Yesterday, I replaced my old SCA coolant with OAT, and used Brett's excellent instructions. (Third coach I have used his write-up and benefited from his guidance.) Anyway, I have a coolant leak today.
See the photo of the driver side of the engine. If I understand my anatomy correctly the block in the upper part of the photo is the thermostat housing. The pipe below it is the inlet for the water pump. Am I getting this right? I cleaned the area with brake cleaner, and the leak seems to be at the joint of the pipe, where the larger angled pipe appears to slip over the straight pipe attached to the block.
What type of seal is in there?
Is this a good candidate for Bar's Leaks? When sitting, the drip is about one per eight seconds. When idling, the drip is about one per 1-2 seconds.
The happy news is that I got the new Haldex dryer on this morning with no more trouble than smacking big wrenches with big hammers. It is tight in there!
That seal would probably be an O ring. What keeps the angled pipe from coming off? It must have support below to hold it. Any picture of that area?
I found this thread the second time I searched for M11 water pump, but not the first. ?? Anyway, it appears that a person removes two bolts that hold the small pipe to the block, and then three bolts that hold the pump to the "other big thing." Then the pump and the small pipe rotate as a unit before the small pipe is removed and the o-ring exposed.
I am wondering about all of this. It is hard to even SEE the bolts. I should check the three bolts for tightness.
Still wondering of the Bar's Leaks might do it.
m11 water pump (https://www.foreforums.com/index.php?topic=29601.msg251782#msg251782)
Sealers don't work very well with something that has movement. I haven't tried to seal an O ring with a sealer so can't help there. Have had good luck with gaskets and radiator header leaks.
So I have been thinking this through, and I think I am getting enlightenment toward two different directions.
First, going by the M11 repair manual. It looks like the water pump can be twisted outward without removing the water pump, or the belt pulley. Remove the two bolts (cap screws) that hold the water outlet to the block. Then remove the three bolts that hold the water pump in place. Absent any obstructions, it looks like the pump would then pivot outward, hopefully giving enough space to free the water outlet from the pump. The only things holding it in would be the o-ring and grime. I looked at the layout - alternator might have to come out, but that is simple. New o-ring, five bolts, refill and done.
Has anyone done this, or is able to confirm that it can be done.
Second, when I was hosing off the work area after the multiple flushes, including the one with the Fleetguard alkaline cleaner, I remember there being a lot of small dark brown fragments. It reminded me of the black stuff from my old engine bay insulation, but I had vacuumed that up. I remembered all of this while going through the work yesterday, wondering how flushing the cooling system could create a leak.
I think there was a leak before, and a PO treated the system with Bar's Leaks. The alkaline cleaner removed the Bar's, allowing the leak to restart.
What do you think? Which direction would you go?
As an aside... This morning I was weary from yesterday's big adventure and disheartened by the leak. Actually I found TWO leaks. The second one appeared to be coming from one of the CAC hose connections. My first analysis was that I had a massive failure of some sort, and the CAC was half-filled with coolant, and was leaking out. My second analysis was the correct one - the screw clamp at the bottom of the plastic overflow reservoir, directly above, needed another 1/4 turn.
I gotta be more optimistic!
Matt,
1. Yes
2. Yes it can be done BUT it is a lot harder than what you read in that paragraph. That makes it sound like it is a 15 min. job not the 4hr. job it is.
3. Take the alternator off is a big help.
4. If I was going that deep I would replace the thermostat and the "O" rings on the oil cooler as they are right there when you get that deep. Somewhere in the past I posted about those "O"rings and will see if i can find it.
Mike
I know it would not be a quick job. My thought was about half a day to a day - I can see spending 45 minutes on getting a bolt to start in its hole. Not like you can eyeball it to line it up. Gotta get the coolant out and back in too!
Good advice on the thermostat and o-rings, though that might be for another time. Those might be a good project for summer, when it is too hot to travel! On the other hand, I think I have a seep from around there.
Matt, On mine that O ring would only leak when it was cold, but I couldn't stand to see that puddle underneath. I'll try to post pics of the parts diagram and the Cummins Invoice for parts. I changed out the thermostat also. The old O ring was basically dry rotted and brittle.
Matt,
I looked around and couldn't find where I wrote up about the oil cooler "O" rings I did find a reference to them but that was all. The problem with working on that area is you are right up next to the frame rail with no room to work. If that engine was in a class 8 truck you can just tilt the hood and walk right up to the water pump and get after it. With this location you will end up doing part of the work from the bottom side and part from the rear.
Mike
The brown residue was probably the Bar's leak. Cleaner does remove sealers put in the cooling system. The radiator header was leaking on my crane and Bar's leak stopped it. When I did a flush I would have to add a bottle back in the system to stop it from leaking again.
