Re: The leak in the back is not a leak

I took my 2000 Boxster S for a little drive this morning. I planned to do an oil change (more on that in a separate posting) and went to get some supplies.

When I returned home, I noticed coolant dripping out from the left front (running out under the bumper). I said some choice words and then decided to look at it while the car is jacked up.

When I jacked the rear of the car up, I heard fluid running out from under the car. There was a HUGE leak in the right rear of the car. I popped the trunk lid and saw the coolant level drop and then stabilize.

Since then, it has been steadily dripping. I have a picture of the source (or what seems to be the source) of the leak. I have no idea what this part is (I think it might be associated with the water pump). I tightened the bolts, but no luck.

By the way, I removed the bolt and re-installed it to see if the dripping increases or decreases. No change. More choice words were spoken

Any suggestions?

The pressure relief system dumps the coolant out a tube the right rear wheel. Try checking the fans in the front to see id they are operational. Search PPBB for "radiator fan hack" for more details.

I wonder why it dumped when I jacked the car up and it has not stopped dripping for hours.

How about the leak in the front?

The leak in the front is probably the weakest part of the system in the front.

Blocked radiators
Radiator fans not functioning properly
Air in the system
Incorrect mixture (too much coolant)
Failing water pump
Rapid elevation change
Contamination in cooling system

I think that about covers it. The most common is the fans (as per my previous post).

As always if you had any recent work done that is the first place to work. Unfortunately, the weakest spots on these cars are often created by mechanics, not the factory.

I got under the car and squeezed the coolant tube. Everytime I did that, coolant would start dripping out of that spot again.

I removed the coolant pump (WHAT AN ORDEAL) to see the condition of the pump and gasket.

See the pictures below what I found. There is no play in the bearing.

Could this be as easy as just the gasket? Can I be that lucky?

How would I know if it leaked at the pulley?

The areas that I marked up are very rough and could be the source of corrosion/leaking.








Edited 1 time(s). Last edit at 10/09/2011 08:10PM by crumbum. (view changes)

It sounds possible that like one of the hoses has a cut in it or one of the clamps isn't on correctly. From the pictures of the pump and gasket I don't see clear signs of a problem.

The fact that there was a problem in the front and the back points to overheating and/or high pressure. I would think about the possible causes of that that might apply to you. Did you try spinning the pump to make sure it hasn't seized? (Doesn't seem likely since your serpentine belt would make a racket and eventually break and you would probably have mentioned that)

... there was a coolant leak up front, that can only mean that either a radiator or it's associated hoses is the culprit.
When coolant leaks out it also means that air leaks in.
When air is present in the system, eventually it will dump a lot of coolant from the vent valve in front of the right rear tire.
I would recommend you put some pressure into the system to find the leak.
Once found, fix it. Finally refill the system and burp all of the air out.
If you read my DIY instructions you'll find that it isn't a big ordeal.
You can find them under the DIY Projects page of www.PedrosGarage.com
Happy Boxstering
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

at the front of the car then there's a leak up there. (I know this reads like I"m stating the obvious but coolant from a leak can travel some distance. Also, I spotted what I thought was a huge coolant leak from the passenger's radiator area and it turned out to be the coolant tank with some coolant flowing along the top of the underbody panels and leaking out closer to the front of the car.)

Anyhow, if the leak is at the front of the car, the radiator is certainly suspect. Corrosion takes its toll on these. Rock damage less likely because each one is hidden/protected behind the A/C condensor.

Or a hose/clamp has failed.

Or the car bumped a curb stone or hit a dip too hard and the lower portion of the radiator is very exposed and a hit can cause the fitting at the bottom to crack and leak coolant.

Water pump gaskets never fail is my experience. I can't recall anyone posting this happening. Water pumps seldom gush coolant unless they fail catastrophically. Then you'd know it. They first (almost always) get noisy, and if ignored and the car driven too much longer the water pump can fail catastrophically (break).

At the back the likely culprit is the coolant tank.

Install the water pump. Since you have the old one out up to you if you want to replace it or reuse it. You can replace the T-stat, too if you want. Test it along with the old one in a pan of hot water on the stove and a digital thermometer to ensure both open at the proper temperature and open fully. New T-stats can be bad or mismarked. You want to find this out before you install one.

With the cooling system buttoned up and empty you need to do a pressure test to help locate the leak at the front and the back of the car. Shouldn't be hard to find... the hissing air will tell you where the leak is.

Sincerely,

MarcW.

I literally just got my car back from the shop (Vertext in Miami) for the same problem on my '01S. It was the expansion tank (small leak for some time), left radiator (hit an uneven construction related road surface a few weeks back) and oil separator (straw that broke the camel's back, I am guessing).
Good luck.

unless you have an early 996.

Hi guys,

Thank you for the responses. The water pump turns and does not have any wiggle at the bearing. Just quite a bit of calcification in 2 spots.

Pedro, I did follow you instructions. It was very comprehensive and easy to follow. There was just one bolt under the engine mount that I had a hard time with.

Before I removed the water pump, I pressed on the coolant pipe a few times. Every time I did that, it dripped at the spot that I posted the first picture. Strange.

I just heard from the vendor where I ordered the new pump that they were sold out. Before I order a new pump, I am thinking of cleaning it and reinstalling it with a new gasket and then pressurizing the system as suggested above.

Thoughts?

The vendor where I purchased the replacement pump from, said that they were out of stock and cancelled my order.

So I decided to clean the old water pump and reinstalled it with the new gasket. When I performed the vacuum test on it, the system would not hold pressure. It made a terrible noise in the area of the water pump, so I decided to use a turkey baster to squirt some coolant in that area. Right on the bearing, I could hear the sucking noise when I squirted fluid. WATER PUMP IS A GONNER.

Now for the question: I kept the bolts in the order that I removed them, but bumped them later on. I could not tell which bolt went in which hole. MarcW helped me with a good idea, telling me to try the long bolts in each of the holes. That worked well, but when I tightened the bolts, two of them felt like I was about to strip them.

Do any of you remember which bolts go where? And how much torque to put on these bolts before turning it into a bad day?

7ftlbs).

Perhaps you are not the first to do a water pump job and the bolts were not in their correct locations to begin with? And this accounts for what you feel, the bolt is threading into threads but the threads are possibly gummed up some by corrosion.

A quality tap (taper probably) used to *carefully* clean out the threaded holes may be called for. Do not attempt to cut the threads any deeper and if you run into much resistance back off.

The new metal seal must be cut for the coolant pump and water guide housign at teh connecting webs. Hopefully if you have the old seal intact and can go by that. If not, I have a page from the Boxster factory manual that shows (via a drawing) where the cuts are to be made. If you want a copy of this page email me and I'll send you a PDF of the page.

Sincerely,

MarcW.