Thermostat in Quad 4

[Racerdude15]

well i was wondering, since im tired of my car overheating...
where is the thermostat located? im pretty sure it is sticking

please tell me its easy to change!!


thanks for any help in advance

[Ralph]

here is all the info you should need.

http://www.gaownersclub.com/forum/showthread.php?t=37705&highlight=quad+thermostat+location

[Racerdude15]

thanks alot man

sorry for not finding it before
thats wat happens when u got a slow ass computer haha

[Ralph]

no problem man it took me a little while to find it since you have the oddball year

[Racerdude15]

ha .. wats that mean?

btw im new to the grand am thing...i know bout fieros not grand ams lol

[Ralph]

95 is a transition year for the Quad 4. Its kinda in between a normal quad 4 and a twin cam. Some of them are OBDII, they have balance shafts, Thermostat is in a diff spot, different cams, new power steering pump. There is a bunch of crap different on it. Not saying it is worse because of this but those of us who have the older quads have to double check to make sure things are in the same spot lol

[Matt95GT]

Under the water pump - it's in the end of the hard tube that runs under the oil pan to the passenger side of the radiator.

Hopefully it's just the t-stat... changing the water pump sucks.


please tell me its easy to change!!


The 2 bolts for that pipe aren't the easiest to get to, but it doesn't suck as much as changing the whole water pump.

95 is a transition year for the Quad 4. Its kinda in between a normal quad 4 and a twin cam. Some of them are OBDII, they have balance shafts, Thermostat is in a diff spot, different cams, new power steering pump. There is a bunch of crap different on it. Not saying it is worse because of this but those of us who have the older quads have to double check to make sure things are in the same spot lol

Actually the 94's have the t-stat down there too.

[Ralph]

Actually the 94's have the t-stat down there too.

Not that it matters since I have a 93 engine but I thought the thermostat was only there with the 456 head and my 94 had a 753

[Racerdude15]

well thanks for the help...

turns out i just didnt have enough water in my antifreeze
but im pushin 170,000 so i will prolly have to do something with the waterpump soon..........i hope not but nothing will surprize me.

[95whitese]

Yea I remember changing that thermostat on a '95 Quad, and I must say that is a very nasty spot to put the thermo.

[urownstupidity]

..ok im lost i have to change my t-stat and i cant find it lol some say its here some say its there.....WHERE IS IT REALLY

[Ralph]

Do you have a DOHC quad or a SOHC Quad? Also if you could take your engine cover (the thing that says Quad OHC or Quad 4) and look between the Timing housing (Big black thing on the passanger side of engine) and the Cam housing and read the last 3 digits off the head. It will either be 303, 456, or 753 if you have a DOHC im not sure of SOHC off the top of my head.

[95whitese]

Or he could just see if it has two cam housings...

[Ralph]

the head casting is really the main thing that will tell you because ive seen 3 castings on "stock" 94s 753, 456, and 303. Obviously the 456 has a difference thermostat spot. And SOHC its even easier to read the cover lol

[95whitese]

Yea I agree. i am just saying that when I worked on a '95 Quad 4 it was behind the motor right by the water pump...

[Ralph]

yup thats where it is on the 95 456 head but most quads have it higher up

[Matt95GT]

My money is on "under the water pump"

yup thats where it is on the 95 456 head but most quads have it higher up

I'm not sure I would base 94's on your car, since you don't know the entire history of it - never know if the head was swapped sometime before you got it. Every 94 I've seen had the t-stat underneath. The lack of mention in the 94 GM factory service manual set of a possibility of the t-stat being in the head also points towards most (if not all) 94's having it below.

[Ralph]

I was going based on other 94s on my forums its really hard to tell with how scetchy GM was about doing engine swaps for blown heads during those years.

[95whitese]

This sounds deep... Lol.

[93GAseV6]

my 95's was under the exhaust manifold. and next to the water pump. It was a royal pain to get to.

[zjoe]

Hello all, sorry to hijack but I've got a '92 quad ohc that I need to change the thermostat on. On a '92 it's at the end of the upper rad hose? and not at the end of the lower rad hose by the water pump?
Thanks

[Ralph]

correct its on the drivers side of the head under the thermostat housing.

[zjoe]

Clever, putting it under the thermostat housing like that.

[Ralph]

you laugh but in 94/95 they call it a thermostat housing but put it near the water pump

[Matt95GT]

you laugh but in 94/95 they call it a thermostat housing but put it near the water pump

I thought it was more amusing on the 2.4 LD9, considering the t-stat was never found there.