1989 928 GT Recently Acquired: Advice Required!

First the good news: I have recently acquired a 1989 928 GT with 44,000Km on the odometer, owned for the last 40,000Km by the equivalent of a little old lady who just drove it to the church once a week, and kept it in a heated garage every winter. It is in cosmetically mint condition (I don't think the passenger seat has ever been sat on).
Now the bad news: I think I am going to have to treat it as a "Barn Find", or maybe worse, as I can find no significant evidence that after the first 4,000Km that the car was subject to any systematic maintenance, other than perhaps an engine oil change at the local garage, and the possibility of a new water pump (but no invoices) over the past 20 or so years.
So.....what to do to get it safely back on the road??
- New timing belt, and probably the others too?
- New fuel lines; quite apart from the age factor, (the advent of ethanol-added fuels probably makes this mandatory)?
- Change all fluids?
- Check age of tires?
- Check A/C?
- Other?

The "Information System" on the car appears to be working correctly, to the point that "Toothed Belt Service" warning appeared on the Instrument cluster on the dashboard just before I completed the (thankfully brief) drive home.

Any comments or advice would be gratefully received.

Dave

Hi Dave,

Congratulations on your new acquisition. The 928 GT is a phenomenal car. I would strongly encourage you to start by educating yourself about your new car. If you have the tools and willingness, your ownership experience will be best served if you do all of your own maintenance. There are many great tech resources available via the internet. In fact, there is a culmination of DIY write-ups on this very site; The Technical Library. There is a write-up with step-by-step instructions for that all important timing belt service.

I can tell you how I would treat this car if it were going home with me. I would start with replacing the timing belt and water pump. On the tensioner, there are options. The most practical choices are to rebuild the original or replace with the Porkensioner - an aftermarket alternative. Many people choose the latter as they prefer it in functionality. Be aware that if you choose the Porkensioner that your timing belt tension warning light will no longer work. Also, I would recommend purchasing the Kempf tension tool and flywheel lock as these are required tools for the timing belt job. They are inexpensive.

Beyond that I would suggest to drain out all of the coolant. Not all of your coolant will be discharged during the timing belt job. You will need to drain the coolant from the block as well. There are two drains - one for each bank of cylinders. Replace the coolant with a phosphate and silicate-free free formula.

Next, I would change the oil. Use any suitable oil of your choice. Unless you plan on driving in extreme winter temperatures, I would advise running a 15W-50 or 20W-50 oil all year. As important as using the correct viscosity, you will need an oil with sufficient ZDDP (Zinc dithiophosphate) content. This is to preserve the flat-tappet lifters in our engines. The consensus recommendation is any oil with at least 1200ppm ZDDP.

Aside from that, my recommendation would be to drive it once this maintenance is caught up. Unless there is dry-rot on the tires, driving may tell you a lot about their condition where the eyes can't judge for. Drive it and and assess future maintenance needs.

Welcome to the 928 Owners Club!

Regards,
Austin Embry
928 Owners Club - Trustee

Hi Austin,
Thank you! Any hesitation I had about the need to replace the timing belt...and the water pump...was overcome by the appearance of the "toothed belt service" message, and the high water gauge temperature indication, as I drove the car home ; luckily a short drive!
Much as I would like to undertake the necessary repairs myself, my lack of expertise in dealing with a car of this complexity... my last significant rebuild was a Triumph TR3A...makes me reluctant to risk it. However, your advice regarding engine oil selection, and coolant is much appreciated, tasks which I believe I will be able to handle:-)
Watch this space!!
Dave

Congrats. Along with the advice above, Tires and Brakes, And I mean Brake Fluid, Pads and Sensors. The last part only to get into the calipers to make sure that they don't stick. Car is no good to you if you can't stop.

After Brakes and tires, Transmission and torque tube. Make sure everything is good there and make sure you get bolts adjusted and checked.
IF NOTHING ELSE, BRAKES!!!!!!!

Good luck!