Re: Low Coolant

Car is an '06 base Boxster with 45k miles. My indie replaced the water pump about 2000 miles and four months ago. This morning I get "low coolant" warning message. I'm pretty fastidious about the car and I've never seen any liquids underneath it. I'm thinking I should start by topping-up the coolant and replacing the reservoir cap with a brand new one.

I read Pedro's notes about OAT coolant, so I know I can find proper coolant without visiting the Porsche store... my next question is can I buy a new cap at Autozone, or do I need to drive to the inconvenient dealer to get the cap?

I bought a genuine Porsche replacement cap, and made sure it had the right part number (i.e. the most recent iteration - I can't recall the number now, but a search here will reveal it). I wouldn't look for an aftermarket part, not for something of this importance.

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Spanky
Car is an '06 base Boxster with 45k miles. My indie replaced the water pump about 2000 miles and four months ago. This morning I get "low coolant" warning message. I'm pretty fastidious about the car and I've never seen any liquids underneath it. I'm thinking I should start by topping-up the coolant and replacing the reservoir cap with a brand new one.

I read Pedro's notes about OAT coolant, so I know I can find proper coolant without visiting the Porsche store... my next question is can I buy a new cap at Autozone, or do I need to drive to the inconvenient dealer to get the cap?

It could be that your mechanic didn't completely "burp" your system after replacing the water pump and refilling the coolant. This would allow pockets of air in the system. As they work they way to the reservoir, it might look like you lost coolant even though you didn't.

First thing I would do (with a cold engine) is top up the coolant with distilled water. It might only take a 1/2 quart or so to bring it to the full level. Remember, that your 2006 holds almost 6 gallons of coolant, so a half quart of water will not dilute the 50/50 mixture very much. Then keep an eye on the coolant level to see if you lose any more.

the car has been parked way off level recently, should that be a factor.

Good idea, Gman.

As I recall, last time I changed my coolant, I had to add a bit more a week or so later, after a small amount of air had worked its way through the system. All was good after that.

When my cap acted up, there was occasionally vapor on the rear trunk lid, above the coolant cap. That was a sign. The new cap was a relatively inexpensive and happy fix.

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Roger987
Good idea, Gman.

As I recall, last time I changed my coolant, I had to add a bit more a week or so later, after a small amount of air had worked its way through the system. All was good after that.

When my cap acted up, there was occasionally vapor on the rear trunk lid, above the coolant cap. That was a sign. The new cap was a relatively inexpensive and happy fix.

The vapour over the reservoir on the trunk lid is a good indicator of a coolant cap leak. I think it's important to check that after the car has been run with a warm/hot engine for a while. As you mentioned, the coolant cap is a pretty inexpensive fix.

When my 06 was about a year old, the coolant was down a bit. I took it to the dealer to have them check it as it was still under warranty. They pressure tested it and found no leaks. The topped it up and I decided to buy the newest version of the cap at the time so I'd have it in case it was the cap. Never did use that cap, but always had it in the car just in case.

confirm the cap is leaking before you replace it top up the tank with distilled water and then making sure the cap and tank where the cap screws on and seals is clean install the old cap.

Start and run the engine until up to temperature. Drive the car around town in stop/go driving then back home raise the RPMs to 1500 and hold until you hear the radiator fans come on. Shut the engine.

Put a tent of aluminum foil over the fluid access bay and wait.

If the cap is leaking there'll be some condensation around where the cap is. If the tank is leaking there will be condensation all over. Or the tank will let go and gush coolant to the ground.

If there is condensation around the cap wait until after the car cools down then replace the cap.

Afterwards, just to be sure, you might want to book the car in for an inspection that has the car on the lift and from underneath a check can be made the water pump is not leaking, and there are no signs of any leaks from other areas of the car's cooling system.

It was a small crack in the plastic cooling manifold. Coolant was seeping slowly at various amounts on different days and different operating temperatures. The replacement part was hard to find (only found one and it had to be shipped from Canada)... and my mechanic said it was a bear of a job in labor.