Congrats on a great car!
The ’90 is nice year, you have the second generation cockpit and the 1st generation exterior (which I’ve always liked).
If it hasn’t been performed already, here’s what I would service on a C4 if I had just acquired it. I’m the kind of guy that would do these things for my own piece of mind. May be overkill, but gives you some things to consider.
1. Drain and flush the radiator
2. Check air intake at front and back of radiator for debris (leaves, cigarette butts, etc)
3. Install new air filter (and or) clean if it’s a K&N and lightly re-oil
4. Drain power steering fluid, replace with new
5. Check all underhood hoses integrity
6. Clean injectors
7. Inspect tires on all surfaces (inside sidewalls as well) for any trouble.
8. Lube all ball joints (upper and lower) Can’t remember if the ’90 C4 has the fittings at the rear. They’re easily accessible up front.
9. New serpentine belt is an easy thing to service. Save your old one and keep it in your rear cover storage compartment if you use your ’90 on a long trip. Not sure how easy it would be to locate a ’90 serp belt in an out of the way place, especially the doulble-sided ribbed ones
10. You could tackle the spark plugs and wires if you are so inclined. But if everything is running fine, that’s one I’d probably wait on. I HATE CHANGING PLUGS!
11. Engine/oil and filter change would be a given
12. Replace Positive Crankcase Venation Valve (PCV valve)
13. New transmission fluid. Not sure about changing the autos tranny filter (’90 have the auto tranny filter?)
14. Lube all contact points that require it. Underhood, doors, etc.
15. Drain differential fluid and replace with new, may need differential additive that will help keep noise down
16. Lube all weather stripping: under hood wheel well strips, doors, targa, rear window, You can purchase this at your GM service department.
B17Crew
otfl
