Can leaking main seal cause [A, B and C]?

[NismoTyler]

I recently bought an S13 coupe with a KA in it that was running and driving fine for about 3 weeks and it now has some odd issues. The guy I bought it from said the main seal is bad and I have a friend lined up to replace all the seals but in the meantime I've been regularly checking the oil level and it's been fine. I'd like to know if some problems are symptoms of this main seal issue. Thanks in advance!

A) ONLY randomly: car driving fine, holding revs in gear fine, cruising fine, decide to floor it, revs drop as if i took my foot off the gas, when i actually DO take my foot off the gas it stops slowing down as much and SOMETIMES when i go half-throttle its fine again. Other times I have to turn the car off/on to get it running right again

B) hesitating in low rpms

C)running rough at idle, died twice today

D) white smoke coming out from exhaust only a little until today; white smoke was coming out from under the hood...


I'm baffled because I know oil can leak onto the manifold and cause smoke from under hood. I know the white smoke is coming out of the exhaust because of the seal issue or burning oil. What I don't get is all the other problems. Thank you for any information that you can give me!

P.S. I haven't had the maf checked yet. Doing that tomorrow.

[codyace]

The symptons you describe are more related to vacuum or maf centered items. Another thing to obviously check are the condition of the cap/rotor and plugs.

A bad main seal (front or rear) won't cause any issues in terms of how the engine operates. A very bad rear main leak can obviously stain/ruin a clutch, however that won't make the car hesitate or have a rough idle.

Just go over the main vacuum hoses and ensure there are no leaks (spray starting fluid around the vacuum connections, you'll know right away if there is a issue) and go from there

[daryl337]

The crank and rear main seals should not be causing those issues, unless you are oil soaking your harness, or your oil pressure is dropping to seriously low levels. Assuming your oil pressure is fine, and your wiring is clean of oil, then the seals should not have any effect on your idle, or hesitation.


Question for you though, which may or may not be of a related issue.... how is your crankcase breather operating? A faulty ventilation system can cause excessive crankcase pressures, which can do all sorts of cool things including excessive oil consumption. That could cause idle concerns possibly, particularly B and C in your categories. Might want to check spark plugs for signs of oil burning. Of course, you may have a completely unrelated issue, as well as simply a worn main seal.

I usually look towards the PCV system when I start popping seals/gaskets (although I would have expected the valve cover gasket to start leaking before a main seal) and have idle issues at the same time. Its worth looking into if you think they are related.

[NismoTyler]

The symptons you describe are more related to vacuum or maf centered items. Another thing to obviously check are the condition of the cap/rotor and plugs.

A bad main seal (front or rear) won't cause any issues in terms of how the engine operates. A very bad rear main leak can obviously stain/ruin a clutch, however that won't make the car hesitate or have a rough idle.

Just go over the main vacuum hoses and ensure there are no leaks (spray starting fluid around the vacuum connections, you'll know right away if there is a issue) and go from there

Great info :) The bad seal is the front seal and I need to get it taken care of quick...

Thanks for the 411 on the spraying starting fluid around the vacuum connections. I'll do that tomorrow. Another thing: I was told the KA in it is an S14 KA...OBD1 or 2 I don't know. I DO know however that it has an S13 maf. If it's an OBD2 KA I can see that causing issues no?

[NismoTyler]

The crank and rear main seals should not be causing those issues, unless you are oil soaking your harness, or your oil pressure is dropping to seriously low levels. Assuming your oil pressure is fine, and your wiring is clean of oil, then the seals should not have any effect on your idle, or hesitation.


Question for you though, which may or may not be of a related issue.... how is your crankcase breather operating? A faulty ventilation system can cause excessive crankcase pressures, which can do all sorts of cool things including excessive oil consumption. That could cause idle concerns possibly, particularly B and C in your categories. Might want to check spark plugs for signs of oil burning. Of course, you may have a completely unrelated issue, as well as simply a worn main seal.

I usually look towards the PCV system when I start popping seals/gaskets (although I would have expected the valve cover gasket to start leaking before a main seal) and have idle issues at the same time. Its worth looking into if you think they are related.

Great info on the pcv system stuff. I'm not sure how the breather is doing but I'll check that too.

I'm concerned about what you first said though...the harness being soaked in oil. I need to look closer at it. Tonight on my way home my heads up display faded on/off/on/off/on/off/on/off then finally stayed off. Not cool. Electrical issue. :-/