| Author | Message | ||
     Jeff Cheng Prolific User Username: makeshift Post Number: 111 Registered: 2-2016 |
So the water pump on SRH23650 has developed a slow weep out of the telltale weep hole of the 40yr old water pump, and so I figured I may as well change it out and call it done for another decade. When I removed the WP, I found a chunk missing out of the internal o-ring lip of the WP housing plate. Any guesses as to what happened here? Effects of long term cavitation? It's only under 5mm in length and at its deepest still proud of the o-ring groove. More importantly, what would you do? I think I'm just going to clean up the mating surfaces and ignore it. It never leaked from there and being the internal lip, the o-ring clearly still made a good seal against the outer lip/WP flange. Also, is it standard practise to apply gasket sealant (non-hardening) to the WP face prior to mounting? I know the o-ring 'should' be enough, just seeing if the collective experience says otherwise. Jeff.   | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 946 Registered: 2-2013 |
Jeff the missing metal has been caused by electrolysis which is in itself due to the cooling system not having the correct inhibitor in it and sometime during its life. I recommend you replace the water pump entirely with a new water pump. To do otherwise is to risk cooking the engine which would mean the car would be a write off. | ||
| Maxwell Heazlewood Prolific User Username: tasbent Post Number: 203 Registered: 9-2017 |
As Vlad points out. There could possibly have been a gas bubble in the casting which has slowly been eaten through. I'm wondering how often and what type of coolant has been used? If the mating surfaces are perfectly flat and a new water pump and new 'O' ring should suffice but it would not hurt ti se a very thin smear of an RTV silicon sealer such as Dow Corning's Silastic on the mating surfaces as added insurance. | ||
| David Gore Moderator Username: david_gore Post Number: 2917 Registered: 4-2003 |
My suspicion is the car has been left idle for a long period of time with old coolant in the system. Standard Ethylene Glycol has a safe working life of 2 years before it starts to break down and become corrosive. So-called "long-life" Ethylene Glycol has a safe working life of 4 years. Note the corrosion is at the lowest point in the pump body which is an indication of stagnant sludge/corrosive fluid "ponding" being a contributing factor. My decision would be to replace the water pump and keep it as an "emergency spare" for economic rather than technical reasons. As Vladimir points out, the difference in the likely cost of an engine failure versus the cost of a new pump makes pump replacement a sensible and logical choice. | ||
| Jeff Cheng Prolific User Username: makeshift Post Number: 112 Registered: 2-2016 |
Thanks everyone, I apologise for any confusion I may have caused. The pictures show the engine after water pump removal. The damage is in the engine side. (In my past lives, the 'waterpump' is what you bolt on/off as a unit, and the 'housing' what the pump assembly gets bolted to on the engine.) I am indeed replacing the water pump with a rebuilt unit from Flying Spares as the cost is quite reasonable along with being a straightforward procedure. I would normally keep the WP as a spare, but with its weepy condition and the FS core surcharge it makes more sense to buy another down the track if required. I would probably flatbed the car home before roadside-swapping a waterpump. Prior to my purchase in 2016, the car had only covered 200 miles annually since 2004, so I'm sure it is was overdue for a good coolant flush. Jeff. | ||
| Maxwell Heazlewood Prolific User Username: tasbent Post Number: 205 Registered: 9-2017 |
..>>>> Prior to my purchase in 2016, the car had only covered 200 miles annually since 2004, so I'm sure it is was overdue for a good coolant flush. Jeff.....>>>>>> Hell!....200 miles annually??....just the sort of un use that ruins good cars like this. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 947 Registered: 2-2013 |
Jeff I got myself all confused. There is a product called Devcon. I would thoroughly clean the damaged area on the engine, apply the Devcon and then sand it back until it is level with the metal surrounding it. You may also want to consider taking out the radiator and getting it rodded by a radiator specialist because its most likely blocked up with corroded gunk. Don't tell the radiator people its out of a Rolls Royce because the price will immediately fly upwards. The white lie of it being out of an old Austin taxi should work. For about $260 Repco you can get a cooling system analyser with which you can pump up you cooling system to 15 psi, then look under the car for any leaks. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1555 Registered: 4-2009 |
Dear Jeff, I agree with Vladimir. Use Devcon. But make sure you get the right Devcon as this comes in various steel putty combinations (aluminium, steel Stainless etc). What makes you assume that the water pump has not been changed in 40 years? A lot happens in 40 years and one will never really know. Good lUck. Omar | ||
| Jeff Cheng Prolific User Username: makeshift Post Number: 113 Registered: 2-2016 |
So just a quick update... My rebuilt water pump from Flying Spares arrived today, and I am pleased to say that it has sealed up well with just the factory o-ring and a very light application of non-hardening gasket sealer on the very outer edge of the water pump mating face. Thanks Vlad and Omar for your suggestion to use Devcon to 'rebuild' the missing material. I must admit I also thought of doing this, but finally decided against it. My reasoning behind this was that the area is essentially inside the cooling system, where I cannot monitor it, and should it dislodge, I would have a sizable piece of hard epoxy circulating where it may damage delicate parts like a heater tap or water pump itself. I have used Devcon in the past to repair fuel tanks and engine sumps, but have always used it externally, where I could keep and eye on it and if it fell off, just reapply. All's well that ends well  | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 968 Registered: 2-2013 |
Jeff in decades I have never seen Devcon come loose internally or externally though I understand your reasoning. Good luck with your repair. Perhaps also you should check whether the weep holes on each cylinder in the block are leaking coolant as that is a good indicator of the extent of electrolysis damage over the years. | ||
| Jeff Cheng Prolific User Username: makeshift Post Number: 114 Registered: 2-2016 |
Vlad, the extent of possible electrolysis damage has me somewhat confused. As you can see in the photo's, there is a (relatively) large piece of material missing, with what can best be described as localised scale on the 'wound'. I would not be surprised at all if this was the effects of long term electrolysis. However, the rest of the cooling system does not show any signs of electrolysis damage. The water pump impeller was solid and not missing any material. Neither were the water outlets (where the radiator hoses connect), which is where I usually see first signs on corrosion. There was no rust particles in the coolant that I could find although the cooling system had a light coating of 'silt', which I've often found to be normal in orlder cars, and nothing to worry about with frequent coolant changes. In short, that damage seems to be extremely localised and doesn't match the rest of the cooling system. Perhaps it was mechanical damage from a previous clumsy water pump replacement...? Does electrolysis take the path of least resistance much like electic current? My block weep holes leak oil, but not coolant. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 969 Registered: 2-2013 |
My experience is that electrolysis damage is like gold - its where you find it. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 972 Registered: 2-2013 |
If you were really worried about that missing piece of alloy Jeff, you could have it welded but it would be a hell of a job to groove the excess weld out. You definitely need to pressure test your system when you have it all back together to make certain the water pump is not leaking. |
