The engine has the fairly solid block, but has problems with low oil flow to the valve gear. Listen for excess rattle around the valve gear when the engine is warm; it might mean some work is needed. If possible check the compression, it should be in the 175-185 range (cold).
This is the car’s main problem area. Listen for excess noise and feel for worn synchros. If you suspect problems here you can nearly guarantee that a new\recon box will be required.
The selector linkage also suffers from worn bushes which can make gear selection awkward. Suspension / driveshafts:
If the car is a Rotoflex car check the state of the rotoflex couplings (look for cracks in the rubber donuts), if these let go they tend to destroy the stub driveshafts – can be expensive!
Listen for excessive differential noise.
Listen for universal joint clunks. Expect that at least one U joint will be loose and want replacement. These are all fairly cheap and available, but a pain to install. Same for all the rubber bits in the suspension. Worn rear radius arm bushings, especially, will cause slightly weird handling over bumps.
Check the steering rack gaiters for tears and the rack mounting bushings for play. Overdrive:
If it works, great. If it doesn’t, you’re probably looking at a replacement.
Body work is more expensive than mechanical work. So you want as rust free a car as possible. If the car has already been restored check for filler and painted over rust with a magnet. Probably the most important thing is the bulkhead; the car relies on this for structural strength. Look to see if the transmission cover mates well; if it doesn’t, you’ll get heat and fumes into the passenger compartment.
Check the battery box area and the floor underneath it – your usual owner will replace the battery box only after it has caused severe rust on the floor under it.
Check the rear shock mountings to the body on Mk2’s and Early Mk3’s. Check for chrome trim: there should be trim strips along the front and rear wings on Mk1’s and 2’s and rear wing only on Mk3’s. Check for bonnet shake and the integrity of the rubber seals at the rear of the bonnet and the inner wheel Arches.
The chassis is a main spine with outriggers. Check the outriggers for rust; they provide most of the transverse strength of the car. Check the rear frame members for rust.
Unless the optional Servo is fitted; before writing off the brakes as weak, make sure the rears have been adjusted.
Look for leaks around the master cylinders.