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Thermostat Alternatives/Brands?

Q

Quailman

NAXJA Forum User
Location
Hunt Valley, MD
Hi everyone, sometimes my 96XJ Sport runs a little hot while at idle/in traffic. I know that's fairly normal, and it never gets hot enough for me to be overly concerned about it. I'm planning to install some Napier hood vents at some point.
But for now, I'm wondering if replacing the thermostat will give me a little relief in the short term. Has anyone had experience with installing an alternate temperature thermostat (180F as opposed to the OEM 195F)? If so, would you recommend the swap?
Also, I can't seem to figure out who the OEM manufacturer is for the XJ thermostats. I've heard horror stories about some brands for these, and would prefer to get a Mopar thermostat if possible.

Thanks!
 
Switching to a 180 thermostat will do nothing to lower the operating temperature, in hot conditions, unless the existing thermostat is defective and only partially opening.
A cooler thermostat may provide lower mileage in cold weather, since the engine is designed to run in the 200-210 range.
 
lazyxj said:
Switching to a 180 thermostat will do nothing to lower the operating temperature, in hot conditions, unless the existing thermostat is defective and only partially opening.
A cooler thermostat may provide lower mileage in cold weather, since the engine is designed to run in the 200-210 range.
Click to expand...

that's what I figured. I was really just looking for confirmation. I appreciate the input. I'll stick with a 195.
 
I have ordered from several of the on-line Dealership Parts Departments websites. I look and see if the website contact info matches an actual Dealership. Usually the parts are discounted 30% from the retail price, and I save by not paying state and local sales taxes.

They usually ship parts the same day or the next day, and I have always received genuine Mopar parts.
 
I had good results with a Stant thermostat (195 degree) and Stant cap on my '96. If you think it's running a bit hot at idle I'd verify that the fan clutch is in good shape as well (had a similar problem on my '96.)
 
The t-Stat is not the droid you should be looking for.

Try a new mechanical fan clutch first. It is the very first part should think of replacing. Also make sure the radiator and condenser fins are clean, with no leaves or dirt or dried mud blocking the air flow.

I have had great results with Murray T-Stats the last 10 years, made in Israel. Many parts houses stock them if you ask for the Murray brand
 
JeepNoob said:
I had good results with a Stant thermostat (195 degree) and Stant cap on my '96. If you think it's running a bit hot at idle I'd verify that the fan clutch is in good shape as well (had a similar problem on my '96.)
Click to expand...

I had horrible results with the Stants. 3 vehicles. Warranteed each stat. All 6 were quick to open and spiked at high temps. Factory stat, also made in Israel, fixed all 3. .
 
cruiser54 said:
Factory stat, also made in Israel, fixed all 3. .
Click to expand...

Interesting!!!! Ones I had problems with, after market, were made in Mexico over 10 years ago IIRC. Read many complaints here about non OEM Mopar T-Stats including Stant.

98% of the vehicle parts I have bought the last 45 years were NOT dealer parts.
 
It's not a terrible idea to add a manual override switch for the electric fan - this helps in slow moving conditions. The PCM doesn't turn the fan on until about 220 degrees...which is already overheated. Better to stay ahead of it than try to catch up.

Also I believe the '96 has the older style electric fan - you can get the OEM fan from a '97 up and it will bolt right in and move more air. It has a different blade design.
 
Number21 said:
It's not a terrible idea to add a manual override switch for the electric fan - this helps in slow moving conditions. The PCM doesn't turn the fan on until about 220 degrees...which is already overheated. Better to stay ahead of it than try to catch up.

Also I believe the '96 has the older style electric fan - you can get the OEM fan from a '97 up and it will bolt right in and move more air. It has a different blade design.
Click to expand...

Yes, it's possible and I thought about doing it on my '96 before it got totalled, but to do it right is a bit involved. The lazy way to do it is to just provide your own manual switch on the ground side of the fan relay coil to a non-PCM ground. Doing this however will set a CEL and a DTC for the fan relay ground circuit every time you flip the switch and activate the fan. (I have confirmed this in the past.)

The "correct" and more involved way of avoiding this problem is to wire up a secondary fan relay. You will have to tap into fused power somewhere for the relay coil, as well as the 87a (high amperage "neutral" position) terminal on the primary fan relay and also the fan power wire.
 
JeepNoob said:
The "correct" and more involved way of avoiding this problem is to wire up a secondary fan relay. You will have to tap into fused power somewhere for the relay coil, as well as the 87a (high amperage "neutral" position) terminal on the primary fan relay and also the fan power wire.
Click to expand...

I'm in the process of doing this right now. It's not very "involved", I'd say much easier than changing a thermostat. $5 relay, $5 switch. 4 wires. They even sell relays now with built in fuses. Super convenient. Tap into a fused source for your switch wire, and bingo. Hardest part is probably running the switch wire through the firewall...
 
Number21 said:
I'm in the process of doing this right now. It's not very "involved", I'd say much easier than changing a thermostat. $5 relay, $5 switch. 4 wires. They even sell relays now with built in fuses. Super convenient. Tap into a fused source for your switch wire, and bingo. Hardest part is probably running the switch wire through the firewall...
Click to expand...

That can be debated. Just my $0.02. I had plenty of spare relay spots in my engine fuse box that were the same size as my factory fan relay. I wanted to wire the whole thing up so that the only thing you noticed was an extra relay with no lid label and a rocker switch near the steering wheel. My biggest problem was finding terminals to put in the spare spots in the fuse box and I didn't feel like hacking up a junkyard fuse box to do it...
 
Normally the temp sensor in the thermostat housing applies a ground to the aux fan to energize it when the engine temp reaches 230* or so. That's too late, when I want the fan on I don't want to wait for the temp sensor input while sitting in a hot summer traffic jam. I've been using the below circuit to do the same thing using a dash switch that applies a ground to ECU pin 31, the aux fan input on OBD1 vehicles. It works great and there are no CELs or other problems as the dash switch simulates the temp sensor ground. For OBD2 vehicles a diode could be inserted as shown to prevent a CEL if it occurs. And of course the ECU fan pin for OBD2 rigs would be something other than pin 31.

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