Thermostat

I like the suggestion of upgrading the cooling system. Radiator, Transmission Cooler,..... But I seem to be stuck on the Thermostat.

The Jeep Horizons cooling upgrade recommendations suggested a 180-degree Hi Flow Thermostat with a Hi Flow Housing.

However, with the 2000, based on forum advice, I will probably go with a 195 degree OEM or Stant Thermostat.

Do I still go with a Hi Flow Housing or just get the housing made for the specific thermostat?

Does the Hi Flow Housing provide a separate advantage compatible with an OEM thermostat?

Thank you

What year?

I've suffered no ill effects from running a 180* thermostat with RENIX and the stock housing, so I don't really see why you'd need a high-flow housing. Emissions results and fuel mileage both improved, so I don't see a big problem there.

Now, if you're running OBD-I (1991-1995) or OBD-II (1996-2001,) running a cooler thermostat may end up throwing a code for you - but RENIX doesn't do codes (it's "pre-OBD,") so it's not a problem. Running a 180* stat may throw a code in OBD-I, but it's fairly likely to with OBD-II. That's why I asked what year.

Also - what, specifically, are you trying to accomplish in your rig? I tried to depress the operating temperature of the coolant (and succeeded!) with my RENIX rigs, but that's because I don't like the idea of an engine that runs around 210-215*F normally - I came up on SBChevvy. So, I decided to depress the temperature a bit - and I managed to pull it down to 190-195*F from 210-215*F - which fact makes me a bit more comfortable. But, it's up to you.

Reader said:

I like the suggestion of upgrading the cooling system. Radiator, Transmission Cooler,..... But I seem to be stuck on the Thermostat.

The Jeep Horizons cooling upgrade recommendations suggested a 180-degree Hi Flow Thermostat with a Hi Flow Housing.

However, with the 2000, based on forum advice, I will probably go with a 195 degree OEM or Stant Thermostat.

Do I still go with a Hi Flow Housing or just get the housing made for the specific thermostat?

Does the Hi Flow Housing provide a separate advantage compatible with an OEM thermostat?

Thank you

Click to expand...

It is a 2000. Unless I misunderstand the other posts I have read, the 2000 comes stock with a 195 degree thermostat.

I am just trying to make sure it does not overheat. I intend to install a new radiator, hoses and a transmission cooler too.

I am new to working on my own car. For instance, what is RENIX?

Anything else I should be aware of or should do while I am at it?

Thanks

All AMC242/4.0L inline sixes came with 195* stock, and typically run 210-215*F as "normal" operating temperature. This can be altered slightly, but newer models will have a hard time with the alteration.

"RENIX" refers to the joint RENault/bendIX control system used 1987-1990. The RENIX system is "pre-OBD," and is therefore more tolerant of modification. OBD-I was in the XJ from 1991-1995, and OBD-II from 1996 to 2001.

If you want to make sure it runs normally, and don't feel like modifying anything, then install a 195* thermostat, and you'll be fine. The OEM housing will also serve, so no worries there.

I do advise you flush the radiator BEFORE you change any parts - the flush and drain will get MOST of the stuff you want to be quit of, and changing parts will help to get rid of the rest.

And, if you don't understand something - say so! We were all learning at one time or another, and if you say you're a neophyte, you'll get more explanations and be cut a bit more slack in explaining something that most of us would normally think you'd get. There's no-thing wrong with being inexperienced. As long as you say so, you'll be able to benefit from the experience of the rest of us, and that's what places like this are all about...

A better chaper solution is to ask at Napa/Advance/Murrays for a #330-195 p/n thermostat. It is a Robert Shaw and lasts longer and performs better. Stay away from the ones on the "rack."

Yes, they cost more.

Sorry to butt in on this thread. But I was reaing 5-90's post and was wondering if a radiator flush would help my problem as well that I posted on another thread...

First off I have a 87' Cherokee Chief, automatic....Ok... sooo... this past weekend I went camping with my wife and some friends. Long story short, I went up a hill and 3/4 the way up it turned into really loose dirt and was rather steep... Jeep slides back and I get caught up on a stump...so I try going forward getting off the stump, no worky, try it a couple times different ways and the Jeep overheats and so I pop the hood a little to let it cool out and it just starts smoking something fierce and coolant is shooting out the bottom like there's no tomorrow... so... the next morning we go up there and I hack at the stump with an axe for about 3 hours... it was more than a foot in diameter... get the Jeep down finally back to our camp and it starts getting hot again. So, we take the radiator hose off and there is a large leak where it burst due to pressure (i'll get a pic of it) and so luckily my father in-law had a spare radiator hose but for his F250... so we cut it down a little to work with my Cherokee.

