Regular operating temp has increased - 986 Forum - The Community for Porsche Boxster & Cayman Owners

I have a question regarding change in normal operating temp. Apologies in advance for the long post. I have a 2004 base Boxster that I've owned since 2006. About 85K miles. Its my daily driver, mostly in-town commuting. I live in Central Texas, where it has been unusually cool this spring/summer - it only hit 92F today. In all that time, once I'd been driving for a while the temp gauge would read just a tick above the 180. About a month ago, I noticed that the car seemed to be running just a little warmer than normal. The needle was vertical, or a little past vertical; it wasn't reaching the next tick on the gauge (anyone know what temp that corresponds to?), and certainly wasn't reaching the danger zone. But the loud fan was coming on more frequently. Something had changed. So, I took it in to my regular mechanic, who checked out the cooling system and said everything was within normal operating parameters. Maybe I just noticed a change because the days were getting warmer, he suggested. I remained unconvinced. Fast forward to this past weekend, I see a puddle under the engine one morning and the coolant reservoir in the trunk is empty. Back to the mechanic, who says I need a new water pump. OK, that probably explains what I've been noticing, right? Get the car back with new water pump today and, if anything, its running hotter than before. Still not quite reaching that next tick mark on the gauge, but close. So, what am I dealing with here? Might this just be a symptom of aging (the car, not me)? Do I even have a problem, if the operating temp is still within acceptable parameters (and yes, I know that the actual water temp is 20+ degrees higher than what the gauge reads). To me, the change from what had been ten years of normal operation is more telling than the actual temperature. But maybe I'm worrying about nothing? I'd appreciate suggestions.

To illustrate what I was saying above, here are a couple of pictures: "Old Normal" operating temp "New Normal" operating temp and it will get a little higher than that. One other data point. This morning, I got stuck idling/crawling in traffic behind an accident. Outside temp was about 75F. While I was sitting, the temp spiked up beyond that second hash mark; the needle was going through the 2 on 250. It took about ten minutes before this occurred, but it when it did happen, it wasn't gradual, it happened over a couple of minutes in a couple of leaps. I've never seen it that high. The moment I started moving again, even slowly, the needle came back down to the new normal. Should I be concerned?

Have you cleaned the radiators? If not...6 years worth probably has major blockage. Take off the front bumper.

I've been touching the "0" but not the "2". New to me '99 with 74K. Search is you friend. Cleaning radiators, checking fans/ballast resistors, and possible over flow tank replacement all on my list.

Quotes source post: 452543

Totally out of the subject, and I apologize in advance... But how can you get 3 lines in the OBC display? I can get only 2... Maybe because I have a 2003?

That is the exact temp difference I see winter to summer and I have a low temp stat. Going to check rads but that's the exact swing I get.

Quotes source post: 452554

Mine shows 3 lines. There's options to scroll through each line.

Quotes source post: 452556

Yes, I can scroll between the different menus, but I have only 2 lines available: total mileage + the chose menu. That would be sweet to add that 3rd display

Here's a couple of other thoughts. 1. The front fans have 'ballast' resistors in their circuits. If these fail, the fans will not operate in low speed and assist in cooling. You can test these in the following way. With the engine cool, start the car with the AC on. You should hear the fans running in low speed on both sides. If not, then you either have a failed ballast resistor on the side the fan isn't running or a broken fan. 2. When the car gets hot, do you ever hear the fans run in high speed. If both fans don't run in this mode, I would suspect you have a bad temperature sensor in the cooling system. If one comes on and the other doesn't, this might be a clue that you have a broken fan on the non-running side 3. You might have air trapped in the cooling system after the refill when the water pump was changed. Other post suggest how to bleed the system. 4. Is the amount of fluid in the tank staying at the same level? If not, it could be lowering as trapped air releases though the value. Or, it could be you have a leak somewhere in the system. A pressure test will help you find out if this is the case. Hope these ideas help

Thanks everyone for the input. I have been searching the forum for similar topics, and have learned that I need to check/clean the radiators, etc. Though, you'd think my mechanic would have checked all of that when I first took it to him asking him to check out the cooling system. Thom, to your points: 1. Yes, I've tried this test and both fans come on 2. Yes, I definitely hear the fans run at high speed 3. I thought about this possibility, though this all started before the water pump was replaced. Still, can't hurt to try this. 4. I'm not sure, its only been a day since the water pump was replaced, though the system was pressure-tested about a month prior to that. Thanks again for everyone's input, I'd appreciate any additional insight.

