Carrera356

I noticed my 95' carrera was consuming oil so I started monitoring it.

After 380 miles it has consumed a little over half a quart. I'm praying it's not the valve guides... The car does not smoke at all. I even had a friend follow me while I did the acceleration test (6000 to 2000rpm and then flooring it) and again, no smoke.

What do you guys think? Could it be something else? I know I have a slight gasket leak on the timing chain cover but I don't think it is significant. No oil on the garage floor or anything.

My car has 65,000 miles on it.

goofballdeluxe

It could be the valve guides, and if you have over 60K miles, it may well be.

If it is your valve guides, I've heard that it's not really a major concern until you're burning a quart of oil every 600 miles. If you're burning a half a quart every 380 miles, you're still at a quart every 760 miles.

If you're not seeing blue smoke at start up, I'd check for leaks elsewhere and just enjoy the car. But I'd also start saving up for a valve guide replacement job, because it's coming sooner rather than later, based on your oil cosumption; that is, if you have no other leaks. But you may have a while before you get to a quart every 600 miles.

Benton

While my car does consume some oil, I thought it was using much more than it actually is. I knew I had a lower valve cover leak, but had not inspected. No drips on the floor at that point. Last year at the Daytona 24, we were queued up to enter the infield, and I saw smoke wafting out of the rear fenders. The only time this was noticeable was when the engine was hot and the car was sitting.

As it turns out, the lower valve cover leak was pooling on top of the heat exchangers and burning off. When cold, reach up on the top side of your heat exchangers and see if there is a oily grime up there. New VC gaskets are going in my car in the next few weeks.

axl911

Uh oh.

At 800 miles per quart, you're getting close. Begin monitoring very carefully.

Also, see if it smokes at idle when fully warmed.

If you think it's due to leak, then check the rear of the car for wetness or oil splashing when it is driven. Check on top of the heat exchanger to see if oil is pooling there. If it is, you'll definitely notice it by the smell when standing next to the car.

Carrera356

I forgot to mention my car has 65,000 miles on it.

And I always keep on eye out for smoke. But so far, there has been absolutely NO smoke.

Shouldn't I be seeing smoke if the car is consuming this much oil?

axl911

Any change in driving witin the last 400 miles? If you were on a track and just flogging it, that could have caused the oil consumption.

Quadcammer

Have you tried leaving your oil level at 2/3rds full on the stick and not refilling all the way when it gets low?

From what i've read, some people experienced rapid burnoff when the stick showed full, but it tapered almost completely when they didn't fill it up so much.

Catalytic converters do a very good at masking all but the worst smoking.

Your valve guides probably are worn, but try not filling up the oil all the way and see what happens.

kjr914

^^^^Try this first and see if it keeps going down to 1/4 or stabilizes. Like quad, I've seen lots of posts that confirm this exact behavior. These beasts have their special quirks, that we all grow to know and love!

Carrera356

I'll give that a try.

I haven't really changed my driving style lately but I do have a very short commute. I'm not sure if that would affect consumption but I drive 3 min to and from work several times a day.

goofballdeluxe

A very short commute is no good. It doesn't give the oil time to reach operating temperature.

By the way, welcome to Rennlist.

Now, post some pics of your car!

slickster85

Not to hijack the thread, but what does it cost to fix the valve guides? It is a top end rebuild?

CorrdoBrit

Thats like asking how long is a piece of string. Seriously I've seen quotes range from $5K to $10K. There is other 'since I'm in there' stuff to do that make sense when the engine is out, which adds significantly to the final bill.

Quadcammer

yes, the repair is to replace the guides, clean up the head, inspect the valves, seats, etc, and reassemble.

prices range from $3000 to $12000, depending on what else needs to be replaced, where you have it done, and what if any extras you include.

Slow Guy

From what I see in that dipstick photo you're overfilling your oil to begin with. From that spot I'm surprised it didn't take less than 380 mi to burn that off. I only fill mine up to the 1/2 way point in the twist, any higher than that it will burn off.

Make sure of a few things when you check your oil level
1) engine is running (these are not American wet sump engines)
2) engine is warm to hot (temp gauge is at least the 8:00 position)
3) car is parked on level ground/concrete
4) dipstick is fully inserted after wiping it off and check it 2 or 3 times to be sure
5) don't add oil until it gets lower than the twist or at least at the very, very bottom of the twist.

Most of these instructions are in the owners manual.

Carrera356

Thanks Bill, I have been following those procedures. The only thing I'm confused on is how far to fill it? Are you saying half way up the twist is the full mark?

When my oil is reading half way up the twist my oil gauge in the car will be in the red (with engine up to temp and on a level surface). Does my gauge need to be recalibrated?