Warm up time ?

[bigfella70]

Hi all

A week into 996 ownership and im very happy with my '98 C2.

Changed the ignition switch yesterday afternoon which cured the variious electical snags like heater blower not working, no cig lighter or rear wiper etc. (Thanks Richard for the advice / procedure)

My next query to look at is the warm up time. Driving from home to local town - 5 miles steady through mainly 30mph zone - outside temp was 18 degrees c. The temp gauge registered halfway between the 40 and 80 markers by the time I got to town. I would have expected the car to come up to temp a bit sooner ?

It did get to the 80 mark but only after about 30 mins running about so im suspecting thermostat might be stuck open ? Unless this is normal behaviour for these 996's in which case ill leave well alone !

Any advice / comparisons would be much appreciated !

Regards.

Dave

 

[sulzeruk]

Hi Dave, sounds like the thermostat is stuck open to me. Best way to check is to leave it idling from cold and see how long it takes to get to normal running temp at 80 degrees. If it is less than 30 minutes that you say is normal, it is open. Alasdair

 

[bigfella70]

Thanks Alasdair. Update from a run this morning.......... 1.6 miles from startup at a steady 30mph for the gauge to read bang on the 40 marker. 8.0 miles from startup and a good 20 mins at 30/50 mph and stop start traffic to get about 1mm below the 80 marker. Then later in traffic, needle went up to within the "0" of "80". Im not sure whether the warm up time is about normal and compares to others ? With regard to the general running temp - after a long run the other day the needle went to jest the far side of the "0" of the "80" marker, when in stop start traffic after a 300 mile run. I though that this was a little high and maybe the rad fans should have come on (the air con was switched off at that time). I have never heard the front rad fans or engine bay fan come on. Today I switched the air con button on and this settled the needle back towards the 80 segment marker on the gauge. Back on the drive with the engine running I noticed the fans were not running without the aircon button being on - so I think the resistors on the fans may have packed up hence them not coming on at a lower temp. My understanding is that the ran fans work as follows : Stage 1 - low speed operation Coolant more than 100 degrees c or aircon switched on (and outside temp more than 8 degrees c) Stage 2 - high speed operation Coolant temp more than 105 degrees c Of course for the coolant temp to be 100 degrees and cause stage 1 fan actuation, the needle would be on 100 which I make to be the unmarked segment between 80 and 120 - mine's only ever got up to half way between the 80 marker and this next un - numbered marker on the gauge. So, my thoughts are that I could have a sticking thermostat, causing slow warm up and that my fan resistors may need changing - I guess i need to use the car and monitor more closely to decide !!! In fairness I have only had the car a week so getting used to it etc ....... Regards. Dave

 

[rhkumar]

If you do decide to change the thermostat then I would say it makes sense to change for the low temp thermostat from Hartech. I think it's approx 60 pounds. Thx Roy

 

[thirteeneast]

Didn't think that Baz recommends the low temp stat for MK1 ?.

 

[thirteeneast]

http://www.porscheclubgbforum.com/tm.asp?m=643396&mpage=1&key=low%2Ctemp%2Cthermostat&#643757

ORIGINAL: bazhart We very rarely have a cylinder scoring problem with a 3.4 because the temperatur distribution in the engine is better and the low spee torque is less. However our advice is not so much that it will be a bad thing but rather more that it is not really as necessary as it is with the larger engines - but no harm will result and if you car ever developed a cooling fault - it may well delay damage so the fault can be found and rectified. You must remember that we will always give honest advice rather than that which will benefit us financially and so we would not suggest fitting the thermostat to 3.4's if it was not strictly necessary. Also - as time goes by - we sometimes come across and engine that has failed that has cylinder scoring (when we have never previously seen it before in that model) and so may well revise our advice accordingly. Regards, Baz

 

[Richard_Hamilton]

The coolant fans will always run at high speed if there is an A/C demand. If you can get access to a Porsche tester, you can use it to check the fans run at low and high speed. From what you have said, it isn't necessarily the case that the ballasts have gone. It sounds to me like it is taking longer than it should to warm up, and I agree with Alasdair that the thermostat could be stuck open.

