Overheating?
 

My 2001 Boxster S has been running like a champ, but today i started smelling antifreeze, but i just figured it was because it was hot as hell out and traffic was slow. So when i get iff work, the red light is blinking on my temp guage, and by the time i get home, there is steam pouring out of the coolant cap, and the temp is pegged at 250. Did the thermostat go, or does that sound more like a water pump?


Joe

Also, the cooling fan runs nonstop after the car runs for a few minutes.

Shouldn't have driven it if the light went on and gauge pegged. :eek:

Is there any coolant left in the expansion tank?

Could be a bad coolant cap, bad coolant tank, water pump, belts, etc etc. certainly you have lost coolant - look at the tank and see how much - and maybe look under the rear trunk carpet to see if it leaked there.

This does not sound good. Hate to say it, but you've likely cracked a head. If there is any coolant left in the tank, does it look at all like chocolate milk? I'd also recommend at least dropping the oil filter and checking to see if there's any coolant contamination there.
Good luck.

The tank was empty when i got home, but the car ran just fine. There was a puddle under the car where it drained out. It was a very sudden thing, i googled the blinking red light and thought the coolant was just low, so i wasnt that worried. The temp guage didnt peg out until i was almost home.

I'm guessing water pump failure. Just a guess. If you had the constant on fans, then the blinking low-coolant light, then the high temp... I can imagine lack of circulation leading to the drainage and overheat.

I hope its just the water pump, im supposed to take a trip to Tennessee in less than 2 weeks! Thanks for all the info fellas.

Joe

I think im gonna change the water pump myself. Im leaning towards the Pelican kit with the low-temperature thermostat. Anyone used that kit? It has a composite impeller instead of metal, so im curious if it will last.

Joe

I'm not an expert in this area. I believe the composite impeller is OEM.

Composite
Pro won't chew up block if bearing goes bad
Con Could break and leave pieces stuck in cooling channels causing hot spots and additional damage

Metal
Pro won't break into pieces
Con, could chew up block if bearing goes bad rendering block unusable.

Some consider the WP a consumable and replace at XX miles or XX years.

You should first pressure test to make sure that you don't have a leak in the system before throwing parts at it. It could certainly be a bad water pump or it could be a cracked coolant tank. Look under the carpet in the trunk for coolant. If there is any then you have a bad tank that needs to be replaced. Once the system is water tight, you can then begin looking elsewhere.

It's a complicated system and quite big:

https://s-media-cache-ak0.pinimg.com...bd4021005b.gif

To improve performance, clean the area between the AC condenser and rads.

http://www.gjlenterprise.com/radiator/4.jpg

Good luck and let us know...

I used the same parts that are in the kit, Pierburg composite pump, low temp thermostat.
This job is typically a preventative maintenance project so you would not be throwing money away replacing
Do a Coolant replace at the same time
Using a Vacuum fill tool will verify any leaks in the system
I've had a bad tank and old cap and did not get the temp issue you experienced.
So I would lean towards WP, thermo as possible culprits.
Once you get WP off, you may see broken vanes which could cause blockage and contribute to overheating.
Also important is to remove front bumper and clean radiators

I am one of the heretics that uses the metal impeller water pump. When my metal impeller pump's bearing went South, I replaced it right away. The light on my temperature gauge started blinking, indicating coolant was low. I made it home and had it flat bedded to my indie Porsche specialist. The impeller did not come in contact with the block. The thing that scares me about the composite impeller is that heat cycles can cause the impeller blades to break off and travel into the cooling passages in the heads where they get stuck and create hot spots. Either one needs to be replaced at regular intervals.

Thanks again fellas, you guys are a huge help. Ill keep you posted of my progress.

Joe

Definitely bleed the cooling system and pressurize. Check the cap is not faulty. To me it sounds like their was air in the system. Once you get your temps in check i'd recommend the low temp thermo and installing some manual fan switches for the front and possibly for the engine compartment fan.

I have this setup and on a 90+ F degree day highest temp reading is around 185 according to the torque app. On the canyons going downhill in gear i can get my temps down to the low 170's. Don't know if that's good or bad though.

Well, i drained the oil tonight and it looked fine. No water in the oil, and still no metal shavings in the filter, so thats a plus. I also pulled up the carpet in the trunk, and it was dry, so that pretty much means it about has to be the water pump. And on another positive note, i found the source of a very annoying exhaust rattle! Lol.

Joe

So ive got the access panel off, and im looking at the water pump, and there is no sign of coolant anywhere. The tank was empty, so the coolant had to go somewhere, so where did it go? Would it have steamed off when it over heated? Im hesitant to replace the pump, if thats not the problem. I figured id pull the hatchboff and see all kinds of crusty residue, but i dont see any. Hmmmm....


Joe

Joe,
If you're right there and have the serpentine belt off, spin the pulley by hand and gauge what it feels like.
You'll be able to feel a sketchy bearing quite easily.
Mine didn't leak either, but the pulley didn't spin very freely.
When I pulled the pump off, you could see the slightest bit if friction wear on the edges of the pump vanes as they were rubbing on the inside of the pump cavity.

But where did the gallon and a half of coolant go? I suspect i didnt give the coolant cap enough consideration. Im gonna do like you say and pop the belt off, and if it feels good, im gonna just try a new cap and see what happens. I didnt realize the coolant cap on that tank was actually the seal for the entire system. If its leaking, then the pump would pump all the coolant right out of the cap, right? Which would mean the pump is still good. Did i mention that im not a mechanic? Lol.

Joe

As far as Truck leak, you looked under the Foam pads under the Carpet?
When my tank went, carpet was dry. The coolant that got to the trunk floor, under the foam pads, found any hole and dripped out.
Have you taken the plastic cover off the Expansion tank. This exposes the Purge valve. There is a drain hole between the purge valve and Fill. This hole connects to the overflow tube that drains down just in front of right rear tire.
Look for signs of dried or leaking coolant. The purge values can go bad as well. Though these typically lead more to condensation on the trunk lid, not a gallon + loss.
Take out carpet and foam pads, expansion tank cover plate refill you system with distilled water and get car up to temp to see what's going on