Where is a typical water pump leak?

[blairwag]

If you followed my previous nightmare thread: http://index.php?topic=1446
then you'll probably sympathize with me. I had a coolant leak that was hidden behind this huge "elephant bracket", as Cees puts it. Unfortunately in order to get the bracket off the car to expose the problem area, I had to remove the vibration damper, and thus remove the radiator, so the cooling system was emptied, and I could not run the car to trace the leak to it's origin. The Thermostat bypass hose was in bad shape, so I erroneously assumed replacing it would solve my problem. It did not   . I replaced every rubber hose and belt in the engine compartment.

Here's what the side of my engine looked like after running the engine for a few minutes, Saturday:

Download Attachment: Leak.jpg
60.66 KB

...yes, I was quite sad. See the fluid on the block? IT should be clean and dry!

Question: does this look like a water pump problem to you? Perhaps it's the water pump housing gasket? Is this the typical location for seeing leaking coolant when a water pump goes south? I assume the fluid is headed rearward due to the wind blown by the cooling fan.

Using a small mirror I tried to get a good look at the location where the thermostat housing mounts to the head. This appears to be dry. I suppose I could have a cracked head or block but ...well... I don't want to even think about that.

Does anyone have a documented procedure for water pump removal/installation for a 1971 280SL?  My BBB, printed in 1970, only has such a procedure in section 20-1 (pages 20-1/2 thru 20-1/3), which discusses removal/installation of the Compact Bearing Water Pump for Model 280 SE/9 3.5 and 300 SEL/9 3.5.  What a piss! This is what I was complaining about in another post. This book doesn't have everything for every carr. It seems to sometimes only discuss updates? Where's the procedure for the 280 SL?  

Can I get the water pump housing off the block without removing the vibration damper? Is this a part that's typically replaced, or just the gasket?

Any advise on chemicals to use for removing the gasket from the block? I usually use paint remover. No problems on a cast iron block, right? Any "no-no"'s?  Anything I need to know about using RTV sealant to help install the gasket?

Oh, yea, can I get the water pump off without removing the crank shaft's vibration damper? That would be sweet.

As always, all of you help is invaluable. Thanx for anthing you can offer!


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[knirk]

William,

The crankshaft damper must be removed if you need to remove the main housing of the water pump. But you can remove the impeller and change this gasket without removing the damper.

Per G. Birkeland
69 280 sl aut 834
Norway

[mulrik]

To answer your question first William. THere is a description on how to remove the water pump in the Haynes manual. The car they used in that book is a 280 SL with A/C, so that'll likely be good for you.

Well, my problem is that after running fine for a couple af hundred kilometers my engine all of the sudden had blue smoke coming out of the pipes. Motor sounded fine though. I found out that it had last all of the coolant in the expansion tank (and likely more). Now the working hypothesis is that because the engine was not efficiently cooled, the oil got so thin that it runs into the cylinders. The thermometer was at one time during this drive up very high, but dropped down, slightly above normal.

Now I need to find the leak, replace the tubing and test my hypothesis, which I hope is true!!!! Any comments on my case??

'67 250 SL Papyrus White 113043-10-000023

[knirk]

Have you seen the blue smoke again after you topped up the coolant water? If it was white smoke with disappearing coolant, but no water leak from the engine, I would have guessed on a blown head gasket.

Per G. Birkeland
69 280 sl aut 834
Norway

[George Des]

William--You could have a couple of things going here, but before you ponder the worst--head problems--you might want to check a few things a little more closely. First thing I would check is the water pump vent pipe. That's the little U-shaped line that runs from the water pump housing to the front of the head. There are two hollow bolts that attach on either end. Make sure the leak is not coming out from under these bolts. There are sealing rings on either side of the banjo fitting and you may have upset these when removing the a/c bracket assembly. Next check the housing itself--there is a gasket between it and the block. You can't check it direct;y, but it is under the face of the housing against the block. Again, the housing to block seal may have been upset in the bracket removal process. Finally, the thermostat housing also has a gasket between it and the engine. Looking at your picture, I would guess that the leak is coming from one of these three things. The water pump replacement process should be no big deal if the leak turns out to be there. I say no big deal only because I've seen from your earlier posts that you've had the engine front disassembled before and you know what and how things come off to get at the pump itself.Good luck--George Des

[blairwag]

Thanx Per, I was afraid I'd have to do that.