 

[rhkumar]

ORIGINAL: thirteeneast http://www.porscheclubgbforum.com/tm.asp?m=643396&mpage=1&key=low%2Ctemp%2Cthermostat򝊭

ORIGINAL: bazhart We very rarely have a cylinder scoring problem with a 3.4 because the temperatur distribution in the engine is better and the low spee torque is less. However our advice is not so much that it will be a bad thing but rather more that it is not really as necessary as it is with the larger engines - but no harm will result and if you car ever developed a cooling fault - it may well delay damage so the fault can be found and rectified. You must remember that we will always give honest advice rather than that which will benefit us financially and so we would not suggest fitting the thermostat to 3.4's if it was not strictly necessary. Also - as time goes by - we sometimes come across and engine that has failed that has cylinder scoring (when we have never previously seen it before in that model) and so may well revise our advice accordingly. My bad. Sorry Regards, Baz

 

[thirteeneast]

@rhkumar, Thanks just re read it. And still dont understand what Baz is saying as I questioned at the time. He says "We very rarely have a cylinder scoring problem with a 3.4 because the temperatur distribution in the engine is better and the low spee torque is less. However our advice is not so much that it will be a bad thing but rather more that it is not really as necessary as it is with the larger engines" And therefore wheres the harm in the fan mod if that were to be the case that your 3.4 was getting too hot.Its the same as turning the A/C on to use the fans to lower the temp. Or changing the resistance values of the ballast resistors so the fan speeds would be different to stock speeds?. Surely whatever keeps your engine at 180 fan mod or stat or stock ? Is 180 not where there supposed to run?. And lower or higher could cause problems.

 

[bigfella70]

Well an update re warm up time / running temp's - I stripped the front PU and cleaned between rads / condensers, lots of leaves found and I blew through with an airline. The car now runs a bit cooler, on a motorway run the gauge settling halfway between 40 and 80, slower in traffic just below 80 and if stationary in queue just above 80 - so I still think the thermostat is stuck open. Havent had chance to take the car in to local independant (Porschtek Leeds) for rectification. Cant see that any damage is being done so long as I dont thrash the car from cold , will update once I get the stat out !!

 

[thirteeneast]

I would say thats normal and wouldn't want to see it any lower. I'm a bit confused as originally you said it was taking too long to warm up but now you said its running cooler. thats going to take even longer to warm up then?. The rads having leaves would have made it get warmer quicker. Temps Seems fine to me anyway.

 

[bigfella70]

Hi Takes a little longer to warm up, about half hour to get just below 80 with local running about, once cruising at motorway / A road speeds the temp now sits lower, at halfway between 40 and 80 markers. Before cleaning the rads it would sit just below the 80 pointer when on the motorway cruising. Temp will rise when running is slow moving traffic around the 80 mark. To be fair I can live with all this providing im not risking harm by the car running cooler on motorways / A roads ie between the 40 and 80 mark. Dilemma is do I have the thermostat changed or just leave well alone as the car is running very nicely otherwise........... In fact am I doing the engine a favour by this increased "cooling" effect ? ............................

 

[sulzeruk]

If it is running at 60 degrees, it is too cold. You are also lengthening the warm up time of the engine so your oil and coolant are taking longer to heat up to temperature which is not good. With a cold engine, contaminants and moisture in the engine are also not burnt off with the combustion process thus buggering your oil more quickly. Change the stat and you're engine will be much happier, you are also less likely to have a cold seizure which will cost you about £6000 to fix for an engine rebuild as your overfueling engine will be washing all your oil off the bore. Alasdair

 

[bigfella70]

Sounds like good advice to me Alasdair - time to get in touch with Porschtek I think !! Regards. Dave.

 

[bigfella70]

Had the car down to Porschtek Leeds to investigate the over cooling. Upon stripping the themostat housing - there was no theromstat fitted , and the housing was damaged where the stat would sit so had to be replaced. Im gusiing that sometime in earlier life the stat has stuck closed and someone has butchered the housing trying to change it then just not bothered putting it right. Either that or someone removed it to make the motor run much cooler ? Anyhow, car is now ready for me to collect tomorrow morning. Both fans were tested for operation via computer and also functioned correctly with the car idling stood still, so good news really ! Very, very impressed with Porschtek, in fact best communication and service ive ever had from a garage full stop. Can highly recommend !!! Regards. Dave

 

[Richard_Hamilton]

I'm pleased to hear you got it sorted Dave. I've also heard very good feedback about Porschetek, and am told they are very reasonably priced too. It is good to have someone you can trust.