Direct Water Injection (i.e., Blown Head Gasket)
 

196,289. That's the magic number for my little 1.6. Boosted since 181,561. Head and block never separated. Last timing belt swapped at 150K (did not change water pump).

I was "cruising" (ala Sebastian Vettel) to UPS to return a core part for the wife's Mercedes. I thought I smelled some coolant -- but the part I'm returning is a cooling system part, so I don't think anything of it. As I get close to UPS, I have a long downhill stint where I just let the car roll in gear (high vacuum). Back on the throttle a bit and . . . what's this . . . a miss?!? Oh, oh.

Do my business at UPS. Come back out, pop the hood and look around. Nothing amiss. No leaks, no obvious issues with the spark plug wires, etc. Get back in the car and crank -- its starts, but more slowly than normal. And it has an obvious miss. Rev the engine a bit to clear the miss and a huge cloud of steam emerges from the back of the car. Yikes. Babies cry. Women look and frown. I smile and wave . . . what the hell else can I do?

Drive home slowly with the heater turned on and watching the temp gauge. Everything seems normal and as I drive the miss clear up and the steam stops spewing. Wierd . . . self-healing head gasket?

Pull into the garage and it's missing again. Shut down. Let the car cool and take another look. Oil is clear -- there's been no mixing with the coolant. Radiator is way down.

So, now I need to find time to pull the head and see what's up. My initial guess is a head gasket, although it might also be a cracked head. While I'm at it, I'll assess the condition of the cylinder walls -- wish I had done a leakdown before this happened. At the very least, I'll be getting the head rebuilt, new head gasket and maintenance (timing belt, water pump and that pesky little oil leak by the AC bracket that is probably a missing or broken bolt). Don't have a lot of time on my hands right now, so don't really want to get into a full build . . . but maybe I should?

Sigh. I've got too many projects. :bang:

15 year old daughter just walked in. "Dad" she says, "What did you do to MY Miata?" This is going badly.

:bowrofl:

I feel for you, man.

tell her it's due for an unforeseen, forced upgrade.

If you're pulling the engine to do the work, I see no reason not to do a semi-full rebuild while it's out.

there's an ebay seller (Cylinder heads International I believe is who I got mine from) that sells remanufactured heads for $350 shipped, which includes the postage for returning your old head. Mine arrived in very good shape, although it has yet to actually be put on. Might as well do rings/bearings/oil pump at that mileage as well as water pump and tb while you're at it.

You can find 323 oil pumps for cheaper that miata pumps, even though they share the exact same part number.

One quick-and-dirty test you can perform is to remove the radiator cap and then insert a leakdown tester into each cylinder one by one. If pressurizing any cylinder causes bubbling at the radiator cap, you have a pretty good indication of a head gasket failure.

For what it's worth, I can't recall ever hearing of a head failure on a B6 that involved a crack allowing coolant to enter the combustion chamber. Unless there's some overriding justification for a full teardown, I would honestly be predisposed to just pop the head off and replace the gasket. (And, of course, the water pump while you're in there.) You can go ahead and check the head for straightness and maybe pop off the valve springs and give them a few twists with some valve grinding compound if you're feeling bored, but I certainly wouldn't tear down the whole engine for something that is hopefully quite simple.

I'm predisposed to do the quick fix right now (plus a TB and WP). I need to pull the heads off my Fury too (broken exhaust studs). Might be able to get a package deal somewhere local if I drag in 3 heads.

I promise to post entertaining carnage pics this weekend.

Ew. Just buy a 1.8 longblock for $400 and a new manifold and happy it up

I hear ya'. And, it's in my nature to tear into it. But my problem isn't funds, it's time. I really just need to quick fix this (assuming a quick fix will do, which it probably will). If I go the route of pulling the engine, then an endless list of items become available for "upgrades" and I know that I'l just "have to." Sound familiar Fae?

