coolant leak

just moved to colorado from Georgia in my P5.

Running about 185,xxx for milage.
5-speed, NA 2002

after a one hour drive through the mountains while in a parking lot I noticed the smell of antifreeze/coolant. sure enough it was coming from my car. While looking under the hood I noticed a leak directly under the coolant resovoir. I could not find any coolant on the splash guard under the motor/trany only on the mounting bracket for said resovoir and along the chasis and on the splash guard under the resovoir.

what could the source of my leak be?

temps in GA rarely dipped below freezing. the past month in CO has been under 32 for the most part..



the coolant was bubbling in the resovoir when I was looking on that day. the radiator still has fluid, and I have not lost anymore coolant from the resovoir ( I dont drive much in CO so I have yet to address this issue after 3 weeks) the fluid level is flush with the hose that connects it.

now for a little more background, maybe even my assumption, I topped off my coolant tank with purified water before leaving georgia.
could that water have frozen over in my resovoir, possibly causing a fracture?

can anyone show me a link or provide info on how to find the source of this issue?

its bitter cold here in CO so I want to spend as little time under my hood (No more garage (shrug))

Pull the reservoir off of the bracket and check it for cracks.

When you say the coolant was bubbling, was it almost overflowing? that's never a good sign. How's the exhaust smoke looking? Smell sweeter than usual?

my exhaust smells pretty rough for the most part. My cat-converter went bad around 150k and I just installed a nonfouler to bypass emissions. it does not smell sweeter, just sulpur-ish.

i still have the same amount of fluid in the coolant resovoir as I did a couple months ago. I drive 20mi a day 4 times a week and have not had any issues with running temps of the car (then again the temps here in CO are between -20 and +30)

i do not have a garage anymore and my car stays covered in snow so I have not been able to work on it. fml!

Unsupa said:

Pull the reservoir off of the bracket and check it for cracks.

When you say the coolant was bubbling, was it almost overflowing? that's never a good sign. How's the exhaust smoke looking? Smell sweeter than usual?

Click to expand...

I was thinking problem with the head or head gasket as well

I'm pretty sure you have air in your system now. You probably sucked it up through the empty reservoir after it overflowed then cooled off drawing the remaining fluid then air back into your rad. You probably need to "burp" your system.
With the engine cold remove the rad cap then start the car and wait for it to warm up. You'll see the fluid start to move once the thermostat opens then bubbles will come out and the fluid level in the neck will drop. Add more fluid (you can get pre-mixed to save some trouble but if you mix it yourself be sure to use distilled water from the grocery store, it's only a buck or two for a gallon). Make sure your heater is on in the car to circulate any bubbles out of your heater core. Rev the engine a bunch of times to "pulsate" the bubbles through the system better. Make sure you fill the reservoir as well (to the full mark, not the top). That should clear any air in the system. It's a good idea to pump the big rad hose after the fluid starts moving, it forces the bubbles to the filler neck.
Now as to why this happened in the first place,... check to see that the fans come on after the car gets nice and warm (while you're burping it). If not, that's your problem. Perhaps the thermostat is stuck in which case the fluid won't circulate even when the engine is hot. Keep an eye on the temperature gauge as you're burping. If it rises above that middle mark the car is way too hot. If it reaches that point and the fans aren't on and you don't see flow in the filler neck then you've got two problems. You may have a bad rad cap too which is supposed to hold 12-18 PSI (I don't know what it is for our cars). They are probably worth less than ten bucks at a parts store so maybe just do that anyway (they're not easily tested). My friend had the exact same problem on her car. I suggested a new rad cap. She decide to take it to the mechanic,... it cost her $100,... for a new rad cap. Spend the ten bucks and replace it. Think of it as a wear item that may fix your problem.
If everything works out just keep an eye on the reservoir level. It should never reach the bottom of the reservoir or it could suck in air. If it keeps dropping, you may have some serious problems. (warped head)

pcb said:

I'm pretty sure you have air in your system now. You probably sucked it up through the empty reservoir after it overflowed then cooled off drawing the remaining fluid then air back into your rad. You probably need to "burp" your system.
With the engine cold remove the rad cap then start the car and wait for it to warm up. You'll see the fluid start to move once the thermostat opens then bubbles will come out and the fluid level in the neck will drop. Add more fluid (you can get pre-mixed to save some trouble but if you mix it yourself be sure to use distilled water from the grocery store, it's only a buck or two for a gallon). Make sure your heater is on in the car to circulate any bubbles out of your heater core. Rev the engine a bunch of times to "pulsate" the bubbles through the system better. Make sure you fill the reservoir as well (to the full mark, not the top). That should clear any air in the system. It's a good idea to pump the big rad hose after the fluid starts moving, it forces the bubbles to the filler neck.
Now as to why this happened in the first place,... check to see that the fans come on after the car gets nice and warm (while you're burping it). If not, that's your problem. Perhaps the thermostat is stuck in which case the fluid won't circulate even when the engine is hot. Keep an eye on the temperature gauge as you're burping. If it rises above that middle mark the car is way too hot. If it reaches that point and the fans aren't on and you don't see flow in the filler neck then you've got two problems. You may have a bad rad cap too which is supposed to hold 12-18 PSI (I don't know what it is for our cars). They are probably worth less than ten bucks at a parts store so maybe just do that anyway (they're not easily tested). My friend had the exact same problem on her car. I suggested a new rad cap. She decide to take it to the mechanic,... it cost her $100,... for a new rad cap. Spend the ten bucks and replace it. Think of it as a wear item that may fix your problem.
If everything works out just keep an eye on the reservoir level. It should never reach the bottom of the reservoir or it could suck in air. If it keeps dropping, you may have some serious problems. (warped head)

Click to expand...

They're 1.1 bar (16 psi'ish)

IshSonP5 said:

They're 1.1 bar (16 psi'ish)

Click to expand...

I had an 85 626. I replaced the rad cap with one rated about 4 lbs higher than the original,.. didn't think it mattered,.. blew the heater hose off the fitting,... warped the head,... the devil is in the details.