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Gone but not forgotten
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4,672 Posts
if it says its for a GTO, then i would expect it to work w/o problems or SLP would catch an ear full from. or i would just get my money back.
 

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Oh my f*ck!
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6,464 Posts
And for that $8 UPS or whomever gets to play soccer with your package (I know this happens as a good friend from college worked for UPS). Ah, what fun what fun.
 

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Yes, it has a car seat
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1,884 Posts
The answer is maybe. Apparently early in the production of the GTO's they went from the traditional LS1 thermostat / water pump to a new '2004' style. From what I'm reading, this is for the new style water pump. IIRC you got your car pretty early on - so it's possible this one wouldn't work for you.
The chatter on ls1tech was that the 'new' style was much like the lt1 style thermostats which are typically cheaper. From what I've seen, the traditional t-stat was more expensive. The cost here tends to imply to me that the supposition of a 'return' to a cheaper style for '04 seems to make sense.
If you search on here, there is a thread with the differences discussed a bit. In simple terms, the new style water pump has a circular fitting for the t-stat and the old one had openings for 'wings' on the t-stat. I think the safest bet would be to pull yours and verify that the one you order matches what's in your car.
Dan
 

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GTOholic
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1,504 Posts
If anyone discovers they need the old style thermostat housing with a 160 t-stat, I have the Hypertech brand I bought from LS1Speed. It does not fit my car because I have the new style. I have been meaning to send the Hypertech back for a refund but cannot seem to get around to doing that. But for a forum member, I'll get off my lazy behind and ship you this one, cheap.

I agree with Dan. The low cost indicates it is the newer style "drop-in" t-stat which does NOT come with a t-stat housing. You just replace your stock t-stat with this one. Remember to change your fan on/off temps when you change your t-stat. You'll need PCM software to do THAT.
 

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13 year owner
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16,384 Posts
redneck said:
$20 plus $8 shipping for a thermostat. Whoa. I'm in the wrong business.
Keep in mind, the t-stat on these cars just isn't the thermostat itself. It includes a whole new housing.
 

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GTOholic
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1,504 Posts
The new t-stat design does not require a new housing. The t-stat "drops into" the existing housing. I know this because I have had mine out TWICE checking the fit of the Hypertech housing and stat.
 

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13 year owner
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16,384 Posts
Excuse me, it's the $40 one that includes the housing.
 

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Yes, it has a car seat
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1,884 Posts
Well, here's the short version. Heat is power. EXCEPT there are sensors in the engine that measure 'detonation' of fuel before the spark due to excessive heat. The computer will then remove timing (power) from the engine if it senses detonation. You want to run the car as hot as possible without having this detonation. It appears that stock tunes on certain fuels at certain atmospheric conditions cause detonation in the LS1's. Therefore, many of the racers have lowered the thermostat and fan settings to run their car cooler. Ultimately, IMHO, you should get hptuners or another monitoring program to check for detonation. If you have it, then you can get increased performance from your engine if you cool it off. You also may be able to adjust some of the other tune items to eliminate detonation without having to change thermostats (lowering fans).
Dan
 

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GTOholic
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1,504 Posts
Need Pics of Old Style Housing

I took some pics of my water pump and tstat housing. I definitely have the "new style" with the "drop in" tstat. If anyone knows they have the "old style" (CMNTMXR), how about checking these out and seeing if there is an obvious external difference. Otherwise, the only way to know for sure if we have the "old style" or "new style" is to 1) remove the tstat housing and check out its internals, or 2) try to get a VIN breakout number where they made the switch.

Eureka! I just realized there IS an obvious external difference. The "old style" housing has TWO fasteners on top and one on the bottom. Here is a pic of the "old style" Hypertech housing I bought from LS1Speed (which I STILL have not sent back for my refund.)
 

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Yes, it has a car seat
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1,884 Posts
That's interesting because Helm's says "Important: The water pump inlet and thermostat MUST be replaced as an assembly. The thermostat is not serviceable separately." At the same timepicture definitely shows only 2 fasteners holding it on. Knowing the visible external difference now - maybe we could do a VIN check and try and narrow down an approximate breakpoint. I'll try and check mine this evening.
Also DY - could you maybe add this to our FAQ and link Florit's pics?
Can i used the standard LS1 thermostats to replace mine in the GTO?
That depends on how early your car was build. The early production cars (we still don't know the cutoff) had the existing LS1 style thermostat that includes the inlet housing as a complete unit. Most of the cars have the '2004' water pump that includes a drop-in thermostat.
How do I tell which thermostat I have?
The 'old style' complete assembly thermostat is connected by 3 fasteners (http://www.ls1gto.com/forums/attachment.php?attachmentid=1168) and the new style is connected with 2 (http://www.ls1gto.com/forums/attachment.php?attachmentid=1165).'
Dan
 

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GTOholic
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1,504 Posts
Don't take my word for it. It might be that the Hypertech housing is different than the GM housing. We really need someone who DEFINITELY has the "old style" to take some pics of their housing and water pump. The only person I know for SURE who has the "old style" is CMNTMXR.
 

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Knight Errant
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1,800 Posts
T-Stat housing

210635 has the re-born 'new' thermostat housing. The thing actually looks like it might take a standard old small block thermostat at first blush. I'll try one as soon as the weather breaks again here. I keep spares for the S-10 engine.
 

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May I quote you on that?
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22,046 Posts
Old Goat said:
210635 has the re-born 'new' thermostat housing.
Is that the VIN breakpoint?
 

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Knight Errant
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1,800 Posts
Not sure

mistermike said:
Is that the VIN breakpoint?
Not sure, but I offer the info in the hopes that we might determine one. If enough folks chirp in, we might.
 

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GTOholic
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1,504 Posts
speed_demon_freak said:
This housing on my car looks like the Hypertech one. I guess I have an old thermostat.
My VIN ends with 193217. I have the NEW style housing. speed_demon_freak, thanks for the pic. We now have an easy way to see whose car has which housing. Your's is definitely the OLD style.
 

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Registered
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881 Posts
My VIN is 182xxx, and I have the new style. Maybe they were just grabbing LS1's
out of a big parts bin.
 
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