Auxilary Water Pump

wildrage · #1 (**permalink**) 05-07-08, 01:47 PM

I was having a coolling issue, and found through testing that my AUX water pump (the one on the front driver's side) was bad. I installed a new one, but I don't know how to test it.

When does the pump turn on? One place I read it was at 194 degrees, another post said 212 degrees.

Also, can someone decode the guage for me (or atleast try). What is the MIN and MAX? What temp is the midpoint?

I'm getting really frustrated because I can't test the connection for electrical current unless the pump is powered on - and I have absolutely no idea at what point that is.

I would appreciate any help.

Thanks.

lakesidepark · #2 (**permalink**) 05-07-08, 05:32 PM

From an earlier post of mine:

Quote:

4) Water Pump (all of them) - make sure they work. There is the aux pump (on radiator - runs when temp is above 205 and engine is shut off with the aux fan to cool the radiator - I will recheck this, I don't have my factory service manual with me). The heater aux pump runs when engine is on (quick note - if this pump fails, and if you are lucky, the wire for the pump has a foot extender coiled under the battery...temp rescue is to unplug the aux pump and power it with the heater pump connector - this will help some until that pump is replaced - learned that one last summer).

This is a link to that post. I re-worked my cooling system a year ago and I think the post has some good ideas for the coming summer.
http://www.cadillacforums.com/forums...ml#post1127937 (My Cat Lives Again!)

Army_MP_From_MO · #3 (**permalink**) 05-07-08, 07:44 PM

Test it like you tested the first one to determine it was bad.

lakesidepark · #4 (**permalink**) 05-07-08, 08:33 PM

Quote:

Originally Posted by Army_MP_From_MO

Test it like you tested the first one to determine it was bad.

His logic is sound. Now I'm aggravated I didn't think of that before all that typing.

wildrage · #5 (**permalink**) 05-07-08, 10:14 PM

I know the pump itself works (tested it on the battery). I think there's either a short in the wire going to the connector, or the relay is bad. I can't test the power to the connector if I don't know the computer is sending power to it.

I was thinking - If I wired the aux pump to come on with the heater pump (run all the time), would that have any negative effect? It looks to me that the pump itself only pumps coolant from one side of the radiator to the other, so when the thermostat is closed and the car is warming up, it shouldn't affect that.

My next step is to see if I can find a short in the wire, then to replace the relay (although I can't find the 'K22' relay on any of the dealer part sites!).

frank moran · #6 (**permalink**) 05-08-08, 09:39 PM

Quote:

Originally Posted by wildrage

I know the pump itself works (tested it on the battery). I think there's either a short in the wire going to the connector, or the relay is bad. I can't test the power to the connector if I don't know the computer is sending power to it.

I was thinking - If I wired the aux pump to come on with the heater pump (run all the time), would that have any negative effect? It looks to me that the pump itself only pumps coolant from one side of the radiator to the other, so when the thermostat is closed and the car is warming up, it shouldn't affect that.

My next step is to see if I can find a short in the wire, then to replace the relay (although I can't find the 'K22' relay on any of the dealer part sites!).

Rage, this wont help you right now, I have to think about this. That aux pump is not turned on by a temp controlled switch, at least not on my 97. I went through this diagnosis also and frankly the serv manual is wrong . Leave it all connected , if i remember , when the fan kicks on the pump runs, put a screw driver on top of the pump and press your ear up to the handle and listen for the pump running (or a stethoscope etc) when the fan kicks on. The fans, however are temp controlled. The heater pump on the RF inner fender runs all the time. I'll look at the book later and maybe my brain will remeber...again I did what your trying to do and all was well.

wildrage · #7 (**permalink**) 05-08-08, 10:08 PM

I took a closer look today. It almost looks like one of the wires that comes out of the temp sender directly underneath the upper radiator hose goes directly into the harness for the pump. Maybe I'm wrong, but I could have sworn I saw a brown/light blue wire coming from the sensor harness into the pump harness. I verified that the pump isn't getting called on. It isn't running, and I tested the connector for juice and it doesn't get any - even when the fan is on. I think it may either be the temp sensor on the radiator or the 'Aux Pump Relay'..i beleive it's relay #3 (K-22 I think).

Also, can someone tell me the order in which the fans come on? So far I've only seen the fans (that are side by side) actually run. I've never seen the condensor fan turn on.

It's strange because the pump I replaced was definately dead, so I thought I solved the problem. I want to make sure the pump is operation before I start tearing into the thermostat.