Drive home and it's doing fine... the next day (Monday) I get home from work and it starts leaking near the coolant bottle. After about 15-20 minutes of driving the temp gauge creeps up past 210... I ran a test yesterday, put some water in the coolant bottle to the line... ran the Jeep for awhile, started getting hot, got to 210 so I turned off the Jeep and watch the coolant bottle... the top hose that spurts it back in just keep spurting it in and doesnt stop... the bottle eventually fills up almost to the cap and is bubbling bad so I slowly open the cap to relieve some pressure... I asked my dad what might be wrong and he said it might be the t-stat not operating the way it should. I'm hoping that's the problem since it'd be fairly easy to fix. Anyone have some input on this? I checked the hoses... no holes and all are tightened properly...

Could be a small coolant leak you can not see, or the bottle cap may be bad, thus not holding proper pressure. Could also have air trapped in the system from the hose replacement. See related threads here on "burbing" methods for the entire coolant system that need to be done after doing coolant system repairs!!!!!!

Also does the lower hose you used have a spring in it to keep it from colapsing, thus starving the water pump?

Eco, what lower hose do you mean? I've only replaced the radiator hose...Would the coolant bottle cap do that? Go bad and cause that kind of problem? I'll try burping it, that could be the cause since I replaced the radiator hose. It's just weird that it was fine for a day after fixing it then went back to overheating..

5-90 said:

All AMC242/4.0L inline sixes came with 195* stock, and typically run 210-215*F as "normal" operating temperature. This can be altered slightly, but newer models will have a hard time with the alteration.

"RENIX" refers to the joint RENault/bendIX control system used 1987-1990. The RENIX system is "pre-OBD," and is therefore more tolerant of modification. OBD-I was in the XJ from 1991-1995, and OBD-II from 1996 to 2001.

If you want to make sure it runs normally, and don't feel like modifying anything, then install a 195* thermostat, and you'll be fine. The OEM housing will also serve, so no worries there.

I do advise you flush the radiator BEFORE you change any parts - the flush and drain will get MOST of the stuff you want to be quit of, and changing parts will help to get rid of the rest.

And, if you don't understand something - say so! We were all learning at one time or another, and if you say you're a neophyte, you'll get more explanations and be cut a bit more slack in explaining something that most of us would normally think you'd get. There's no-thing wrong with being inexperienced. As long as you say so, you'll be able to benefit from the experience of the rest of us, and that's what places like this are all about...

Click to expand...

First a question for "READER", what are you wanting to accomplish by upgrading, are you having any problems with the stock system, planning changes that might lead to overheating, etc?

5-90 (and others) I was looking at my 4wd.com/cherokee paper catalogue and noted some interesting things on page 42 (summer 2007 issue). It shows 3 thermostats available for 84-95 cherokees (none for after 1995!), but even more interesting they have three opening temperatures available, 160, 180 and 195 F!

Even more interesting (to me at least) is they have a fourth thermostat listed, "JET performance" 180 F, claiming precise water flow metering, more consistant engine temperature control and MORE HORSEPOWER due to reduced engine operating temperature! It does not list the years it can be used on.

I am inclined to agree with 5-90 that any year after 1995 might need the 195 F thermostat due to possible OBD-II issues, but perhaps someone here has tested that theory and run a 180 F on the 96 or later models and determined if it is an issue?????

The lower radiator hose - the one that runs to the water pump inlet - should have a stainless coil in it. You don't need to pull the hose to check - just grab the middle of the hose and try to squeeze it. If it doesn't squeeze, you have the coil inside.

When changing radiator hoses, I'll typically pull the coil out of the old lower hose and hang it on a hook in the garage after I clean it up and inspect it. If the new hose doesn't have a coil in it, I just pull one down and screw it in there. It may not be absolutely necessary, but the hoses do soften with age, and I'm used to putting "support coils" (that's what they're called) in hydraulic suction hoses anyhow, so I may as well. It's cheap insurance.

