Ok, so I have been fighting this issue of a misfire/stutter that only occurs under full boost. Needless to say I have tried literally everything. Well the other day I noticed my car beginning to over heat. I shut it off and pulled the thermostat out to make it home thinking that might be the issue. well it made it okay and after replacing the thermostat still over heated and has been loosing coolant (not leaking anywhere but I also haven't noticed any white smoke). When I pulled the radiator cap on a cold start to try to burp the system I noticed that the coolant was bubbling..... a lot. And the coolant began overflowing from the cap as well. Like I said this is on a cold start, first one of the day actually.

I know I should probably do a leak down but wanted to try to save money on buying a tester if this is a dead give away of a blown head gasket. Going to post a video tomorrow so everyone can see for themselves.

If I do end up doing a head gasket would it be okay to use a MLS if I get the head milled? the block was decked only like 15k miles ago and was hoping it would be okay to use one with out doing it again. Don't want to take too much off because I have 9:1 pistons and head has been milled twice. Thanks for any help.

If you were burping the system, bubbles are completely fine. Also if you are running the engine the coolant is going to expand due to heat so it will begin to pour out. Slow down before you pull the head and PRESSURE TEST your cooling system. You are jumping to an end conclusion when you may just have a leak.

Yeah I guess you're right I probably should. When I did a compression test I had 170 across the board. But I know that doesn't mean it's not a blown head gasket. I just thought on a cold engine it shouldn't be expanding that fast. I mean as soon as I start the car it's bubbling and overflowing. I'll put a video up as soon as I can and do a pressure test.

Here's the video. Sorry it's all side ways and stuff. I didn't realize my phone didn't rotate it. You get the idea though. Didn't have time to pressure test coolant system today. I will in the next day or two though.

While I agree it is wierd how quickly it seems to come out. I still wouldn't call Headgasket yet. When did the overheating occur? In town driving? Sitting at a light? While cruising on the highway? Do you retain heat while this happens? Cooling fans operating correctly.

Also noticed it looks mostly like water... do you have a proper 50/50 mix?

If your radiator cap is old and not holding pressure, it would explain losing coolant, overheating, and no white smoke out of the exhaust. Have you replaced your cap? If not, its super cheap, and easy obviously.

I have replaced the radiator cap. it was leaking a little pressure actually around the time this started and it still overheated after being replaced. The fans are operating properly. I did retain heat every time it overheated. And the overheating seemed to be mostly at idle. The first time it happened it was still overheating once I started moving and then went down a bit. At that time I didn't want to risk it and pulled the T stat to get it home and It was okay the way home. Once I got it in the garage it started to get a little hot again even with it out. it was also down on coolant a lot. Its losing coolant fairly quickly.

Also the mix is proper it just mostly looks like water because that what I had just added to top it off.

also I should mention the over heating is inconsistent. I added coolant after the first incident and then drove it for a few days and it was fine. then one day after doing a pull it happened again and started going up. It was low on coolant again. It may be just overheating because of the loss of coolant. I just don't know where its going. Also I didn't notice until after I took the video but my overflow was filled to the top. That could be where some of the coolant is going?

You really should do a leak down test. Only two other options I can think of are a radiator restriction or exhaust being pushed into the cooling system.

Are you on oe fans and radiator?

Yes I am on oe fans and radiator. Like I said fans work properly. Radiator may need cleaning, but would that really cause all those bubbles and foam? I want to do a leakdown but don't have a tester. I dont think AutoZone rents them and I'm sure the harbor freight ones are junk. I'll try to track one down and see what I come up with. Hopefully I can get a Wiseman to chime in. I really wanna know what I should for sure do so I can start it on Wednesday if I gotta pull the head. I do think you're right about the leakdown though...

Any update to this? I'm curious to see the cause.

leak down test just confirmed that the head gasket is leaking and im getting pressure into the cooling system. Or there is a crack somewhere. Head should be coming off tomorrow and ill have more details. Do you think that since the block only has 20k on it since its been decked that just getting the head milled and using a MLS will be ok?

I can't say for you for shure, but when I changed my head on my car I used a 3 layer mls I believe. Block was not decked just cleaned really well. I did use a straight edge and feeler gauges I think my step dad had me using .025 not sure though. But it was ok meaning level so I put on new head. My engine has 150k your 20k I would think would just fine. But it's up to you. Hope this helps

Make sure the head is leak tested to rule out a crack! Good luck!

The head is going to go to the machine shop tomorrow and they'll give me the low down. As far as the block goes ill definitely check it with the gauges. Im sure it will be fine though. The real question is why did the gasket go bad. Im guessing its because of my 9:1 compression... well... more like 9.6 probably because of the fact that the head has been milled 2 times and the block decked once. I got a thicker head gasket this time around in hopes that it will help lower it a bit. Hopefully that's it. I got a 85.5mm gasket. That's the right one for a .10 over bore right?