ELI CAYMAN S

I have a 2008 Cayman S with 47,000 miles and it's overheating when in traffic. I have replaced the coolant cap inside the trunk compartment because I have read the seal wears out and steam escapes. I have been monitoring the coolant level and it is not loosing any significant amount of coolant. However, when it gets hot, I sometimes smell coolant by the passenger side air intake. I'm thinking it's the fan or water pump. Has anyone experienced this or can anyone provide insight on how to diagnose this whats causing it to over heat.

Thanks,
Eli Cayman S

Ubermensch

I had a 996 which had similar issues. It turned out to be a bad fan on one side. More specifically it was the resistor leading to the fan, but I replaced the whole assembly. Get the car up to operating temperatures and then confirm that you hear the fans running on each front radiator.

DaveMann

Could be as simple as blocked ducts too? Have you tried cleaning them out at all?

ELI CAYMAN S

What do you mean by blocked ducts? I did visually inspect the grill area where the radiators are for leaves or any debris. I also checked the air intakes on the side of the car and everything looked fine.

Anker

The radiators will get clogged with debris over time. I recommend that you clean out all 3 radiators. This does require removal of the front bumper and the AC condensers. If there's a lot of gunk in there you will also get corrosion of the radiators and they will eventually leak.

Before you do that vacuum out whatever leaves and other stuff you can get at through the air ducts. That may be enough to improve air flow. Andm of course, check the fans. Easy enough when the car is hot.

I would recommend annual or bi-annual radiator cleaning.

Anker

ELI CAYMAN S

I drove home yesterday and the car was up to 200 + degrees and the fans were not on. I turned on the ac, then the radiator fans kicked in. It seems the fans are not turning on when they are supposed to. At least I know the fans work, I looked up the price they are around $450 each. Does any one know what controls the fans obviously that sensor or component is not working.

Macster

200F+ may not be hot enough to trigger the fans to come on.

The fans are controlled by the DME. When the coolant temperature climbs above a certain threshold -- with my Boxster it is 212F -- the fans should come on low speed. If the temperature continues to climb to 216F the fans are switched to high speed.

The fans are shut off when the coolant temperature drops to 205F.

I know from experience with both my Boxster and my Turbo that even if one fan is not running the other fan will keep the car cool, even if I have the A/C on and am in ~95F+ heat.

If there is a problem a tech with the proper Porsche diagnostic computer can check for fan stage errors and if any found then know what to do.

Smelling antifreeze is a sign of a leak. You have replaced the cap. I trust the cap is properly installed and tightened?

With an odor of anti-freeze from the engine compartment my experience has been this can be from one of two sources. The first is a leaking coolant tank. They will develop a crack/split along the bottom seam that leaks when everything is up to temperature and one shuts off the engine. The extra heat load raises the coolant temperature and pressure and if the coolant tank has developed a split it will leak.

The other source -- at least with my experience -- is a leaking water pump.

You need to get the car in the air and check the pump for leak sign. If it is leaking it should be obvious from the large stain of dried anti-freeze residue or even signs of wetness and even a build up of dried anti-freeze crust.

r553

I would check the water pump and the coolant tank for the coolant odors. LN Engineering recommends replacing the water pump every four years like the spark plugs using a Porsche water pump.

I don't know why your fans aren't coming on when the car is hot without AC. Perhaps the coolant temp sensor is not working.

ELI CAYMAN S

Thanks Macaster & R533

But remember I'm not loosing coolant. The fans work but what controls them is malfunctioning. I will change the water pump when I service it because Porsche says it a replaceable part, but that is not what is causing my problem. This is my daily driver. I need to figure out why the fans are not operating normally

MrMoose

Let's back up a sec here: when you say it's overheating, what are the symptoms and how hot does it get?

Note that there are two coolant caps. The cap in the trunk at the fill that you replaced is just a sealing cap. There's a pressure cap on the tank itself (in the engine bay) that's designed to vent at a specified pressure. This can fail and vent at too low a pressure, which can cause the coolant to boil.

ELI CAYMAN S

Thanks for your response MrMoose,
The car droves great except when i get stuck in traffic for an extended period of time. If a have to sit in traffic, the temperature starts going up. I'm taking it to repair shop, this is my daily driver so I need to repair quickly. I will post the outcome. If anyone gets a similar problem hopefully these posts will be helpfull.

ELI CAYMAN S

Thanks for your response MrMoose,
The car droves great except when i get stuck in traffic for an extended period of time. If a have to sit in traffic, the temperature starts going up. I'm taking it to repair shop, this is my daily driver so I need to repair quickly. I will post the outcome. If anyone gets a similar problem hopefully these posts will be helpfull.

Dave in Chicago

If the fans come on with the A/C, then the fans work... right? Does this result in the expected reduction in engine coolant temp? If so, looks like fans are good.

The 101 Projects for Your Boxster book seems to indicate there is a resistor pack on the fans (similar to one I had on the climate control fan in my 944/968 cars). Could be a culprit. not sure how hard it is to get at and swap out. This article may indicate it.

http://www.pelicanparts.com/techarti...n_Radiator.htm

If it's easy to access and take in / out, you may be able to borrow a known "good" resistor pack from another friendly Boxster owner to try it. If it works, that should be the issue.

I would expect the P-car dealer or your P-car repair shop can chase it down even quicker.

Jeff Chi

Hi All, first time posting here. There seems to be a lot of knowledge in this group, so I'm going to ask for some help/advise. My Cayman has about 105K, drives great but recently started to overheat after 6-7 miles of driving (casually). At cold start, I'll drive it and allow it to warm up to operating temp. Gauge will sit at normal temp for about 6-7 miles and then starts heating up. What do you all think is the cause? TIA for any advise.

JC

sasilverbullet

Please post this question as a new thread.