Running Temperature

[minny]

just a quick question about the normal running temperature of the 3.4 engine... everyone says theirs sits about 80 but mine is midway between the 80 and 100 mark which i assume is 90 degrees... the car is running fine otherwise with no coolant loss and fans all working as they should

 

[Richard_Hamilton]

The reading sounds too high to me. There are several things that could cause it. A stuck thermostat, blocked radiators (most likely externally, but not impossible internally) dodgy temperature sensor, gauge etc. I would start by checking the rads are clear of debris and then try a new thermostat if it was me.

 

[minny]

The radiators are clear - i flush them out weekly and use a long reach hoover to get any debris i can't see. Where is the thermostat on the 3.4? Are there any special tools i need. What about the filling of the system after. Is there a special procedure to bleed the system.

 

[Richard_Hamilton]

Search is your friend: http://www.porscheclubgbforum.com/tm.asp?m=340084&mpage=1&key=thermostat&#340147 [] []

Edit: Sorry, I didn't mention bleeding the system. Basically, without a vacuum tool to evacuate the system, it's a pig to bleed. The original workshop manual outlines a procedure, which involves revving the car to a certain speed and holding it there, the process being repeated several times. Some people find it better to lift the back of the car on ramps. If you can beg, borrow or steal a vacuum tool, so much the better. They tend to be quite expensive, but I have seen them on eBay for about £50.

This one looks very similar to the Porsche tool: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=160021841639&ssPageName=STRK:MEWA:IT&ih=006

 

[minny]

Thanks again Richard. Something to do next weekend!

 

[minny]

before i start with replacing the thermostat, just wanted to check - when the car is moving, the temperature needle sits between the 8 and 0 of 80... in traffic, it moves to the middle of the 0... is my car running hot?.. i connected an eobd meter i have that can show actual running parameters and when the needle is between the 8 and 0, the coolant sensor reads 86 degrees... when the needle is in the middle of the 0, the coolant sensor reads 89.6 degrees...

 

[Richard_Hamilton]

Sorry, I'm a bit confused. When you said that during normal running the gauge was reading mid way between 80 and 100, then I thought this was a higher reading than normal. If it is at between the 8 and 0 during normal running, but going up to 90 when stuck in traffic, I don't think it is unusual. From what you say in the last post, I don't think you have a problem.

 

[minny]

sorry for the confusion richard... my mistake for not giving more detail... when moving, the needle is between 8 and 0 or just a small bit past it... when stationary or in slow moving traffic, it moves up to the middle of the 0 which is midway between 80 and 100.... from what i've read in other threads, i probably don't have a problem... did buy the vacuum tool though from sealey (code vs 0041) for £70... handy to have as i change the coolant in my other cars and fed up with slow filling and bleeding

 

[smj996c]

ORIGINAL: timsjones

???

Now I'm worried! Think mine runs a little hotter than that! On a normal run - moving well - the needle sits just above the 80 so to the right of the 0 (maybe 85?). In traffic, it goes up to the middle between the 80 and the 100 mark i.e. 90, but never been above that. All indicated, don't have any other gauge.

The radiators are pretty clear as just had the aircon condensers done! (though there is obviously still a fair amount of residual muck at the bottom - will jet wash in due course and warmer weather!).

Guess that yours sounds like it's running fine then! (and mine too, hopefully!)

Hi Tim, your temps seem fine to me - mine runs just over the 80 mark under normal driving conditions and creeps slightly when in traffic or during an italian tune up[]

- Simon

 

[minny]

useful to hear others had same worries about temperature but we all seem to have similar running temperatures and all's running well... i'm going to see an independent in belfast this weekend just for him to look at it and will keep you posted... i've spoken to him and he says there's nothing to worry about but he'll look at the temperature himself when i'm there

 

[penfold944]

Mines about the same... just slightly over 80 normally... any heading towards about 90 in heavy traffic...

considering I hammered mine on a track for an entire afternoon and the temp never went above normal, I think its normal

Was funny to see all the air cooled guys trying to cool their engines with the lids open

 

[bobafett]

Yep ill second that.

 

[minny]

just to update the forum, although my radiators appeared clear - i hoover them out weekly and then flush them with a hose, i removed the front bumper which only took 20 minutes considering it was my first time and didn't have the instructions in front of me, parted the aircon condensors and radiator and OMG, the amount of stuff stuck between them!!! the radiator fins were full of crap.. used a power washer and cleaned the whole lot out, straightened some crushed condensor fins and put the whole lot back with no hassle (remember my car is now entering its 10th year)... my running temp is now more stable... when driving on A roads, the needle sits on the left white (between the inner and outer margins) of the 0... previously it sat in the middle of the 0... in traffic it now sits in the middle of the 0 where it would previously have moved up to the right outer margin of the 0... will keep an eye on the temperature as i checked with an indie prior to the big clean and they felt it was running slightly warmer than usual although not badly so... as per richard hamilton they also recommended cleaning the radiators first then maybe changing the thermostats...

 

[Mercurial]

Overall, the radiators and condensers combo is not the greatest of designs.

 

[slick0007]

hi would say the easiest and cheepest thing to check and change first is the thermostat
check it by feeling your radiators while the car is warming up they should not get warm until the car is at running temp
if they get warm then your stat has stuck open and requires replacment

 

[minny]

Could be an airlock that hasn't cleared and it moved to around the temperature sensor area hence the temperature drop as air is a poorer conductor. After I had the coolant tank replaced, it took about 2 weeks for the coolant level to stop dropping which indicated that air was slowly being purged from the system over that time. The old Porsche way of clearing airlocks goes something like this : lift the expansion valve clip on the expansion tank, get the car up to temperature and rev the car every so often to over 5000rpm. Richard Hamilton is probably the person to ask for the exact procedure.
Of course it could be unrelated to the radiator change and still be the thermostat.

 

[Mike IRL]

I was thinking of thermostat. How quickly does it normally take your car to warm up to running temp? I've always found the 996 quite slow.