My 98 dos this exact same thing. I use to think this was odd. From the other numerous threads on here about his same issue I have found out our temp gauge is a true gauge and will fluctuate. I did a water pump with a lower thermostat with new fluid flush and it still does it. My radiators are clean after I flushed and cleaned them. You also have a engine compartment fan that kicks on the driver side vent and sucks in cooler air into the compartment. See if you hear it kick on, on hot days. If it doesn't look into replacing the sensor. My fan was blocked by a mud wasp nest and it burnt the fan motor so I had to replace it. As long as it doesn't get to the next white harsh mark for me I don't worry about it.

Quotes source post: 452568

Thanks Antny. Any idea how I can check whether the engine compartment fan is working correctly? When the car is at temp, I can hear the front fans on high - sounds like a Hoover under the front of my car - but I can't distinctly hear a fan in the engine compartment; or rather, I can't tell if the sound I hear is coming from the engine compartment or from the front fans. Also, how concerned should I be that the temp spikes when idling? When I parked the car at work this morning, I got out to listen to the fans while the car was running, and in the couple of minutes I spent doing that, the temp gauge spiked from its 'new normal' to about midway between the fourth hash mark and the 250 mark. I plan to clean the radiators this weekend. I'm not normally a DIYer when it comes to vehicles, but that seems doable.

Quotes source post: 452561

There's a YouTube video that shows how to remove the front bumper cover. Fairly easy to do, but the video makes it a piece of cake. You said you heard the fans run at high speed; were you able to confirm they run in low speed. If low speed doesn't work, then you'll see a new a new gauge benchmark. In my case, my gauge sat on the hash mark to the left of the 8 in 180. After a recent coolant change, it moved to the right. After a few weeks, I noticed a coolant level dropped in the tank. My mechanics guess is that an air bubble in the system was causing the higher gauge readings. Once the system was bled, the gauge has returned to its lower reading and the coolant tank level has remained rock steady after topping it off.

Quotes source post: 452543

I would not be concerned, but rather be prepared to replace parts. My 02 was running hotter than normal, like yours just moving gradually beyond the 8. Never near 250 though. Mine was the water pump slowly failing. The pump finally began to regularly leak fluid after sitting a few minutes after being driven.

Is your regular mechanic a Porsche specialist? After discovering the puddle, did he try, as our resident mechanics here have suggested, UV coolant dye to spot a leak in the system? Given that you're in Texas (it gets hell like there when in traffic right?), did he suggest installing the lower temp T-stat? Did he change the coolant cap or did he reuse the old one? If not I would consider a new shop that's more up to date on your car. I've had clogged radiators in the past, a leaf blower or one of those hoses at coin car wash help to clear it out, but the needle has never gone past the 2 while sitting in traffic. But that thing is not really accurate (hence the need for the lot temp t-stat). I can't believe someone hasn't come up with an aftermarket solution for accurate reading of both the oil level and this. Must not be much demand, just demand for new engines once the heads crack and oil starvation takes it down. p.s. Since installing the low temp t-stat, it takes a long while before my needle is at high noon, let alone to the right of that. 100K mile car now driven year round.

Quotes source posts: 452607, 452618, 452619

Thanks guys, I really appreciate the continuing input. Yes, I saw that video, which is what convinced me that I can probably handle the job myself! If that doesn't make a difference, I think I'll have the system bled. I believe the test for low speed operation of the fans is to turn the AC on when the engine is cold and see if the fans are blowing under the front of the car, correct? If so, then yes, I've confirmed they run at low speed. Yes, this problem started a month ago, then the water pump went earlier this week. I thought that replacing the water pump would return everything back to normal, but so far, no. My regular mechanic works mainly on Porsches and BMWs, but I don't consider him a Porsche specialist. He is reliable, honest, and close, so he gets my business for routine stuff. Normally for major stuff, I go to a Porsche specialist that is further away, and probably should have done so this time (but the thought that I had a cooling system issue discouraged me from driving it any further than necessary). I don't know whether he did a dye test (though he wanted my car to sit in his shop overnight so he could see what accumulated under it), he did not suggest a low-temp stat, and I think he used the old coolant cap. One additional data point: since the water pump change a couple of days ago, the car seems to get to temp much more rapidly than it did in the past. That, and the way it spikes up at idle, has me a bit freaked out. Anyway, the input I've been getting here is leading me to believe that I need to have the system bled. I'll clean the radiators this weekend, then take it to the Porsche specialist next week. Thanks again for everyone's input, it's been very helpful.

When in doubt flatbed it to the specialist. When my waterpump went, luckily right next to a gas station, I had it towed to the my independent specialist right from there. My insurance (Progressive) covered the cost. I'm wondering if you don't have air in your system that might be creating heat surges. If you start fresh, make sure you have the pink coolant, don't top off with the off the shelf stuff, get a new coolant tank and make sure you have the 2004 coolant cap. And I wouldn't recommend trying to burp it (needless hassle), get it done with the Airlift.