Iv'e had a problem where my freeze plugs started popping out. Been happening ever since I started making real power so about 5 months now. The first time it happened it was my #4 cylinder plug and the tranny side plug. Replaced the head gasket and popped some new plugs in. Everything seemed fine. A while later the tranny side popped out again. Put a new one in and again it seemed fine. Then today my #3 cylinder plugs popped out. Well after kicking and screaming I started looking around.

Well I noticed my overflow reservoir was bone dry. I started thinking about why I keep blowing plugs. I was wondering if the tank was dry will that cause air to get sucked into the coolant system instead of coolant causing air to get trapped then blow out plugs. That's my theory anyways.

I have TS left, right, and front mounts. They're 75 durometer bushings so my tuner is thinking I might just need to put the stock mounts back in.

Aside from that will the dry coolant tank theory cause freeze plugs to pop out?

tl;dr
Freeze plugs popping out. I think the cause was my dry overflow reservoir. Could that have been my problem?

 

No. Small amounts of air in the system will simply vent out the radiator cap. Large amounts will cause overheating.

Its likely a head gasket. You are over pressurizing the cooling system. Could be a bad cap that isn't letting pressure out, but more likely is you are blowing combustion gas into the water jackets. The over flow is dry because the combustion gases push coolant out the overflow and then when the motor cools it sticks back in what it can but over all, you have lost coolant out the overflow.

 

I hate to say it, but it sounds like a text book blown hg. Cylinder pressure getting past the seal and into the cooling system. Have they all blown out under load/high boost?

 

03whitegsr beat me to the "post" button. Check your coolant and oil for any signs of mixing. If nothing obvious then do a leakdown check and look for bubbles in the system.

Also if there is a cloud of white smoke behind the car, that's another bad sign.

 

The head gasket is what caused the 2 plugs to blow out the first time but the gasket has been replaced recently. I have a feeling it's a gasket problem too though.
Every time it's happened is when I was under boost. I peak at 38psi but I'm not even reaching that when plugs blow.

On a side note. I witnessed my tuner ripping my car up and down the street and spinning all fours just proving it's reliability and overall integrity of the maintenance done. Not a single issue. I drive my car for 3 days and do a couple pulls and again, not a single issue. Suddenly today my car felt like popping a freeze plug.

Wouldn't a leaking HG be a little more consistent? Could the block be flexing or something?

I'll check the oil tomorrow and see if white smoke is coming out of the exhaust.

 

Sounds like a headgasket sealing issue. Something is going on where the seal isn't holding causing combustion gasses to pressurize the coolant.

 

Check the plugs for signs of detonation and coolant contamination.

You kind of answered your own question though. Last time they popped out, it was the head gasket and now they are popping out again...

What head studs?

 

L19 head studs and OEM gasket. I can't wrap my head around why the car will be fine after numerous road tuning sessions where the car is WOT in 3rd gear up to 10,000 rpm. And the car was fine for the first couple weeks when I had it, where I did 2-3 3rd gear pulls. Then out of no where plugs start popping out. It may be a head gasket but wouldn't it be more consistent?

 

No, a head gasket will go when it feels like it. How were the surfaces of the block and head? MLS gasket require a fairly high RA finish to seal properly. And even then, k&w copercoat on both sides of the gasket really ensures a good seal.

 

The head surface was checked when the hg was replaced the first time. When the #4 cylinder and the plug over the tranny came out. I got a new hg and reused my l19s.

 

Will o-ringing the block help seal under high boost applications? My head is already o-ringed.

 

Define "head surface was checked"

Did you check it yourself with a straight edge and a feeler gauge? How meticulous was it actually checked?

Reason I ask is because I've gone through the blown headgasket game and I think my situation may relate. Way back in the day ~2008 I blew a freeze plug and the culprit ended up being a blown headgasket. I had the head checked and it was deemed "fine"

Now fast forward to well about a couple months ago or say the past year. I had been trying to track down an oil leak. After countless hours I couldnt for the life of my figure out where the oil was coming from. My last thought was a oil seeping from the hg. I just figured I would leave it well enough alone and keep an eye on my oil level. I dd my car and auto-x it as well. While I do my best to maintain my car and not abuse it, it's an evo after all so my car gets its fair share of beating. Now I dont mean clutch dumps and that nonsense but its driven hard at times.

So anyway it was about a month ago and I was at an auto-x and I noticed for the first time that my car was pushing coolant to the spillover. At that point I knew my hg was compromised. The car did not overheat or anything I finished the day and drove it home. I pulled the head and had it "checked" by a different machine shop this time. What he found was that my head was out .003". He said technically this is ok but given a boosted application it would be best to have it resurfaced.

Now I'm telling this story because I think it may apply to your situation. In my case my theory is that after all these years my head had a slight warp to it from the original hg failure. This is why oil was leaking from it. Slowly the oil built up and the seal was finally compromised.

If you have good headstuds in there which you do I think they may be covering up the fact that your headgasket still isnt sealing properly.

EDIT: I just saw your last comment. Im no expert but I was under the assumption that if you have your head o ringed then the block must be properly "grooved/ clearanced" in order to accept the o-ring and insure a proper seal?

 

/\/\ This on the o ringing. It occurs to me that the o ring job may not have been done correctly and the head is not compressing the gasket properly. After 2-3 weeks it gives way and boom pressurizes the crankcase cooling system. Sudden pressure spike blows out one of the freeze plugs. Reason for not seeing any white smoke is the very short time frame it does this in

Having said that a warped head may also do this. As will a cracked head or cracked port into the water jacket.

I would recommend pulling the head and having it properly cleaned and then checking the head for flatness. You also need to check the block deck for flatness and figure out a way to determine if the o-rings is causing an issue not allowing the head to seat properly. If the head needs surfacing, you have decisions to make. New one or try to cut the one you have, if it still in specifications.

Make sure to have the machine shop check the head for crack in the ports going thru to the water passages.

 

Orings setups are a nightmare.

The shops that actually have them figured out keep the info sealed up tight. Done right and done wrong is nothing you will pick up on with your eyes either as you are talking thousands of an inch difference between right and garbage.

I'd go to orings as an absolute last resort on HG issues because more likely than not, it's going to cause more problems than fix.

Unless the shop that did it has a solid track record of oringing the 4g63, if bet they were done wrong.

 

Well I spent 13 hours at the shop having the mechanic run some tests. We pressurized the coolant system, no leaks, held pressure just fine. Ran a compression test on all four cylinders, don't remember the results, I have the paper here somewhere, regardless, it passed. We went ahead and replaced #3 and #4 cylinder plugs since those have come out before and we had one extra plug to use up.

After everything was done the coolant was pressurized again to double check for leaks and to make sure pressure holds and every thing was fine. The oil was checked for coolant and the coolant was checked for oil, again everything was fine.

When we were done for the night the shop owner and myself went out and ripped on the car for a little while. Doing 1-3 gear pulls, slamming gears trying to lift the head. The head stayed put and all freeze plugs stayed in. I'm at a lost for words.

I'm not ignoring all the advise I was given or anything, but is it possible the TS mounts are too stiff? I have the left, right, and front mounts in. They're rated at 75A durometer. Tuner suggests putting the two stock side mounts back in, that the rigidity is flexing the block under constant loads thus blowing plugs.

I'm not beating on the car anymore. I think there's something fishy going on with the head too but for the time being every thing seems fine, and all tests came back negative. I'm going to save up to send the motor back to BR to have them freshen everything up.