Oil level increasing?

The car: 1999 C4, 154k miles Rebuilt engine w/LN Nickies ~1200 miles ago 3.4 -> 3.8 Heads reworked by HAM New injectors, MAF, O2 sensors (and many other things too). Injectors are the white Bosch 0280156053 ( 99660612200). Bank 1: RKAT=0.8; FRA=0.98 Bank 2: RKAT=0.94; FRA=0.95 Smoke test = tight (induced smoke from intake elbow) The issue: I just got done with my first oil change after a full rebuild. Filled to 1/2 way between the marks on the dipstick with Driven HR5. Put ~150 miles on it over the weekend and also driving it to work 18 miles round trip this week. Checked the oil a couple of nights ago and it seemed higher than I remembered, but I chalked it up to me not remembering correctly. Checked it again tonight, and it's now above the top mark by about 1/16". It seems to smell a little like gasoline, but it's hard to really tell. Coolant level is the same as when I filled it right after the rebuild. No milkshake, and the oil I drained (the BR40 break-in oil) was clean and normal appearing. No other symptoms, seems to be driving fine. I did notice on a couple of hot days after sitting outside all day at work that starting took a bit longer than when colder in the morning. Tailpipes are not sooty and both appear the same. Question: has anyone seen this before? I could see if an injector was leaking while the engine is off that the fuel would drain from the cylinder to the oil pan. I haven't been able to find other experiences with this happening on these cars. Thanks in advance for any thoughts or guidance on this. Charley

Get a oil analysis kit and see what is in there.

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It's a good thought for sure, I do an UOA for all of my vehicles for each oil change- one should be coming back shortly for the first run of break-in oil for this engine. My bet is that it's fuel, mostly because I don't know what else it would be- likely not coolant, as the coolant level is right where it was at first startup after the rebuild. It would be strange for one of the brand new injectors to be leaking after shutdown, but that is my suspicion. This weekend I plan to do a fuel pressure test, both ignition on and pump running as well as idling. I'll also do a 'leak down' pressure test which should tell me something. I have to get an adapter for my old-school Bosch CIS fuel pressure test rig to connect to the test port on the 996 fuel rail. Much easier to go that route than break into the supply line and tee in the CIS test rig. Charley

Sorry to hear that. Genuine Question: Wouldn't the fuel evaporate/boil out of the oil when it reaches operating temperature as that is higher than the boiling temperature of petrol (at 60�C/~150F)?

Best be careful here. If there is that much fuel in the oil, likely the oil is highly contaminated and its lubrication properties are compromised. Do yourself a favor and drain your oil now, then refill with known quantity. In other words, don't run the engine, take the hit and drain that oil out now. Put some in a glass jar and see if it separates into oil/gas. Gas is lighter viscosity and will rise to the top.

My bet is that you aren�t checking the oil the same way consistently. I only check mine after the car has sat for 12+ hours. Stone cold and on a flat surface.

What Mike said might be right too. These cars are very inconsistent with oil readings. Unless you're measuring in the same exact spot every time it's possible to have readings be off. The dip stick enters the sump on the driver side while the electronic sensor is on the passenger side. I've had many instances where my electronic gauge would show full but dip stick half full.

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Also good thoughts...I check in the morning before starting, sitting in the same location in my single car garage. I mostly ignore the electronic gauge and trust the dipstick, as I can't imagine that being wrong. I usually take three readings to make sure. I put the engine together so I can visualize how it sits in the oil pan cavity. I also had the pan off for inspection for the first oil change and all looked good in there. I'll drain a little oil (pull the filter off) and put some in a mason jar to see how it looks after awhile. Charley

Do the 996.1 and 996.2 models both have electronic oil level gauge and dipstick? I only have a 996.2 but learned on RL that the electronic gauge should be read ONLY when car is on flat ground and has sat overnight and is cold, while the dipstick reading should be taken ONLY when the car has been fully up to operating temp, then turned off on flat ground and left to sit for 10-15 minutes for the oil to drain back to the sump. With my 997.2 I have no choice since there isn't a dipstick. It requires the car to be idling while sitting on flat ground while a timer counts down between 30-60 seconds before producing a result.

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Hmmm. Not what I have seen with mine (996.2) with regards to variance between dip stick and electronic gauge. Both of them were spot on equal when measured cold. Note - this was prior to shifting to the shorter .1 dip stick I currently run. With regards to OP problem... 100% you need to be consistent in your method of checking, so make certain you are. If that is covered, DBJoe has the ticket. Collect a sample for you and send a sample off to your test house of choice ASAP.

Second, or triple, or quadruple the change oil now message. If you aren't sure what's in there, put something known in there. I'm at 1000 miles after initial 100mi(?) break-in at FSI. Similarly, I check in the mornings, same location in the garage. I check with both gauge and dipstick. DNO the middle of the range. They agree 100% of the time. I've never seen the level go up. If I check the oil 30 miles into a drive, the level is at the bottom of the gauge and stick. Then the next morning it's back to the middle as expected. Good luck!

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I don't think that it will, not even when you re-word and replace viscosity with density I would say the gas will stay solved in the oil and not separate as if it were a mix of oil and water. After all crude oil has to be distilled to separate the gasoline from the base crude oil. https://en.m.wikipedia.org/wiki/Fractional_distillation

Gasoline evaporates at about 140F. If there were any quantity of gas in the oil, it would likely evaporate out when the engine was running. In fact, in the bad old days of radial engine aircraft the planes had something called oil dilution. If you were shutting down and it was very cold out you'd pull a lever that would pour gas into the oil just before you shut down the engine. The gas would reduce the oil's viscosity so you had a chance at starting the engine after it sat overnight in below freezing temps. Once the engine was running the gas would quickly evaporate. This isn't very good for the engine, of course.

Did some fuel pressure testing. Cold, running pump manually by bypassing the relay- 50 psig (a little lower than spec: 55 +/- 3 psig) Held for 1 hour- 48 psig (dropped 2 psig, calling that ok...no spec) Cold, started car with gauge attached- dropped to 47 psig. (in spec: 48 +/- 3 psig) Shut off engine- dropped to 44 psig Held for 2 hours- dropped to 36 psig Drove car to fully warmed up, ~90 deg C oil per Durametric Idle, hot- 47 psig Shut off engine- 44 psig Held for 2 hours- dropped to 10 psig Definitely a difference between hot and cold behavior. However, gasoline does expand/contract a fair amount w/temperature, so that may explain much of it. Has anyone seen a spec for the allowable fuel system pressure drop vs time? I don't feel what I'm seeing is too terrible but could be wrong. When cold, dropping 11 psig in 2 hours seems ok, given all of the points of potential leakage...likely mostly the check valve after the fuel pump. The point of doing all of this was to see if I had a grossly leaking injector leaking into a cylinder after engine shutdown, and it appears that no is the answer. Oil sample is on the way to Blackstone. I should be hearing back from them also on the sample I took a week ago on the first fill of oil after the rebuild. Charley

Another clue I had was periodic trouble starting when hot. Not the slow cranking issue due to the Y-cable, but turning over fast and no start for 10 seconds or so, lots of gas smell. Happened before the rebuild, still happens now. I may be trying to diagnose two things at the same time, I know. Looking at this guy tonight...I didn't replace this during the rebuild. We'll see what I find.