Knackered old Porsche with loads of miles - 996 content
Discussion
poppopbangbang said:
For the most part no but that is with a pinch of salt. If the car isn't overheating in traffic as is then adding the centre rad won't help or make much of a difference as it has no fans on it. The centre rad is really for cooling during periods of high load at speed e.g. fast motorway cruising or circuit use. However the centre rad does help get the bulk temp of the coolant down MUCH quicker once you are moving again so in that respect it can be very useful.
The most important thing is to make sure the fans are working, rads are in good order and clear of debris and if you so desire you can fit a low temp thermostat which whilst won't help the maximum temperature achieved in traffic it will reduce the starting temperature so on average reduce the overall coolant temperature average.
.The most important thing is to make sure the fans are working, rads are in good order and clear of debris and if you so desire you can fit a low temp thermostat which whilst won't help the maximum temperature achieved in traffic it will reduce the starting temperature so on average reduce the overall coolant temperature average.
Regardless of the permanent 30c heat here in Florida summers there are far too many State Troopers and police around to spank my car too much..... :
Thanks for taking the time to reply, now back to the thread
poppopbangbang said:
In high 30 degree ambients the standard two rad cars are fairly close to the limit of their cooling ability.
Cheers. I've always heard they got near left side of the 0 in higher ambients, but never actually heard of that high while cruising at fairly good speed. Were you able to check in evo what was the oil temperature in that moment? 
ooid said:
Cheers. I've always heard they got near left side of the 0 in higher ambients, but never actually heard of that high while cruising at fairly good speed. Were you able to check in evo what was the oil temperature in that moment?
Put simply you have about 150KW going into the coolant system at 130mph cruise, the oil is cooled via a water oil heat exchanger so the coolant system has this additional heat to lose as well. In a 20 degree ambient on my car this gives a stable coolant temperature of 80 - 84 degrees or so, in a near 40 degree ambient it gives 95 - 99 degrees. Not a lot you can do about that as it's a function of ambient air temperature and heat transfer for a given surface area of radiator. What I can say from experience is that a standard car would be another 10 degrees up on this. At this the oil temp is around 120 degrees C which shows just how efficent the little heat exchanger is.The ideal point for cooling is around 80mph as this gives the best air speed through the rad ducts for the amount of power being used and therefore heat the cooling system has to deal with. At this in a 20 degree ambient all cars in good health should run on the thermostat temperature.
JS1500 said:
Interesting stuff.
My 996 overheated on the way to and from getting some new tyres fitted at the weekend. Believe it is the driver's side radiator leaking...but fans didn't seem to be coming on...requires investigation! Wondered about the possibility of fitting a centre rad too...
Did it actually overheat in terms of boiling over and steam or did it just show high on the gauge/start flashing the red light at you?My 996 overheated on the way to and from getting some new tyres fitted at the weekend. Believe it is the driver's side radiator leaking...but fans didn't seem to be coming on...requires investigation! Wondered about the possibility of fitting a centre rad too...
toastyhamster said:
Just caught back up with this thread, great stuff. I really shouldn't be browsing autotrader, 10k for a 996? These things are money pits right?? Argh.
No I'm sure it will be absolutely fine... 
Pop over to the "what's an early 3.4 996" thread as there are good cars being posted on there every now and again.
crosseyedlion said:
Superb thread.
Really sorry if its been mentioned before, what sort of fuel consumption does it see on a 80-90mph cruise? I'm currently hunting for something interesting for my 145 miles a day commute.
Mine doesn't have OBC & I've never actually worked it out but on a run you should see high 20's, possibly even low 30's on a gentler run.Really sorry if its been mentioned before, what sort of fuel consumption does it see on a 80-90mph cruise? I'm currently hunting for something interesting for my 145 miles a day commute.
crosseyedlion said:
Superb thread.