Reader - don't feel bad. We all had to learn somehow. Wisdom comes from experience, and experience is what you get when you don't get what you want. Learn from the wisdom/experience of others - you'll have plenty of your own mistakes to make later... :laugh3:

Bdiddy - you've probably got air trapped behind the thermostat, and that will make the thermostat not open. Also, a thermostat is considered "ruined" if it's got one overheat in its history - and they're cheap and fairly easy to replace. Search up my posts on "thermostat drilling" to find out how to make the system purge itself of air - I haven't done a good writeup yet, but I've covered it more than a few times here in the recent past...

Thanks 5-90. I'll look up the thermostat drilling... hopefully that will get rid of the problem. I can replace the t-stat but would rather have that not be the problem and be more of a simple 'burping' fix. I'm semi car parts retarded. The hose that would have the coil in it like you said to squeeze and see if it's there... where is it located in relation to the radiator hose. I've never had to really work on cars till I got this Jeep. It's all a learning experience for me. Using a early 90's Ford 250 radiator hose would cause a problem would it? It fits in there fine, no harsh bends or anything like that... just jimmy rigged a little and had to cut to fit...

The lower hose - on the driver's side of the radiator. Just grab the middle of the hose and squeeze (engine OFF!) and see how far you get.

Ecomike said:

First a question for "READER", what are you wanting to accomplish by upgrading, are you having any problems with the stock system, planning changes that might lead to overheating, etc?

Click to expand...

I plan on towing a boats from time to time. They will weigh between 2,000 lbs. and 4,000 lbs.

I understand that the towing capacity on a 2000 XJ can be up to 5,000 lbs. with a transmission cooler, automatic transmission and a 3 coil radiator. A posting on Jeep Horizons suggested a Hi Flow Thermostat housing and 180 degree hi flow thermostat. However, with a 2000 XJ I am told it might be better to stick with the 195 degree stock figure in a thermostat.

Thanks,

Read
2000 XJ

I run a Jet 180 stat in my 2000 and has worked good for the last 3 years (no codes) A Hi-Flow housing won't do much good unless you port the block to match the Hi-Flow housing's size. Another cheapo mod would be to wire in a fan override switch so you can turn on the aux. fan as you see fit.

Jer

Reader said:

Ecomike said:


I plan on towing a boats from time to time. They will weigh between 2,000 lbs. and 4,000 lbs.

I understand that the towing capacity on a 2000 XJ can be up to 5,000 lbs. with a transmission cooler, automatic transmission and a 3 coil radiator. A posting on Jeep Horizons suggested a Hi Flow Thermostat housing and 180 degree hi flow thermostat. However, with a 2000 XJ I am told it might be better to stick with the 195 degree stock figure in a thermostat.

Thanks,

Read
2000 XJ

Click to expand...

"Three core," not "three coil." That means that there are three layers of tubes for the coolant to transfer heat to air, not two (stacked one behind the other.) I'd rather see a "staggered two-core" than a "three-core" for the XJ, but I don't see that happening anytime soon.

With towing, you're going to be more interested in the transmission cooler anyhow. It doesn't make any sense at all to me to "cool" transmission fluid with the hot-side radiator circuit (which runs around 210*F) when the operating temperature range of ATF is 190-230 or so (IIRC.)

Get a cooler kit with a thermostatic control valve, and bypass the OEM internal cooler. The thermostatic valve will route the fluid directly back into the transmission until it hits operating temperature, and then open up and route it through the cooler. Best of both worlds - shorter warmup times and more effective cooling.

If you're going to tow boats over 3,000#, I'd get a "four-pass" cooler - the line runs back and forth through the fins a total of four times. Check Flow-Kooler and Trans-Dapt, and get a unit with "turbulators" if at all possible - since they generate turbulence in the fluid and expose more of the heated fluid to atmospheric air (by way of the tube surface.) B&M should also be decent - but I haven't dealt with them since before they sold out to the Koreans (and their transmissions aren't worth a damn anymore, according to reports from the field.)

Removing the AT cooler circuit from the radiator will also improve the cooling efficiency of the radiator. Even with the AT cooler mounted in front of the radiator, it's still a small enough core that it doesn't block airflow much, and you're not trying to cool a hot fluid with a hot fluid - which doesn't usually work too well. Removing a thermal load from your radiator will help.

5-90 said:

"Three core," not "three coil." That means that there are three layers of tubes for the coolant to transfer heat to air, not two (stacked one behind the other.) I'd rather see a "staggered two-core" than a "three-core" for the XJ, but I don't see that happening anytime soon.

