I mostly use OEM, but I have run FEL-PRO before without issue. Currently running OEM and always do unless it's a panic-fix in which I run FEL-PRO.

 

Thanks for the input gents.

Hey Lars, remember how I said I didn't want the cheapest I could find?

Well, I bought a $32 (closeout) fel-pro off rockauto. should be good hahaha....

 

OK Guys, I'm venturing into an area of personal noobness.

Tomorrow I'm going to tear into the head gasket issue. I've never done a head gasket before.

Aidan helped me realize that, duh, I really should have the head resurfaced when I pull it off.

I believe this head gasket likely popped due to detonation, not overheating -- the car has not been overheated this time around, at all.

I'll be posting pictures tomorrow, then decide from there, but I do need a machine shop for resurfacing.

Many adult beverages will be had.

 

Curious to hear Pat's response, perhaps one day we will all be carefully rotating sharpening stones across our heads

 

Yes, at the very minimum you want the head to be lightly skimmed to prep the surface. If it's warped it'll need a more significant shaving, if it's REALLY warped then it'll probably need to be replaced.

The question is, how many "while I'm in there" things do you want to do?

Is Fel-Pro an MLS gasket? Do not use a composite/cork/whatever gasket.

--Ian

 

If the head is flat, resurfacing it doesn't make it more flat. If you take it to a shop, they can check it and if it is not flat, they can machine it to make it flat. Usually detonation breaks a piston, not blows a head gasket but it could happen. Blown head gaskets are a rare failure on a miata since factory is MLS.

FWIW with a reroute if you lift the nose of the car up like that to get air out, all the air goes up and you get a bubble of air in the front of the head that needs to someohow go downhill to get to the thermostat. Lifting the front is perfect for stock thermostat cars to get the air out. For a reroute, it's the opposite of what you want if your goal is getting air out of the system.

I would confirm the head gasket is leaking before pulling the head to replace the head gasket.

EDIT: Yes flepro is MLS

 

Glad I posted. Feeling like a serious noob at the moment.

Would doing a coolant pressure test be a good way to confirm the HG is leaking? Wait... I did a compression test... Let me go find the numbers.

 

Usually if a head gasket is leaking to the point of blowing bubbles, a compression test would show a problem, you could measure the presence of combustion gasses in the coolant with a test kit for measuring this, and the offending cylinders spark plug/piston top would be steam-cleaned very clean and not match the cylinders that are operating normally. A coolant pressure test is a good idea. Note that if the gasket is bad, and you fill a cylinder with coolant during the test, and then try to start the motor, it will at best freeze up, or more likely bend/break a rod. If the test shows it leaks coolant and you can't spot an external leak, I'd look down the sparkplug holes and inspect.

 

A leakdown test is the best for checking head gaskets.

--Ian

 

Good point. If you got a leakdown tester, that's better than coolant pressure tester.

 

will obtain leakdown tested in the morning.

 

feeling a little stumped.

I have not been able to get a leakdown tester, turns out oreilly doesn't rent them. So I've yet to do that test.

BUT... I got a block tester, and there are no exhaust gases in the coolant.

I pulled the catch can, and there is zero coolant smell in there. There was some watery business in it but I really don't think it's coolant, seemed like water. Again, it looks squeaky clean under the valve cover -- no milkshake under there.

I re-did a compression test, and it came out right around 100 psi, all even. HF tester so not super worried about lower PSI.

So, I didn't pull the head. I'm really not thinking it's the head gasket. Could it be the turbo CHRA allowing oil into the coolant, but not the other way around?

Thoughts?

 

Probability of chra is next to 0

 

so, wtf?

 

My guess is you got air in the cooling system from lifting the nose as I described, steam was created, and that blew bubbles you saw, or just air coming out. Oil could be from the turbo if it's a new issue, or from some contamination getting in the lines while it was serviced recently. That was a tiny amount, could have been contamination.

I would get a new tester and redo the compression just to make sure, cause 100 is pretty low.

 

hmm. need to retest compression. Using this same HF tester, all cylinders tested around 150 last year.

So either I didn't get it tight, or there's definitely something up there.

The car runs perfect, though. Smooth idle, runs absolutely sweet.

 

I mean, this is typically an indication of a good running motor.

 

Indeed it is.

I'm going to order a leakdown tester and test that, but in the meantime, I'm going to flush the coolant and drive the silly thing, keeping an eye on the catch can for more milkshake.

It ran great yesterday, AFRs right where they should be, smooth boost, just... everything felt A-OK, just as it has the last year and a half since the car was built.

 

Which catch can? Milkshake catch can is not so unusual with condensation cooling down and such. Doesn't necessarily mean that coolant and oil are mixing. I think I have seen it on my car occasionally at certain times of year, can't remember when though.

 

If you're looking for recommendations I haz this one and I like it. It did an excellent job of showing that my intake valves were allowing alloftheleakage.