I tried doing a search and couldn't find anyone else having this issue. I have a 08 Evo X with built block, head, and running a 8374 at 35 psi. The car is tuned only for a 8500 redline because of fuel pressure issues on the radium engineering double pump kit. The fitting popping out of the thermostat housing happened once on the dyno and the shop replaced the housing because it's a press in fitting. Well last night while doing a pull it happened again and I can't figure out why this is happening

 

My first guess would be that the head is lifting, sleeve cracked, or other reason you are pressurizing the cooling system and popping the line. Unless the Evo X has inherent problems that could cause this.

 

The block is a new sleeved one from MAP so I hope it's not that. I haven't heard of anyone else having this issue which is why it's so baffling to me. I just literally picked up the car from the shop on Thursday.

 

Hopefully it's just some weird Evo X thing, though, if so, you would think a search would bring up some results.

 

It doesn't look like there's any coolant in the oil.

 

Welp...

 

Please explain

 

I had a similar experience with my supra. The top of the stock radiator opened up like a clam after doing a burnout at the track. Thought it was a blown headgasket leaking pressure into the coolant jackets , but found no coolant in the oil. Turned out was my fans that i had installed (removed the crank fan) blew a fuse and stopped. This spiked the temp and pressure and boom. Switch to a fluidyne radiator and put the crank fan back. Never had the problem again. I would check your compression though just in case.

 

Thanks, I'll check that.

 

I assumed you checked the temp, but if you didn't then that's a possible cause. Sorry about that. I sometimes forget to bring up the simple, obvious stuff because I assume it's been checked already.
:cheers:

 

I hope for your sake it's not a cooling system pressure issue! How much slack is in that line attached to the fitting? Is it possible you're getting enough engine movement at that power level that it's just yanking the connector out? How are your motor mounts?

 

What sleeves did MAP use? And when did you order this block? Please don't say Darton MID sleeves.

A while back (a couple months, 2018) my local shop ordered two 4b11 sleeved blocks from MAP, both blocks sleeve's starting sinking. While I was on the facebook group, someone asked whether they should go with MAP sleeved block or from some other vendor, I think it was AMS, and I suggested the latter based on my local shops experience and actually caused a huge debate. One of MAP's rep finally chimed in and claimed that it was a problem with the Darton sleeves, and not their fault as everything was in spec, they also claimed that they've since switched to different sleeves for their sleeved blocks.

If they are indeed Darton sleeves in your block and depending on how much the sleeves have sunk, it may pressurize your coolant system since Darton sleeves are wet sleeves.