awork

I have a 97 Jeep cherokee 4.0
Does the thermostat go in just like that in the motor? Does it need to be horizontal like that or vertical?

Thanks

caged

that's how i put them in, but i'm sure orientation doesn't matter. spring always goes in towards the engine.
if the thermostat has the jiggle valve, the valve goes to the top, but the housing will have the bulge for the valve to fit in.

djb383

Look to see if there is a "V" notch.....the "V" goes up.....and as already said, spring goes into the head.

awork

No v notch on mine, does that mean it doesn't matter which side goes up>

djb383

Hummm, u looked very closely?......it's very small. Just make sure the spring goes inside the head.

Turbo X_J

Only fits one way.

awork

It only fits one way? Mine doesn't have any type of v notch on it or anything. Nothing on the back is different on either side of it.

djb383

I think he means that the stat cover won't bolt down if the spring is facing out.....so in order for the stat cover to bolt down, the spring must be inside the head.

IJM

And for those of you who remember things easier this way, just think about the fact that the spring needs to be sitting in hot coolant in order to open properly, hence why it has to go in with the spring facing the head. Otherwise it would be sitting in cold coolant and wouldn't open until the engine got way too hot.

firehawk618

The spring doesn't open the T-stat. There's some wax gimgrack inside the copper thing in the middle that does the work but as stated above, the spring end goes into the head.

I would personally go get one that has either the jiggler thingeymcboob or the little hole in it. Makes filling the system MUCH easier.

'90Cherokee

Orientation doesn't matter if you have a big a$$ hammer.

'90Cherokee

Wax slug (copper thing with the spring around it) toward the head. If there's a notch, hole, or jiggle valve it should be up to let air vent best.


Or just

Ianf406

Hahahaha- Just put it in the way you took the old one out. I've never heard a thermostat broke down so far.. wax slug... jiggle valve...

DFlintstone

The (presumably by-metal), spring, goes toward the side that gets hot, (the head). Any hole would go up. It's to let air through to make filling/burping easier. A little RTV or anything can help keeping it from slipping down on install, easy for that to happen. Then the lower ear on the housing may well break and of course it will leak.

I once let a washer fall from the lower bolt, that fell right where the serp belt goes around the crank pulley. Made the belt brake as soon as I fired it up.

It's really not a bad idea to 'bite the bullet", and fork out for a quality Mopar/Motorad thermostat. Just not worth wondering if it's still working right in a few years, for the $10 difference. (that said by about the stingiest guy on the forum!)

djb383

The wax pellet (heating up/expanding) over powers the spring, thus the stat opens. The spring is what constantly forces the stat to the closed position when the spring is no longer over powered by the expansion of the wax pellet. The spring is what determines the stat rating/open temp, i.e. 195, 180, 160, etc.

Technically speaking, it doesn't matter which direction the spring faces....what's important is the positioning of the wax pellet. The wax pellet MUST be in the head since that's where the flowing coolant that's rising in temp is. Everybody knows what a spring looks like but some might not know what a wax pellet looks like so we just say put the spring in the head. In the case of the XJ and most other vehicles, the spring, which surrounds the wax pellet, both need to be inside the head. There may be some stats out there where the spring and wax pellet r opposite each other......if that's the case, the wax pellet MUST go inside the motor.