Coolant leak - not reservoir, not cap - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Jinster · 02-05-2007, 11:53 PM

I have been losing coolant lately, to the tune of 1L every 3 days.

This morning I found a small puddle under the car. I jacked it up, and took few photos.

There seems to be a constant drip coming from the lowermost point on the waterpump (straight arrow). But it's not leaking there. There is water collecting in the area of the curved arrow too when I get my finger in there. So it is dripping down from there, at least. Beyond that, I can't see or feel much with any certainty.

Does this look like a water pump/seal failure on a Boxster? Or is there any other hoses on top of it that might be leaking that I just haven't seen?

MNBoxster · 02-06-2007, 04:57 AM

Hi,

You're going to have to remove the rear firewall to see above the pump. I suspect that what you have, from looking at the photo is a Coolant Pump Bearing starting to go bad. This will require replacement of the Coolant Pump.

But, to be sure, you'll need to pull the Firewall and look/feel around to see if you can isolate the source of the leak. I see from the pic that you already have one non-standard Worm Clamp on the system. This indicates previous work was done to the Coolant Pump or Oil Pumps as Porsche recommends replacing the OEM Spring Clamps with traditional Worm Clamps if the system is dismantled for any other service. Actually, on second glance, I'd be sure that the Worm Clamp in the picture is properly seated and tightened. It looks to be very close to the end of the goose neck and this could cause a bad seal and possible leak. Hope this helps...

Happy Motoring!... Jim'99

Jinster · 02-06-2007, 05:25 AM

Thanks again for the reply, Jim. Putting out fires everywhere for me.

The coolant hose was probably disconnected during the tip rebuild.

I will move the worm clamp a bit closer to the pump tomorrow but I don't think that's where the leak is. There was no water around the connection when I felt around today. It is coming from somewhere high up.

As you suggested, it could be a pump bearing leak, or maybe a bad pump gasket and then water somehow just trickles down - this would have been much cheaper to fix, I suppose.

I actually already removed the firewall and everything looks bone dry from there. I will take another look tomorrow.

I have replaced water pumps on my Mazda before. I am hoping I can do this one DIY, too. Though the space around the pump looks pretty tight. I hope the engine doesn't need to be lowered to replace the water pump...

MNBoxster · 02-06-2007, 06:29 AM

Quote:

Originally Posted by Jinster

Thanks again for the reply, Jim. Putting out fires everywhere for me.

The coolant hose was probably disconnected during the tip rebuild.

I will move the worm clamp a bit closer to the pump tomorrow but I don't think that's where the leak is. There was no water around the connection when I felt around today. It is coming from somewhere high up.

As you suggested, it could be a pump bearing leak, or maybe a bad pump gasket and then water somehow just trickles down - this would have been much cheaper to fix, I suppose.

I actually already removed the firewall and everything looks bone dry from there. I will take another look tomorrow.

I have replaced water pumps on my Mazda before. I am hoping I can do this one DIY, too. Though the space around the pump looks pretty tight. I hope the engine doesn't need to be lowered to replace the water pump...

Hi,

The Coolant Pump can be changed in situ...

Happy Motoring!... Jim'99

Jinster · 02-06-2007, 02:56 PM

Ok, the water pump has been ordered.

Is there anything special about replacing it? The way I figure, flush the coolant, undo the pre-tensioner pulley, undo the serpentine belt, unscrew the water pump, cut the old gasket and scrape off, fit the new gasket, screw on the water pump to certain torque specs and refit the belt. Is there any tricks and tips you can offer, Jim?

Looks like certain bolts would need to be unscrewed from the bottom while others from the top through the firewall.

ohioboxster · 02-06-2007, 05:13 PM

where did you order the pump from?

MNBoxster · 02-07-2007, 09:00 PM

@ Jinster,

Hi, pretty straightforward removal/installation. A couple things to consider though, you need to remove the Serpentine belt, it may be wise to replace it now. Also, you need to drain the cooling system, so new Coolant and maybe even a 'T'stat is a good idea. Also, be aware that you'll need to cut the gasket as it is shared with the Oil Pump which you won't remove, so be sure to have a drywall knife or razor blade.

One tip - with an Alloy Engine, you need to be very careful when scraping off old gasket material that you don't scratch or gouge the mating surfaces, or you may risk leaks. One trick I discovered serendipitously while doing a valve job on my Esprit - we mislaid the gasket scraper and rather than stop the project to look for it or go buy another, I had a polystyrene light switch plate (available for under $1 from any Lowes, Menards, etc.). I snapped it in two and it worked great. It has a sharp edge and being softer than the aluminum, you could really reef on it with no fear of scratching or marring the mating surface. It worked so well, that it's now the preferred tool in our Lotus Club for removing gasket material. If it dulls, you just snap it again to have a fresh sharp edge. I now always have several in my tool chest.

Another tip is to use a thin coat of Hylomar on the gasket (both sides) to insure a leak-proof seal. Hylomar is an anaerobic sealant which never truly hardens, so it seals any irregularities in the mating surface. It was invented by Rolls-Royce and is much better than any of the RTV Silicone sealants because unlike Hylomar, these RTVs will harden and not continuously seal through repeated expansion/contraction of heat cycling, eventually developing leaks. If you PM me with your email addy, I can send you the Coolant Pump replacement procedure step-by-step as a Word document. Hope this helps...

Happy Motoring!... Jim'99

MNBoxster · 02-09-2007, 09:04 AM

Quote:

Originally Posted by ohioboxster

where did you order the pump from?

Hi,

You can get a reman'd pump here w/ 2-year warranty for $139.99. The Reman consists of all new parts (Impeller, Impeller Shaft, Bearing, Pulley), only the Pump Body is retained. see: http://www.********************************************/acatalog/Boxster_996_Remanufactured_Waterpump.html

A new pump (made by OEM Supplier Lasso) goes for between $257 and $295 : http://www.pelicanparts.com/catalog/shopcart/996M/POR_996M_WATpmp_pg1.htm#

Hope this helps...

Happy Motoring!... Jim'99

Jinster · 02-19-2007, 05:32 PM

Sorry about the late reply.

I got the water pump from Ebay. There is a guy selling them for $125USD brand new and it came with a gasket. I got mine 2 days ago in Melbourne Australia. It worked out to be $210AUD including shipping. Which is a far cry from the local dealer's $500+ asking price.

Jim, you have PM.