cooler. I guess I was always of the opinion that in general, the thermostat starts to open at 75 degrees C [instead of 90 c for the factory unit], so it opens sooner...but does that mean that it regulates the temperature to a cooler level? I was of the opinion that the thermostat runs pretty much wide open above 75 c...
N!
'85 S2 5 Speed
05-01-2003, 01:38 AM
#5
Dennis Wilson -you out there Dennis?-,
Told me at last years SITO, Sharks In The Ozarks,
aka shARKANSAS EVENT, that there is a 944 thermostat that is Identical -at least for the early models- and can be purchased at most Auto Parts Stores.
Told me at last years SITO, Sharks In The Ozarks,
aka shARKANSAS EVENT, that there is a 944 thermostat that is Identical -at least for the early models- and can be purchased at most Auto Parts Stores.
05-01-2003, 03:20 AM
#6
Drifting
Thread Starter
i may try the new and different thermostat and carefully test. if the engine runs hotter then i will have no choice but to find a matching replacement part. i will let you know how it goes.
05-01-2003, 04:21 AM
#7
Burning Brakes
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Normy:
<strong>
............. the thermostat starts to open at 75 degrees C [instead of 90 c for the factory unit], so it opens sooner...but does that mean that it regulates the temperature to a cooler level?
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Erik wrote:
On a 928 the thermostat works 'in the opposite way' - I.e. when it open, it close a bypass (internal circulation in the engine) and force the cooling water via the radiator
----
Normy,
Yes - The cooling takes place in the radiator, and the cooling water do not pass trough the radiator before the thermostat is fully open and close the bypass - Therefore it is so important that the seat behind the thermostat is ok, and this is often overlooked - I did it myself when I renovated my engine first and second time! And maybe that's a part of the story why my engine with new block 'smashed' the piston rings on the rear (the warmest) cylinders! <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" /> <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />
From 1984 is this seat a rubber seat (earlier models alu-seat with tendency to corrode) The strange (and dangerous) thing is, this rubber seat is not included in a complete gasket set
According to the spare parts list, Porsche have a exchange service for the thermostat house from old to new model - Can also be machined locally so the rubber seal can be installed. <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />
<strong>
............. the thermostat starts to open at 75 degrees C [instead of 90 c for the factory unit], so it opens sooner...but does that mean that it regulates the temperature to a cooler level?
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Erik wrote:
On a 928 the thermostat works 'in the opposite way' - I.e. when it open, it close a bypass (internal circulation in the engine) and force the cooling water via the radiator
----
Normy,
Yes - The cooling takes place in the radiator, and the cooling water do not pass trough the radiator before the thermostat is fully open and close the bypass - Therefore it is so important that the seat behind the thermostat is ok, and this is often overlooked - I did it myself when I renovated my engine first and second time! And maybe that's a part of the story why my engine with new block 'smashed' the piston rings on the rear (the warmest) cylinders! <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" /> <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />
From 1984 is this seat a rubber seat (earlier models alu-seat with tendency to corrode) The strange (and dangerous) thing is, this rubber seat is not included in a complete gasket set
According to the spare parts list, Porsche have a exchange service for the thermostat house from old to new model - Can also be machined locally so the rubber seal can be installed. <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />
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05-01-2003, 04:22 AM
#8
Drifting
Thread Starter
just checked the old thermostat operation and i can now see how and why it is needed, wont be installing the new and different type. here is a link (i hope) to a pic of the two thermostats. you can see that the original actualy has two diaphrams that operate together and this is how it can both open a cooling flow and close/divert another!
<img src="http://www.momentoffame.com/snapshot.html?id=36398" alt=" - " />
<img src="http://www.momentoffame.com/snapshot.html?id=36398" alt=" - " />