Thanks all! The current mood is to replace the cooling o-ring, but undecided on the oil o-rings - I need to look at that job some more. The thermostat will be another time. I will probably get into it this weekend - my hands and back are still smarting from other projects. Long ago, I had this idea that RV systems were big, so there was plenty of room to work. I now know the reason for the variety of socket extensions, wobbles, pivoting ratchet handles, stubby wrenches, thin-wall sockets, ratcheting breaker bars, ratcheting box-end wrenches, inspection mirrors, magnet-on-sticks...
Cost of that o-ring ranges from $15 to fifty cents, depending on the source. I am guessing there is nothing magical about it.
We had planned to be on the road this weekend, but our intended destinations seem all filled up. Maybe a couple of day trips and we can take the coach after Christmas.
I will let you guys know how the project goes.
If the picture in reply #7 is the O ring it is a silicon one and might be hard to find at a hardware store.
Good point! I just ordered the official Cummins part. Actually a bag of 10 for a decent price. I will share!
If your actually going to remove the water pump I would seriously consider replacing it.
Does anyone have the thermostat and gasket numbers handy?
"In for a penny, in for a pound"...If your going that far, might consider replacing the non-silicon hoses as well.
Cummins 3076489 Thermostat 180° Cat 4w4794 for sale online | eBay (https://www.ebay.com/p/1117776104)
Cummins Part #'s...M11 1998
Thermostat 3076489 $71.33(Cummins price)
Seal, Thermostat. 186780. $17.42
Seal, Rectangular Ring. 3080770. $6.49
Here's a deal.
Cummins 180* Thermostat #3076489 (CT21-123-01) | eBay (https://www.ebay.com/itm/Cummins-180-Thermostat-3076489-CT21-123-01/293164746390?epid=1117776104&hash=item4441fb0696:g:YK8AAOSwQmhdOgfJ)
Thanks for the numbers, guys! I was out and about all day, and your info allowed me to get the order in before the weekend. Maybe get it a couple of days earlier!
I have learned so far that the "five bolt theory" almost works. It frees the block fitting enough to spin, to wiggle, to shake, but about 1/8" shy of being released from captivity. The thermostat housing must come off so the fitting can go up and out. I will replace the thermostat since it will be exposed. The pump shows no signs of weeping, so I will give it some more time.
I ordered a replacement for one silicone hose I perforated while removing. I will check the other short hose. It looks like most of the hoses are silicone already.
Matt,
When you pull the thermostat housing you will find a orifice in there. It belongs in there.
Mike
Thanks!
I found it, and made note. It was in the 1 5/8" hose just below the pump. Looks like a silver dollar with a 1/4" hole in the center.
That is it make sure you put it back in where you found it. It is real important for proper cooling.
Mike
Not sure on yours but the 8.3 has one hose with a spring inside that the new hose does not come with.
How to change M11 ISM water pump.
https://youtu.be/shX1ZdfngGE
Mark
So it is back together. I am letting some sealer set before I reinstall the coolant. The old o-ring was black (non-silicone?) and was brittle enough to break when bent with fingers. It had brown goo on it, which I assume to be Bar's Leaks. Removing the thermostat box did not free the block fitting, but it did give enough room to remove the old o-ring, clean the mating surfaces, and get the new o-ring in the channel, while the fitting was still captive. The thermostat and the box seals all looked pristine, so I cleaned the seals and reused them. New thermostat.
It was not necessary to remove the water pump. With the bolts removed, it pivots. I did not go into the oil cooler o-rings. No leaks from there, and I thought it best to leave it alone. I respect the notion of going on, but not for me today. The seep of oil was from the oil fill tube. All of the bolts were just beyond finger-tight. I gave then a "snugging," and will clean the area and observe later.
I spent a total of about seven hours on this. Subtract at least 1.5 hours of trying to free the block fitting before I worked around it. (it was sooooo close!!) Probably another hour getting one damn hose clamp started that could simply have been slipped over the hose before installing the thermostat block.
Subtract an hour of hell for a big, dumb rookie mistake. I was using my new cordless ratchet to remove the water pump bolts. One of them is in a very tight space. I got the bolt loose, but it pinned the wrench in the hole. Reverse it? The reverse tab was way beyond seeing or touching with anything. I eventually was able to use a screwdriver to push the socket off the wrench, and shake it vigorously until it all came loose. Plan B was to jumper the battery to see if reverse polarity would reverse the wrench. NO plan C. I think I got very lucky.
So four hours (less draining the coolant, but including the normal fussing, head-scratching,. and walking to get ANOTHER tool) was a good estimate.
That is so rich! I have been in vaguely similar situations and I would bet numerous other DIY'ers on the Forum have been as well.
Richard
Here is a piece of the o-ring. I tried to fold it end to end, and it broke before it got half way. Rust-brown stains on the surface, though not a hint of rust where it sat.
I guess it was time for a new one.