Semi-overheating?
 

Needle is always on the 8. Always.

I'm driving the 60 mile commute home with the top down and enjoying myself. I got stuck on an exit ramp to another expressway and decided the car is not as much fun when it's standing still, so I decide to stay on the expressway. Here comes some fun. Merging into 60-70mph traffic from a standstill. The P-car normally has no issues with this. I get on it and somewhere after the first shift into second, I hear a thump. Not enough for me to back down, but enough for me to notice. When I settle down, I notice my needle is on the zero. See above. It's never on the zero, so I start to freak out a little bit. Traffic is flowing fine and the needle stays there. Traffic backs up and the needle stays there. 40 miles later, I arrive home and the needle is still there. I check the coolant after it cools down, and it is low. About 1/2 gallon low.

Next weekend I buy some distilled water (I have no idea what coolant is in there and I'm making plans to flush it in the next couple weeks). I fill up the reservoir and idle the car until it hits operating temperature. Then I run the A/C. Coolant level does not move. I decide to take a spin and put some fuel in it and the needle sits on zero. Coolant level is unchanged and no matter how hard I beat on it, it stays on zero.

Anyone have any ideas so I don't have to drive a car with a measly sunroof all summer?

The cap is the wrong (old) type and it is on order as of 5 minutes from now. Could that be the source of my problem?

Check to ensure that both fans are operating correctly.

Of course check the simple things, e.g. pressure test cap, fans, leaks in coolant tank, etc....but the thump is of concern and you may want to consider the possibility of a water pump failure. If that is the case, running it may not be a good idea. I assume you already checked for water in the oil and oil in the water...

Sometimes I like to run on the interstate in 4th gear and a while back I noticed mine creeping up to the 0. Recently I took of the front bumper cover and cleaned between my condensers and radiators, and got a ton of junk out of there, cigarette butts, and mostly a lot of leaves and straw. Since then it has been staying right on the 8. We are getting back to hot weather so it may go back up from time to time, but I do not recall a single instance of going to the 0 since I did this cleaning.

The thump, I don't have any definitive feedback on that. Maybe a wheel weight coming loose, or maybe you spun a rock up when you were crossing back into the main driving line of the highway?

Both fans are working at hi and lo. Changed the cap. Still hits the zero and stays there. I checked for oil in the coolant, but not coolant in the oil. I'll run a crackle test tomorrow. I'm planning on flushing the coolant next payday, so I guess that's as good a time as any to replace, what I believe, is the original water pump (92k).

It just strikes me as odd that that it only gets to the zero. But I guess that could be a water pump thing.

When it gets to the end of the '0' is when the fans turn on, ~210F-~212F according to my obd2 temp readout.

Your water pump may be in the process of failing, and can still circulate water, just not as effectively as a new pump. The fans are most likely able to pick up the WPs slack, which is why the temp gauge would get up to 0, but not go any higher.

Check underneath and look to see if you have any seepage around the water pump.

your thump might have been transmission or motor mounts moving.

m

I'm hoping it was the motor mount. That's on the schedule to be replaced in the next few weeks. The water pump / thermostat is going to set me back a couple weeks though. I have a go live date of June 20th due to finances. My project list for the next few weeks is:

Pull front bumper and clean radiators - Done
Relocate frunk cable - Maybe today
Replace broken brake wear sensors. Probably today
Tie rods - This weekend
Flush coolant
Water pump / thermostat
Center engine mount
Oil change

the engine likes to steady-state at 180. folks with low temp (160) tstats note that their cars still run at 180, even with the tstat open sooner and more often. so, something has thrown your engine off. the coolant loss is disturbing but perhaps was low before and just not noticed? similarly the bang might just be coincidence. as all have noted, a visual inspection is the best step - underbody panels, serpentine belt, coolant hoses, water pump, tstat housing, idler pulleys, a/c and alternator pulley, radiators (noting that the a/c condensers are in front and block full view).

Beg to differ; folks with the 160 stats coolant is actually running cooler (usually around 170-174F steady state) while the inaccurate and non linear dash display continues to indicate around 180 or so. Cars with the OEM stat also show nearly the same dash indication, but are actually running at more like 210F. The dash gauge is little more than an idiot light that moves, and any indication that is even remotely correct is pure coincidence..........

i'll buy that. so presume then that engine wants to steady-state at around 174 and low temp tstat lives in the open position.

oem tstat at 180 cycles on and off, resulting in temp peaks and overall higher average operating temp (theory being that Porsche used a 180 tstat to increase start-up temps for emissions; competition cars not required to meet emission standards run 160 tstats as standard).

in the context of this thread, what would cause the engine to lock-in at a higher temp. initial assumption is that the gauge is too inaccurate to be trusted. what if the tstat stuck closed? would the engine find a higher steady state temp (engine bay fan cooling, etc.)?

