Hello all, I'm looking for a little help here, I'm starting to think my car has a blown head gasket, but I'm really not sure...

Motor is an LS-VTEC built by certified Honda mechanic, B18A block JE low comp pistons, Eagle rods, ACL bearings, no block guard, cometic head gasket and the head (GSR) is bone stock.

It only has about 1k miles since build, I recently put my turbo kit on and all the sudden I can't figure out why it overheats, it was running perfectly fine before.

About two weeks ago I was driving and noticed the temp going down on the gauge, I wasn't too alarmed and kept driving it, thinking the thermostat went bad... at idle it would go back up, that kind of confirmed it had gone bad when that happened. I drove it last weekend and same thing, except now the temp went all the way down, I was about 30 miles away from home when that happened and decided to head home, shortly after I noticed it was going up, running hot (about 2/3) but not overheating, it stayed that way and I was fine with driving it like that to make it home...

Put a new thermostat in the next day (oem Honda), bled the system, and watched the gauge to find that now it would overheat just idling within a few minutes, I thought I had air still in there, so bled it again, and again it overheated. Lower radiator hose had a lot of pressure but I couldn't feel any flowing there. I thought maybe the new thermostat was stuck closed so I biught another one today along with a sending unit for the gauge (1 prong, below the distributor). Started the car and the temp went straight to where it normally should be (about 1/3), stayed like that for a little while until started overheating again (car sat since last thursday when I last messed with it)...

I can provide more info if necessary, can anyone give me any ideas on what to do next (before I run it overheated into a tree )

Thanks!

 

Is the turbo water-cooled? Check the lines. A bad line will make your coolant system not airtight, lowering the boiling temp and overall efficiency. Also, a bad line could continue to suck air into the system, leading to overheating.

Did the water pump go out? Making the LS-VTEC means changing the head. The water pump should have been changed as well. If not, it could have taken a dump.

LS bottom ends do not match up perfectly with VTEC heads - they are prone to blown head gaskets and overheating. Check the head gasket.

Try removing the thermostat entirely. If it works a bit better, then the car probably has a small coolant leak somewhere, or a blown head gasket. If not, my bet is on the water pump.

 

Korman, thanks for the reply. The turbo is not water-cooled, I should have mention everything is brand new and OEM Honda.

One piece of info that could be helpful is the fact that today I noticed quite a bit of pressure on the lower radiator hose but never really felt coolant flowing through there, should I be able to actually feel the coolant on that hose, maybe even hear it flowing?