Really sorry if its been mentioned before, what sort of fuel consumption does it see on a 80-90mph cruise? I'm currently hunting for something interesting for my 145 miles a day commute.
Mine does 20ish knocking round, and 26ish at 85-90mph.Really sorry if its been mentioned before, what sort of fuel consumption does it see on a 80-90mph cruise? I'm currently hunting for something interesting for my 145 miles a day commute.
Does a bit more if my wife is driving.
PPBB,
My 3.4 C2 has had a FVD sump fitted (actually after reading one of your threads at the other forum helped with my decision); on track day do you add additional oil or just top up to the 'max' level?
I am going to take my car to Thruxton and it's got many long high speed sweeping corners (110mph+), hence my question.
Thanks.
My 3.4 C2 has had a FVD sump fitted (actually after reading one of your threads at the other forum helped with my decision); on track day do you add additional oil or just top up to the 'max' level?
I am going to take my car to Thruxton and it's got many long high speed sweeping corners (110mph+), hence my question.
Thanks.
BrotherMouzone said:
PPBB,
My 3.4 C2 has had a FVD sump fitted (actually after reading one of your threads at the other forum helped with my decision); on track day do you add additional oil or just top up to the 'max' level?
I am going to take my car to Thruxton and it's got many long high speed sweeping corners (110mph+), hence my question.
Thanks.
Just top up to the max level, due to the sump being deeper the max on the dipstick is now +0.6L or so more than the standard max on the dipstick...... if that makes sense? My 3.4 C2 has had a FVD sump fitted (actually after reading one of your threads at the other forum helped with my decision); on track day do you add additional oil or just top up to the 'max' level?
I am going to take my car to Thruxton and it's got many long high speed sweeping corners (110mph+), hence my question.
Thanks.
Mine has been on Thruxton with no issues however keep an eye on your oil pressure gauge on the first couple of laps and if you see it sinking during long corners then don't continue to push on or you will have issues, depending on your engine setup, number of scav pumps etc. you can have issues with clearing the oil back to the sump.
Having said that if you are on road tyres you are extremely unlikely to have any sort of issue
poppopbangbang said:
JS1500 said:
Interesting stuff.
My 996 overheated on the way to and from getting some new tyres fitted at the weekend. Believe it is the driver's side radiator leaking...but fans didn't seem to be coming on...requires investigation! Wondered about the possibility of fitting a centre rad too...
Did it actually overheat in terms of boiling over and steam or did it just show high on the gauge/start flashing the red light at you?My 996 overheated on the way to and from getting some new tyres fitted at the weekend. Believe it is the driver's side radiator leaking...but fans didn't seem to be coming on...requires investigation! Wondered about the possibility of fitting a centre rad too...
Think the fan might be buggered too...
JS1500 said:
On the way there the light started flashing just before I reached my destination. Just as I parked up it began pishing coolant from the driver's side radiator. KwikFit said the radiator had a hole (genius) and they couldn't do anything about it so put my new tyres on and topped up the coolant. Car had been sitting cooling for three hours so thought the six miles home would be ok...but half a mile from home the light started blinking again and I saw a wisp of steam in the mirror. Boiled over and rad unsurprisingly still leaking. Pulled over, let it cool, topped up with water and got it home. Ordered a new rad.
Think the fan might be buggered too...
If the rad is holed enough that the cooling system can't hold pressure then it's very likely to boil over unfortunately. The flashing light is coolant level low, solid is an overheat so it's likely a combination of loosing quite a bit of coolant + no system pressure is what caused it rather than the actual engine temps getting silly high. Think the fan might be buggered too...
Change both rads if you are doing one, it's easier to do them all at once and they are fairly cheap things so it's not worth getting all the front end apart to change just the one unless the other is fairly fresh. If they've never been done it's likely they have rotted from debris stuck between the air-con rads and the coolant rads.
