SubzeroX

1) I popped the engine compartment and saw that this fluid level was low. I don't know what it's for. It's located on the left side at the top.. Has a max/min level indicator mine was below the min. What is it? What should I fill it with? Available at autozone? Any specific/good brands? What causes it to be low?

2) vacuum noise - sometimes, usually after highway driving, when I come to a hault at the off ramp, I hear the fan/vacuum/noise turn on, sometimes really loud.. Just like how u turn on a vacuum. Them goes away like 5 seconds later - or when I turn off the car. What is this? What's it for? I'm in Philly and its like 30* out.. And my temp doesn't raise past the beginning of the 0 in the 180.. So I know there isn't an over heating issue


TIA

Barn996

1- Coolant tank, anti-freeze. Many would say stick with Porsche fluid.

2-Probably the air pump(forget the name) located at the left front corner.

SubzeroX

btw the noise comes from the engine.. not from the front of the car.. i believe back left side.

another question - what causes antifreeze to decrease in volume? does it get used up? burned?

Barn996

Left front corner of the engine area, NOT the frunk.

Barn996

It leaks. Hoses, coolant tank, water pump etc. Do you smell anti-freeze ?

SubzeroX

oh okay...

but why does the fan come on when the engine's not hot?

also i dont know what antifreeze smells like, but i dont notice any new smells since getting the car (i'm already used to the burning porsche smell that comes after hard driving)

kromdom

may need to check your t-stat. And as Barn996 already suggested: also check the coolant reservoir, cap, hoses and water pump

shyamvenky

I think these 2 could be related issues. As others pointed out, the tank is for the coolant. If the level is below the min level, it definitely means low coolant. Do you have the red LED at the end of the temp gauge blinking when driving? If yes, then the car is aware of the low coolant level. Even otherwise, since you saw that the level was below the minimum, there definitely is a shortage of coolant. There could be a leak somewhere in the cooling system (if its an old car, it mostly is the coolant tank or its cap) In either case, if there is a leak, you'll probably see the stuff dripping after your drive - check under the car after parking and switching the engine off.

The temp. gauge measures the temp of the coolant coming out of the engine. So if there is less coolant, chances are that the sensor doesn't have enough of the stuff to give a proper reading. This would be my guess.

As for the fan noise - I believe this is the engine purge fan that kicks in when the temperature of the engine is higher than normal. The fan doesn't run for long durations and comes on intermittently. This could be related to the low coolant levels you have in the car. Or, as pointed out by kromdom, it could be the thermostat that's off by a bit.

DO NOT pour in any antifreeze in there. Even if you buy Porsche antifreeze/coolant, there are multiple ones out there (green, yellow, pink) and there could be a potential gelling if the varieties aren't compatible. Your best option would be to fill up the coolant expansion tank with distilled water. Upto a gallon or maybe even two should not change the concentration a lot. Beyond this, I'd probably suggest an inspection of the cooling system - tank, tank-cap, hoses etc for leaks. In case you've lost a lot of the coolant, it would be best to fix the leak and replace the coolant in the system completely.

I recently had a low coolant issue and the culprit was the tank. They do tend to wear over the years and develop cracks. In such cases, you'll see leaked coolant dripping on the drive side exhaust and onto the floor.

Imo000

Take the car to someone that knows what they are doing.

fpb111

Assuming your car is a 996 Porsche:

You don't say whether the engine was hot or cold when you noticed the low coolant. How low was it?

1. Check the part number on your blue coolant tank cap. If it doesn't end in -04 buy a new one from Porsche, less than $20. -04 is the 3rd and latest generation of these. The older ones tend to fail.
DO NOT REMOVE IT WHEN THE ENGINE IS HOT!!

2. Most likely your Secondary Air Injection Pump, it comes on the help light off the cats and keeps the cats hot. Almost always for ~12-20 seconds at first start. It will also come on under other conditions when driving. This lives in engine compartment near your left knee when you are standing gazing into the engine compartment

kromdom

I wanted to say this earlier after reading the OPs opening line:

Have your indy do a "pressure test" of the cooling system, hopefully to pinpoint/locate/identify the cause of your "disappearing" coolant.

SubzeroX

yes car is a MY03 C2. I was checking it in the morning in Philly (ambient temp 28*F).

The secondary air pump does go away after like 10-15 seconds. I've been reading that it's normal.

I'll look under my cap today.. actually now lol and will update soon.

distilled water... same as mountain spring water for drinking? or should i get the kind that says specifically distilled... and why not just buy the antifreeze that's supposed to go in there anyway?

Barn996

Grocery stores have distilled water in gallon jugs.

Macster

Distilled water is best.

"Mountain spring" water may be tap water in a fancy bottle and could evem have minerals added to the water.

You can add Porsche anti-freeze but not many have a jug of it laying around. I have but have used just a few cups from the jug since buying it years ago.

Generally I just add distilled water when the coolant gets low and every time it has gotten low there has been a leak in the cooling system.

First time was due to a coolant cap, the second time due to a crack (split) in the coolant tank.

There's a concern that in adding water this will raise the freezing temp of the coolant so adding distilled water is a temporary solution to a low coolant level.

The reason the level is low needs to be found and fixed and the coolant topped up with anti-freeze to ensure the coolant has sufficient anti-freeze protection for your location.

In the case of the tank repair the tech just drained the system, replaced the tank, and refilled it with fresh coolant. If the coolant is fresh the system doesn't have to be drained completely, just enough that the level is below the tank fittings. Of course after the new tank is installed the system must be refilled/topped up. This is best done by a vacuum system to ensure complete filling with no air pockets.

WalterRohrl

I think mine does a similar fan thing to what the OP described and it is not the SAI pump.
My SAI pump comes on first thing at first start, then goes off after up to 30 seconds, the noise is fairly high pitched and actually has a bit of a squeal to it. I then drive to my kids preschool, almost always stop at 2 lights within 3 miles. then accelerate and slow back down after another mile at the third light. (I almost always miss all these lights due to the nature of the intersections). At that third light as soon I come to a full stop a fan comes on. It is NOT the same sound as the SAI. It stays on for about 5 seconds then goes off and is not heard from (or noticed) again until the next day. When I vary my routine and go somewhere else (like on the weekends) I have not noticed it. It's weird and does not seem like anything to worry about but I was curious what it was.