water pump 280z

[MH77280Z]

On 5/9/2024 at 5:28 AM, Namerow said:

Recommend that you use an impact driver* to free up the bolts.  To gain the required access, you'll need to drain the cooling system and remove the radiator.

(* Do not use an electric or pneumatic impact driver.  Use the good-old-fashioned, hammer-blow type.  It may take a bit more time and effort, but it prevents overpowering the bolts.  A high-torque power impact driver will snap those long bolts just as surely as you leaning on them too hard with a wrench.)  

Here's a picture of what you'll be working with.  The numbers refer to the wrench size...

x

The pump is secured by a total of five bolts.  Three of these also help to secure the Timing Cover to the front of the engine block. 

• The small-head bolts at 1 o’clock and 4 o’clock are short and  thread into the cover – M6 (10mm wrench)
• The large-head bolts at 7 o’clock and 9 o’clock are long and fat and thread into the block – M8 (12mm wrench)
• The small-head bolt at 11 o’clock is long and skinny and also threads into the block – M6 (10mm wrench)

The long, skinny bolt @ 11 o'clock is usually the one that snaps off when removing or tightening.  The rad, pulley, pump, and the timing cover will all have to come off to get the access needed to extract the remains.  Removing and reinstalling the timing cover will open up the potential for oil leaks where it meets the oil pan. 

In other words, there's going to be a high price to pay if you snap off one of these water pump bolts.  It doesn't need to happen... but it very well may if you try to rush the job and use too much tool and not enough caution.

Dumb question as I have not looked into the engine bay around the water pump. I received the AISIN pump and the gasket has more than 5 holes than what you are showing for these 5 bolts. What are the other holes for?

 

[Dave WM]

alignment dowels

[Namerow]

7 minutes ago, Dave WM said:

alignment dowels

Yes.  If you look more closely at my marked-up photo of the timing cover, you'll see two little pins -- one at ~ 2 o'clock and the other at ~ 8 o'clock.  I think that their job is to hold the water pump firmly in (rotational) position relative to the timing cover, so that any pulses created by the fan belt drive don't, over time, destroy the integrity of the seal at the water pump gasket interface.

While we're on the topic of the gasket, we should also discuss the use (or not) of a sealant in conjunction with the gasket itself.  This topic has been discussed often on this site over the years.  One respected member with a long career of racing his Z said that he had used Permatex High-Tack 'red' spray-on sealant for more than two decades and had never had problems with leaks. Another respected member said that he put the water pump and thermostat housing gaskets on dry and had never had a leak problem.  A third respected member said that he used Permatex 'Aviation Gasket Sealer', but admitted that he considered the use (or non-use) of gasket sealant to be a matter of personal taste.  In his words: "It's like antiseize.  The factory never used it, but I do."

[zKars]

Comments pertain to simple water tight areas

Flat clean even surfaces, new gaskets, proper bolt torque = no leaks. What the heck you think rtv in there is gonna do? LEAVE when you tighten it down is what it’s going to do. WHY?!?!?!?!

Old cars, less than even flat surfaces (gotta stop using a razor blade to scrap with, sheesh…), LITTLE RTV ain’t gonna hurt. Any excess gets squeezed out. Gasket won’t stay in place while you put the (fill in the blank), add some adhesive glue stuff to stick it there. Ain’t no downside to a LITTLE. Gobs of squeeze out on the inside is your only danger. L I T T L E people!   (Apolgies to the vertically challenged.)

 

[MH77280Z]

1 hour ago, Namerow said:

Yes.  If you look more closely at my marked-up photo of the timing cover, you'll see two little pins -- one at ~ 2 o'clock and the other at ~ 8 o'clock.  I think that their job is to hold the water pump firmly in (rotational) position relative to the timing cover, so that any pulses created by the fan belt drive don't, over time, destroy the integrity of the seal at the water pump gasket interface.

While we're on the topic of the gasket, we should also discuss the use (or not) of a sealant in conjunction with the gasket itself.  This topic has been discussed often on this site over the years.  One respected member with a long career of racing his Z said that he had used Permatex High-Tack 'red' spray-on sealant for more than two decades and had never had problems with leaks. Another respected member said that he put the water pump and thermostat housing gaskets on dry and had never had a leak problem.  A third respected member said that he used Permatex 'Aviation Gasket Sealer', but admitted that he considered the use (or non-use) of gasket sealant to be a matter of personal taste.  In his words: "It's like antiseize.  The factory never used it, but I do."

Yeah the package has 2 small studs and 4 longer ones. Smaller probably like you explained and longer ones on the front to hold the fan thermo clutch. I got it. I ordered the 5 stainless bolts from ZCD today as well.

[Dave WM]

it may have something to do with the quality of the gasket material re the use of sealants. That and how well you prep the surfaces, that is get all the remnants off and NOT gouge anything in the process. I have used the aviation sealant, just a very fine amount, with no leaks. I do not like RTV for anything except a tiny bit on the seams where the FSM specifies. One thing that really sticks out in my memory is the front cover around the water passages. The connection from the front cover where the pump resides and the block carries water, a leak there is internal into the oil pan. IIRC the FSM calls for a sealant there but maybe wrong on that one. Def an area you want to be sure on.

There looks to be a weep hole and water channel around this same area machined into the inside of the front cover. I presume the design is to allow for any seepage from the junction of the cover to the block to have a way out before getting into the oil pan. This channel around the water passage has a small exit hole just visible on the front cover under the water inlet. A small rectangle hole. I know from experience that incorrect application of RTV (too much) will clog that passage, defeating the purpose. An O ring is more fool proof but that is not how its designed.