996 OVERHEATING PROBLEM

Hi Has anyone experienced problems with the coolant temp light flashing red. The gauge stays at about 90 degrees and does not actually go on to overheat. I have a 1998 996 with 37K miles so hardly used. Thanks - Jon

The light will flash when coolant is low in the tank or there is a problem with the level sensor at the bottom of the tank. It will also flash if their is a problem with the engine compartment fan circuit.

that means your coolant is low...

I hate to scare you, but my coolant temp was fine but the warning light went on when I needed a new engine (oil/coolant intermix)... Check your level, hopefully it's just a little low...

Did this happen with your 2001 Turbo car? Bill

Yeah, mine too...but the light is simply a warning of low coolant level....or bad sensor...Or problems were that the level was low because it was leaking into the engine and getting burned off.....

The light does flash for a few reasons. Low coolant. And faulty solenoid that turns the engine fan on. As an aside though the 1998 and 1999 did have some issues with "not over heating", but getting hot. That's why in 2000 ot 2001 Porsche changed the design of the front air dam - the new one was more "scooped" at the sides to suck in more air. My 1999 C2 did sometimes get hot. I think it was par for the course for all early 996's.

Nope, had a C2 before this. Kinda hard to say that without sounding alarmist... probably shoulda kept my mouth shut...

The higher operating temps is not a result of front air dam design...I have a TT bumper which would have been designed for better cooling and have noticed the same operating temps on my 99....I would say its radiator capacity, fans, and thermostats...but that is my opinion, because I dont actually KNOW why the 99-01's run hotter...I do know with the 3rd radiator kit, the car operates at lower temps, more like the 02+ cars....

Thanks very much I will get both checked out - appreciate your help - Jon

All the cars run at about the same temperature at low speeds, regardless fo what your temperature gauge tells you. They all run at a minimum of 190F once warmed up, regardless of vehicle speed. Pofrsche simply lowered the reported temp on the dash gauge.

so...the 99-01 is accurate, and they actually dumbed down the -2+ gauge so it doesnt alarm the owners? wow....interesting.

99-01 is NOT accurate, just closer than the later years. They still show lower than acutual coolant temp.

hmmm....interesting.

so hovering around the 190 mark is typical........?

194F is the target temp for the engine with maximum air flow.

I noticed my temp gauge flashing a few days ago and now ive got a massive water leak.. anyideas as coolant was pouring out when i parked up after a short journey, i`m hoping there has been no serious damage to the engine does anyone know what may of caused this apart from the obvious as i can`t get to a garage till tuesday i`m presuming it should be towed there too? Thanks in advance XT

cracked coolant tank or bad cap. Was it from the rear of the car, drivers side?

Usually, a massive coolant leak is due to the reservoir tank cap failing. The cap seal fails to withstand pressure and allows the tank to purge the coolant through the cap. Tank failures are usually small cracks that allow coolant to drip onto the exhaust, evaporate, and create the smell of burning coolant. Cap failure is very common, and the cap has been redesigned.

Thanks for all your responses its from the rear of the engine passenger side although with you saying "cap" your refering to the water tank cap? it isnt that it seems as though its from the lower part of the engine?? getting worried now thanks again for the help.. XT

Ohhh! 996 OVERHEATING problem. I thought you said 996 OVEREATING problem.

I guess thats the American model then?

what a perfect thread! I just took my car in for the flashing light too. My temps have always been right at the 180 with the needle sitting on the zero or just slightly past it. The light was flashing and I quickly RTFM and realized low coolant. I then remembered seeing white smoke coming from the car the day before in traffic. So I must have a small leak somewhere since the car is not over heating. It is at an indy shop right now as I type this. No dang dealerships are open on Saturdays! Sucks. On another over heating note, I also have that "fan mod" done that I can overide the factory fans and have them turn on when I want. Those have come in handy in traffic. Sitting on the freeway...when I see my needle creep past the 180 zero...I turn those puppies on and it brings it down. Very easy and useful mod.

check the following things in this order: 1. coolant tank cap. 2. hose 3. tank.

I heard that when the light flashes it's also an indication of air in the system... In my case it was a leaking reservoir.

That's why this is such a good forum - people work together to problem solve. On a number of other message boards, posters just flame one another when they don't "check the f-ing archives" etc. Here, with a few exceptions questions are addressed and answered civililly. Porsche owners really try their best to help one another out. Great forum!!

OK Update!!! well my car wont be on the road this Easter Weekend.... so just as discussed...my resevoir/expansion tank has about a 2" crack in it. Been leaking for awhile..I went underneath and you can see the trail of coolant running down my headers and mufflers down the driver's side. Oh yeah I had "green" non OEM coolant in there as well...but I dont want to start the whole coolant debate. Sooo...now I made a RSVP to take the car to TRE Motorsports in North Hollywood for the fix. Approx estimate?? $670 This shop has been reco'ed in the past and has a good rep..plus it is near where a co worker lives so I can hitch a ride to work. I spoke to a Dave there...very nice guy and assured me no problemo bring it on in. Replace expansion tank... Flush and fill system... labor and parts... oh well...there you have it peeps. Another one of those.."its gonna happen sooner or later fixes" More once I get the car back.

I heard they are a great shop, a couple of dear friends of mine use them.

I`m guessing this is exactly the same fault as I have!, currently i`ve no means of getting underneath it but i can see green coolant pouring out from above where i cannot see, whereabouts is the expansion tank? Is it viewable from underneath the car or from the rear? thanks again for all the helpful comments BR XT

Open the engine compartment lid. The tank is on the left side. It has a blue cap.

180-190 woud be perfectly fine... If you are flashing red, also, check the cooling intakes on the front...you will be surprised at what you find there...anything from a bird, to a squirrel...to paper to pounds of leaves... I caught a bird on mine...I didn't even notice until my car overheated...upon stopping to examine it...I found a dead bird....

You don't have to get under it to change out the coolant tank. It's accessed from the engine compartment. I looked up the DIY instructions on RennTech...comes with detailed written instructions/pictures. It was my first real attempt at a DIY project and I got thru it with a few choice adjectives...but it only ended up costing me $168 for the tank. Took about 1.5 hours for a guy who didn't know the procedure and was reading my way thru it.

Quick update for those who advised me of my problem last week I took it into a Porsche Specialists who replaced the water pump and header tank for �465 inc VAT. I`m now back on the road however the car doesnt seem to be running as well as it was before all this happened Any ideas ? Thanks again to all those who helped before

Even tho this issue looks to be solved, there's another angle to this common problem that is worth mentioning. The failure prone orig equip coolant cap can cause an overpressure because it's valve gets stuck. This could cause a blow out somewhere else. That's what happened to me. I read somewhere that if the coolant cap # (it's in big letters on the cap) ends in 00, then it's the failure prone. Apparently there's been several redesigns. My new one says 01 and I'm not loosing coolant anymore.