Likely cause of coolant leak?

[eyeballkid]

I'm a new (and somewhat anxious) 951 owner (88 with 72k on the clock). The PO had belts and water pumps done six months ago, but I'm noticing a coolant leak. Can't tell where it's coming from, but it puddles on tray directly in front of oil pan.

Should I look for a source for this leak other than the water pump?

[mikepellegrini]

It's not overfilled? I just went through that with my NA in the past couple weeks. I could smell coolant somewhere, but see no source. Then I noticed my resevoir was over the max line and put 2+2 together - it was coming out the overflow tube (which exits in about the right area) when it was hot because the level was too high.

If the level is okay, if you haven't already, I'd take off the belly pans and with the car up on jackstands, run it up to temp and just watch and see if you can spot where the leak is coming from.

There are a bunch of hoses in the front engine area. If the WP was done six months ago, hopefully that's not the source.

[jmj996]

It could really be anywhere from up front - there are LOTS of places to check and to my knowledge there are no common/likely specific sources for a leak. You're really looking at warming the car up and looking everywhere. The easiest places to check first are the hose connections and the front cylinder head connection (because it's right on top, in front) - you'll see a metal pipe going into a short rubber hose that connects to a bracket on the top front of the cylinder head. Also, this bracket has a bolt in it can be loosened to vent the air out of the coolant system - make sure this bolt is still tight. It definitely would have been loosened to bleed the air out when they changed the water pump and refilled it, maybe they didn't remember to get it completely tight. If you're looking at the front of the car, the bolt will go straight left and up a bit out of that housing. Should be a 12mm socket head, on a long extension to reach in there under the plug wires. Good luck.

[eyeballkid]

Thanks for the suggestions. Now if it weren't 30 degrees and blowing here.

[nize]

a common point of failure is the seal between the plastic radiator end caps, and the aluminum radiator fins. if the seal (glue) failed here, your best option is to replace the radiator. it might be a good time to upgrade to a custom griffin all-aluminum welded radiator.

[eyeballkid]

And that would cost me what part of an arm and a leg? Had to sell the first born to get the car, and I'm never gonna reveal what I had to promise the wife. Thanks for the info.

[nize]

you might also be able to pick up a good used radiator for cheap.

[nynor]

my buddy just got a new radiator for his 944 and it wasn't terribly expensive. under $300, IIRC.

[eyeballkid]

So I had the car to the local shop to mount and balance new tires. Since it was going to be up on a lift, and I don't own a garage, I asked the mechanic ("If it ain't a 350, I don't know too much about it") to take off the belly pan and report. He said it seems to be leaking up by the coolant reservoir tank, but that could mean just about anything, so I guess I'm on a snipe hunt. Thanks for everyone's replies to date.

[bleu951]

Go to Autozone and borrow a cooling system pressure tester and pressurize the system and start your search. It should not take long to find.

The car is 20 + years old. At this age, if the hoses are original, it is time for new ones.

[mikepellegrini]

There are several hoses that pass through that region. That's good news.

If you get the pressure tester and then take off the airbox, you oughta be able to see in there pretty well - you oughta be able to see where it's squirting out when the system is pressurized. (Depending where the leak is, you might also have to take off the one hardpipe and/or the J-boot as well. Just gotta see).

[eyeballkid]

Thanks--you're serious, it may not cost me $599? How that slip past the censors---best not talk too quickly or risk incurring the wrath of the Porsche gods.

[lleroyb]

Check the temperature switch while you have it pressurized. It is high up on the drivers side but can be accessed from below. Mine was leaking very slowly and it took me a month of looking.

Instead of a formal leak tester you can buy an extra reservoir cap and modifiy it like the one in the picture so that only the upper seal remains. Put it on the car instead of the normal pressure cap. Now you can carefully remove the overflow tube and connect a 10 psi air source where the overflow was. This will pressurize whole system.

Let us know what you find.

Lou

[eyeballkid]

Excellent suggestions--I will report when I track it down. It seems to have slowed quite a bit--hey, maybe these cars fix themselves.

[buffluv]

I had the same problem recently and from the same area, turned out the PO had used what looked like a garden hose to connect the electric turbo pump. There is an entire hose kit sold, I think I paid somewhere around $100. You will realize when you start to replace these hoses they are not the same size on both ends, this requires you to buy Porsche "specialty" hoses. Good luck, just replace them all for peace of mind.

[eyeballkid]

Thanks. Over the Christmas break I figured out it's the turbo cooling pump. It's leaking from the pump and I'll need to replace it. Thanks for the heads up on the hoses.

[TexasBlake]

Originally Posted by eyeballkid

Thanks. Over the Christmas break I figured out it's the turbo cooling pump. It's leaking from the pump and I'll need to replace it. Thanks for the heads up on the hoses.

If it's just leaking from the bottom you can replace the O-Ring in it. Mine had flattened out and was leaking.

It lasted a while, but I guess there's an impeller shaft seal as well, cause it's leaking from the top of the pump. I can't disassemble it any further.

[eyeballkid]

Nice suggestion; I was about to shell out 200 for a new one, but I'll check the O ring first. Did you use a generic O ring or a Porsche ($$) specific part? Thanks for the pics.

[TexasBlake]

I went down to the hardware store with the pump broken in two (it's just four screws that hold on the impeller housing) and found one that fit. Cost me 50 cents for a new O Ring. Remember to chose the BIGGEST one that fits, cause it'll just shrink down when installed.

[eyeballkid]

Thank You