Roler

My Cherokee 1997 XJ 4.0 ltr 6 cyl autotrans Temp gauge reads low-normal-low etc. I've had some overheating issues is past, no coolant is leaking now and fluid is not decreasing either.
From what I understand and read, this could be the thermostat +/- temp sending unit and (correct me if I'm wrong) my 97 ( I think Nov 97) is having 1 unit, instead of the 96 and older, who have 2 temp sending units.

My question is: if I was to replace the temp sending unit to try solve the incorrect low reading on the gauge, do I get a new thermostat with one temp sending unit IN it, or are these two seperate items? Or do I have to replace the thermostat alone?

Thanks in advance for your advice.

tjwalker

They are separate items.

I don't go over 60k on my thermostats. If you buy one, buy it directly from Jeep for the best reliability and temperature control. They're about eight bucks. Get a 195 degree unit.

I wouldn't replace the coolant temperature sending unit (located in the thermostat housing) unless you have confirmed an issue with an infrared point and shoot thermometer pointed directly at the thermostat housing and compared to the dash gauge.

If you've had issues with overheating, address it immediately. Time for a review of all cooling system components as they work in concert. Radiator, radiator cap water pump, thermostat, fan clutch, serpentine belt, hoses and of course.....a fresh 50-50 mix of conventional (green) coolant.

Dollar for dollar, there is no better money spent than that spent on cooling system maintenance.

Roler

Since I'm quite new to the maintenance business, a point and shoot thermometer is not something I have. Is there another way to distinguish between thermostat and temp sending unit?

And I'm in Australia. Every Jeep part here costs at least 600% of what you guys pay for it in the US and the Jeep dealership here is a complete rip-off. So you can prob understand I would like to make sure what to get.

tjwalker

Since the thermostat goes bad far more frequently than the coolant temp sender, start there. It is also a normal maintenance item. 195 degree only.

Easy to replace. You will lose a bit of fluid as you loosen the bolts, have a pan underneath to catch the small amount that drains out.

But while you're doing this, you should absolutely consider a full flush/fill of fluid. At least drop the lower radiator hose and drain out what is in the radiator and refill that with a 50-50 mix.

Roler

Is it under pressure, squirting out?
And do I remove radiator cap as well for this, or leave everything else untouched? The temp sending unit will likely need to come off as well, just unscrew and replace on the new thermostat?

Thanks for you time again, TJ.

djb383

For safety reasons, motor should be cold before doing any cooling system maintenance.

Roler

So, where does the actual thermostat live? I can see the housin, but have no idea about getting to the thermostat. Do I remove the 2 nuts (...) that are holding the housing? And the hoses that are connected to it, leave them on the housing?

tjwalker

First, you remove the hose. Then there are two bolts that need to be removed and the housing will pull off with a bit of a pull. Be sure to clean both surfaces very well as if any debris from the gasket or RTV material is on the surfaces when you reassemble, you can have a leak. If you use a MOPAR thermostat, the "jiggle valve" should be at the 12:00 positiion. Do NOT overtighten these bolts when you reassemble or you can crack the housing. There is an actual spec for how tight these bolts should be.

You should really get yourself a maintenance manual. Absolutely invaluable if you are going to be doing any work on your XJ. These manuals will walk you through most repairs step-by-step. The Factory Service Manual is the best. Haynes and Chiltons are just OK, but are pretty generic, cover a multitude of years and have been known to have a few errors.

Here is a link to a licensed, legal digital copy for $7.95 US

http://www.pacificcoastmanuals.com/F..._cherokee.html

Roler

Thanx for the link. With my 11/97, should I take the 97'-year or the 98-year. Some say the later 97's are different to the early 97's. bit of a split year.

tjwalker

Go with the 97 year manual. Odds of having the most accurate data is with the document for the actual year of your vehicle.

Roler

Back to the topic.
Now, I found a thermostat here online in Oz, it states 180 F, so I guess thats not the 195 F. But why does it need to be the 195?
The 180 just will open sooner, sending coolant to the radiator. And the engine itself will be warmed up before this.

Furthermore, I cant find a 195 online here.

Edit: and I forgot that I actually DO have a repair/maintenance manual, just scrolling through the PDF files is a bit dragging

tjwalker

The 195 is what the 4.0 was designed for and is your first choice. I'd try to find one.

If you absolutely can't, then go with the 180.

Roler

What you reckon? This is another one, appears better quality, cant find the specs though. Maybe you recognise this as a 195?

http://4x4point.com.au/cart/index.ph...products_id=11

tjwalker

Can't tell as the temp spec isn't listed. You could call them. Any way you can source an OEM Mopar thermostat in Australia? They are my favorite, hands down for reliability and temperature control.

cruiser54

FWIW, the Jeep part number 83501426 is the 195* stat.