MS911

Just bought a Manual '96 C4 in Slate Grey. Gorgeous!

Previous owner was told by "His Guy" the engine through (thru?) bolts need replacing and he advised me prior to settling on a price.

We also agreed that a PPI at my OPC was a good move. Compression test was also performed and passed. Nothing bad other than oli leak revealed through the PPI.

My OPC during PPI said slight weep from LHS through bolt, but when asked how much to repair they said between $8K and $15K, they could not say as "the engine has a lot of oil around it, we could quote after we start the work!!"

The great thing is I was able to drive the car for 2 weeks prior to making a decision - I kept a check on oil use (and everything else, hey why wouldn't you if you had 2 weeks to be sure this car is "the one"!) I drove about 2,500 kms and no oil use. Dipstick shows good level and warm engine after a hard drive on level ground shows oil level mid way up the oil level guage.

I asked my mechanic who looked after my previous 911 (German Factory Trained, 30 yrs exp on air cooled 911's and has several current 993 clients, one of whom has 220K kms on his car) and he said unlikely to be through bolts, probably just a valve cover gasket weep. He is well known and trusted but he is an independant. He suggested go to the local hot wash and hose down the lower engine, hard drive, back into my garage for a day over a new oil drip tray.

For 2 weeks - NOT A DROP OF OIL had hit the tray! The underside of the engine was bone dry for that entire time. (the car is a daily driver)

Just now (4 weeks and approx 3,500kms after 1st drive) there is a little oil moisture on the bottom of the engine (crankcase?), but still nothing on the drip tray. Oil levels are fine.

I am all for preventative maintenance, but don't want to blow $??K when there seems to be no oil loss.

What I want to know ....

Do the through bolts "fail" (break) or is it just the rubber 'O' rings either side that allow oil to leak out? For all practical purposes, if I am keeping an eye on my oil level, oil temp, etc is that safe enough?

Or is it possible that an otherwise slow and manageable oil leak past the through bolt 'O' rings could very suddenly let go and I will lose all my oil inside a trip?

If this were to happen, would the oil temp guage show an increase in temp? What other symptoms might there be?

Any experiences or suggestions appreciated.

(New car pic attached - apologies for the quality, its a camera phone pic!)

Best,
Mark

Current
1996 993 C4 Manual (Slate Grey)
2003 Saab 93 Aero (Silver)
2001 Mercedes VITO (White)

Former
1990 964 C2 Manual (Midnight Blue)
Too many Saabs to mention!

AOW162435

Beautiful 993

Just keep an eye on it and drive the car as much as you can. They do not like sitting for extended periods.

Remember that your total oil capacity is around 12 quarts - it would be nearly impossible to account for the weeping oil on the dipstick. I would not lose sleep over a bit of oil under the case halves.

Andreas

TheOtherEric

Like Andreas said, you won't get measurable oil loss, but eventually you'll have to get this fixed. It definitely could be a cylinder thru-bolt leak; I had this exact problem on my car when I bought it. To identify, we cleaned up the underside really well and ran it for a few hours, and saw the weeping coming down near the base of a cylinder. We also saw dye marks there, indicating that the PO used dye to find this problem.

So the 1st thing you need to do is identify exactly where the leak is coming from. Valve covers gaskets are just a few hundred$$. I disagree with your mechanic who said "it's unlikely to be a cylinder thru bolt", but I would agree that it's more likely to be a valve cover gasket. Also keep in mind that cylinder thru bolts can be easily misdiagnosed; the oil will run down (near valve cover gaskets) and aft (onto the bottom of the timing chain housing which makes it look like a timing chain housing leak.

Unfortunately, a cylinder thru-bolt leak requires a rebuild (called "reseal" if you're not doing any other work). It'll set you back $4k, not including any upgrades. On a positive note, you'll be able to get the SAI passages cleaned easily, and can replace valve guides if your mileage is high.

Hope that helps!

