So just bought a 87 supra, blowing white smoke on occasion

[ewrtertiuer]

So i bought it on monday and then by thursday i saw it blowing white smoke, i know with this usually means but its odd because the coolant isnt bubbling. when i hit the throttle the coolant goes down as normal and then rises when i let off no bubbles. Oil looks clean, but i havent been able to check inside the cylinder. Today i started it up no white smoke, drove it around and then the battery shorted and lo and behold the white smoke started again. Does anyone have any clue what could possibly be occurring?

 

[Grandavi]

I was going to answer, but then thought I would ask for more detail. A tiny bit of white smoke or clouds? Why did your battery short out? Why would you look for bubbles? Does the white smoke stay while accelerating and increase?

Details.... and... how mechanically adept are you?

Your engine bay looks like some thought and care was put into it and the body looks really clean. Not a fan of how the intercooler piping is routed because your AFM is not forward enough for my tastes (too close to the hot zone for air).

Nice ride, though!

 

[ewrtertiuer]

Well today hasnt been much only after the battery shorted and turned off. but the other days when i would rev alot would come out so i find it strange there are none now. I believe the Battery shorted out because of some faulty wiring done by the previous owner. i looked for bubbles to see if their was any exhaust gases getting into the radiator. and the white smoke would fade as i would drive from what i could tell.

Im somewhat mechanically inclined, i know a lot about the 7M but not enough mechanical experience to work on it myself you can say.

 

[Grandavi]

Well, a failed headgasket would be constant white smoke (and mine was billowing white...), its better to do a CO2 check (kit is 65.00 on Amazon or I think you can rent one from an autoparts store) and I would really make sure you track down the short. Supras are adverse to fire... lol. I had a battery blow up due to faulty wiring and a short and it lifted my front wheels about 6" off the ground. Luckily the hood was closed when it overcharged/shorted.

Normally the signs of a bad headgasket are oil in the coolant and your coolant reservoir raising in level when running warm (can actually pump coolant out of there). Intermittent white smoke can be due to forged pistons depending on your engine. I could smell my bad headgaskets. Now... Im not a mechanic so what I say here is based on second hand info, but my pistons have a .04 tolerance due to forged pistons (yours may have forged, just judging from looking at it). If I idle for a while, I will end up with smoke due to oil slipping past those tolerances, but it will stop after I increase my RPMs. I am used to that on V8's - where high power builds will smoke a bit, but when I saw it first time on my 7M I kinda panicked. Do you know your engine specs on your car? It helps to have a background and know what you currently have.

We tend to think bad head gasket with 7M when its not always the issue, but with a newly purchased Supra I have seen that normally being the first problem to rear its ugly head quite often. (all but three of the Supras I have owned had head gasket issues due to negligence and bad repairs.

Remember, everything I say here is based on reading and experience, I am not a mechanic, so you cant take what I say as gospel truth, there are others here that are far more qualified to answer. (Just saying... cause I hate advising when I am not 100% sure)

 

[ewrtertiuer]

Yeah im gonna work on the electrical system today. no i dont actually, i know the size turbo and such but not exact specs which i should try to find out.
After today when i check it out closely and look into the cylinder heads and such ill find out.

I completely understand thanks for your assistance, i'll keep you up to date with my findings

 

[ewrtertiuer]

started blowing smoke out again, lots when i hit the throttle. Not sure what to do at this point.

 

[Another MkIII]

Now... Im not a mechanic so what I say here is based on second hand info, but my pistons have a .04 tolerance due to forged pistons (yours may have forged, just judging from looking at it). If I idle for a while, I will end up with smoke due to oil slipping past those tolerances

Oil is not white smoke.

Do a compression test and pressure test the coolant system. A leakdown test wouldn't hurt either.
-AM3

 

[bandit1730]

My 2006 750Li BMW has the same symptoms due to its nemesis (valve seals). As a result, it consumes lots of oil. You will see the smoke if you idle and then hit the throttle as you describe. Un-fortunately, I've been advised to just wait until the engine dies and replace it since the cost of overhauling this engine is extremely high and too complicated for a DIY attempt (an used N62 engine goes for about 4~5k) . Doing the valve stem seals on the 7M is a walk on the park compared to most German engines.

 

[Grandavi]

Yes oil is usually blue, but can look white in the rear view mirror if its not a lot. Generally, I put my hand in the exhaust plume and them smell my palm. If you smell the sweet coolant smell it can usually point to the beginning of a BHG. Heavier white smoke can be smelt at a distance quite plainly.

The smoke I get occasionally after a long idle is grey with a hint of fuel smell. All my little issues will be solved or identified over the next two-three weeks.

If your a mediocre mechanic (like me) it can be difficult to troubleshoot the little problems. There are multiple problems that can occur and tracking them down frustrates me, so I use the professionals. Not the cheapest thing in the world... Lol.

Never regretted paying though, because it has saved me a lot of time and I don't have tiny problems that big the hell out of me.

You should see if the previous owner can give you an idea of what's under the hood.