Anyways, here are my cheapo Autolite's after 15K miles at 10psi. They look pretty good. It looks like my water injection isn't finding its way to cylinder #4 very well (or maybe I just have more wear in cylinder #4 -- pretty common given our stock cooling system). Hard to see any effect from the coolant leak here. Maybe on cylinders #1 and 2?

Warming up the wrenches for the Saturday head pull!!

just run more boost, it will help seal the headgasket :party:

Might not be the WI. That plug just looks richer to me. Mebbe less air? Mebbe just oil dripping down onto it? I am not sure since it looks like you oiled the plug.

To me, pulling the head, getting it redone etc all sounds like A LOT OF WORK. Pulling the motor is easy. Parts Group has a longblock with EVERYTHING for like $500 or something.

?

You can have the head off and on in one day.

Remove accessory belts. Drain and disconnect the upper coolant lines. Remove the crank pulley and timing belt. Remove turbo, but leave exhaust manifold in place. Disconnect intake pipe from throttle body but leave intake manifold in place. Remove head bolts, and lift the complete head-and-manifolds assembly off the engine. You may need to exert some leverage upon it (hence the retention of the manifolds) in order to break the 20 year old seal between the head and block. One option is to jack up the front end, place a 2x4 between the ground and the manifold, and then lower the car very slowly.

Assembly is reverse of disassembly.

Or, he could fill the radiator to the brim, keep the cap off, and crank the engine while watching the radiator neck. If the water bubbles - or shoots out of the radiator - in this process, it would be time to order a new head gasket.

Much easier, and simpler to do, IMO.

Yeah, I thought of that after I posted it, and hesitated from correcting myself in the hope that nobody would come along and demonstrate just how much I had managed to over-complicate the procedure.

So thanks for that. :D

You're welcome.

I tried this and it was working great, until I hit a traffic signal. :vash:

I know, I know, I'm a wimp.

Head gasket ordered!

Props. I like it. I was thinking that dealing with the manifolds would end up being one of the main PITAs on this job. Not dealing with the manifolds is ideal.

Much easier pulling the head than the whole engine... i'v done both... several times :facepalm:

A simple "head" job should do the fix. I am sure you will need some new valve seals as yours are 20 years old now. I may know someone who has a built 1.6 head in Granbury if you're interested Rick, we can figure something out either way.

Fixed (added 3 years -- i.e., much older than you!! :bowrofl:).

If I can get a built head for less than the cost to rebuild mine . . . .

But, all conjecture. I need to pull it and see what I have. I've got other nagging maintenance issues to fix also. Plus, there's the suspension.

Heck, now I'm almost glad it happened.

When I originally pulled my 99 head off I looked at it and said "well since we're already here might as well rebuild the bottom end", it's just fun tinkering until you have to do more and more of it.

I will check into the head I mentioned so I can give you an idea, I am sure the shop should be much much cheaper but maybe he just wants this thing gone :)

Carnage -- But not what I expected
 

I used Joe's method and got the head off without any drama. Cylinder #4 was steam cleaned. All the others were nominal. I was astounded at the condition of the cylinders. No scoring, still had nice cross-hatching. At 200K no less. No signs of det that I could see (thanks, MS).

Here are the pix, pretty boring except you can see what a great crud-cleaner steam was on #4:

Cylinders and Piston Tops:
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860
https://www.miataturbo.net/attachmen...ine=1349662860

Carnage was on the exhaust system. Turbo to downpipe was fine, but as soon as I unbolted the downpipe, it bacame obvious that my turbo was loose. It turns out that one of the bolts had sheared, and the other three had a bad case of thermal creep. I sheared them during "removal." Lucky for me, the safety wiring and well-supported downpipe kept everything together and fairly leak free. Inconel studs, here I come . . .:
https://www.miataturbo.net/attachmen...ine=1349662860

The only other heat-related issue was the turbo oil drain hose. It was cooked. Cracked while trying to remove it. Hard as a diamond.
https://www.miataturbo.net/attachmen...ine=1349662860

So, some long-term turbo lessons learned. The above is 15K miles and about 1.5 years of turbo'd DD.

