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I'm currently changing my water pump on my 07 4.2L NA. I got the water pump out but my understanding is that there is 2 pieces. If true I'm unable to get the second plate part off and i dont want to pry on it in case I dont have all the bolts off. Attached is the picture of it currently. Is there a bolt I havent taken off yet or should I pry on it a little or does the plate stay on it?
If that's the AC Delco one-piece I used, compare it to what's still on the car. There are 2 bolts that hold on the back half of the two piece. Replacing with a one piece AC Delco, you can toss those two bolts in the spares bin. The five bolts in the front hold on the entire one-piece version. The one piece has a metal gasket and an oring.
The bottom pic you posted is only the front half of the two-piece. The two piece PoS uses paper gaskets.
Make sure you thoroughly clean all the crap off the area in contact with the rubber oring and the metal gaskets.
Yeah I bought the one piece waterpump from the thread. I just wasn't sure what else I should take off to get that plate off. I guess maybe I'll pry on it and see if it come off
Judging by the visible threads on right and left, it looks like that's the back half of the old pump. It should break loose with gentle pressure. Likely a pile of Permatex gluing the back half to the engine. Make sure you thoroughly clean the mating surfaces, and like it said, gloss up the o-ring and the gasket rubber with silicone grease so everything settles in smoothly as you torque the 5 bolts.
Last edited by panthera999; Jan 23, 2023 at 03:36 PM.
I tried prying on it even wacked the side of the housing with a prybar and hammer but it didnt budge. I'm going to order a new thermostat housing and take the old one off so maybe I can pry or hit it from the other side that the thermostat housing is covering.
I have to ask the group because I've gotten confused by the pic.
Is DVD's pic the rear half of the two piece pump, stuck to the engine mount with permatex etc, or is that the actual mounting point for the one piece pump, again covered by layers of crud?
Thnaks.
Last edited by panthera999; Jan 24, 2023 at 08:43 PM.
I've never changed the water pump on our XK but surely all you need to do is buy the new pump and then compare that to the aperture in the block and it will be obvious whether it will fit or not?
He has the new one. It's a one piece Delco. This looks to me like the back half of the old two piece Jag pump instead of the engine pump mounting point, but I'm not sure and don't want to give bad advice. His pic of the removed pump looks like the front half only. If the engine picture is the back half, it needs to be removed. Probably held in place by a bucket of Permatex and another paper gasket. If it's the actual pump mounting point, it absolutely shouldn't be removed, of course. The screw hole threads on far left and right look like the ones for the 10mm bolts that hold the two piece pump together, so indicate what's visible is the back half.
Any opinions: back half of the old pump or mounting point for the new? I should know, but not confident.
He has the new one. It's a one piece Delco. This looks to me like the back half of the old two piece Jag pump instead of the engine pump mounting point, but I'm not sure and don't want to give bad advice. His pic of the removed pump looks like the front half only. If the engine picture is the back half, it needs to be removed. Probably held in place by a bucket of Permatex and another paper gasket. If it's the actual pump mounting point, it absolutely shouldn't be removed, of course. The screw hole threads on far left and right look like the ones for the 10mm bolts that hold the two piece pump together, so indicate what's visible is the back half.
Any opinions: back half of the old pump or mounting point for the new? I should know, but not confident.
If he has the new pump then just offer it up to the block. If it fits, it fits. If it doesn't, the something is blocking its fitment.
This seems so "mechanic 101" that I wonder if I'm missing something?
Richard
The back side of the new one-piece pump is machined, and expects the mate to also be machined. The metal gasket needs a smooth engine mating surface, which I recall was the case when I installed a one-piece pump. The mating surface in the picture looks like crap. Looks like it needed a paper gasket and a heavy coating of permatex. Thats why I think it's not the right plate.
So, dvd, hold the new pump up to the pictured surface. See if the new one mates exactly to what you see, including the Delco center fitting where you mount the oring.
Below, on the Delco, the blue line points to where the oring gasket fits. The red line points to the machined surfaces. Both the gasket and the mating surfaces need to match exactly. The metal gasket needs to fit smoothly against both surfaces -- see the second pic with the metal gasket. The metal gasket is stronger and a better fit, but expects a more precise surface than the paper ones do. The oring mates into the large center hole. The mating surface in DVD's pic is definitely not machined. This why I'm suspicious that the picture is of the back half of the old pump.
Last edited by panthera999; Jan 25, 2023 at 08:11 PM.
The old pump which has been removed has the impeller protruding beyond the flange of the pump whereas the new pump has a fully recessed impeller. They are clearly incompatible as things stand.
I would remount the old pump but only insert the two extreme left and right hand bolts which appear to be only threaded into the remains of the old pump. Check against the bolt length that they are not long enough to be threaded through into the block. You then have the protruding old pump which you can hit with a rubber hammer/use a pry bar to free off the complete assembly.
The old pump which has been removed has the impeller protruding beyond the flange of the pump whereas the new pump has a fully recessed impeller. They are clearly incompatible as things stand.
I would remount the old pump but only insert the two extreme left and right hand bolts which appear to be only threaded into the remains of the old pump. Check against the bolt length that they are not long enough to be threaded through into the block. You then have the protruding old pump which you can hit with a rubber hammer/use a pry bar to free off the complete assembly.
Richard
Good point. dvd, you might consider a torch to warm the back half of the pump, loosen the permatex and twist it off. Warm meaningfully, but not hot.
The pic of the two piece is pretty convincing that dvd's post #1 photo is of the back half of the pump fastened (glued with Permatex) to the engine mounting.
Last edited by panthera999; Jan 25, 2023 at 08:10 PM.
Sorry, I was busy yesterday at work. Correct, I was replacing the original two piece water pump with a one piece water pump. I have only got the front of the two piece water pump off. I just ordered a new thermostat housing so I can take off the original and have more access to the second piece of the water pump that is connected to the block. I compared the original water pump to the new one piece and the one piece is longer due to the second piece of the original water pump still on the car. This weekend I'll do my 3rd attempt at getting it off and use heat as suggested. Thanks everyone for helping out.
Water Pump help