If you switch the air con on and the low speeds fans don't activate then it is likely the fan resistors have died. The high speed will still work but not the low. Suitable resistors are available from RS for a lot less than Porsche
poppopbangbang said:
JS1500 said:
On the way there the light started flashing just before I reached my destination. Just as I parked up it began pishing coolant from the driver's side radiator. KwikFit said the radiator had a hole (genius) and they couldn't do anything about it so put my new tyres on and topped up the coolant. Car had been sitting cooling for three hours so thought the six miles home would be ok...but half a mile from home the light started blinking again and I saw a wisp of steam in the mirror. Boiled over and rad unsurprisingly still leaking. Pulled over, let it cool, topped up with water and got it home. Ordered a new rad.
Think the fan might be buggered too...
If the rad is holed enough that the cooling system can't hold pressure then it's very likely to boil over unfortunately. The flashing light is coolant level low, solid is an overheat so it's likely a combination of loosing quite a bit of coolant + no system pressure is what caused it rather than the actual engine temps getting silly high. Think the fan might be buggered too...
Change both rads if you are doing one, it's easier to do them all at once and they are fairly cheap things so it's not worth getting all the front end apart to change just the one unless the other is fairly fresh. If they've never been done it's likely they have rotted from debris stuck between the air-con rads and the coolant rads.
If you switch the air con on and the low speeds fans don't activate then it is likely the fan resistors have died. The high speed will still work but not the low. Suitable resistors are available from RS for a lot less than Porsche
eltax91 said:
Any chance of engine damage/issues if it gets hot like this and spits its coolant out?
Usually no, the head gaskets/head sealing on the M96 is pretty robust. Later cars with plastic coated pistons will be more prone to damaging the coating and therefore having bore scoring issues some time later than early ferrous coated piston cars though. They can briefly do 120 degrees if they aren't put under load without much issue. I've done a few odd jobs over the bank holiday weekend. Firstly the car is due front wheel bearings so I've made a start building up some spare uprights ready to swap on. I want to make a few mods to these for strength so not done yet but at least one is dipped, crack tested and assembled with a new bearing:
The hub was also dipped, crack tested and checked for excessive run out before being pressed (or pulled more accurately) into the bearing.
I also got round to fitting the OMP wheel I ordered quite a while ago. Red is definitely a better match for a Porsche interior than yellow!
The OMP horn push was a bit OTT though but a bit of carbon solved that:
Has made a very positive difference to the seating position as it's a good 55mm further towards the driver than the original wheel was. If nothing else it's a good stand in whilst I get the original wheel re-trimmed and draw up a spacer to move that a bit further out.
It will need discs shortly too, I would like to go to floating discs on the front but when the OE Porsche 997 350MM Turbo disc can be had for around £120 it's hard to justify it. Either way 60K miles from less than £250 quid of brake discs is pretty good going
The hub was also dipped, crack tested and checked for excessive run out before being pressed (or pulled more accurately) into the bearing.
I also got round to fitting the OMP wheel I ordered quite a while ago. Red is definitely a better match for a Porsche interior than yellow!
The OMP horn push was a bit OTT though but a bit of carbon solved that:
Has made a very positive difference to the seating position as it's a good 55mm further towards the driver than the original wheel was. If nothing else it's a good stand in whilst I get the original wheel re-trimmed and draw up a spacer to move that a bit further out.
It will need discs shortly too, I would like to go to floating discs on the front but when the OE Porsche 997 350MM Turbo disc can be had for around £120 it's hard to justify it. Either way 60K miles from less than £250 quid of brake discs is pretty good going
poppopbangbang said:
I also got round to fitting the OMP wheel I ordered quite a while ago. Red is definitely a better match for a Porsche interior than yellow!
The OMP horn push was a bit OTT though but a bit of carbon solved that:
Looks great. IMHO the 996 OEM wheel design was a little bit weak and these three-spoke racing jobs really do lift the interior. I am sorely tempted by them!The OMP horn push was a bit OTT though but a bit of carbon solved that:
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