Thanx George. The leak is what got me into this mess. The leak is what made me remove the bracket - to try to find the leak. Anyway, I checked the fittings on the, what was it, water pump vent tube? Yea, they are clean and dry. Water pump is clean and dry all around. I believe, now, that my leak is from between the block and the water pump housing. Just my luck! It couldn't be something a little easier to get to and replace. Now, I've got to remove evrything, all over again. Oh, well. I hope the kids remember what I look like.

Can I get the waterpump housing off the block without removing the water pump from the housing? Should I attempt to replace just that gasket, or go the whole nine yeards?

Being I really don't want to do all this a third time, I'm considering replacing the water pump housing gasket, the water pump gaskep, and the water pump. It'll cost about $100.00 more thna just replacing the gaskets, but I shouldn't have to worry about this again for a while.

Ulrik Moerch, that doesn't sound good. I 'm interested in the answer to Per's question. After refreshing the coolant, and perhaps the motor oil, did the blue smoke stop? If not, you may have bigger problems.


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Tom]

Blairwag, et al.

While you are into that area, consider replacing the front crank shaft seal that is notorious for leaking.  Much easier while you have the front end opened up.  There was an article in a back issue of the Star regarding preparing the seal before it goes in-I don't recall the exact procedure, but sounded important.

Good Luck!

Tom

_____________________________________________

1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
_____________________________________________

[64sl_robs]

water pumps only last so long
seems like you have most of stuff off
needed to replace water pump
what's the price of a new pump??
whats' your time worth?
seems like replacing the pump is in order
replace all hoses and gaskets while you are in the area
refill system get it hot check for leaks

[blairwag]

Yup you're right.  I replaced the water pump housing gasket, water pump gasket, and waterpump. All cooling and heater hoses have been replaced, as have all the belts. I just got the car assembled tonight. Too tired to try to start it. Besides, I haven't tested the new Crane XR700 (installed it too).

I'm worried. There is this big kut on huge stud looking thing just unde/behind the thermostat housing. What the heck is that thing? Could it possible be the source of my leak. Oh, God, please let this leak be fixed!


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Naj ✝︎]

The 'kut' is the hydraulic tensioner assembly for the timing chain. Can leak oil but not water
naj

65 230SL
68 280SL

[blairwag]

Hey Naj,
Wow, I hope you're right!

This thing, right?  This is the 'kut'... that big nut looking thing square in the middle of the picture?

Download Attachment: BigNut.jpg
69.4 KB

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Naj ✝︎]

William,
Yes, right  
naj

65 230SL
68 280SL

[blairwag]

Well, I got the car back together, and start it up tonight. It started well, and I tuned the ignition. all is great, except...


...I still have my leak  

Now that I know where the gasket is between the water pump housing and the block, I know this was never the leak. THe leak is up too high on the engine.  :x

I suspect I've torn the font of teh engine and engine compartment apart 2 times, all for the wrong reason. Tomorrow, I'm going to try to replace the thermostat housing to head gasket... at the same time I might as well replace the thermostat and the thermostat gasket. I'll do that and try it all over again.  I should buy stock in Prestone - as I'm feeding them a ton of money for antifreeze!  I NEVER reuse drained antifreeze.

Anyway, I'll keep ya posted (if anyone's interested). If this doesn't resolve my leak, well then I'm at a loss. Cracked head or block i Guess  :evil:   ...I'll just pray to God that this resolves it.


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[knirk]

William,

Maybe this is a too obvious saving proposition;

To save some money on anti-freeze I would fill it up with plain water to check for leak first. Good luck!


Per G. Birkeland
69 280 sl aut 834
Norway