mdss6

Greetings. I need help confirming what a failing water pump looks like.

My situation is this, I moved to Belgium this Summer and had my 1990 s4 shipped over. It arrived two months ago, with the AC not working, and a coolant leak. Just a few drops made it to ground, and I stuck my head in the sand and didn't go looking to see if there was a serious problem. But the low coolant light eventually came on. Long story shorter, I ended up adding more than a quart of coolant, and when I did a better inspection found coolant all over the front of the oil pan (and on top of the belly pan). Although I'd put in a new Laso water pump when I replaced the timing belt in May 2009, I feared that a significant new coolant leak from under the T-belt covers indicated (premature) water pump failure. Either a failed seal or failing bearing.

I was not expecting to have to do a timing belt while in Belgium, and don't currently have all my tools (no breaker bar to remove the 27mm nut on the damper as an example), but I was able to get most things apart, short of removing the damper. And thus short of removing the center T-belt cover. I also seem to have gone partially blind as I also couldn't find the lower drain for the radiator, and as a result coolant got a lot more places on the front of the engine than I wanted, making it difficult to see exactly where it is leaking. But when I pulled the T-belt cover back to look at the water pump impeller bearing, it was one of the few things on the front of the engine that was bone dry. I haven't removed the T-belt, and there was also no movement whatsoever in that pulley. Water pump looked great. T-belt looked great.

So I'm perplexed. Does a failing water pump impeller bearing leak someplace over than at the front? I know there is a leak that runs down the front of the engine. It was covered with coolant, and I've lost a more than quart. Just to confirm, there's no coolant in the oil, or oil in the coolant and the the exhaust isn't at all smokey to indicate it is burning coolant. The loss is fairly clearly going out through an exterior leak.

The water bridge has long had a small leak. Though now it is perhaps a large leak? If so, it unfortunately wasn't especially obvious.

I'm going to have to get more tools to get the damper off to remove the center T-belt cover to really look at all sides of the water pump. But it looked good from above.

I've tried to attach a photo of the pulley and bearing, but I've never posted a picture before and am not sure if it will work.

Any inputs on what the failing bearing looks like will be appreciated.

Break break
Roger Tyson - I hope you are well. I've tried contacting you directly through e-mail and through your 928RUS website, and haven't seen a reply yet (this has been over a period of weeks).

Thanks,
Christopher
1990 s4 Dunkle Blau (the "black" 928)
1989 s4 Stone Gray 5-spd (sadly left in the USA)
1986.5 S 5-spd Grand Prix White

P.S. Hello to all my former 928 colleagues in Texas. Belgian roads suck (they are rough, and there are speed cameras everywhere), but the Autobahn is awesome. It's why Porsche made the 928. Hit 150 MPH (per the GPS - speedo was only off by 1 MPH, no joke) driving back from the NurburgRing (Panamera 18" rims with Micheline Super Sports felt awesome - one hand on the wheel stable in curves at 120. Not necessarily recommended...but readily possible when you have to reach for something.). While there I had a real interesting conversation with a journalist testing driving a 991. He was upset that Porsche was turning the 911 into the 928, since you can "never" us such abilities in North America vs. the fun of "driving a slow car fast." That can certainly be discussed for and against, but I will say that being close to Germany and the Autobahn I understand the corporate (German) interest in a car that is both nimble and easy to drive at 150 MPH. And yes, I'm aware of how lucky I am. Cheers.

docmirror

Clean the front of the engine with clear water, and blow dry it. Get a coolant pressure tester which pumps up the cooling system to ~14PSI. Use a hi intensity LED kind of light to see where the coolant is coming from. It may take a while if the engine is cool.

I saw Roger last night, he's in the office and doing fine.

Bjbpe

I suspect the picture for docmirror is oboma burning the constitution. If that is the case, I aplaud docmirror's inference. As for the pump bearing, it does not always produce a leak but it can sure raise hell with the timing belt aand, obviously, if it gets bad enough you could get in line for a valve job. I would say that you should use a dial indicator to check how true the pulley is running. At least that is how I found my problem.

GregBBRD

The "weap" hole for the water pump is on the lower right side of the pulley, as you face the pump.....right at about 5 o'clock (again, facing the pump.) You can see the hole, if you shine a flashlight down the right side of the pulley. If the seal inside the water pump is leaking, you should have a telltale "trail" coming out of that hole and running down the face of the water pump.

mdss6

Thanks for the inputs. I tried to remove the 27mm nut on the damper today, with no luck. Quite the opposite actually. I want to multiple car and hardware stores, but wasn't able to find anything like a break bar or really large wrench, so I ended up just putting a long section of pipe on the handle of my 1/2" drive. I put as much force on it as I could and it eventually moved and made a loud noise. Though it wasn't like the explosive pop/bang I'm used to when that damp nut cracks free. But when I went to starting turn the 27mm nut for removal, I saw the damper turn and I heard noise in the valve train. I immediately stopped, but the engine has been backed up (turned counter-clockwise) several degrees. I know you're not supposed to do that, but I'm not sure how bad it is?

