Frozen Cat Starters

[John C.]

Client called me today asking if I seen a Cat engine starter freeze. It won’t turn at all. He pulls it out takes the back cover loose and it frees up. Turns easy now. Checks it with free spin on jumper and it’s OK. Puts it back in and it’s fine. Two or three days later it happens again. He had replaced the starter twice now with the thing happening some months later. Today he had moisture inside the starter. No idea how that got in there. We are looking for any similar events or ideas of what is happening.
Thanks in advance!

 

[skyking1]

no idea how it is drawing water, but I would try heating it up next time rather than get out the wrenches.

 

[John C.]

I’ll put that on the tablet for next time it freezes.

 

[heymccall]

Zero info given, besides frozen.
Dry flywheel housing drain plugged?
Delco Remy starter?
37MT?

I have a C4.4 on a tree chipper that had a hood opening (exhaust) that allowed a steady stream of rain runoff to continually soak the starter. It rusted solid.

 

[JPV]

Not really related to this problem but our John Deere 490 excavator started eating starters about every 6 months, I finally figured out that the ignition switch was sticking in the start position sometimes and you couldn't hear it in the cab. I was working on something else and could hear it one day. It had never crossed my mind, I would have assumed it would be louder.
I can't see how water would be getting in this one even if it is being dripped on unless it has one of those little rubber vent tubes and is mounted upside down? I have seen plenty of starters on motors exposed to the elements and I have never heard of one freezing like that.

 

[John C.]

Sorry about the lack of info. I didn't get much over the phone and I was driving at the time.

It a C9 in a crusher. Starters were from Cat dealer, this one today is just out of warranty. Client claims the engine compartment has sheet metal enclosure that keeps rain water out. We are in a moist climate so humidity is almost always over 80%. Makes things colder in the winter and warmer in the summer. Apparently this thing has a clutch between the engine and crusher drive. I don't know if it is a jaw, cone or impact crusher. The only key thing is that they take the back loose once the starter is on the bench and the armature loosens up and it works for awhile. I asked about the key but ruled it out because if it were stuck on the flywheel it would throw off the armature bars. I told him if it were freezing and had full amps to it he would know by the smell and smoke.

I volunteered to go up there tomorrow but he said wait until the next time it freezes. I suggested he put a dab of grease where the armature goes into the brass support bushing in the back plate.

Thanks for the thoughts so far!

 

[Delmer]

So they can't turn the armature without removing the back plate? I wonder how hard they try to turn it? they're not real easy to turn, especially new.

When I've seen starters "frozen" up from moisture, it's been rust holding the brushes from moving and contacting, that will keep it from smoking and smelling funny. That's on brushes that aren't worn out, and don't get run frequently.

 

[56wrench]

Well, if they check the starter draw current(amperage) when its frozen, that would indicate if the brushes are contacting the commutator adequately, before letting the smoke out of the wires

 

[John C.]

So they can't turn the armature without removing the back plate? I wonder how hard they try to turn it? they're not real easy to turn, especially new.

When I've seen starters "frozen" up from moisture, it's been rust holding the brushes from moving and contacting, that will keep it from smoking and smelling funny. That's on brushes that aren't worn out, and don't get run frequently.

They said it was froze and would not turn no matter what they did until they let the end cap loose. This machine gets run every week at least.
I was thinking of a volt check during the phone call but I was driving so it didn't get to the conscious part till after I got home and finished the office work. Usually I will just put a volt meter on the batteries and watch for the drop when the starter is engaged.

 

[Truck Shop]

If the starter was staying engaged {running after start up] the volt/amp gage would drop to negative.
Besides the oil gage I watch the volt/amp gage on start up [ I do it out of habit because of the 40mt's}

 

[heymccall]

If the starter stays engaged, would it not become a generator, ie, the amp meter would NOT drop?

 

[Truck Shop]

Oh yes it will-I had it happen in my own truck on the highway at night gage dropped to negative 60 and
lights dimmed.

 

[ahart]

John-
Any way you can get a part number on the effected starter? We are seeing issues with the new D5 dozers with PN: 516-2856 starters installed "freezing" when temps are below 20 degrees F. I'm told CAT knows about the issue and it is due to moister entering the starter somehow. I know it has also been an issue on the motor graders, same situation. When I have went to both machines, no voltage issues and starter will only click when engaged with the key. I've been successful at going between off and start repeatedly until you get some starter movement then hold the key to start and it would slowly start to crank until it was normal cranking speed and then engine would start. Otherwise, zero starter movement as you described. CAT is coming out today or Monday to replace both starters, I'm under the impression that it is currently "replace with same PN" as they have no solution as of yet.

When temps are above freezing, no starting issues at all, in fact, during summer months they don't even crank slower than usual so it appears to be a freezing temp situation.

 

[Truck Shop]

John does this starter mainly have a aluminum case except for the field housing?

 

[John C.]

ahart, I'll ask about a part number when I call the client later this morning. It has been freezing hard overnight here this week. I had asked about that in the conversation but the client said it had happened when things weren't freezing.

Truck Shop, I haven't seen the starter but will ask the question.

 

[Truck Shop]

The reason I ask is cold temp seams to be the issue-Shrinkage on the case.
To back that up a little known fact VW engine cases are aluminum because
of that the cranks are turned on the high side of tolerance. In cold weather
the cases will shrink enough around the main bearings that if they do start
it won't run long and lock up. Sounds strange but a fact. All engines with
aluminum cases or blocks tend to have more clearance on the mains.

 

[John C.]

Steel cases. He will check draw down voltage next time the issue happens. He didn't know the part number right off but he is think the moisture is part of or maybe all of the issue. We will keep and eye on it and let you know if it comes up again.

 

[Truck Shop]

in all my years and seeing starters hanging out in the elements it makes me wonder
why this particular starter has issues with moisture.

 

[kshansen]

in all my years and seeing starters hanging out in the elements it makes me wonder
why this particular starter has issues with moisture.

Agree it sounds strange. Don't recall every seeing a starter that would work at say 35ºF but then not work at 20ºF. Seen starters on engines that had a coating of ice on them from melting then freezing snow when parked outside in winter and they always seemed to work just fine.

 

[ahart]

Truck shop: Only thing I can figure is cat likes to either switch suppliers on a known good product or reinvent the wheel as if it wasn’t already round enough. For instance, the new next gen excavators are having issues with the swing case bolts coming loose. They’ve only been putting swing drives in excavators for the last 50 years, you’d think they would be past that problem by now. I think a PSSR once told me that a CAT machine is something like 95% parts supplied by suppliers whereas CAT used to be closer to 80% sourced in house. Once again a problem with having a “global economy” IMO.