Snoop Dogg Coolant Steam Out of Exhaust
 

1991 longnose 1.6 stock top end, stock bottom end, 61k miles, MS2PNP (Rev), Flow Force 640s, Begi Shanghai, SS lines, Turbosmart MBC 14.8PSI with occasional spike to 15.2, KN 3" filter, ebay FMIC, silicone hoses everywhere, Allstar Performance catch can, AEM WBO2, Autometer Boost Gauge, Tunerstudio + MLV, Koyo large radiator, AC delete, Manual rack, Timing belt/Waterpump done at 45k, 949 motor mounts, 2001 Torsen with single piece axles

Sometimes, after a lap on the autocross course the car will billow out Snoop Dogg levels of coolant steam, I mean, sting your eyes, choke you to death coolant steam, after getting up and going at the start it will subside after a launch, and will only come back if my co-driver is driving and idling in the grid (different driving styles?) WHEN it steams from the exhaust, the turbo will steam from the water (in?) fitting closest to the engine block, and from around the exhaust side turbo housing, where it meets the CHRA...


Checked coolant, seems to be no oil in there
Checked inducer, clean
Checked charge piping, clean
Checked spark plugs, trace amounts of oil on combustion side of crush washer, otherwise clean
Checked Spark plug boots, clean
Checked Shaft play, 0
Checked compression with cold car, 200, 200, 190, 205 PSI (WOT, 8 second hold)
Tune seems fine
AFR's remain unchanged whether or not it's steaming if only a little lean, but that could be due to CLT MAT correction. I wouldn't know as it's hard to keep a laptop in the car on course or in the grid.




Bad turbo?

how much coolant do you lose per event/run? Is it drops, cups, or gallons?

About 1/8th of a cup. It's not much at all, and ONLY happens at autocross.

Oil loss is similar, I lose about 1/4 of a quart between changes.

Did you like have a total brain malfunction and like connect the radiator overflow hose to the intake manifold thinking it was a vacuum line?

Yeah, that's it. Great contribution jackfuck.

the chra would have to crack almost in half to puke coolant into the hotside.
I've yet to ever see that.

Leafy's comment isn't actually even that much out there. We've had similar things happen on here, and OP actually had enough humility to admit it afterwards.

I've been told twice now that I would absolutely know if the CHRA was cracked that badly, it's just such a weird problem that theoretically seems to fit the bill exactly. Obviously it only occurs in extremely high heat conditions. If the car was running on that much coolant though, I'm almost positive the idle would show it, it just runs and runs like nothing's wrong. Also, the steam emitting from the turbo from around the housing (maybe just the inlet line, and it's kind of making it look like it's seeping through the housing...) it's just so fuckin weird man. It's not like I can point the blame at my valves, like so many oil burners. I'm at the point where it's pretty much just guess and check I suppose. I was hoping someone had or has something similar. I followed several threads from here on that and no one had symptoms exactly as I describe. It doesn't do it at idle, partial load, cruising, revving at a standstill, only after a hard run, and only until I get air moving through the engine bay again, then nothing. It's a slippery slope that ends in a lot of money.

....Take head off to do HG, well, the head's off, might as well do X, Y, and Z...

On a plus side, we're 15,000 miles and 10 autocrosses on that knockoff of a knockoff ISIS turbo that BEGI sold me, and it still seems fine!

I would bet on hg over turbo

Have you done a hydrocarbon test just to check?

I haven't had oil or water analyzed, dyed, or combustible gas checked. I think 18PSI is right and there's no avoiding it. It's gasket time.

Fel-Pro okay? Or should I buy the Gucci FM one?

Fel-pro or oem. You need to get the head surfaced also. Have it checked for straightness too. If its not straight get a new head. Make sure to clean out the threads in the block really well before putting the bolts back in.

Do a new intake+exhaust manifold gasket while you are in there. Maybe a thermostat too depending on when it was replaced.

Make James do all the work. He is a glutton for punishment

James is too busy for trubo nonsense. I'm going to have to take it to Get Money garage in Renton.

I use eBay head gaskets that run $26 shipped. I have used over a dozen without any issues.

In my experience, the composite HG in the 1.6 don't stand up to competition use with FI. Fine for street use.

If you're going to continue competing, I'd recommend ARP studs and switching from composite to MLS. An MLS gasket is more finicky about surface finishes though.

1.6 lyfe

Well I did not really read the first post. So the solution is to um, install a 1.8 and win.

Eh, I've got to squeeze every ounce out of this motor I can. I got the Gucci FM one. In fact the whole kit. Should be a "fun" as in "running backwards naked in a knife factory" project. I'll post pics and shit if there's engine carnage.

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

https://www.miataturbo.net/attachmen...ine=1467442853

Alright tur-bros, can't find any obvious signs of damage here. The head lifted with extreme ease by bearhugging both manifolds and suplexing it. I was told that's pretty suspect of a blown HG. Also looks like turbo seals are blown. As I wrestled the head off the fuel rail let a shit ton of fuel out onto the pistons, which is why they're wet. The rust is from the old steel impeller that was on the waterpump as the car sat in a barn for 23 years before I bought it. I flushed the system 15 times, and now I change and flush coolant about every 2 months, and it's still in there.

Looks like a simple blown headgasket. Cylinders 3 and 4 look like they've been consuming coolant for awhile -- long enough to have steam-cleaned the tops of the pistons.

I was thinking the same thing today was I was conditioning the block for the HG replacement, plus cylinder 3 was lower than the rest.