zcar78

All:

I am new to the forum and wish it was under better circumstances. Here's the story, I have an 06 Z and the radiator started leaking in October so I went and got the Mishomoto radiator, silicon hoses, etc and put it all back in. I filled up and spent what seemed like an eternity bleeding the damn coolant.

As some of you know, getting air bubbles out of the Z's cooling system is a not easy, apparently it was designed by a third grader. Anyways, I could still hear bubbles going through the heating core and kept bleeding and bleeding. Later that month, I noticed white smoke coming out of the exhaust and building up on my bumper....freaked out cause I thought the head gasket was blown and coolant was leaking into the oil but suddenly it disappeared.

I drive the car once in a while in the winter and never saw any smoke buildup on the bumper or smelled coolant but now that the temps have risen again, the white smoke has returned and I can hear the bubbles again. Thinking that obviously since the temps have risen, the coolant is running hotter and with the air bubbles expanding, the coolant is going into the engine via the gasket. Engine never overheats....

I know there has to be more air in there somewhere and I will continue to bleed it but what are your thoughts on a potential head gasket issue due to the white smoke and buildup on the bumper? The car seems to run just fine but I see the buildup and can smell coolant with no leak anywhere.....

Is there any way for coolant to get into the engine aside from the head gasket? If not, any ballparks on how much it will cost to replace the gasket?

I may dump this car if thats the case and just get something else, figure Nissan will charge me my firstborn to replace it...

Any thoughts would be greatly appreicated...the car's mods are below if you care to know...


- 06 6MT - 60,000 miles
- Pulley set, MREV2/spacer
- Nismo Intake and Exhaust
- Stillen Cats
- Uprev tune
- Stillen short shifter
- Hotkis sways, Bilstein PSS10 coilovers
- Stoptech slotted/drilled rotors, SS lines, blah blah

JCITY

iTrader: (2)

With other cars,coolant loss can go through the intake channel.That may be where your
problem is.

konrad

iTrader: (15)

does the coolant smell like coolant out of a bottle or does the exhaust just smell weird? Reason I ask is that when coolant burns in the combustion it doesnt smell like coolant anymore. Maybe you have a leak somewhere on the car? did you notice any wet spots?

e30cabrio

iTrader: (30)

Is the oil foamy and oddly colored? Does the exhaust smell oddly sweet? How much coolant is it losing?

Unless all of these are yes and there is significant coolant loss I'd say leak. The easy way to find out is to send an oil sample to Blackstone. They will test it and tell you exactly what is in the oil.

djamps

iTrader: (1)

Check under the radiator cap for brown/oily film. But it really sounds like you are pushing air into the system, most likely HG.

konrad

iTrader: (15)

The oil in coolant doesn't always happen with a blown HG , if it blew only by the cylinders than he will just push air and exhaust into the coolant. If you don't have a sweet exhaust smell than its a leak or its blowing cooland out the overflow

binder

iTrader: (8)

when it's fully warmed up feel the lower drivers side radiator hose. if it's still cool to the touch then the t-stat isn't opening due to air behind the thermostat.

If that's the case get a spill free funnel. Air behind the tstat will cause it not to open thus overheating the coolant inside the engine and it boiling over (bubbling sound).

If the lower rad hose is red hot when the car warms up then something else is going wrong.

zcar78

Thanks for the feedback guys...today I jacked up the front end of the car and did the funnel method, put a big funnel into the radiator neck and let it run. More air bubbles came out so hopefully progress. The thermostat is turning on because when it does and the fans kick in, the fluid level in the funnel drops down.

I checked all the coolant lines very very closely and no leaks, no fluid on the garage floor...nothing.

I also ran the car on level ground with the radiator cap on and do smell sweet coolant smell. Did some research and found that the mishomoto radiator caps have a tendency to leak a bit and let out air so I am guessing that's where the smell is coming from....changing the cap to Nismo or other.

The exhaust doesn't have a coolant smell but based on one of your posts, the coolant combusts so it wouldn't smell like coolant coming out of the exhaust. The exhaust does have a noticeable gas smell though. I hooked up my Bullydog watchdog computer and the A/F is at 12.7 at 750 RPM warmed up. Not sure what to make of that.


I guess I am just gonna bleed it again tomorrow with the funnel and change the radiator cap and give it a go. Really frustrating.....will keep you posted.


