KuHL 951

The 944S has suddenly started to use about a quart of oil every 400 miles. This just happened after not even using a quart in 1500 miles as the norm. On cold mornings, engine warmed up, you can see blue smoke under hard acceleration like getting on a freeway. My son just brought the car back today so I have to look at things. Is there any condition that can draw more crankcase oil from the OAS that can cause this? The car still runs excellent, starts on 2 cranks, idles well, no noises, no puddles, and continues to get 28 mpg on the highway. I plan on checking the intake track for oil as well as a compression/leakdown test but I don't think it's a piston ring issue.


Any suggestions are always appreciated.

Thanks

Luis de Prat

Blue smoke = rings?

KuHL 951

Yes, usually it's rings but oil can be also drawn in through the intake tract by vacuum and be burnt but I'm not sure how? Hopefully it's not rings because that means something happened all at once to cause this rather than slow wear.

M758

valve stem seals.

my 88 Turbo S would burn oil. More so at higher RPMs. So I changed the valve stem seals and most of the oil burn is gone. Now despite a leaky pan gasket I get very little oil consumption.

KuHL 951

Thanks, I'll pull the valve cover and look for brittle seals if everything else checks out OK. I'm starting to think it might be viscosity related. The PO had just changed the oil before we picked it up and we then drove 400 miles home, no oil use. I found the receipt and they used 5W-30. It's been about 3.5K now. I've never had good luck with low viscosity oils in any 944 I've owned, especially a car with 175K on the clock. I might switch it to 20W-50 Castrol GTX and see if there's any improvement. The weather has been warm here so I need to do this anyway before the Hell we call Summer begins.

DarylJ

If it is valve guide/stem seals, letting it sit at idle (high vacuum) and then getting on it ought to make more smoke than if you'd been at a reasonable RPM and then get on it. Also, check the intake for signs of oil - could have an AOS issue throwing oil through your intake.

jmd_forest

Oil cooler seals? Check your coolant tank for oil.

jmd_forest

KuHL 951

Short update. Coolant tank is clean, oil cap has no mayonaise, and oil is clean. What I did find was the oil filter was loose IMO and it took a full 3/4 turn with my hand plus another 1/4 turn with a filter wrench with very little effort to seat. What Daryl describes is close to what my son said it was doing. Cold start after sitting overnight, warm the engine, and smoke only when getting on freeway the first time. The rest of the day it's fine with no smoke behind the car. I had a Chevy that smoked at start-up from bad valve seals but it was more leakage overnight and smoke at start-up. I wasn't able to check compression today as I'm doing upper/lower ball joints on the F250 and it didn't go well as usual so I'm running behind. Damn those ball joints are beefy ******...screw that rental ball joint clamp...it wouldn't budge them but the 3T load it took to break loose with a friends shop press did.


Can someone explain how an OAS problem might effect oil consumption on an NA?

Thanks

Bri Bro

1+. And it gets real interesting if they pop out of the seat and get into the spring.

KuHL 951

If it is bad valve seals has anyone done seals using compressed air or rope to avoid removing the head? Just asking in case. Also do valve seals ever go bad that fast? Brian, what were the symptoms when your valve seal popped off?

Bri Bro

Just like yours, never used oil and then it suddenly got thirsty. Smoke on acceleration but good fuel mileage and ran fine. The little metal ***** in my oil pan were a little hard to source but they were the remains of a valve seal that popped out.

KuHL 951

Why were the metal ***** a valve seal? I thought they were either rubber or Viton. Do they have a spring like an oil seal or was it failed parts from something else?

Bri Bro

The top has a metal collar that is coated and the springs just tear them apart and roll them up. I found out from my supplier that some 944 seals got mixed in with 944T seals and I might have gotten some of the 944 seals. So, after cleaning out the entire engine, I put loctite 518 sealer on the new ones.

KuHL 951

Did you pull the head to replace them?

Bri Bro

Had to rebuild the entire motor to be sure I got all the metal out of it. If I was just going to replace the seals, I would pull the head. That way you can have the machine shop check everything out.