No Fix
 

Finally got the car back together. Went for a drive and no change. Car seems to drive fine for the most part. Pulled into a gas station and it started missing at idle. On restart, big cloud of steam. Got it back home and, sure enough, coolant is low. It's going somewhere.

Head was checked out and rebuilt. No issue there. New headgasket, water pump and TB (I was overdue for some maintenance).

Could I have a cracked block? I didn't even think to check that when I had the head off. I've never heard of a cracked block unless someone is making insane power on an overbore. My power level is pretty tame, but the block is well-seasoned (pushing 200K).

I'm bummed.

Sorry to hear about this Rick, I was looking forward to hearing good things about the car this weekend.

Seems coolant is getting into the exhaust some how. Possibilities would be cracked head, block or head gasket. You have 2 crossed off your list but I wouldn't come to conclusions just yet. How does your oil look? Any signs of milky oil or is the exhaust the only place you have noticed so far?

I would start with a leak down test to see if it is getting into the combustion chamber. The smallest cracks can be so very hard to find. They can cause over heating or coolant loss.

If you need any help I am just around the corner, let me know!


PS: Where did you get your head gasket and what brand was it? My coolant loss problem I had a few months ago lead to a junk head gasket, your new gasket could be your problem I have seen many come damaged or not properly sealing right out of the package.

Oil is perfect. It was fine first time as well.

Gasket is Mazda OEM.

Drove with the new suspension. It was nice. Very comfortable, especially considering 500/375 spring rates. Sitting a lot lower.

Is it now dragging up and down your driveway like mine does? :vash:

My first check would be a leak down test just for the hell of it. Next stop would be Auto Value for a Fel-Pro MLS gasket. My OEM gasket I had gotten from Mazdaspeed Motorsports turned out crap right from the get go. Not saying yours is it just seemed to be the fix for mine. Completely look it over for any cracks on the cylinder walls and water jackets.

We even had the same results on #4 cylinder.

https://www.miataturbo.net/attachmen...ine=1339987234

Did a compression test.

#1 166
#2 162
#3 165
#4 212 ?!?!?

Tip of compression tester came out of #4 dripping coolant. I'm guessng the water in #4 is raising the compression ratio. Still don't know where that water is coming from.

Next step is the same no matter what. Pull the head (again).

For original rings those are great numbers. But you're correct on the raised compression, most people add a little oil to increase their numbers when testing.

Seems like a lot of trouble but if you pull the head and don't see anything I would try to throw another head gasket on there and try it out. Knowing the head is good a new Fel-Pro (or whatever these other gays may suggest) may fix it, if not your problem lies in your block.

Get rid of those cardboard gaskets, OEM is over-rated. You need the metal 4-ply ones.

How could it be a cracked head? You mentioned it was checked by the machine shop fully rebuilt. Would take it back to them, whoever it is.

I had a similar problem on my car, went crazy checking left and right, and turned out to be a bad block, which by the way I am working on it right now.

http://www.enjukuracing.com/products...m,-.040in.html

https://www.miataturbo.net/attachmen...ine=1355160068

I bought ARP head studs, shaved cylinder head, double metal head gasket, etc, and nothing fixed the problem. It seems that block is junk...

If looking for engine blocks, Mercury Capri (also the cyinder head) are the same if when you go to a junk yard and all the Miata ones are gone.

Yeah, I'm pretty sure I'm down to the block. The compression test really doesn't point to a head gasket. On my original tear down, the head gasket didn't look bad. It was still well-adhered and there wasn't an obvious path from any water passage to the cylinder (see pix above). I've seen pictures of bad head gaskets and mine just didn't look like those.

I've got other issues with the short block anyway. I've been living on a Locktite fix to the small-nose crankshaft for 50K miles. Probably overdue to fix it right.

So, that's one other that has had a block crack. Maybe it's not as rare as I think. I also don't have a coolant reroute. Contributor?

Stock HG is MLS.

Only on 1.8's, the 1.6 cars got the graphite or whatever it is.