CincyScott

Ok, I posted a few weeks back about my cold startup mosquito fogging machine (97 993TT). Basically, I'm getting a huge plume of white smoke on cold start. It's happened several times since then, so here's what I can figure out so far:

1) Car has to be stone cold, never happens on a warm start.
2) Losing a quart of oil every 700 - 800 miles
3) No visible leaks in the engine compartment
4) Small oil filter is the Porsche one (no double-gasket either)
5) No discernable oil burning on accel or decel
6) Intercooler hoses are "wet" but not dripping

So, where do I go from here? Higher viscosity oil? (Running 10w40 Redline) or check valves?

Thanks!

ca993twin

Scott,

I wouldn't change viscosity... I would probably get two new factory oil filters and replace those. I don't know which is the main one that seems to cause this problem (big or small filter), but this is so typically the problem, I would start there. The check valves are a great idea, even if the filter change fixes the problem.

Good luck.

Barney1

"The check valves are a great idea, even if the filter change fixes the problem."
This is a known problem with these cars...Spend the money and get the valves and be done with it. If you look a 996TT, the check valves come stock and there is no oil problem. Viper Bob has the kit for sale... I did mine and not a drop of missing oil since...Make sure you clean out the intercooler and hoses to do the job for best results. Also...15/50 Mobil One oil is the oil to use in these motors.
Mike

Felix

An overtightened small filter can cause the back flow problem. After the car has sat for 24 hours remove the turbo sump plugs and let us know how much oil drains out.

NoSubEDU

2nd.

chris walrod

3rd that one!

CincyScott

Ok, that seems mostly unanimous

What's Viper Bob's PM? May as well do the check valves if I have to put the car on the lift to change the oil.

I thought from everything that I've read here is that newer flavors of Mobil 1 lacked certain additives that the older cars need. Redline and Amsoil still have them(?)...or is this another old wives tale?

IamSMC

http://www.mobiloil.com/USA-English/...Oils_FAQs.aspx

Barney1

Bob Brooks
Vortex Motorsport
5217 West Hillsborough Ave
Tampa, FL 33634
818.874.1911
bob.brooks@vortexmotorsport.com

Texas993

[QUOTE=CincyScott;

I thought from everything that I've read here is that newer flavors of Mobil 1 lacked certain additives that the older cars need. Redline and Amsoil still have them(?)...or is this another old wives tale?[/QUOTE]

There is a lot of disucssion about that for the NA 993 motors. All of the experts on this board recommend Mobil 1 15/50 for our turbos.

CincyScott

Thanks Patrick, I wouldn't have thought that there would be any difference between the two motors, but I'm thankful for the clarity!

MarkD

we just don't have as many options since these things need the full syn due to the heat generated at the turbos.

It is all debatable anyhow... and it certainly has been!
FWIW, the M1 Diesel and Truck oil has the ZDDP that went missing in the other M1...

Also worth noting, OHC engines don't have the high valve spring pressures that push rod engines do, so... it *may* not be an issue with our engines. Others say it is... the debate will go on forever and it is hard to pin down since the wear can go unnoticed for a long, long time.

It is likely that the oil change won't solve your issue anyhow. The other things mentioned above will.

hal m

Bob is no longer with Vortex. Check Brooks Motorsports. He has posted lately with the new affiliation

Greg H.

How many people have the check valves? I don't, and my car is not a mosquito fogger. I think there is something wrong with his car. These things didn't smoke from the factory.

Greg H.

hal m

I had it done last time my turbos were out. Too many people with problems relating to oil backflow.