First place I would look would be how clean are the radiators, we often find literally pounds of crap (leafs, grass, paper, even a dead bird or two) between the AC units and the radiators on these cars.

http://www.gjlenterprise.com/radiator/4.jpg http://www.autoscope.co/wp-content/u...6/DSC00369.jpg

Check your coolant tank, pull the rear trunk carpets and see if you have a leak. What color is your tank? If yellow its old and may have a pinhole leak. Check your water pump and thermostat. Maybe the thermostat is not working well. Finally clean the radiators. The 9x6 cooling systems all suck.

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Cleaned out the radiators last week. they weren't too bad.

http://i896.photobucket.com/albums/a...49024113_n.jpg

The coolant level might have been low before hand. It's not something I check normally as I've never had the temp drift past the 8 before. With 92k on the pump and thermostat, I figure it's probably best to replace them both anyway. I'll post pics of them when I tackle this one. Probably June 7th-ish.

ETA: The coolant tank is original and still white. I don't notice any moisture when I lift up the carpet in that area.

Toady.....
If the water pump has run for 92k miles, there's a good chance that the impeller blades are worn or even broken. In he real world this can point to poor pumping action so less coolant is pumped around the system......maybe it's just general wear and tear causing the slight overheating, so replacing the pump & t'stat as you mention may be the way to go.

What revision cap are you using?

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I had a similar experience the other day...but it was really hot here in CLT and I was in serious city traffic. Mine went to the '0', but no higher. Both fans kicked in and it seemed to stabilize. I have only had my car since January, so I have no idea if this was normal. Took it to P dealer here for an oil change yesterday and asked service consultant about it - he said it was perfectly normal.

I know JFP is adamant about these gauges being woefully inaccurate, but it seems the end of the '0' is when the fans should kick in...but I am a newbie to watercooled P cars.... I miss my VDO gauges :(

I have owned my boxster for a year and the temp needle hung just past the middle of the 8 in 180. Just recently it has started to creep up between the 8 and the 0. I monitored the temp with an OBDII gauge and it seems to actually be running in 192-205 range and 212 sitting still when the fans kick on. Is this a normal temp range or is it running a tad warm?? Just changed to new cap with same results.

Just to add another data point. 2000 base. Fans operate correctly on Lo and Hi. I sit in LA traffic alot and so know my temp gauge like my watch. Lo fans turn on when needle is just before the right side of the '0', turn off when it drops to about 1/4 from the left side of the zero. The reported temp at turn on via either the OBD data or the climate control hack is 104-105 C. This is perfectly normal behavior by all accounts. I have actually never had the fans kick up to Hi when driving, even in summer traffic and my temps run in the low 90s when cruising at speed and not pushing the car particularly hard.

I no longer worry about this. I leave it to you newbies....

Mine, 2000S, is EXACTLY the same! Thanks Teleski for the confirmation. I guess my local dealer is pretty spot on. After all, I was going to pay to have the problem diagnosed and he talked me out of spending money...and then gave me a discount on my oil change...:)

I know its not exactly the same but the results should be similar. I recently cleaned my radiators on my 996TT and now my temperature needle no longer goes into the 0 rather it sits to the left of it. When cleaning the radiators i noticed i had a small leak so ordered a set of cfs all aluminum radiators I'm hoping they do the job.

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Ebell914 I am in Charlotte also. Where do you go for service. I also noticed my gauge getting close to the zero but not reaching it.

Finally was able to pull the pump and thermostat. Pump looks and sounds good. Tested the thermostat and it started opening at 182 degrees and from what I could tell, was fully open at 195. (Not easy to tell what is "fully open" in a pot of water.

Radiators are cleaned and both fans operate at low and hi speed. Radiator cap is the 04 series and coolant level has stayed right where it supposed to be.

What could be causing my needle to sit on zero instead of 8 like it used to? I'm running out of ideas. Because it happened all of a sudden, I'm doubtful that the coolant all of a sudden decided to quit working. (I'm really running out of ideas obviously.) All I can think of is there is a minor blockage in the motor, but where it is and what caused it is beyond me.

The thump I heard was not caused by the center mount. Pulled that also, and it appears to be in good shape after 92,000 miles. Seems a bit odd as according to the well documented history of the car, this was never replaced.

I'm open to any ideas. I'm replacing the thermostat with the upgrade so while that may make the needle sit on 8 again, there obviously must be some other issue somewhere and I'd rather not leave it to chance.

Also, when I replace the pump and thermostat, should I use some sort of sealant? There did not appear to be any to begin with. I have the metal gasket.

Sixpact - I took it to Hendrick Porsche. Talked to Scott - he is really helpful. I am used to doing all my own work, so I am extremely skeptical of shops, but I hate doing oil changes these days, too messy. Hendrick sales guys are annoying
(went to them many times in my 18 month search for my Box), but their service guys seem ok.

One thing I realized with all this talk of where the needle sits, on the 0 or 8 or whatnot - gauges have subtle differences over the years...I am no expert on these, maybe someone else can chime in on this, but the my gauge being on the zero is still well before the second to last tick mark (which is like 215, I gather). My thought is as long as it is between the two middle ticks, it is within spec. I have confirmed this with the climate display diagnostic readout.

My only concern is that my needle was always on the 8. Then all of a sudden, now it sits on the zero. So something had to have changed.

