Leaking Coolant into Exhaust. Gods of Nico I need your input.

[ShaunakaRichard]

I have a 92 240sx with a sr20det w/ gt28r.

1 day I noticed smoke coming out of my exhaust. If I revved up the motor more came out. White smoke. I'd shut the car off. Wait. Then restart it no problem. I knew the seals were going in my stock t25 so figured it was that. I knew because the inside of my intake was covered in oil. Smoking problem would occur maybe once a month or so. Maybe longer.

I finally got some money and swapped out the t25 with a gt28r. Everything has been running amazing. About a month after the swap same thing. White smoke coming out that would get huge if I revved the motor. Shut the car off. Restart no smoke. What could be putting coolant into the exhaust? I've never got the motor hot and the symptoms don't point towards a head gasket since shutting the car off and restarting the problem goes away. New turbo so seriously doubt there's a problem there. What you guys think? Doesn't happen too often but its definitely think white smoke. Gotta be coolant.

And on a side note the gt28r is amazing. I'm still using stock injecting and haven't had a single problem getting enough fuel running consistent 18 psi. Pulls so much better than the t25 and doesn't run out of breath. Only issue i've encountered is my exedy stage 1 clutch is having problems holding the power if i'm not careful. If you can upgrade! Well worth it.

[sx moneypit]

I don't know if this is your problem but i thought i would share this info.About 15 years ago i was working on a late 80s Supra and when you started up every now and then it would blow out a huge cloud of white smoke.After it ran a minute or two it would clear up.I was thinking head gasket but it turned out that the brake master cylinder was leaking fluid into the brake booster!When you started it up it suck the fluid into the engine .Just something to think about.

[ShaunakaRichard]

I've never thought of that. But I've started my car without pressing on the brake pedal and its happened. I've let it run maybe 3 or 4 minutes doing it and it didn't clear up. So I shut it off. Restarted and no smoke. It all makes no sense to me. So my question is: what common part has connections to both the exhaust and coolant?

[IanS]

Just because it is white smoke, dont assume its coolant. If you burn oil at the correct temp, it will create a very light greyish smoke. Ive seen the problem on SR 20s before.

What does the smoke smell like? Is it acrid, or syrupy, almost sweet?

When you replace the turbo, did you remove and clean/replace the oil drain? One of the biggest causes of blown turbo oil seals are clogged oil drains that cause excessive pressure inside the CHRA. This will destroy even brand new seals in a matter of weeks. Its also possible that you did not install the correct oil restrictor for the turbo, thereby feeding it too much.

Have you noticed coolant getting low? If not I would start looking for an oil leak.

[ShaunakaRichard]

Its not oil. It smells like coolant. Oil drain was cleaned because I had to modify it to fit on the new turbo. Yes I used the correct restrictor. What doesn't make sense to me is if you turn the car off and back on real fast the problem goes away. If it was the turbo it would be consistent. Possibly spurratic but not consistently stop once you turn off the car and back on real quick. Then not do anything for a month.

Its definitely coolant. Oil level is perfect and coolant is consistently missing some. Not lots but its going somewhere. I did my turbo install by the book. Most likely not the turbo.

[IanS]

What doesn't make sense to me is if you turn the car off and back on real fast the problem goes away. If it was the turbo it would be consistent. Possibly spurratic but not consistently stop once you turn off the car and back on real quick. Then not do anything for a month.

Sorry to burst your bubble, but you just described almost to a T the symptoms of a blown exhaust turbine oil seal. Ive seen it again and again. Completely random smoke that goes away if the engine is shut off, then restarted. The smoke is often noticed after the engine is stalled.

Plus you wont see a drop in oil level, because the amount of oil needed to create smoke is increadibly small.

Its a very common issue with the SR20s, Ive rebuilt 4 turbos for 2 engines because of it, some because of plugged oil drains, or in my case, a poorly routed crankcase vent system.

But if you say it smells like coolant, and it is disapearing, then I would have your cooling system pressure tested, and it may also be a good time to test for combustion gasses in the cooling system. You may have a cracked head.