I'm needing some help and opinions and I'm getting pretty annoyed. I recently had my engine built and we're in the middle of tuning. Car is running a 6266 at 43 psi.

Last Saturday at the top of 2nd gear, my heater hose decided to pop off. I chalked it up to a weak factory spring clamp so I replaced the clamp and car ran great doing multiple pulls on Sunday and Monday morning until my last pull, the front freeze plug on the passenger side decided to pop off at the top of 2nd gear.

I got the freeze plug replaced and decided to do a pull tonight. First gear at about 7k rpm the same freeze plug pops off again. I've replaced the tstat, radiator cap, did a block test to make sure there were no signs of head gasket failure or cracked block or head and everything is fine. Retorque my l19s to 105 ft lbs.

My question is what would cause excess coolant pressure to have this keep happening? It's obvious that the pressure in the radiator is under 15psi since coolant isn't overflowing into the reservoir but pressure inside the block has to be high. I'm ready to tack weld every single one on but I don't want it to be a band aid fix if something else is going to give. I don't know what else to do though because tow bills and being afraid to get into boost isn't fun at all.

 

Get your turbo rebuilt the seals are bad on the coolant side. Happened to my evo 8 4 years ago.

 

The new pte line of turbos aren't water cooled so there's no coolant going through the turbo

 

Pretty much the only way for that to happen is for combustion to pressurize the cooling system.

 

And that was one of my first thoughts so I bumped up the torque on the L19s to 105 ft. lbs. But I did do a block leak test and it showed no presence of combustion gasses in my coolant. I'm still not ruling it out but it's driving me nuts.

 

Did you test the coolant for hydrocarbons? Sometimes cracks can be small enough that you need all the pressure of combustion for them to leak, and/or they only open up with the heat of the engine running

 

I didn't test the coolant itself just the vapors coming from it. I may do a head gasket anyways just to rule it out. We're still in the middle of tuning and timing is only at 9 to 10 degrees with 11 afrs on e85 so its really conservative

 

any luck finding out the problem? I'm currently having the same issue, head gasket replaced and L19s were torqued down and again the same freeze plug blew out. The 40mm one on the passenger side front of the car

 

Over torquing the head studs wont help the problem. If you go past the bolt stretch it gets weaker. What did you torque them too Cris? and are were the studs new when you bought them? how many times have they been torqued?

 

New headstuds maybe 1k miles on them since work was done. I'm not 100% sure on what they were torqued to, work was done at house of power in pa. I would think they got torqued to oem specs

 

My studs were brand new when I torqued them. I have mine torqued to 115ft. lb. Passenger side 40mm popped out ao I reinstalled with an oem plug and that one is now fine. Then the driver side 40mm popped out and i replaced it with a rubber plug at the track and it has been fine. I read that only oem plugs should be used instead of aftermarket. Maybe thats why i had issues. Oddly enough, the 40mm ones that the machine shop installed were brass instead of steel so maybe that was part of it...who knows?

 

Ah gotcha, thanks for the info. The one that popped was oem replacement straight from mitsu, I picked up another one from them today hopefully this one lasts

 

Just make sure when you're installing it, use a socket that fits all the way to the inside edge of the plug so it doesn't distort it, and make sure it goes in straight. If it pops out again, try a rubber one. A local DSM had the same issue and went with rubber plugs and it's been fine. Mine is good now too

 

Will do, will install it tomorrow and find out in a week or so if it worked lol