With towing, you're going to be more interested in the transmission cooler anyhow. It doesn't make any sense at all to me to "cool" transmission fluid with the hot-side radiator circuit (which runs around 210*F) when the operating temperature range of ATF is 190-230 or so (IIRC.)

Get a cooler kit with a thermostatic control valve, and bypass the OEM internal cooler. The thermostatic valve will route the fluid directly back into the transmission until it hits operating temperature, and then open up and route it through the cooler. Best of both worlds - shorter warmup times and more effective cooling.

If you're going to tow boats over 3,000#, I'd get a "four-pass" cooler - the line runs back and forth through the fins a total of four times. Check Flow-Kooler and Trans-Dapt, and get a unit with "turbulators" if at all possible - since they generate turbulence in the fluid and expose more of the heated fluid to atmospheric air (by way of the tube surface.) B&M should also be decent - but I haven't dealt with them since before they sold out to the Koreans (and their transmissions aren't worth a damn anymore, according to reports from the field.)

Removing the AT cooler circuit from the radiator will also improve the cooling efficiency of the radiator. Even with the AT cooler mounted in front of the radiator, it's still a small enough core that it doesn't block airflow much, and you're not trying to cool a hot fluid with a hot fluid - which doesn't usually work too well. Removing a thermal load from your radiator will help.

Click to expand...

Why not keep the OEM radiator transmision cooler in the loop and route the return line from it to the transmision through the new air cooled transmision fluid cooler and use them both. I would think that would be better system overall and give one a higher BTU cooling capacity for the transmision fluid, especially when the transmision fluid is under stress and getting hoter than the engine coolant.

I did note something in your comment I must also ask about. On my Renix, 87 jeep the tranny cooler inside my radiator is on the cold side of the radiator where the coolant is running typically between 165 to 185 F as the electric fan cycles during A/C use in the summer on an 85 F ambient day (recent test data). But you mention the cooler being on the hot side of the radiator in your post. Did they move it to the hot side on the later years ( and his is a more recent, 2000 model). If so you have a good point (bypassing the radiator) if the radiator on that side is seeing 220 F coolant.

I also have a question about routing for the new tranny cooler. According to a writeup I had seen, the tranny fluid still passed through its portion of the radiator and then from that outlet to the new B&M cooler. Is that better than running to only the new tranny cooler?

I will also be pulling a trailer about 4000 #'s. I want to make sure my transmission is happy.:gee:

5-90 said:

What year?

I've suffered no ill effects from running a 180* thermostat with RENIX and the stock housing

--short hops can allow more moisture into the oil, and without full opperating temp. it might not boil off and may require more frequent changes-- just an FYI, as I also run a 180* therm.


- I came up on SBChevvy. So, I decided to depress the temperature a bit - and I managed to pull it down to 190-195*F from 210-215*F - which fact makes me a bit more comfortable. But, it's up to you.

Click to expand...

-- you think 215* is hot?? The venerable SBChevy in third gen. F-bodies from '89-'92 uses an electric fan that isn't even supposed to come on 'til 228*!!!!! I find that a little disconcerting when I'm forced into my 4 wheel, 2WD cage for a "nice" summer cruise! No grill to speak of, 8cyl stuffed into an engine compartment smaller than the XJ, a cooling system capacity roughly the same, and lower cruise RPM-- somehow, it keeps up, but I've got a switch and relay handy for the first time it even thinks of making me walk:spin1:

--Shorty

Mikey said:

I also have a question about routing for the new tranny cooler. According to a writeup I had seen, the tranny fluid still passed through its portion of the radiator and then from that outlet to the new B&M cooler. Is that better than running to only the new tranny cooler?

I will also be pulling a trailer about 4000 #'s. I want to make sure my transmission is happy.:gee:

Click to expand...

It may actually depend on the entire individual drivetrain package and driving conditions. If the engine coolant is getting hotter than the tranny fluid then 5-90 is right, bypass the radiator, if the tranny fluid is getting hotter than the engine coolant than go through the radiator first. A lot of us here, have different mods to our jeeps and different year jeeps, and with age some cooling systems (radiators and engine coolant) are working better, cooler than others, some are new, some are heavy duty upgrades, like water pumps, radiators, etc.

Also if you get into cooler climates it is best to have it run through the radiator first to warm up the transmision fluid in the winter. In other words it acts as tranny fluid heater at start up in ultra cold areas up north during the winter.