The Rover-Landers of BC

A long-time lurker here with a question on thermostats. I replaced mine today, only to find that I actually had a gauge problem, not a thermostat problem, so it looks like I have a spare thermostat on my hands, but I'm not sure of its origin. It came out of a 2.25L petrol engine in a Series III 109.

Here's a photo of the old thermostat and the new one side by side:

http://www.flickr.com/photos/morganandt ... /lightbox/

The new one is the one on the right, which is a genuine part (at least, it came in a genuine box). The one on the left is the one I removed. I also pulled a couple of metal rings, which were breaking down pretty badly, out of the top of the housing.

Anyone have any idea about the differences between these two parts? Is the old one some sort of aftermarket product?

Cheers,
Morgan

The old thermostat is an incorrect aftermarket part....assuming that your thermostat bypass housing is a 3 piece unit. It should be if it's the original 2.25 from series III. The genuine thermostat has a "skirt" around the base that lowers when the thermo opens and it closes off the bypass so the coolant goes to the rad instead of back through the bypass (easiest route).

Hi Morgan, welcome to the forum,

The Wise Owl parts list shows that the one on the left could be a Series 11 and the one on the right is a Series 11a or Series 111

http://www.wiseowlparts.com/catelogue2/10.html

So as Tolon says, it looks like you need the one on the right with the skirt for a Series 111.
Cheers, Andy