When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Greetings folks, first post here on the 964 forum, but I've been lurking for a while and used to post with some frequency on the 944 side of things. Still have 2 944s, just don't post much anymore.
My father has a '90 C4 that he's had for a while. I think 15 years, maybe a tick more. As far as I am aware, it has not been driven for about 18 months. He and my mom took it our for either their anniversary or his birthday in May '17, came home, put it back in the garage, covered it, and plugged the trickle charger in as usual, and it has not moved since. I have no (reasonable) explanation for this - they're both retired and still in good health, particularly given they're both 80+ now, and he has no issue driving a manual (still drives the 944S stick we own together). My mom is not a huge fan of the car, but no one is suggesting this become the grocery getter! He really enjoys driving it, so the fact that he doesn't is totally baffling to me. I haven't had a chance to exercise it over the last few years mostly due to juggling a day job plus two of my own businesses that I started plus maintaining my own fleet of vintage machines (read: a '93 MB 400E, '85 190E manual, and '01 Dodge 2500 diesel, whose mileage now combines for something around 620k mi) plus, err, life.
At one point a few years ago we talked about him selling it and getting something maybe a little more modern, that my mom might like better, but he didn't seem in love with that idea either. Fortunately that never happened either, because at least right now if he sells it I'll likely never have another chance to buy and drive an air-cooled 911 at a price I can stomach.
Anyway, I'm well aware there is massive a pile of deferred maintenance that should be done, and my plan is to very gradually start working through that list myself while finally starting to give it some exercise with both myself and my dad driving it periodically. My question for the immediate future is, what should I do before trying to start it? I've searched and seen a lot of discussion and a lot of wildly varying answers, from just start it and give it an Italian tuneup, to doing significant amounts of work first.
My current thought process is (before starting) draining the oil and changing the filter, at least partially draining the fuel tank (no idea how much is in there), putting in some fresh gas along with some Stabil / Techron / preferred snake oil, pulling a plug in each cylinder and putting a squirt of Marvel Mystery Oil in, and cranking it with the fuel pump relay pulled. Assuming all that goes okay, then I'd give starting it a try.
So, what does the hive suggest? I know the oil change is supposed to be done on a warm engine, but that becomes a chicken-or-egg conundrum here. Is there a delta to the oil change proc if your forced to do it on a cold engine?
Looking forward to getting another 964 back on the road with some help from the folks here. For those wondering, it's a '90 C4 in Baltic Blue / Cashmere. 2nd owner. AND NOT FOR SALE!
The Bosch Motronic in the 964 has no problem with E10 fuel that is 18 months old. I regularly leave my cars for 12-24 months at a time. First drive is always down to the local gas station to fill the tank... Depending on how it was stored there is a chance that you might have some water in the oil tank and thermostat housing. For piece of mind just change it and don't worry about it being cold. Just be ready for 8.5 of the 9 liters that are going to flow out of the crankcase drain. The only real issue with these engines sitting unused for long periods of time is corrosion on the camshafts.
Good advice from Jason Andreas. The gas should be fine, but I would strongly suggest taking a long drive to burn off the old gas and put in a fresh tank with the Marine Stabil to absorb any moisture in the tank. Good to make a habit of this at every fill up.
The oil should also be fine for a spirited drive, and the you can drain and replace the oil as well. No need to pull plugs...
Do remove the DME relay and crank the engine for a few seconds to build up the oil pressure. Check the tires. If more than five years old, replace them. But I would focus on the oil and the gas after a long spirited drive.
My car spent years under similar conditions: garaged but completely dormant. I pulled the gas tank, emptied and cleaned it, along with the inside of the level sender which was both sticky and clogged at the bottom causing false gauge readings. Swapped in a new battery, reinstalled tank with new fuel and filter, primed in the new gas briefly, and it fired up but with MASSIVE amounts of oil burnoff as you can imagine. it wouldn’t hold an idle and I had to keep it alive for a few minutes, after which I took it out for a long Italian tune up. Only after all that would it idle. Do what you feel is right under the circumstances.
Nothing yet - want to make sure I can dedicate a full day to getting things back on track, so between schedules and other stuff, it looks like I won't be able to give it a go until the 2nd weekend in Nov. I am chomping at the bit to get going though!
Update! Finally the weather and my schedule coincided and I got out to my folks place yesterday. I think I spent the first hour just cleaning out the garage and "unearthing" the car. That makes it sound worse than it really was, but you get the gist. Fortunately the car has been covered, and all the stuff around it is fairly innocuous like shipping boxes full of packing peanuts, plastic bags full of more bags, etc. The cover was hiding the fact that the tires were close to completely flat, so I had to jack the car up a bit to get started. Given this is a 1 car garage w/ stuff against the walls, this took a bit of careful jack maneuvering. Once up on a few 2x10 scraps, I pulled the underbody tray off and then, finally, I could get to work.
