k car runs fine has some ignition/breakup in boost.... its a d16a6 with vitara pistons, y8 headgasket, garrett .80ar t25 and dsm 450s and uberdata, base timing at 16 and .5 retard for boost...also when stopped at red light car overheats take off and cools down a lot at 3000-4500 rpm higher over heats very slow...comp test showed 140 across the board,,,no smoke, radiator hoses seem to not contain fluid when warmed up radiator steams some,,,could it be the thermostat? any help appreciated....

 

OK

Few things it could be

Stuck thermostat - go for one of your phantom drives, keep the speed up, maybe bounce on a freeway or a backroad, when and if the temps start to rise, pull over and grab your lower and upper rad hose? Do they feel the same temp or very close? If not, thermo might be stuck

Another one that Ive done myself

Is if the fan is wired backwards, pushing hot air into the rad, not cooling it. Would cause a slow overheating at any speed if its hot enough out

Also the fan might not be coming on at all, do you ever hear it click on at idle?

 

Bypass the air from the thermostat valve hope that would work

 

id bet on the thermostat, there not that pricy. i just replaced mine like a month ago it was less that $20

 

k couldnt i just open the thermostat up and pry it with a screw driver out and say ---- it....

 

Yes you could very easily just take off those 2 10mm bolts, pop off the thermostat and say "---- it"

But for $7 bucks and 30 minutes work you can put a brand new one in from autozone and say "---- yeah"

I ran without a thermostat before, it sucks, car takes forever to warm up, like literally 15 minutes

Just replace it

Make sure youre fan is coming on

Hell, maybe even flush your radiator if its fairly old

All cheap solutions man, dont ---- up your motor more than you already have being a lazy ***

 

sounds like you are pushing coolant because of that shitty mls headgasket.

i've used 2 mls y7/y8 style headgaskets on two different d16's with arps and had nothing but problems when it comes to pushing compression into the coolant passage and overheating. Once I replaced them with a 88-95 d15 style gasket i had no problems. I know there are people that run mls headgaskets with no problems, it was probably the ITM brand mls headgaskets I used, but i'm going to go ahead and guess that is your problem too.

Look into it at least... if you have pressure in your radiator and it is pushing all the coolant out after a boost run thats a telltale sign along with the crazy temp gauge movement because your coolant system is full of air pockets.

 

You probably had a problem with the mls gaskets for 2 reasons...1, the surface of your head and deck of the block might've been slightly warped; and 2, use copper spray on mls's to help them seal better.

 

possible on the copper spray

but the head and block were decked and shaved by the machinist. I blame the brand of mls i used.

 

Every time I see a D-series pushing coolant and overheating I take out ignition timing. The power comes up, and it stops pushing coolant. If it's still gaining more than 6-8 degrees after a 250+ whp pull I take out more timing. The power comes up marginally, and it stops building up heat entirely. I end up running so little timing under boost that most people tell me I'm full of ----.

Like I ever listen to anybody.

Oh, yah, Y8 headgaskets are awesome. $22 from the dealer. You never have a problem with one, unless you run so much timing that it gets breached by coolant under boost... at that point it is either just plain bad or is on the 3-6000 mile deterioration plan. Same problem you're going to have with any D-series headgasket.

Small bore engines are volatile, D16s only hold together so well under boost because Soichiro was a hardcore ----------er who didn't design crap engines like K-series.