So, the last couple of days have seen her out with the A\C running and she pulled a light trailer yesterday around town...no problems. I'm happily surprised!! I would not have thought I would get the symptoms I had from a bad radiator alone...

Thanks guys!

 

My Disco 300TDi recently blew the head gasket big time! On pulling it down I noticed that the pistons are marked No.1 = 91.395; No.2 = 91.395; No.3 = 91.395 and No.4 = 91.411.
As I'm the second owner has the engine been re-bored and if so too much as the manual tells me the second oversize is 90.903!
Secondly my background is HVAC and I'm familiar with water pump impeller designs and the impeller in the new water pump is crap, I'm surprised it actually causes the water to circulate its so undersized. I checked this by covering it with plasticine and pushing it back into the housing, the gap between the impeller and the housing is over 3.16" or 4.5mm which is ridiculous, most pumps of this backward scroll design work on a clearance of around 0.5mm.
Can anyone assist and is there an after market pump impeller that is more efficient?

 

I have seen an article regarding the pumps failing becuase of the impeller mounting becoming loose and it fails to properly circulate the coolant.

There are several LR parts sellers with a variety of water pumps.

Maybe one of the more experienced members can share with us what the preferred water pump replacement is.

Isn't the S10 water pump supposed to fit and sells much cheaper?

 

This is called a hijack. For best results and assistance, start a new thread regarding your issue.

 

1999 Disco 300TDi (Mechanical - not electronic injection)
Forgive my ignorance but what is an S10 pump ? Series 10?
The other thing to keep in mind is my location - Western NSW in Australia - where ambient temperatures regularly run higher than 25 degrees Celsius (78 degrees Fahrenheit) for most of the year and are happily often in the mid 30's (80 F) so the coolant pump needs to do some serious circulating through the engine and radiator and the problems experienced in Anchorage Alaska may not necessarily correspond.
Currently I'm looking at various options but I'm sure that I'm not the first owner to have found the water pump less that satisfactory.

 

If you start a new thread you will have better luck.
A S-10 water pump is the water pump for a Chevrolet S-10 pick up truck.
If you put your location in your information section we can help you better as not all alternative parts are available everywhere.

 

thanks for that, my location is western NSW - Australia, I'll make enquiries with my local Holden (GM) dealer to see if I can obtain one.

 

Keep in mind that the S-10 water pump will NOT work with your TDI.
It might work with the V8 petrol.
Here in the US we do not have any of the Rover diesels so when it comes to parts we have no idea what we are talking about.

 

Thanks to all for all your assistance.
I've noticed that my original 1999 water pump has a pressed steel impellor, I have seen in other photographs that the replacement unit has revised design with a cast material so it would appear (hopefully ) to be an improvement. As to the the failing of the impellor coming loose on the shaft I'll make a point of drilling through the impellor and shaft and driving in a 1/8" split dowel before I fit it onto the engine.