After loading up my car with a lot of "stuff" to take up to Cape Cod I started the car and was ready to set off when I heard a loud
scraping/rasping noise from the front of the engine.

At idle it sound like metal on metal and uneven as if something is out of kilter and rasps louder as it turns round on one side if that make sense.

Spraying WD40 on the pulleys made no difference. At this point I am wondering if it could be the water pump which I replaced about 10k miles ago.

All pulleys are new as well.

Tomorrow will start looking for the cause with a stethoscope to begin with.

At least it did not start a couple hundred miles into the trip!

 

Ok so suspecting the water pump I loosened the appropriate belt and twisted the water pump pulley. No scraping noise however it made a whining noise
when twisted in one direction.
I made sure belt was away from moving components and started the engine. No scraping noise at all.

So new water pump on order.

 

Getting ready to install new water pump but I find TWO different torque settings for the bolts.

One setting states 25 Nm the other states 8 Nm +90n degrees.

Any idea which is the correct setting?

 

8Nm + 90 degrees.

Dont fret if you only get + 45 to 60 degrees. You'll be fine. As long as you get the 8Nm right your good.

25Nm will snap the bolt or damage the water pump casing... or both! (I think that's the value for the V6 water pumps)

 

Ok as abonano stated I used the 8 Nm torque value and only turned an additional 35 -40 degrees and that felt plenty tight to me. I really felt that I would break something if I were to go beyond that.

All is back together and coolant topped up as per usual procedure.

What is more noise is gone!!!!! Always a little trepidation in these situations when starting the car the first time.

I did the least amount of dismantling as possible. I did have to take off the radiator under shield to get at the radiator drain plug which is always a pita.

The old pump seemed perfectly ok however it has less "drag" when turning it by hand, off the car, compared to the new pump.

 

It's unclear to me.
I understand 90 degrees should be the limit but what if you start from 8Nm and further turn without measuring the torque (with the risk of snapping a bolt if you go beyond 25 Nm after only 30 degrees)?
Shouldn't the limit be a torque value to better preserve the bolts, e.g. 20Nm?

Good!
Do you have an explanation for the "noise is gone": bad bearing of the old (10kmiles only) pump?

 

Serge I can only surmise that when the old water pump pulley was under pressure from the belt it caused the bearing in the pump to make the scraping
noise which was quite pronounced.

When I ran the engine with that belt disconnected there was no noise which is why I suspected the water pump.

The new water pump is identical and felt slightly "stiffer" to turn by hand compared to the old one.

The old one I put on less than 10k miles ago not because the original was broken but because I was "in" there renewing hoses and upgrading the SC pump.

I go on a 450 mile trip up to MA this evening .

I am always very careful when torquing down steel bolts into Aluminum and have three different torque wrenches low thru high capability. The low and the high are "digital".

When I was putting the pulley back on I simply tightened the bolts equally hard as they were steel into steel.

 

The 25Nm torque setting was for a different engine and as far as I can tell there are three different settings in my workshop manual which covers different engines. So
doing a search in the pdf document on water pump I had to make certain which engine and even VIN range I was actually looking at.

I would note also that the "weep hole" on the water pump faces up which I find "interesting" as dirt can get in there more easily.

 

From my understanding the 8Nm + 90 degrees will yield about 12Nm.

As I mentioned I didnt get past 45 to 60 degrees on the bolts and I have no issues.

 

B####y H#ll!!!!

I cannot believe this. The Jag has been sitting for about 3 weeks in the garage and I decided to take it for a spin.

BUT on starting it I heard a familiar scraping noise from the front of the engine. I thought what the heck or words to that effect.

Had to get to an appointment so took the Rover. Just got back and released the tension on the accessory belt and no scraping noise.

This water pump has less than 1,000 miles on it. Cost was $29.

Ordered another one at $89 with the rationale that more expensive means better quality????

I looked at the belt and it shows no wear or signs that it is off kilter at all.

Is this just bad luck or what.

 

Wow, I used Jaguar OEM for mine.

 

Maybe I should have done as well.

 

AC Delco Professional # 252-800

Was not very much, but do not remember just how much.

Good name at a fair price, that works as expected.

Nothing wrong with the old stock one, but changed it out with the thermostat, & housing, while there, at a hundred thousand + miles, felt it was time.

 

Originally thats what I did change it out while I was in there doing other things around 100K There was nothing wrong with my water pump at the time.

I really want to figure out what actually is scraping on this water pump when I get it out. Just like the last replacement pump it feels perfectly fine when I turn it by hand.

So when the pulley is under sideways pressure something makes a fairly loud metal on metal scraping sound. If I disassemble it I think I should see where metal has been scraped? I m thinking the impeller on the sidewall?

 

The cheap Chinese parts can be great, and will consider them.

If their not too hard to replace again, if they do not work, have free shipping, as well as replacement, or refund.

Coils come to mind, as well as coolant overflow tanks.

E bay, & Pay Pal, do keep them as honest as can be expected.

With great service, with any issue (very few) i have encountered so far.

For anything more difficult,or maybe causing overheating issues, i use better parts.

 

Many parts sold in the USA on Ebay, or anywhere for that matter are made in China.

If you buy direct from China on Ebay, and the item is relatively heavy the return shipping can be mind boggling. Many Chinese sellers do not pay return shipping for this reason.

 

Replacing the water pump is not that difficult. The real pain and annoyance for me is having to take the radiator under shield off just to drain the radiator.

It does not feel "productive" to me whereas tackling the water pump does.

 

Thats the reason i try to use name brand parts here, more cash, with better quality control, one hopes.

 

+1 on that.

I was pennywise and pound foolish on my last water pump.

 

Concerning the pump tightening, the service documentation for the 4.2L (both variants) specifies 9 pounds (108 inch pounds) of torque for the retaining bolts. The pulley bolts are supposed to be single use (because they are stretch bolts) and should be tightened to 88 inch pounds + 1/8 turn.