Another BHG?

[5150DSM]

So I'm back with more overheating issues. After this incident... http://www.dsmtuners.com/forums/cyl...439122-overheating-poor-idle-head-gasket.html

I had my head resurfaced to an RA of 40 along with the block deck. I installed a Fel-Pro Permatorque HG (dry) with ARP studs. I torqued the head in three steps to 90 and off I went. For the last three months the car has been running great, lots of power at 22psi, fun and reliable.

The other day my coolant feed hose to the turbo split and blew a bunch of coolant, it got hot but not real hot before I shut it down. Replaced the hose and the coolant and burped the system. Car still ran hot and started using coolant. Had the same hot hose/cold hose symptom so I replaced the thermostat, filled and burped the system, car still ran hot (see overheating). I fill the reservoir and the radiator and by the time I drive 5-6 miles the car starts getting hot, running the heat (great in a Sacramento summer) controls it to some degree but after a while it cascades into full overheating again. Whe I check, the reservoir is nearly emply and the rest of the system is down anywhere from a cup or two to a quart or so.

I ran a pressure test at 15psi, left the tester pressurized for half an hour without loosing any pressure whatsoever. I ran two combustion leak tests (blue fluid) that showed no combustion gasses in the cooling system. I haven't spotted any external leaks and don't see any signs of an internal leak... plugs are clean, piston tops are dry, no steam from the exhaust, no mixing into the oil, coolant doesn't shoot out of the neck when I start the car, and so on.

I'm fu(king stumped.

Anyone who has an idea, please contribute, I'll try just about anything at this point.

 

[3kgt2nv]

You might have air still in the heater core or your thermostat could be going bad. I would suggest a back flush kit like $10 bucks and use that and let it force the air out.

 

[5150DSM]

Thanks.
I have an OEM thermostat that goes in today. I don't see how I could still have air but I'll try burping the system again after I do the thermostat.

 

[vingasoline]

Check the rad cap. A faulty one will dump all your coolant into the overflow while driving. Also, are your fans working?

 

[5150DSM]

Fans are hardiwred to a switch and work all the time. Rad cap is about 3 months old but it couldn't hurt to throw another one at it.

 

[5150DSM]

New OEM cap went on with new OEM thermostat... Things got worse. Starting heating up faster and hotter than before, can't go more than a couple of miles before a bunch of coolant gets pushed out of the reservoir. So, I did another compression test today... previous results were 185 across the board, today I get 145-135-150-185, another block test confimed it... BHG!!!

I'm pissed, I just put a freshly rebuild head on this beast, had it cut to a R/A of 40 (what I asked for anyway), block was prepped to the same R/A (what I was told), installed ARP studs and a Felpro PermaTorque MLS and the fu(ker blew in 300 miles. !!!

I doubt the machine shop is gonna help me on this, they'll say installer error or some shit I'm sure.

Guess I need another head, this one was fairly close to minimum and probably won't stand up to another mill job.

Any guesses as to why the damn thing failed (assuming the machining was done right) I ran 22-24psi on a 30% mix of e-85, AFR's in the low 11's, no detonation, no hot lapping, just daly driving with some tuning runs.