Air!!!!
Air in the lines might have caused this. Kinda makes sense to me. I was about a quart or two low on coolant. I did a spectacular launch on the e-way from 0 to 100 in what I think was about 3 seconds. Perhaps the coolant sloshed and sucked some air up in the line.

The thump I heard? Could have been an unrelated problem that I have not discovered yet. Or perhaps the belt slipped. (The sound did resemble the belt falling off). I replaced the pump and thermostat and will be flushing the system with distilled water before purging again and filling with proper Porsche coolant.

I'm feeling better thinking that the problem has been discovered. (I hope)

Finally got the car off the jack stands and was able to take a drive. Temp is still sitting on the zero. I'm going to re-bleed it again tonight, as I have run out of options. About the only thing I haven't done yet is to replace the temperature sending unit, which since I came this far, I might as well go all the way.

Radiators getting old, clogged, and less efficient? Sometimes it's the simple things… You could use a durametric to see if it is really running hot or just the guage.

I really need to get me one of those.

Or if you know anyone with an android device, you can get the free torque app, and one of these:

Amazon.com: iSaddle Super Mini ELM327 V1.5 OBD2 OBD-II Bluetooth CAN-BUS Auto Diagnostic Tool for Windows XP, Vista, Win7, OSX and Android: Automotive

and check all kinds of generic types of OBD2 data. It won't display cam deviation or overrevvs or anything porsche specific, but all the good things are there: actual water temp, engine fuel trim and loads, timing, maf reading etc..I and many others can attest it works great

I definitely agree with Eppap. I love my Bluetooth OBDII adapter and the torque app. Its great to have all the data at you fingertips right on you android device.

I'm definitely getting that app, but I figured it out finally. After putting in a new water pump and thermostat and double flushing the cooling system and bleeding and bleeding the air, I finally figured it out. When I first tested prior to doing anything and when i tested after I replaced everything, I put the A/C on to get the fans going. Both fans worked great both times. I've been driving it to work the past couple days because it's amazing in Chicago. Today when I got home, I heard the fans going so for the heck of it, I felt if they were blowing. Passenger fan was inop. I put the A/C on and they both worked perfectly. I feel equally stupid and relieved.

Now to try and figure out why one fan don't work on lo...

Could just be the low speed fan relay.

If the fans are not on due to temp and you turn on the AC, both fans should activate to the low setting.

I haven't tested turning on the AC when both fans are on low due to temp. Do they go to high speed operation if AC engaged when low speed fans are already on?

If your car is cold and you turn on the AC and the passenger fan still is dead, then your relay for passenger low speed is dead, which is simple and easy to fix.

If you do the above and the passenger fan comes on low speed, then I have no idea.

They both work fine at hi speed. At lo speed only the drivers side operates.

I'm going to have to take the bumper off again ain't I?

Probably for the best. I misaligned the underneath part of the bumper when I put it back on and said screw it. This gives me a good excuse to fix that I guess.

epapp et all,

Sorry I'm I am straying from the conversation here but since CoBeerToad has found his issue, I figured I would ask real quick - I am reading that this particular OBDII sensor does not play well with the iphone? Is there a better sensor with an app for the iphone please? Thanks

*Most* of the cheap (~10$) bluetooth obd2 readers dont work well with the iphone because they arent *approved* by apple to be able to connect with the phone.

There are a few expensive bluetooth obd2 readers that can pair with the iphone, but they are $70-80.

I use my android dashboard tablet to read data from my $10 obd2 reader (the one I linked) and it works exactly the same as Shehadehd's bluetooth reader that is linked to his ipad (the $70 reader).

I suppose if your iphone is your only option, you have to get the expensive reader, and then use the 'dashcommand' app instead of 'torque'.

Cobeertoad- no not at all. Since they both work fine at high speed, your fans and resistors are fine. All you need is a new $4 relay.

The 4 fan relays are in the relay bank near the clutch pedal (by the fuse panel). There are diagrams floating around here. Two relays control low speed L and R fans, same for high speed. Just figure out which low speed relay is not working and replace :)

It is worth mentioning that the temp gauge in older boxsters (1997-2004) are actually working gauges... in other words, they indicate cooler temps when driving fast (more air through the radiators) and will move to the hotter side when one sits in traffic on a hot day.

The 2005 and up Boxsters have a dummy gauge. It very quickly goes straight to where it will stay no matter what's going on with the actual temperature until it reaches a threshold and WHAM! it snaps to the right and the overheated light illuminates.

Lots of new Porsche owners who've never owned a car with a real temp gauge get freaked out when it moves around.

BTW, I realize the OP may have a failing water pump... I just thought I'd add this information for those in the future who read this thread.

I swore that this whole thing started this spring with me noticing my temp gauge sitting on the zero. Looked at the Time Hop thing on Facebook and saw this little picture. Not sure what I was taking a picture of, but notice the temp gauge from a year ago today.

http://i896.photobucket.com/albums/a...psbf31159b.jpg

I'm never trying to diagnose another problem ever again.

Haha...hahaha..theres always that possibility