On investigating what had gone wrong, I found the lower bolt was out from the fly wheel lock. It was one of the things I'd heard go pop. The bolt was a bit cross-threaded already, and apparently that bit of weakness was the weak link. The first "tooth" on the lock was also pushed/worn through, and I don't particularly trust it to hold the flywheel anymore. Bad developments.

So I ended up just pulling the top of the center T-belt cover back again to look for the weap hole and any signs of a trail. I'm not sure I was able to identify the exact weap hole, but I didn't see anything that looked like a leak or trail. I was hoping to find an obvious issue, but no luck.

Since I'm taken so much apart, I want to see under that T-belt cover before I put things back together. Otherwise I have no good idea of what's leaking at this point. Unfortunately with a really tight 27mm nut, and a bad fly wheel lock I won't be holding my breath that I"m going to be able to remove that nut.

How bad is it to turn the engine counter-clockwise? Is it not worth the risk of the flywheel lock failing again?

Thanks,
Christopher
1990 s4 Dunkle Blau (the "black" 928)
1989 s4 Stone Gray 5-spd (sadly left in the USA)
1986.5 S 5-spd Grand Prix White

Mrmerlin

first for the lock you need to use longer bolts almost double what is in there
That said you may have a leak at the water bridge and its finally filled up enough to run down the front of the engine.

Since you already know about this leak it needs to fixed before proceeding further.

I suspect the waterpump is fine as there have not been any reported failures of new Lasos leaking.

your clue to the leak will be to look at the top front of the engine block on either side of the water bridge,
there are 2 wells that will eventually fill with coolant,

you need to see if either side is filled,
if so then the leak is from the waterbridge or one of the hoses attached to the bridge.

NOTE what happens up top is that the well will fill, and then overflow and drip down the front of the engine making it look like a waterpump leak

the most common hose leak is from the inner wall of the hose getting cut from the small protrusions on the water bridge this will leave a small indentation on the hose and it will eventually leak, so inspect the inside of all 3 hoses that attach to the water bridge.

That said if neither side of the block is filled with coolant then the next place to look is the pump.
Follow GBs info for finding the weep hole what you will be looking for is coolant not a dry trail coming out of the weep hole an inspection mirror is needed to see the hole.

NOTE is is common to see drip trails from the hole but these will be white crusty deposits,
a truly failed pump seal will have liquid coolant in it and dripping down.

Leon Speed

I don't think there's a problem if the crank turned ccw a bit. You will need to use larger bolts than the bolts holding the fly wheel cover plate. Find some 25 mm M8 bolts and secure the fly wheel lock 'nice and tight'. It won't move again.

mdss6

Thanks those are helpful tips I'll use today. I "should" have some extra longer M8 bolts I can use, though unfortunately all the hardware stores will be closed till the start of the week if I don't. Then I'll have another go at the 27mm damper nut.

Per the water bridge leak, both the wells on either side have had fluid in them for years. Both coolant and oil. Though most of the sludge at the bottom on both sides seemed to be oil. Unfortunately I didn't inspect them closely enough before I started taking things apart, to see if they were overflowing. Certainly they were very near the top, and by the time I got done getting the hoses off the water bridge, they were definitely over the top with fresh coolant. The one thing I do remember was noting from my early inspection of that area was that it looked like something wet was flowing from under the intake manifold and into the well (as I could see it on the left/passenger side). Are there any coolant lines under the intake manifold? The hoses to the water bridge were all dry and seemed intact.

I'll provide an update after I next go at the center T-belt cover, and inspection of the water pump. The water bridge however is seeming like a more likely culprit. Perhaps its existing leak just got a lot worse.

Thanks again,
Christopher
1990 s4 Dunkle Blau (the "black" 928)
1989 s4 Stone Gray 5-spd (sadly left in the USA)
1986.5 S 5-spd Grand Prix White

Mrmerlin

as previously stated you need to concentrate on the water bridge leak first,

that is probably your problem.

there should not be any coolant filled in the front wells of the block,
if there is you should put towels in the wells and clean them.
Dont bother removing the timing cover fix the water bridge

mdss6

The longer M8 bolts for the flywheel lock did the trick. I then proceeded to sheer the extension for my 1/2" ratchet trying to remove the 27mm damper nut. I've removed two of these with it, and I guess this was the end of of its service life. Though on researching the forums tonight I've seen 1/2" is considered marginal. Anyway, that delayed things a few hours till I sourced a fresh extension that was able to get the job done.

