Consuming coolant

[dtownmil]

My coolant has been "slowly" dissappearing. Early on I could go hundreds of miles before the light would flash at me, I'd fill it and move on. Now its been more frequent. I do not see any coolant on the garage floor or driveway. I have already replaced the cap with a newer version (had the original). I thought the cap fixed the problem, but its back.

I know it could be the tank, or some "Y" tube I've read about. I'm sure its been thoroughly discussed, but my exhaustive searches haven't found me what I needed.

Any info would be appreciated, or if you can provide a link to a previous thread.

Thanks in advance.

2000 Boxster 2.7L 60,000 miles. 5 speed.

[JFP in PA]

This is not a good sign; the Y tube or the tank would leak onto the garage floor, yours sounds like it is not, and I am assuming it is not in the oil either. Most common faults for this are head gaskets, or a cracked head (not that uncommon). Testing would involve pressure testing the cooling system, and doing a “leak down” test on each cylinder to pin point where it is. In any case, the M96 will most likely need to come apart…………..

[N41EF]

Are there any signs of leakage on the underbody? When I replaced the front engine mount I was struck by how many joints there are in the cooling system. The hard and soft hoses run to the front of the car behind black plastic panels, if you had a slow leak there, you might see some evedence on the panels.

If you have leakage into the oil slowly you might not ever see it on the dipstick.

You might try draining the oil to take a look at it, you'd need something huhe, then check for coolant and pour it back in.

Might also do a compression check, remove all 6 plugs, screw the tester into each cylinder and crank it checking for low compression, if you are sucking coolant into a chamber, you'll have low compression.

Try removing the coolant cap with the car running to see if it is pressurzing.

I think leaky oil coolers leak oil into the coolant syaten, not coolant into the oil.

I would also do a very good visual check. You could have a minor leak that is dripping onto headers or something that is burning it off, hence it wouldn't leave a puddle.

Keep us posted what you find.

[por986]

A cracked tank won't necessarily lead to fluid on the floor. Check underneath the carpet in the rear trunk. My 01 had the smallest of cracks that I didn't detect for a long time - it took a while for it to pool up in the trunk.

Also, run your hand under the tank and look for obvious wetness and or residue (dried fluid).

Edited October 14, 2010 by por986

[txhokie4life]

My coolant has been "slowly" dissappearing. Early on I could go hundreds of miles before the light would flash at me, I'd fill it and move on. Now its been more frequent. I do not see any coolant on the garage floor or driveway. I have already replaced the cap with a newer version (had the original). I thought the cap fixed the problem, but its back.

I know it could be the tank, or some "Y" tube I've read about. I'm sure its been thoroughly discussed, but my exhaustive searches haven't found me what I needed.

Any info would be appreciated, or if you can provide a link to a previous thread.

Thanks in advance.

2000 Boxster 2.7L 60,000 miles. 5 speed.

Pull the trunk carpet around the coolant reservoir -- see if the pad underneath is wet.

I finally caught it drip leaking -- but it took a long time.

If not there -- things get worse like others have said.

Mike

[c337cc]

Are there any signs of leakage on the underbody? When I replaced the front engine mount I was struck by how many joints there are in the cooling system. The hard and soft hoses run to the front of the car behind black plastic panels, if you had a slow leak there, you might see some evedence on the panels.

If you have leakage into the oil slowly you might not ever see it on the dipstick.

You might try draining the oil to take a look at it, you'd need something huhe, then check for coolant and pour it back in.

Might also do a compression check, remove all 6 plugs, screw the tester into each cylinder and crank it checking for low compression, if you are sucking coolant into a chamber, you'll have low compression.

Try removing the coolant cap with the car running to see if it is pressurzing.

I think leaky oil coolers leak oil into the coolant syaten, not coolant into the oil.

I would also do a very good visual check. You could have a minor leak that is dripping onto headers or something that is burning it off, hence it wouldn't leave a puddle.

Keep us posted what you find.

A craked head will also pump oil into the cooling system,and you won't see it in the oil. Seen that one before too.

Howard