Can a water pump go bad with no check engine light?

Well you're in that engine problematic mileage and time head gasket blah blah blah may not want to hear all that but you're right about where this happens so there's always that and you're losing coolant and you don't see it on the ground so there's always that so where is it going into the engine.

 

Likely your head gasket is leaking.
And/or you have some air in the system.
If the water pump is not working correctly, it will cause the engine to overheat,
and allowing it to fill and overflow out of the coolant tank.

You need a scanner to test the waterpump to see what the rpm is.

 

Yes, the engine coolant pump can go bad without triggering the P261B trouble code like the symptoms you are describing. You should replace the pump ASAP.

I'm just curious: Did you replace the engine coolant at the recommended intervals (at 100k, 150k, and 200k miles)?

 

In theory just your water pump could be bad causing the temp to go up and causing the coolant to overflow at the reservoir. I don't think you "necessarily" have a bad head gasket. That being said, that's often the case for WHY head gaskets blow, so chances are you could be there. Either way if you intend to keep the car I don't think a water pump is a waste of money because it'd be recommended in almost every repair scenario now that you've had over heating instances.

 

General consensus seems to be to go with OEM or AISIN equivalent.

 

I agree with you. You will notice that the high temperature light will come on during periods of high throttle usage, and the light will go off as you reduce the throttle usage.

FYI, the high temperature light comes on when the coolant reaches 120C (248F).

 

I like ASRDogman's suggestion to watch the pump RPM to see if there's an issue there or not. A head gasket issue would be enough on its own to explain the symptoms here, so stopping first to replace the water pump might just be a distraction, unless you first confirm it isn't working.

 

This is what I wrote 4 days ago in a different thread:

 

If you have a scan tool that shows the Engine and ECT data list, you can watch two RPMs: the RPM the ECM is telling the water pump to run at, and the actual RPM the water pump is doing.

If the water pump is in fact struggling to turn the RPM being asked of it, then of course all theories of how that might contribute to overheating and coolant loss are on point.

If it's happily sitting there doing what it's asked with no trouble, then replacing it just because somebody else's failing water pump could cause the same symptoms in somebody else's car might just use time that could be used pinning down what the issue is in this car.

 

If it runs fine when you have enough coolant, but over heats when it's low....
Just think about that for a bit....

 

When our generation 3 2013 persona went down this head gasket road we never had any overheating none at all car was running great No issues just the stumble and stutter and then all of a sudden the rod broke broke the back side of the engine the girdle etc was toast it was running fine right before that rod broke I mean running fine a little bit of noise and then snap I was running 50 miles an hour thing it never heated never shown any dash lights of anything just all of a sudden bam in the car had decent service history the two owners prior to me live next door to each other in the same town in Virginia bedroom community of DC and other than having a short rock driveway the car was driven to and from work on the highways it's life to that point that was very disappointing.

 

Maybe just use a Bluetooth OBD2 reader and car scanner app to monitor your engine temperature when you drive. Also losing coolant in a Gen3 is the first sign of early stage of head gasket failure which happens to all Gen3 on or before 200K miles, which is why putting a used gen4 engine in is the best solution because Gen3 also have premature piston ring failure.

In the meantime regularly clean your EGR system which will help keep engine temperatures lower.

 

My latest theory is the heat in the cylinder between #1 & #2 where the headgasket fails is because when the engine is turned off in a very specific position that spot is hotter than boiling and once enough heat damage has weakened the gasket in that spot it can pull steam, which makes it bigger, which eventually leads to coolant in the cylinder and eventually fatigue in the piston rod causing it to bend, then fail. I bet if you had a way to get a thermal camera on that area when then engine is hot just after shut down you'd see a hot spot there.

Of course maybe @ChapmanF would like to dispel my latest theory, which he usually does quite well most of the time.

 

There’s also the one thing that’s asymmetrical on the intake manifold: EGR entry.

I’d second water pump replacement, they seem to go any time after 150k; couple with belated coolant change?

 

I'd second checking the water pump, right away, to decide whether it is a current problem or not.

I'd take Mendel's suggestion, about replacing it preventively "any time after 150k" as a good idea for the next time you are doing preventive maintenance.

At the moment, as there are active symptoms of something, you are in a corrective maintenance situation, where the priority tasks are identifying and correcting a current problem.

So if you confirm a water pump problem, definitely swap the pump. Or if there's a head gasket problem, you'll certainly have enough other stuff apart to swap the pump preventively at the same time. But otherwise, it wouldn't be my choice to spend time on swapping the pump that hasn't been spent on finding the problem yet.

 

Is that for sure the case? Couldn't it be overheating when coolant level is OK and then expelling coolant out the reservoir (which it's seems to be doing) making it seem like it was low?

In regards to checking a water pumps RPM readings, could a pump with bad impellor show proper RPM command and rotation, but still not be allowing proper coolant flow? I seem to recall impellor failure as a failure mode in these, but I could be mistaken.