The thermostatic capsule is a temperature sensitive actuator that pushes/pulls on the cold start/base timing lever. It is coolant fed, and designed to hold the idle up until warm, as well as alter timing to assist in warming up. I replaced mine because I had some issues when I first picked mine up.
A factory XJ/MJ diesel doesn't have an in tank pump. The only pump is a vane style lift pump built into the injection pump, and I believe there may be one in the fuel filter housing on the firewall. I just rechecked my parts book and my Renault injection book to confirm.
I would be real worried about the rebuild. There are different size head gaskets based on what was required to meet the deck height and combustion chamber needs when it was assembled. Many people don't know this, and they slap in whatever gasket they get their hands on. It could lead to problems. I would especially be worried about them saying they had to redo it because of "Debris" on the surface/gasket. If you miss a crucial step like maintaining a clean area or proper prep of your job, you probably shouldn't be in there.
The engine is an interference engine, and if timing isn't just so, pistons can kiss the valves also... Leading to a bigger mess. They should have also replaced the timing belt along with all that work.
Questions I would ask of them:
Why was it rebuilt?
Where was it done?
Competent shop?
Warranty?
What was replaced?
The Renault is tricky. If it wasn't taken care of, it's going to be nothing but problems or a money pit. Aluminum head, block, easily warped... All it takes is one person under there that doesn't know what they are doing to mess up the works.
If it's already not running, I wouldn't treat it as anything but. Unless they realize that they are selling a non running vehicle that is uber hard to find parts for and price it as such, I would move on. Keep in mind that the only things to get the 2.1L Renault in the states were the few years of XJ/MJ and the Winnebago Lesharo motorhome which stopped production at about the same time. Parts, when you can find them, are expensive.
Rob