The bolt still had plenty of anti-seize on it, so it was a little unclear why it as so tight. But the exterior of the end of the crank showed signs of corrosion, so I understood why everything else was so difficult to remove. Was this from normal exposure to rain snow and salt, or a symptom of the coolant leak down the front of the engine?

I was disappointed not to find an obvious problem behind the middle T-belt cover. If that's the location of the leak, I didn't see it. There was lots of coolant (and oil - making a messy slurry) on the top of oil pan and below the crank, but if it is leaking from the water pump it is still hidden behind other covers.

As suggested, it looks like the thing to do is to remove and reseal the water bridge (the effort to remove the T-belt covers and check the water pump was probably just a huge waste of time, though perhaps "better safe than sorry"). Unfortunately this leaves me stuck, needing to source parts. Mail from the States is painfully slow, so I will need to look for and consider European sources for some items.

What parts do I need to specify, besides the water bridge O-rings, paper seals and new bolts? I don't intend to get involved in a massive project as I don't have the time or resources right now, and I'm considering selling the car next year. But I'll have a fair bit of stuff apart and want things to go back together smoothly and to replace any common problem/maintenance items while there (I'm considering putting on a new T-belt and PKtensioner for this reason, even though everything was just refreshed in May 09).

There was oil in the bottom of both wells. From my forum research it sounded like there are common problems with the oil filler, though their exact nature wasn't clear to me.

Suggestions for orderable parts would be appreciated.

Thanks,
Christopher
1990 s4 Dunkle Blau (the "black" 928)
1989 s4 Stone Gray 5-spd (sadly left in the USA)
1986.5 S 5-spd Grand Prix White

Mrmerlin

FWIW go to the dealer and buy the parts there,
Fix the water bridge leaks first

Sander_Baas

Hey,

I live in Eindhoven (The Netherlands) not too far from your location in Belgium.
http://www.rosepassion.com/en/sel is not too bad, there are in France and not too expensive.
Else there is here in the NL ALPO (http://www.alpo.nl/) they don’t have an online shop you have to email them but have everything original Porsche.
And else there is also V-Zweeden (http://www.v-zweeden.com/) les experience with them. (also in NL)

Hope it’s any use for you, Maybe Leon Speed knows any German (cheaper addresses for you?)

Greetings,
Sander Baas

Erling G-P

Not entirely true. I've just had my 2009 Laso (same vintage as Christopher's) fail in the bearing, with coolant leak as a result - as described in this thread:

https://rennlist.com/forums/928-foru...31-000-mi.html

That is, if you consider a Laso from 2009 as 'new', but found it important to point out that at least one Laso from the same year as Christopher's, has failed and leaked (Others in the thread chime in with failed Lasos, but can't say if they were older versions).

Regards,
Erling

Imo000

Earlier this year I've replaced a Lasi pump that only had 5000km. I'll check my notes for the manufacture date and report back.

mdss6

Sander Baas - thanks for the list of "local" sources, as they should enable me to get the water bridge re-seal parts this week, without having to travel to Brussles (and counting on the dealer stocking 928 parts). Rose Passion lists everything on-line that I'm looking for, except the additional paper gasket for the water bridge (928 106 167 00). I'll contact them and ALPO and see who has it.

Here is the list of parts I'm looking at:
999 701 627 40 O-ring (water bridge) x1
928 106 227 00 Gasket (water bridge – red ring) x 2
928 106 167 00 “Thermostat Housing Gasket” (additional gasket for water bridge) x 2
900 067 248 02 hexagonal socket head bolt M8 x 70 Z1 x1
900 067 276 02 hexagonal socket head bolt M8 x 35 Z1 x3

999 701 632 40 O-ring (thermostat) x1
928 106 163 00 Gasket (thermostat inner seal) x1
928 106 129 17 Thermostat x1

928 106 321 03 Line (small coolant line) x 1

928 107 307 00 gasket (oil filler neck)

I've noticed a lot of talk of replacing the thermostat. Is this a part that usually goes bad? I guess I haven't noticed any issues with mine.

It also looks like it is difficult to remove the water bridge without lifting the intake manifold. As I too have a bad knock sensor like 1gtx (Mark) in a different thread, I'll look at lifting the manifold and replacing this sensor while there. But I haven't located the part numbers for the "flappy bearings" or the "double O-ring bearings" for the throttle body(?) in the PET.

Cheers,
Christopher
1990 s4 Dunkle Blau (the "black" 928)
1989 s4 Stone Gray 5-spd (sadly left in the USA)
1986.5 S 5-spd Grand Prix White