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Water Pump Replacement - Question


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I'm in the process of changing the water pump on my 95 4.9 Deville. I took the

old pump off, and decided to change the lower hose. While I was pulling the lower hose off

its housing, I notice that the housing unit moved slightly. Is there a gasket between the hose

housing and the plate it mounts to, between it and the water pump. I notice that the bolts

from the water pump hold the housing in place. Will I have leak, I don't want to put everything

together and find leak?

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There are 2 gaskets on the 4.9. One is the water pump gasket itself. The other is the water outlet/thermostat housing gasket that goes under the housing. So yes. If I am not mistaken there is also a thermostat seal or O-ring that is normally attached to the thermostat inside the housing. That part I'm not 100% sure on.

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There are 2 gaskets on the 4.9. One is the water pump gasket itself. The other is the water outlet/thermostat housing gasket that goes under the housing. So yes. If I am not mistaken there is also a thermostat seal or O-ring that is normally attached to the thermostat inside the housing. That part I'm not 100% sure on.

Thanks for your input, on my particular set-up there is as you mentioned the water pump and the thermostat gasket, but there is

also a water pump inlet gasket where the lower hose housing meets the cover that the water pump mounts to. I was wondering if anyone

knows if there is a possibility of developing a leak there. Thanks

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I think Carla is thinking of the 4.6 Northstar, this is the 4.9, the thermostat is on the other side of the engine.

I just looked at the factory service manual for a 4.9, there are 16 screws plus one nut that hold the water pump in place, attached is a scan that shows the torque specs.

The lower water hose inlet is behind the front cover, there is a gasket between the front cover and the pump inlet, but to date I have never heard of anyone having a leak at that location, not saying that it can't leak at that location but it would not be a fun job unless you removed the front cover. I don't think there is much room to work. Are you leaking at that location?

Getting involved with the pump inlet attached to the back of the front cover is not usually touched when a water pump is replaced.

Here is a diagram of the area

49WaterPumpInlet.jpg

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I think Carla is thinking of the 4.6 Northstar, this is the 4.9, the thermostat is on the other side of the engine.

I just looked at the factory service manual for a 4.9, there are 16 screws plus one nut that hold the water pump in place, attached is a scan that shows the torque specs.

The lower water hose inlet is behind the front cover, there is a gasket between the front cover and the pump inlet, but to date I have never heard of anyone having a leak at that location, not saying that it can't leak at that location but it would not be a fun job unless you removed the front cover. I don't think there is much room to work. Are you leaking at that location?

Getting involved with the pump inlet attached to the back of the front cover is not usually touched when a water pump is replaced.

Here is a diagram of the area

49WaterPumpInlet.jpg

I was wrong. I just forgot that the water pump was opposite the thermostat on the 4.9. I had looked it up before, and must have just gotten my info mixed up. I was reading into my water pump housing leak one day, and some info on the 4.9 setup caught my eye so I read it. I have a terrible memory. Sorry bout that.

I remembered as much as the water pump itself is COMPLETELY different than the one on my car...at least I remembered something right. Lol.

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No need to apoligize it takes time to know all of the differences

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I think Carla is thinking of the 4.6 Northstar, this is the 4.9, the thermostat is on the other side of the engine.

I just looked at the factory service manual for a 4.9, there are 16 screws plus one nut that hold the water pump in place, attached is a scan that shows the torque specs.

The lower water hose inlet is behind the front cover, there is a gasket between the front cover and the pump inlet, but to date I have never heard of anyone having a leak at that location, not saying that it can't leak at that location but it would not be a fun job unless you removed the front cover. I don't think there is much room to work. Are you leaking at that location?

Getting involved with the pump inlet attached to the back of the front cover is not usually touched when a water pump is replaced.

Here is a diagram of the area

49WaterPumpInlet.jpg

Thanks for the diagram it's great. My concern was that I took the pump off and then I pulled the lower hose off

its housing, and the housing shifted a little because the water pump screws hold the housing in place. I was wondering if there

could be a possibility of developing a leak there once everything is back together. Thanks

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As long as the gasket is still in good shape and the screws/bolts are tightened properly, I don't foresee you having an issue with a leak there.

big4870885.jpg

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Tomcat, I recall seeing the front cover move away from the intake also, when I changed the pump on my 91. I changed that pump about 4 times during my ownership, once behind a Marriott Hotel

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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