Needed: Nissan Expert--oil in coolant - PeachParts Mercedes-Benz Forum

JEBalles · #1 11-02-2009, 04:27 PM

It's hard to find any experts or forums for nissan's, but my friends 1987 300zx turbo recently overheated. It has approximately 150,000 miles. Driven again, it didn't overheat. Problem is: oil appears to be in coolant. Poop brown and stinky under pressure cap. Expansion tank appears normal color and smell. Exhaust smelled a little sweet and was pretty moist at cold, but went away once warmed up, and stayed at normal temperature today. From what I've read on the MB gassers, that's code for new head gasket. Can this be confirmed? The car is going to be winter garaged anyway, so should that be attempted by someone who doesn't know a camshaft from a fuel injector, but who's willing to learn, with my help? Or is this new engine territory? How about driveability in this state?

mgburg · #2 11-02-2009, 05:07 PM

Quote:

Originally Posted by JEBalles

It's hard to find any experts or forums for nissan's, but my friends 1987 300zx turbo recently overheated. It has approximately 150,000 miles. Driven again, it didn't overheat. Problem is: oil appears to be in coolant. Poop brown and stinky under pressure cap. Expansion tank appears normal color and smell. Exhaust smelled a little sweet and was pretty moist at cold, but went away once warmed up, and stayed at normal temperature today. From what I've read on the MB gassers, that's code for new head gasket. Can this be confirmed? The car is going to be winter garaged anyway, so should that be attempted by someone who doesn't know a camshaft from a fuel injector, but who's willing to learn, with my help? Or is this new engine territory? How about driveability in this state?

A friend of mine (John W.) had a Nissan 4X4 with the I-6 engine and related goodies (A/C, HO Alternator)...

He overheated his and had the same issues, brown in the coolant...

He had it diagnosed as a "warped head" and ended up waiting almost 5 months to come across another engine, from a P&P (new head was almost $1,200!!), that the head could be harvested from. During the re-build, the machine shop had to "shave the deck" of the block to allow the "new" head to be bolted on and seal up properly.

After putting $2,000+ into that, he drove it for another 2 years, then traded it in for something else...I don't remember what.

But, he definately became an overnight believer in paying attention to the temperature guage after that little wallet-wacker...

Have the stealership look it over and give you a written estimate, then go to one or two other "independent" shops and ask them to do the same, then go with the one that you feel isn't yanking you around, but seem to be covering the bases. Your friend maybe just lucky enough that it's just a blown head-gasket, or he could have warped the head like John did. There are a few ways to do this...

Let a few others chime in with their expertise, wisdom and experiences...

450slcguy · #3 11-02-2009, 05:28 PM

Basic mechanics.

Overheated engine + oil in coolant = warped head and blown head gasket. Not rocket science here.

Don't waste your time and money going to the dealer unless you want them to fix it. Find a good shop or two and ask for a quote for head/gasket job.

compu_85 · #4 11-02-2009, 06:48 PM

Before you condemn the head gasket look for an oil / coolant heat exchanger. If that broke due to the extra pressure from the overheat it would cause oil / coolant to mix. The nice thing is you can probably take it off the motor easily and pressure test it.

-Jason

JEBalles · #5 11-02-2009, 07:49 PM

What about driveability? Should he be worried about hydrolocking the engine?

TylerH860 · #6 11-02-2009, 09:22 PM

Quote:

Originally Posted by JEBalles

What about driveability? Should he be worried about hydrolocking the engine?

Not advisable unless you plan on replacing the engine entirely. That coolant gets down in the crankcase and mixes with oil as well, eventually ruining the bottom end. How soon that will happen depends on how bad the leak is.

Doing a motor swap would be easier to DIY, though. I wouldn't trust myself to tear a motor apart, but I'm not that experienced.

Chas H · #7 11-02-2009, 09:27 PM

Quote:

Originally Posted by JEBalles

What about driveability? Should he be worried about hydrolocking the engine?

The symptom is goop in the coolant. It's entirely possible that coolant will never enter a cylinder.
I would not jump to a conclusion the headgasket is kaput without further information. A waterpump going bad can introduce grease into the coolant. And a product named "Waterwetter" can give some oil looking floaters in the coolant.

MAG58 · #8 11-02-2009, 11:58 PM

The VG is a trooper, the single cam versions didn't die without a fight.

With oil in the coolant, a blown HG is usually a good place to start. These motors (at least in the Z31) weren't that hard to wrench on.

With the 5 bolt/cylinder placement even with the alloy heads, warping isn't a very common thing for a VG. However there is a substantial amount of coolant that flows not only between the water manifold (that sits on top of the block) but also the heads. Checking for a cracked water passageway could also be the cause of your problems.

loepke72 · #9 11-03-2009, 11:12 AM

Not a Nissan expert myself, but there is one test you can try to see if you have combustion gases entering the cooling system. With the engine off and cool, remove the radiator cap and start the engine. If coolant gushes out of the filler neck, you have a problem. However, this only works if the internal leak is a fairly major one. Otherwise, there are chemical test kits available to determine if CO2 is in the cooling system. Usually it's a device with a squeeze bulb at the top to draw gases from the radiator through a reagent (normally bromothymol blue). The reagent will change color if there is even a small amount of CO2 in the system due to a leak. Exhaust gases in the cooling system can give an oily appearance to the coolant. Oil in the coolant smells like oily coolant, but exhaust gases in coolant give a stronger odor.

JEBalles · #10 11-03-2009, 05:16 PM

Alright, today, ran without rad. cap and it didn't splooge. Good. My diagnosis at this point is: blown headgasket and possibly warped head (hopefully not) and blocked cooling system. The coolant seems to run to the radiator, so not thermostat, and it definitely moves, so not water pump. The coolant in the expansion tank is not oily at all, so that must be where the blockage is to allow it to overheat. For some reason, though, it cools fine now. We couldn't find any oil-coolant heat exchanger, or even an oil cooler, which I thought was weird on a turbo. We're waiting for a chiltons to come to give us some better insight on this.

JEBalles · #11 11-04-2009, 06:15 PM

Did an oil change today: no apparent coolant in oil. Good. Could this still be headgasket?