Water Pump Replacement Question

[Iconic Ride]

Having dragged my feet for about as long as I can stand it (waiting for a [rarest of the rare] competent Lotus V8 mechanic to surface in my neck of the woods), I am about to schedule the R&R of my cam (timing) belts. The local rebirth of the Lotus Dealership (in combination with the Aston Martin and Bentley marques) has produced a mechanic who has now "been there, done that" on at least 4 V8's to date, and seems to be a fairly bright fellow who knows his stuff. When I was doing my initial inquiries into the matter, and while trying to get a feel for the dealership's service department, I had a lengthy discussion with the service manager about the process. He has since been replaced by a new service manager (have no idea why, as he, too, seemed to be quite knowledgeable about arcane V8 quirks), but I distinctly remember that he was pushing for the replacement of the water pump at the same time, as access to it was readily available when the cam belt covers and accessory drive belt were removed for the cam belt changeouts. At this point in the procedure, the pump appears to be a straightforward "unbolt off, bolt on" replacement. The pump itself was quoted at $450, so, while not cheap, it's not totally outrageous either (for a Lotus part), particularly if no additional (or minimal) extra labor charge is involved. Still, I would like to hear input/opinions as to whether or not this is a "best practice, do it while you can" thing to do, or just another way for the service department to increase income. My gut feeling is that they are not trying to pad the bill, but it's the first I'd heard of such a recommendation. The car is a 1999 MY, with just over 20,000 miles on the clock. I have no idea if, or when the original water pump has been/was replaced. The cam belts have been replaced previously by the PO (Lotus warranty policy program) at around 13,000 miles, and retensioned since.

They (the service department) indicated that, of the 4 V8's they had done, 2 "had bad water pumps." They replaced the other two "as a matter of routine."

So........Yay, or Nay?

TIA, cheers,

John

[lotus4s]

I vote "yay". With the car being 11 yrs old, you might as well do it while you're there but I tend to be pessimistic about those kind of things. With my luck it would go out 100 miles after the belts were done.

Are there rebuild kits available for the V8 pumps?

[freshcut]

I too would vote "yea" on it. I'm actually in a similar boat right now. I had belts replaced about this time last year and didn't even think about changing the WP. Even the dealership didn't make any mention to consider (surprising considering the comments about the tech I went to). Unfortunately now, a year later, I'm forced to do it myself as I've developed water pump noise. It might not be bad now, but give it a year, in my case anyway, and you'll be tearing into the front of the engine to replace it.

[Günter]

John -I would vote ' no'

-if the failure on the two others could be sourced to the US-ways of 'no additional aditives' [Glycohl base mixture, with rust inhibitors and something like that] ...so as those cars have been used on pure water on mostly warm climates. Maybe that was the reason for a failure ?!

There is a clear passage way, where you can see if water drips out ... normally the sealing is meant to 'have a need for contact with water/water-mixtures' ...so if the pump is running dry permanently it can get worse. But if the car was used well, and there is no sign of unwanted 'free-play' on the pulley, and no 'squeeking' sound or something -why would you change a running system ... Just for the acces to the belt covers ? You can undo those covers even with the engine in ..if it comes to a need of work there.

Sidenote: on my engine work I just inspected the impellors for signs of serious damages, and tested the pump for play an signs of a leak. <So it means the pump is still the one that was on the engine as I've got the car... .

[lotus4s]

John,

Check with JAE, I believe they have rebuilt pumps for $175 with exchange, or around $350 for new pump.

[freshcut]

Hrm, didn't know about the rebuilt units from JAE (should have called to check with them). Instead I sourced a subassembly and will begin the replacement process likely tomorrow. Will post a separate topic depicting ease, or lack thereof. Apparently it requires the removal of the pulley hub and impeller as the new unit is just the pump body and shaft.

[Günter]

hope you can handle it well , as for the 'shrinking' (right word ??) on the shaft. The aluminium impellor looks like it is just fitted 'hot' and was cooling down together with the shaft. So it must be a tight fit? But if you pull the aluminium impellor from the shaft in 'cold' -think you will shear of some of the impellor surface where it is in contact with the pump-shaft. So it could be damaged , or will need some DIY handling/marking with a chissel or something -to create an 'not so smooth' surface for the now wider impellor hole in the middle ?!

other alternative: drill a small [M3/M4 maximum size] hole into the side of the impellor wheel. Cut a treat into it and fit the impellor-wheel with a screw ?!

[lotus4s]

If you need to put your old impellor and pulley on a new assembly, be sure to take careful measurements before you remove them in order to get them placed correctly. Impellor clearance is crucial to coolant flow and pulley placement for belt alignment.

You probably know this but you'll need a hydraulic press to fit them and heating the impellor/pulley in an oven to approx. 200 degrees before fitting should make it easier and help prevent galling.

Edited May 8, 2010 by lotus4s