Unrelated but also adding engine damper and stiffer transmission/diff mounts and will let you all know how that goes. Drove a buddies car with these and the shifting was amazing, car just felt like it was more solid, quicker to respond to gas pedal...lots of noise/vibration though but this is not my daily driver so I can live with it.

zcar78

All:

I finally had some time to get in the garage to investigate the possibility of a blown head gasket. The car still puts a white film on the rear bumper after I put a few miles on it in the heat so wanted to see if I was burning coolant. I changed he oil (pic attached) and there is a white milky film on the top of the oil.

Assume I am screwed and the gasket is shot? I assumed that the white milky stuff is coolant in the oil and the only way it gets in there is through the intake (ruled out) or the gasket.

Called the bastards at the dealership and they said 3500 to replace both gaskets.... it may be cheaper to buy a refurb engine or just give up and toss the car...not sure.

Can anyone confirm what I suspect? Also, any idea how much an honest shop would charge for a gasket change?

Thanks

binder

iTrader: (8)

yep, that means a water based fluid is getting into your oil and with the other symptoms i would say head gasket.

that is way too high for the cost to replace it. I changed the head gaskets in my car without pulling the engine in a day. Probably 16hrs total with slow work to pull the front end off, pull the heads, put new on and seal it up. So if you say 100$ per hour shop rate for 16 hours plus parts it should be near 2000 grand.

Since it's a NA car i'm confused why the head gasket blew. When you had the leaking problem did the car ever overheat? I hope it didn't because I would be worried about warped heads.

where are you from in indiana? I still own my house in terre haute but live in st louis for school. I guess for the right price i might pull them and replace them. you can email me if you don't find a shop to do it for you.

zcar78

Jeff,


The car doesn't have many miles on it and it has always been NA so thats why I am confused too. The engine never overheated, but I just thought of something else that may explain it.

I had the radiator replaced a while back and it started shortly after the radiator was replaced. Unrelated to this, I started hearing air bubbles running through the heater core shortly after the radiator was replaced as well. Turned out there was a ton of air in the cooling system, I bled it but the while smoke/buildup continue. Maybe since there was so much air in the damn coolant, the pressure in the cooling system spike very high and busked the gasket? Air expands more than coolant I assume.

binder

iTrader: (8)

air expands but it compresses. Fluids don't compress. Air pressure would not blow a gasket.

What is likely to happen there was air trapped in the passages therefore there was no contact between the coolant and the actual cylinders so even though the coolant temp wasn't high the actual cylinder temp rose enough to warp the cylinders and cause a gasket leak. I tell people all the time the coolant temp is only a measure of how much heat is being removed so just because it's normal temp doesn't mean the engine is normal temp. Especially if there isn't coolant contacting the metal cylinder walls.

so technically with it not being bled properly the important parts of the engine weren't cooled and ran like it had no coolant in it.

zcar78

Good lord, well thats great, so are you saying I need a new engine? The system never overheated but I can see what you are saying. Given the circumstances and timing with the coolant, I guess I know what likely happened.

djmurder

What he's saying is that your guage never SAID that the system overheated. Large amounts of air in the coolant system kept it from cooling your block. Think of it like a clogged fuel filter thats gonna cost as much as an alimony. After your car has idled for about 30 mins, what was your coolant temp guage at? If hes right the coolant temp should be relatively low and your head is melting like cheese. You don't necessarily need a new engine. But you won't know what you need until you tear it down. Your block is probably ok, along with the accessories. But you'll have to inspect the head, valves rods pistons....all the expensive pain in the *** parts. If you plan on taking this on yourself then find a good machine shop, and get the boxwrench dvd. Lots of useful information for rebuilding but its kinda boring as hell after about an hour.

zcar78

Yep the coolant temp stayed slightly lower than dead center on the gauge, never showed any sign of hi temps. I am taking the car to a place here in Indy that works on german/japanese imports. They do a lot of high end work so I am sure they would be able to find the issue and then ask for a million dollars to fix it. I am also asking them if they would do a built engine so we will see. The car drives fine right now, I guess I need to decide if its worth fixing and keeping.

BlueDragonZ

iTrader: (11)

What end up happening to your Z? I'm having the same issues on mine, blown head gasket based on a compression test. Did you ever do a leak down test? I'm waiting to do that to mine

binder

iTrader: (8)

I know I haven't checked this in forever but I wouldn't trust any shop in Indy with doing a built engine on our cars.