98 355 Oil Consumption - Valves? Help!

Hi

I recently got an amazing deal on a 98 355 Berlinetta (no chance to have an inspection!) ... I thought about it long and hard before taking the plunge and, given the amazing price I got it for, risked it. I figured the cosmentic condition of the car, its history and the price gave me room for a serious-ish maintenence bill if/when the need arose (i.e. when I discovered why it was so cheap!).

Well, I think I have found it...It appears to be consuming 2L of oil per 100km. That is 10x the official figure of 2L per 1000km max. There are no visible leaks and, strangely, there is no exhaust smoke (a little white vapour from RHS tailpipe at start up but no particles in it and soon vanishes, figured it was just water from the cats?). Looks like a relatively new muffler is on the car as I easily polished the inside of the tailpipes and after 100km the inside of them is a light grey/white uniform colour both sides.

I think that I have a valve guide problem, the car is booked in for full service including belts on July 25th - so the leak down test will answer the question then and, with the engine out, I guess I'll get whatever done.

My questions are:

1) Given the facts above can any of you offer advice as to what the problem might be - valve guides (possible but unlikely on 98 car) or what else?

2) What will the remedy entail?

3) Any idea of rough cost to remedy (I have read $135x40 for valves - would it also need heads, or given the oil consumption level could it just be a couple of valves)?

4) Just how high is the above oil consumption, should I leave the car in the garage until the service (it drives fine, sounds fine, feels fine, no visible problems apart from the oil disappearing!)?

The car originally came from Germany, has done about 19,000m (which looks genuine given the interior condition and agrees with the complete annual road tax record), has not been used for the last couple of winters and has only done about 1500km in the last year. It's last service was 4 years ago when the belts were done, this isnt a problem regarding the mileage but is obviously an issue re-lack of annual services. Hence my booking it in for a full service now. Having said all that the car appears to be in excellent shape, responsiveness of engine, smooth throttle feel, excellent gear selection etc.

I am a bit of a worrier and am not looking forward to the wait between now and the end of the month, any ideas would be gratefully appreciated!

Many thanks, great community...deep breath...

ps.Just checked, Assembly number indicates early 98 (a lot earlier than steel valves) more evidence I guess.

 

OK having read some more I think I can answer my own questions to save you guys doing the same. If you can add anything then please do.

a) Early 98 with this heavy oil consumption points at valve guide problem most likely.

b) Oil consumption is high but not terminal, having said that as the engine is running sweet now apart from oil issue, dont drive it before service to save any other problems occuring.

Cost of replacement is approx $14000 (£8000) including main service/belts.

Car will be fine after - if valves replaced with steel ones.

About right?

 

Thanks for that! There isnt any real "powder" that wipes off, so I guess its just starting (does look like ceramic coating though - maybe something for next year) however done a search and the Fuchs metal cat insert seems best option and price cool so thats least of my worries.

One other question, should the oil level be read when the engine is hot or cold? I imagine cold but read somewhere that level should be between min and max when hot...it helps to talk, thanks guys.

 

Thanks for the above. I have been thinking the same myself, the car feels fine in every way except the vanishing oil, I was foxed by the lack of smoke. I have stood there looking at the oil filler cap and trying, praying that i was doing something wrong when it just dawned on me, "dry sump", "header tank" ... I think far too much and have such an active imagination, this car was such a bargain that I am subconciously searching for "whats wrong" ... I am measuring the oil level cold and just found the right bit in the handbook!

I REALLY should know better having raced/mechaniced my own single seaters. Now all I have to be before I start it again is remove all the excess Shell 5w40 oil that I have stuck in! little bit of knowledge etc...thanks for your advice guys, got there in the end. I'll carry on the search for whats wrong with it

Thanks a lot David, you posted just as I did, so didnt read your post before the above, I feel a REAL idiot. I looked at the handbook before hand but its so long I initially only saw the first bit about fluid amounts and it saying the distance between marks is about 2L. What a relief, at least i'm a happy idiot now Rookie is the right word, or perhaps nervous ned!

 

Believed high oil rate was due to my not measuring the level correctly, i.e. the oil is still in there!!!

The Assembly number is early enough in 98 to be pre-Steel valve guides though - so there is the chance of that issue cropping up, i'll know more after the service at months end.

I will drain down this week & report back.