JAB12

Hello RL, I am looking for sound advice on the fair costs for an engine rebuild on a 1989 C4. On my last drive (aprox. 40 miles round trip, 37.5k miles total to date. Pseudo Garage Queen) I noticed the car was smoking a little on idle neutral, and after parked and engine off, it was lightly smoking from the rear air grille. Both being a first. Next day I take it to my Porsche car shop and the diagnosis comes back as full engine rebuild needed at an exorbitant cost. As I am not that deep into the technical/mechanical aspects of these engines, I feel like I need a second opinion from other persons more versed than me and/or another shop(s) but wanted to grab as much advice as I can from fellow 964 owners here on Rennlist that have gone through this before in recent times. I am in South Florida Miami Beach area and there are only a few reputable shops around that work with air cooled Porsches properly. While I do like the shop that I take my cars to, in this case, I feel I need to have additional options. This has left me shaking my head as car drives and feels great, no smoking or oil leaks up to this past occasion.

Below is a list of what they suggested to be done:

Main Bearings
-Rod Bearing,Nuts,Bolts
-Inter Shaft Bearing -Piston Rings
-Timing Chain,Rails,Gaskets
-Valve Cover Gaskets
-Intake Valves
-Exhaust Valves
-Complete Engine Gasket Set
-Ignition Cap & Rotor
-Ignition Wires & Spark Plugs
-Belts Sublet Engine Rebuild
-Cylinder Head Machining, Resurfacing, & Repair

And since the engine will be dropped might as well do Cluth/Flywheel etc. for even more $$ damage:

Clutch Slave Cylinder
New Clutch Master Cylinder
New Pressure Plate Bolt
Part Flywheel Bolt
New Clutch Kit

I need some help on this one guys so any and all comments are appreciated. Thank you!

Tarek307

The car only has 37.5K miles?

JAB12

Yes, that is correct. It had not been driven for years prior to me purchasing it. That is why I do not understand fully what is going on. Any help/advice is much appreciated. Thank you.

Jacke2c

Our cars are of such an age that there are MANY places for oil to leak and/or seep that causes the same conditions. Most notably is the crankcase vent line oil pressure switch located on top of the engine. The large (approx 1.5") o-ring ages, gets brittle and then leaks which drips down through the cylinders and onto your manifolds creating the smoke. Valve cover gaskets are also notorius for the same condition. Fix al your known potential leaks first for under $1,00 (DIY) before you get an overhaul. DID they do a leakdown test? If so what were the numbers?, if they did not do this test run as fast as you can from them and find someone you can trust. There is a lot more to this, especially with an engine that is smoking at idle with only 37.5K miles.

JAB12

@Turbotwoshoes.
Nice car by the way the SC. The oil pressure switch might explain why there was light smoke emanating from the rear air grille. There was no leakdown test done.

John McM

Don't walk, run. Without a rationale as to why all of this work is required you are potentially being conned. I've rebuilt a motor; they are beautifully engineered. Sure there are places they leak oil, but they don't wear out in 37.5k.

Marine Blue

Personally I wouldn’t trust the mechanic unless he/she explained in detail what work was required and why.

My Targa recently had a reseal done on the engine to the tune of about $13k at 62k miles. It didn’t include a total rebuild because it wasn’t necessary but any items that are known to wear out early and or due to lack of use were replaced. My guess is that your car may be suffering from heavy oil leakage as you already eluded in your earlier post.

Out of curiosity, how much did the mechanic quote?

abarthguy

Is your mechanic putting his kids thru college ??

JAB12

@MarineBlue: upwards of your cost.
Thank you everyone that has chimed in, all advice and tips well taken. I am just going to pick up my car and have a second opinion at another shop and take it from there. I will keep updating this thread as I go along.

Appreciated.

Steve Weiner-Rennsport Systems

Hi Julio,

Given the car's age and ultra-low mileage, it likely needs to be resealed. Naturally, if it hasn't had the 30K service (this is a big $$$ one), thats overdue.

Unless the car received horrible maintenance, the only thing I can think that it may need is new valve guides (they all do), however everything else should be in almost perfect condition based on my experience.

A914MAN

It's possible that a low mileage car could suffer broken rings, but this would show up in a leakdown and compression test. If they didn't offer any more conclusive test data, I'd say it sounds sketchy to me. Pay them for their time and consult local PCA members as who is the most reputable independent near you. If you were in TN I'd say Pat Williams in Memphis or Wickie Lowrey in Nashville as they are both stand up, solid guys.

JAB12

@Steve,
Thank you for the tips. I am getting it further inspected at another reputable shop that most of my air cooled friends use. I personally don't think the car needs the engine rebuilt. Valve covers an oil vent switch etc. probably yes. Car came with verifiable records and since no leakdown/compression test was done prior to diagnosing full engine rebuild, I am not falling for that. I drove this car barely 400 miles in all of 2017, for car shows and cars and coffee. This is crazy.

Thank you all for reaching out with tips and other personal experiences. All is absorbed and I will act accordingly.

JAB12

I want to thank everyone that has replied to this post and reached out via PM. I now have a good idea of what my next steps are and will act on them next week. Will keep you posted before closing the thread and share the experience. Have a good weekend..

JAB12

Updating this thread: I took my 964 to a suggested well known 'old school' air cooled shop a bit of a distance from me and after a thorough lift walk through, for which I was present, the culprit items are as per @Turbotwoshoes suggestions. Crankcase oil pressure switch and valve covers. oil was seeping down to the top of the exhaust manifold and then burning causing the smoke. No smoke coming from the exhaust itself. I left the car at that shop and after adding a few preventive maintenance items to be done as well will get it back for not more than the cost of an anniversary dinner. Needless to say there is absolutely no need for an engine rebuild. Will share compression numbers as well. I'm still SMH on the thought process of the other shop.
Thank you all for your comments and advice. Much appreciated.
JB

Tarek307

Good news man, these cars have so many areas they could leak from & usually not big deal fixes. Glad you had a good outcome.