So I've been having this weird problem with my car running hot. By hot, I mean it'll get to like 4/5 of the way to the H on the stock temp gauge. First of all, this is crap because I don't know what the actual TEMP is-- can anyone tell me the temp range of our stock gauge? When it gets this hot, the AC usually starts blowing hot too. It'll only get that hot when I boost hard a couple times, then will gradually come down to about 3/4 on the gauge. If I drive it really easy it'll eventually get up to 3/4 on my way home from work (like a 30-45 min drive, stop and go traffic). However, in the morning on the way TO work it almost never gets hot unless I boost it hard.

So here's what I've done to combat or correct temps:
Heat wrapped downpipe & wastegate dump pipe
Flushed & filled cooling system with Prestone 50/50
Added Redline Water Wetter
Silicon upper/lower radiator hoses
Visteon all-aluminum radiator (much thicker than stock)
14"+12" slimline fans (moved a LOT of air).. 12" is dead from melted wiring so its only the 14 now but it was still doing this even with the 12"
Heat wrapped A/C lines to & from compressor
Heat wrapped hot side of IC piping that goes over lower rad hose
Heat wrapped coolant pipe to water pump which goes under the turbo
New water pump (right before I went turbo w/ new timing belt-- wasn't doing this overheating stuff when I was n/t still)
New coolant temp sensors (both of them on the T-stat housing)
Replaced exhaust manifold gasket since it was leaking bad, now its not leaking
Painted manifold with high-temp BBQ grill paint to look pretty & help control heat (think it looks pretty more than anything)

Next step is the turbo blanket and that's really all I have left to do.. other than wrapping the other portions of the I/C pipes and those are on the other side of the engine bay from the T-stat housing.

So, is this just the correct temp for the car to run? What are you other turbo guys running? It wouldn't bother me so much cause it never actually overheats, just runs very hot, but when it gets really hot the AC starts blowing hot too, then just randomly starts blowing ice cold again. It's getting to the point where I just wanna sell the car and be done with it.. I NEED this conquered.

I had some low compression numbers but they were still in the acceptable range (170+). I originally thought the HG was leaking but there are no bubbles in the coolant, no oil/coolant mixing either in the cooling loop or the oil pan. Wtf. I'm just stumped.

You really should get a real water temp gauge. That stock gauge is worthless.

Stock thermostat opens at 195. I'm not turbo, but my car has always run at around 190-205.

Your head gasket can be blown even if there is no oil in the coolant.

Yeah I'm looking into a Prosport water temp gauge. So when you're sitting at 200 degrees, where is the stock gauge sitting? Just trying to get a general idea of how hot I'm getting.

Oh yeah, also wanted to add that I also bridged the relay so that my fans turn on when the key is on as part of my cooling crusade lol.

2gnt: '99 RS-T, killed by a toyota, pending rebuild...
Daily: Volt
Daily #2: '99 EVG ebike- STOLEN by PEDRO

I have logged temps with MS all the way up to 230* with the stock gauge staying in the middle. You deffinately should pick up a real water temp gauge. I just got one for $18 from the parts store. Short sweep electric gauge. Autozone has a 180* stat you may could try. It wont help you overheating but it will open quicker so it may run cooler longer. I really dont know what to tell you, it sounds like you have covered everything. Have you changed the thermo stat any? Its possible it could be bad.

98 Eclipse GS Turbo
Built motor - MS2 - Holset hy35 - Zoom Stg 4 Clutch - 57.5mm TB - ARP Headstuds - Turbonetics wastegate - 3" Turbo back - FMIC - Greddy RZ BOV - Walbro 255 - 650cc Injectors - Fidanza Flywheel - Cobra calipers w/ 13" Rotors - Oil Cooler - DevilsOwn meth injection

1981 Chevy Scottsdale
1987 Nissan 300zx - Chump Car
2001 BMW 325i

I run a watercooled turbo with a 160F thermostat. Based on my "actual" gage my temp runs right at 200 +/- 10F.

Built block.
Refinished head.
Tuned suspension.
TURBO.

I've dealt with just about every cooling system problem you can have since I got my car :\

It can be a loooot of things. I'd check the coolant level for one. Simple and stupid, I know...but if you have a pinhole leak somewhere and are spitting coolant out at high rpm's you won't know it's leaking typically. You can also check the coolant temp sensor(usually throws a CEL though). Thermostat obviously, it's a 15 minute $5 job so that never hurts to do. I reccomend the fail safe ones too- When they fail they stick open so it doesn't overheat, it'll just not get up to full operating temp. Which brings me to my next thought...

On our cars you don't want to let them run hot for a long period of time. A warped aluminum head is not a fun thing to fix!

Just take a real close look at your cooling system, it's a simple process. Belt turns the pump, pump flows coolant through radiator and engine. Just make sure you top everything off and burp the hoses.

LOL yet another thing I forgot to list.. new GST radiator cap 1.1 bar

Sounds like you have a blown head gasket. You could try a leak down test, but that doesn't always show a leaking HG. You've checked everything else, so it's pretty much got to be the HG!