lota of smoke

ambrose · 01-15-2008, 04:19 PM

i have a 87 944 [non turbo] that has a problem that i have been half heartedly trying to fix for about 3 months now. teh problem is that occasionly[maybe once every 3 weeks] when the car is warmed up and going down the road there will be what can only be discribed as a huge billow of smoke out the rear. the smoke is blue but as it happens on no regular basis i don,t know whether it is from the tailpipe or burning off the exhaust. this smoke will continue for maybe 20 seconds and then is gone.the engine runs smooth. i am sort of leaning towards a head gasket but there is no white smoke i am reluctant to start to pull it apart sam

hpservertech · 01-15-2008, 05:05 PM

Check your oil, that will be a tall tale sign of if it's a head gasket. If it looks like milkshake then you definatly have a blown head gasket.

Also check your coolant, although that shouldn't cause a smoking issue.

ambrose · 01-15-2008, 06:00 PM

i have checked the oil and it is clean with no sign of any contamination sam

HondaDustR · 01-15-2008, 06:11 PM

Check the intake, especially at the throttle body. It might be sucking oil from the Air oil separator, very likely due to bad o-rings that seal the AOS to the engine crankcase. If it is, there will be a good oily mess in the throttle body and the intake manifold. Mine does this and will leave blue smoke now and then, especially at high rpms/throttle, and especially if it hasn't revved hard for awhile.

ambrose · 01-16-2008, 05:31 AM

i have checked the intake and i do seem to have an inordinate amount of oil . there is oil in the bottom of the air box also ,the filter is clean . this does sound like a possibility as i said when this does happen there is a ton of smoke for a brief period and then its gone .what is involved in fixing thanks sam

Razorback1980 · Razorback1980's Garage

Hey Sam,

Blue smoke means oil. USUALLY a head gasket will bring coolant smoke (white) with it. Often times but not always, it will also tend to run higher water temperatures. If the gasket is blown between the cylinder and an oil passage, the compression will leak into the crankcase and you'll see excess oil in the intake area. Not saying it's not the headgasket but look for those other signs. And do NOT take the engine apart until you know for sure it's a head gasket because you can't diagnose it then...you have to guess at that point. Have you looked at the spark plugs? Is one black and the rest tan or are all of them black? If only one plug is black, then we need to start looking at only that one cylinder...if they are all black, then it's probably oil coming in through the intake manifold. I am leaning toward what HondaDustr said but we still need to do some more looking before we know for sure. Let me know what the plugs look like.

If it is the oil/air separator, then it's not too bad a fix. The toughest part would be removing the intake manifold or loosening it and pulling it back to get to the part. The oil/air separator is the black tube where you put oil into your engine. There are three bolts that hold it on if I remember correctly and you have to remove those bolts and pull it out, put on new orings and put the three bolts back in. BUT, while you have the intake off, you will probably want to replace all the vacuum lines under the intake as they are probably old and brittle. So, you will need some vacuum lines, intake gasket and the oil/air separator o rings.

ambrose · 01-16-2008, 06:05 PM

i pulled the plugs and all were dry and appeared pretty normal. as stated the biggest problem i have had getting to the bottom of the large cloud of smoke is that it may only happen once every 2 weeks and then it,s gone ssam

Razorback1980 · Razorback1980's Garage

Head gasket certainly wouldn't disappear and then reappear. All plugs were tan and none were blackish in color. That is strange...usually that won't burn off and make the plug tan again unless you clean it. Does that smoke get into the cabin of the car at all? Like maybe the gasket on the back of the cam tower is leaking on the headers. Do you see any spots on the headers anywhere that may look like a fluid is leaking on them? Other than that, I don't have any other thoughts other than the oil/air separator orings.

ambrose · 01-17-2008, 06:26 AM

the oil certainely does get into the cabin area ,big time , but i do know that my rear hatch is not sealing very well i have it run up on ramps now and have run it for 30 min. and i do see where my oil pan gasket is going to require some attention, but nothing that would cause the amount of smoke that i get periodically . in any case i am going to keep at it and will keep you posted sam

hpservertech · 01-17-2008, 08:37 AM

leaky oil pan gasket shouldn't cause that much of a smoke issue. It's low enough where it doesn't get on anything that would get hot enough.

The rear cam gasket though will cause a lot of smoke if it leaks oil.

ambrose · 01-17-2008, 09:51 AM

i got digging a bit furtherr today and i did find that the area on the block in the area of the oil air sparator had a pile of oil and that the undeerside of the throttle body where the tube from the air box hooks up had oil on it also so i am going to start there. does anyone have the # of the seals that i will require thank everyone again for your help sam

hpservertech · 01-17-2008, 10:02 AM

The air oil seperator is only 2 O-rings. Pelican has them, that's where I got mine from.