Fortunately there's been a trickle charger on it for, well, forever, so when I pulled the cover off by the drivers door I saw a reassuring red flash on the door lock post, and when I unlocked it there was a satisfyingly solid kerchunk of the other door unlocking. Then I had to remember how to pop the rear engine cover. Hmm, that one? Nope, that's the frunk. Hmm... Oh, this one on the door jam I think? Success! Open up the engine cover. Of course it won't stay up. Scrounge around for some scrap wood and a rag to prop it up. Ok, finally.
Wow - I did not remember the engine being this clean. I mean, I wouldn't quite call it time-warp condition, but it is super clean. All the brackets and zinc-chromated bits look brand new. No dust or grit on any of the upper engine stuff. Same could be said about the interior, the seats, etc.
Anyway, got about 7ish quarts out of the two drain plugs, put on new crush washers, and buttoned those up. I had opened the oil fill cap and loosened the filter a little before I drained the engine, put some paper towels under the filter, and slipped a plastic bag around the filter before I removed it, but those efforts were clearly inadequate! Removed the filter and created a giant mess that I spent 45 min cleaning up I will have to consider the vent hole approach to removing the filter next time. Added 7 quarts of Mobil 15W-50 and considered that part done for the moment.
Then went around to the side to remember how to get the gas cap cover open. Hmm - what's this random unmarked **** on the dash above the ignition? Yup, that's it! Put about 2.5 gal of fresh gas with Stabil Marine in it. Opened up the frunk, pulled back the carpet to get to the relay panel, jumpered the DME relay (which I was intimately familiar with since it failed on my 944S literally last week), and ran the fuel pump (yay, it works!) a couple of times for maybe 20s each to get some gas circulating through everything. Didn't see any leaks. Closed everything back up and put the cover back on.
I didn't bring my compressor up, and by this time it was getting closer to rush hour, so I wasn't going to drive it anyway. Plan is to head back tomorrow morning and air up the tires, pull the DME relay again and crank it a few times, and then try to fire it up and drive it. Hopefully.
I noticed that the plastic engine air shroud has a crack and a hole in it, so that will need to be replaced. Should I bother taping over the crack/hole in the meantime? I figure it will prevent the motor from cooling as well as it should, but assuming it starts I'm not going to drive it super hard, and it's also only like 40* out.
It definitely needs tires. Plenty of tread, but they're old. My old man spared no expense on the rears, though. I know what you're thinking. Michelin Pilot Sport Cups? Pirelli P-Zero? Something of that sort? Ha! As if you'd want put something as pedestrian as a Michelin tire on a Porsha. No, he went for the "ne plus ultra" in tires.
New update - success! Went up Sat morning w/ a friend and fellow car guy. Got the tires aired up, checked for any obvious new leaks since changing the oil and running the fuel pump, brought it down off the wood blocks, pulled the DME relay, put the key in and cranked it. Sounded like it had been run regularly for years. Checked again for leaks, didn't find any, put the relay back in, and cranked her over. Basically started right up. Really didn't cough or sputter or do much of anything unusual. I kept it at about 1000rpm initially just because I wasn't 100% certain it would hold an idle initially (it was also coldish out - 35-40F) but after a minute or so I gently let off the gas and it settled down to a steady idle. Let it warm some - which was a challenge due to the outside temps - added a little more oil, and then we took it out for a something like 60-90 min. Stopped off to get fresh gas early on, then took it on the highway to let it stretch a bit, then off to a country road for a bit more. Checked the oil level, added a bit more, and switched drivers.
The tires are garbage. I mean, they were to begin with, but they were more octagonal than round when we started. By the end they were a lot better, but still not wonderful. And yikes are they old. It never really reached full operating temp - needle just got to the lower middle mark, barely. Between its first run in a while, the tires and the outdoor temp, neither of us pushed it hard for any length of time, so I'm not shocked it never got fully hot. After the midway oil addition, the oil level gauge had started to bump up at idle. Once back in the driveway, I shut it down, let it sit for a few minutes to heat soak, and then restarted it and ended up adding another little bit of oil, but I think it's sitting at about the right level now.
All in all, fantastic to get it back on the road, and for it to perform so well. It has a few issues - we both noticed a hesitation around 3500 rpm - but just getting it running again was the goal, so mission accomplished!
Buddy suggested getting essentially a PPI by a knowledgeable 964 guy just to work out a path forward, which sounds like a great idea. I do nearly all work myself, but usually on much less valuable vehicles, so there may be some 911-specific stuff I might want to farm out here. If anyone has any suggestions for a PPI in the DC/MD/NoVA area, let me know, I haven't started researching that yet.
10-15-2018, 02:05 PM
Advice needed - C4 sitting for ~18 months
I will have to consider the vent hole approach to removing the filter next time. Added 7 quarts of Mobil 15W-50 and considered that part done for the moment. 