MS911

Thanks for the feedback/advice. From what's been said, it seems that I can continue driving, but keep an eye on oil level.

I am due now for a 120K KM service, so that may reveal that the leak is 'only' a relatively minor weep from the cylinder head, crank-case or valve cover, in which case I will naturally get it taken care of at the same time.

If not, I will attend to the issue at the next engine out service.

Does anybody know what needs (is supposed) to be done at each service? I am intererested to know which servicres require engine out, etc.

Bear in mind that I am in KM not Miles!

Regards,
Mark

Current
1996 993 C4 Manual (Slate Grey)
2003 Saab 93 Aero (Silver)
2001 Mercedes VITO (White)

Former
1990 964 C2 Manual (Midnight Blue)
Too many Saabs to mention!

geolab

Two weeks and not a drop of oil on the tray in my dictionary with a 120 Kkm 993 is no engine leak.
Weep is normal, not perfect, but normal.
3500km with same engine oil level is great.

for service, do a quick search on the 993 board, I have already posted the dealers list of things to do for each service interval
Congrats for the car, beautiful

c993k

Hi Mark,
Welcome to the forum,
Ask the guy you bought it from, how long was it sitting?
I had an 81SC that poured 1- 2 quarts of oil while sitting in a cold garage each Detroit winter
for 6 months. When spring came and I drove it daily again, not more than a drop every week!
They just do that sometimes. Not like my old SC but some drops will come through.
Don't try to tighten the valve covers because it will only make it worse.
Just get new gaskets and change them yourself. It's not hard. Nice car and great color!
Good luck with it! Chris

MS911

Thanks everyone.

Chris, this car was PO's 2nd vehicle, his primary was a new Alfa (no accounting for taste ...! ), so its possible that it may have gone several days to a couple weeks without being driven. I think he did about 8K kms in the year he had it.

I have done almost HALF that inside a month.

On that score, I did get up to about 240K kms in my previous 911 (a manual 964 C2) My payout on this car will be about $26K in 5 yrs so I am not particularly worried about putting KMs on her. I always wanted to own a classic and my thoughts are that I may well hang onto this car at the end of the finance term - it's just such an engaging car!

I have to agree with the popular notion that the 993 is everything the 964 should have been had Porsche had the $$$$. I loved my 964 but I LOVE my 993!

I am reasonably handy (have done simple fixes such as central rear LED brake replacement, and such) but I am not really that confident about gasket cover seal replacement, even though the p-car DIY website shows it as being pretty straightforward.

I like the Pelican parts DIY difficulty ranking 1 thru 10, I would say I could tackle about a 5. On a scale of 1 to 10, where would you rank the valve cover gasket replacemement?

Thanks,
Mark

MS911

Thanks everyone.

Chris, this car was PO's 2nd vehicle, his primary was a new Alfa (no accounting for taste ...! ), so its possible that it may have gone several days to a couple weeks without being driven. I think he did about 8K kms in the year he had it.

I have done almost HALF that inside a month.

On that score, I did get up to about 240K kms in my previous 911 (a manual 964 C2) My payout on this car will be about $26K in 5 yrs so I am not particularly worried about putting KMs on her. I always wanted to own a classic and my thoughts are that I may well hang onto this car at the end of the finance term - it's just such an engaging car!

I have to agree with the popular notion that the 993 is everything the 964 should have been had Porsche had the $$$$. I loved my 964 but I LOVE my 993!

I am reasonably handy (have done simple fixes such as central rear LED brake replacement, and such) but I am not really that confident about gasket cover seal replacement, even though the p-car DIY website shows it as being pretty straightforward.

I like the Pelican parts DIY difficulty ranking 1 thru 10, I would say I could tackle about a 5. On a scale of 1 to 10, where would you rank the valve cover gasket replacement?

Thanks,
Mark

TheOtherEric

I'd say the same as an oil change, around a 3. (I'm talking lowers only) But dont get too far ahead of yourself, since you still need to figure out where the oil is leaking from!