Is there a trick to this plug bolt?

[rundmc]

Received a new water pump plug bolt (the 19mm one on the front with the copper washer beneath) and a new copper washer from DPI Josh (thanks!) and installed it onto the water pump. Had to grind down the end of a 19mm socket to get a ratchet in there to tighten it down.

So I get it tightened down, fill the system, pressure test for 30 minutes. Come back, no obvious loss of pressure, but the pump is clearly weeping coolant underneath the bolt. Not outright dripping, but weeping VERY slowly.

I used teflon tape on the bolt in addition to the copper washer. I cannot seem to get this bolt installed where it won't weep.

Any help is appreciated.

[sean]

Are you 100% its the bolt and not the thermostat housing leaking down? I've never had issue with that bolt leaking but plenty of times with the thermostat housing leaking.

[rundmc]

100% sure. New o ring, dry as a bone.

[DMC5180]

Do not use Teflon tape! This is not a pipe thread. The gasket will suffice. You probable are causing the leak because of foreign material between the mating surfaces.

[rundmc]

Ok thanks. Will remove and redo.

[sean]

If you find your copper washer is no longer good and dont want to wait on mail I have a few here.

[rundmc]

I don't even know where to get that particular copper washer. DMCH doesn't carry it and Hervey doesn't have it separately either.

I removed the teflon tape and tried again. Now it's weeping worse than before. This is so effed up.

[Delorean Industries]

I have never seen an issue with this not sealing. I would advise looking at the water pump housing and making sure it is not cracked. Also make sure that all of the tape is off the threads and bolt. Check to make sure the copper washer doesn't have bind marks as well from tightening.

[rundmc]

I found two identical copper washers at AutoZone and tried again - without tape - clean bolt - clean washer. It was weeping like a sieve.

This is total bullsh%^...

[Delorean Industries]

That is very odd. Pictures of the pump hole?

[rundmc]

Pictures - The last one is a photo of the hole I put in my garage drywall with my fist upon the fifth refill, pressure test and fifth subsequent failure of the plug.

https://lh6.googleusercontent.com/-j_FHqfGYBCU/T2KI66pgdkI/AAAAAAAAAio/uI4KOJjc8qI/s720/IMG_1840.JPG

https://lh5.googleusercontent.com/-4dtbdg9nKIM/T2KI64FbgNI/AAAAAAAAAik/S5BfBJBwdnU/s720/IMG_1841.JPG

https://lh5.googleusercontent.com/-FQ1NJrMo4_w/T2KI6z9Hn_I/AAAAAAAAAi4/htdkcN2OMeA/s720/IMG_1842.JPG

https://lh3.googleusercontent.com/-pyT-g95I_qg/T2KI7qd2ZSI/AAAAAAAAAi0/gnyxtYxLBc4/s720/IMG_1843.JPG

[Delorean Industries]

Why did the wall suffer!

[rundmc]

Because I got REALLY angry as I watched that bolt start weeping for the fifth time, well before the system reached 15 lbs...

Any thoughts on what is wrong with this pump/bolt/seal/whatever?

[ramblinmike]

Because I got REALLY angry as I watched that bolt start weeping for the fifth time, well before the system reached 15 lbs...

Any thoughts on what is wrong with this pump/bolt/seal/whatever?

Could the threads in the pump not be true? The bolt wouldn't seat evenly on the pump body. The copper marks on the pump body look much heavier on one side.

[rundmc]

I guess anything is possible at this point. This whole thing started as a routine coolant flush...in NOVEMBER. I've drained and refilled the system more times than I can count and gone to hell and back getting a new water pump after everything else went to hell. I won't be surprised if this brand new DMCH water pump is also DOA the way my luck is running.

[DMCMW Dave]

What does the mating side of the plug look like?

[rundmc]

It's a threaded short bolt that uses a 19mm ratchet. I have two bolts - one from Josh and one from a Volvo parts dealer here in Atlanta. Both are identical. I've tried both with fresh washers each time. The hole still weeps, no matter which bolt.

[jawn101]

It's a threaded short bolt that uses a 19mm ratchet. I have two bolts - one from Josh and one from a Volvo parts dealer here in Atlanta. Both are identical. I've tried both with fresh washers each time. The hole still weeps, no matter which bolt.

I think Dave means the inner surface of the bolt head - where it meets the washer/pump body. Got a pic of it?

[Bikercmbc]

check a side view of the face where the bolt goes in . just to make sure the top is not sticking out further than the bottom on the new pump. ive never seen this happen on any mercedes pumps (bit different but still have plug holes)

[Ron]

It looks like once upon a time someone tightened down on it w/o a washer and scared the hell out of it to me.
I'd try RectorSeal, or high temp epoxy on the threads and forget about it...

[David T]

The surface on the pump where the copper sealing washer has to seal looks very scored to me. It needs to be smooth. I would try filing it smooth and then smear some silicone sealer on the copper seal. Let it sit for a while before pressure testing.
David Teitelbaum

[rundmc]

Thanks. Will do tonight.