tomcad95 Posted March 8, 2010 Report Share Posted March 8, 2010 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? Link to comment Share on other sites More sharing options...
CarlaValentine Posted March 9, 2010 Report Share Posted March 9, 2010 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. Link to comment Share on other sites More sharing options...
tomcad95 Posted March 10, 2010 Author Report Share Posted March 10, 2010 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 Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 10, 2010 Report Share Posted March 10, 2010 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 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 Link to comment Share on other sites More sharing options...
CarlaValentine Posted March 10, 2010 Report Share Posted March 10, 2010 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 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. Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 10, 2010 Report Share Posted March 10, 2010 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 Link to comment Share on other sites More sharing options...
tomcad95 Posted March 11, 2010 Author Report Share Posted March 11, 2010 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 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 Link to comment Share on other sites More sharing options...
CarlaValentine Posted March 11, 2010 Report Share Posted March 11, 2010 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. Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 11, 2010 Report Share Posted March 11, 2010 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 Link to comment Share on other sites More sharing options...
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