I just picked up a pretty nice '98 XJ with 164K miles on it. It is a 5 speed on 33's with 4.10 gears.
Went for a drive today and it is running between 210 and 220. Granted, it's frigging 97 degrees out today but wondering what is normal temps.
On flats or down hills it's a tick over or under 210. Up hills it's 220 or a tick over. Stays at 210 at idle or in traffic. I haven't trailed it yet so hoping these are normal operating temps.
I have a WK with the Hemi and it never gets over 210.
I just picked up a pretty nice '98 XJ with 164K miles on it. It is a 5 speed on 33's with 4.10 gears.
Went for a drive today and it is running between 210 and 220. Granted, it's frigging 97 degrees out today but wondering what is normal temps.
On flats or down hills it's a tick over or under 210. Up hills it's 220 or a tick over. Stays at 210 at idle or in traffic. I haven't trailed it yet so hoping these are normal operating temps.
I have a WK with the Hemi and it never gets over 210.
That's pretty typical if not ideal, lots of guys creep up to 220 in traffic or high load situations like crawling or long hills. You don't need to seriously worry unless it starts to creep over 220 in high heat situations or is slow to come back down when it has a breather.
If you're not used to XJ's though, be aware that the cooling system is sufficient, but only barely. There's almost no tolerance for missed maintenance and bad parts like a lot of vehicles have. You should service the system (coolant flush and parts inspection) something like every other year or every 30k, whichever comes first. I'd do at least the flush and inspection on any new to me XJ as a matter of course. Thermostats and water pumps seem to get replaced frequently, but things like hoses, rad caps and flushes are often ignored.
Thanks for the info BlueJunior. That makes me feel better.
I figure today was a good test with the high temps and the pretty big grades I was climbing. I sat in some traffic too and it never got over 220. Just when climbing the big, long grades it just barely went over 220.
I will definitely do a system flush and check everything out. The Jeep is very clean though and the PO was good about maintenance.
Thanks for the info BlueJunior. That makes me feel better.
I figure today was a good test with the high temps and the pretty big grades I was climbing. I sat in some traffic too and it never got over 220. Just when climbing the big, long grades it just barely went over 220.
I will definitely do a system flush and check everything out. The Jeep is very clean though and the PO was good about maintenance.
That's good news, still worth a good lookover. Even experienced mechanics often fail to keep up with an XJ's cooling needs because they're so damned touchy. The forum gets flooded with cooling questions every summer. At least yours doesnt have the 0331 issues us 00-01 guys get to worry about.
I just picked up a pretty nice '98 XJ with 164K miles on it. It is a 5 speed on 33's with 4.10 gears.
Went for a drive today and it is running between 210 and 220. Granted, it's frigging 97 degrees out today but wondering what is normal temps.
On flats or down hills it's a tick over or under 210. Up hills it's 220 or a tick over. Stays at 210 at idle or in traffic. I haven't trailed it yet so hoping these are normal operating temps.
I have a WK with the Hemi and it never gets over 210.
205F to 212F is ideal for efficiency, IME. It's warm enough to burn gas efficiently, and cool enough to NOT trigger the fans (fans add drag to engine and reduce gas mileage).
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210 to 220F is normal in Summer. It's fine. The electric fan doesn't come on until around 215F. The mechanical fan clutch doesn't engage until around 215F to 220F. I wouldn't worry until it goes above 220F. I wouldn't even worry at 225F. If you want to reduce engine temp in Summer, the most efficient way is a hood vent, but don't put it anywhere that will let rain where you don't want it.
205F to 210F is normal in Fall and Spring.
Below 195F is normal in Winter, but not ideal. Ideal engine temp for efficiency in Winter is 205F to 210F. My XJ runs 205 to 210F in Winter because I have a Stant 205F thermostat.
I stand by what I said about temperature in my prior post. However it's always good idea to have a 2 row radiator. You don't want it going above 220F if you can help it, and certainly not above 225F. No engine damage occurs until above 230F, but you don't want to be on the ragged edge. So for safety margin I like to keep it 220F or less. For efficiency reasons I like to keep it between 205F to 212F, but that's not always possible on a hot day (even with a two core radiator). But with a two core radiator the situation is definitely better than with a one core.
A two core radiator can help it stay at a good temperature on a hot day. A one core radiator is inadequate IMO. And that's on pavement. For off road a two core is mandatory, IMO.
Factory single core got me around Texas just fine with no issues until abusing the system (RV + >=100* weather + long hill country climbs) finally caught up and damaged the tank/core joint last summer. Previous guy had given it **** maintenance, too. Most of the fluids other than the oil (including the coolant) appeared to be the stock fill with maybe a periodic top-off.
No reason not to go 2 row if you're replacing anyway, but you don't HAVE to run out and buy a new one just because you have a single core and 33's or something.
I agree with what you said with regard to on road use. A one core can be adequate on road, but a two core is certainly better.
However off-road is a different thing. My prior XJ had a one core and it would overheat (230F) when off-roading in the summer-time in sand. A two core radiator fixed that. With a two core it never got above 220F, and seldom above 215F, when off-roading in summer.
Your fans are probably fine but I would still check their operation anyway. The electric fan should come on around 215F. I think the mechanical fan clutch engages at 220F, but I'm not sure. Hopefully some other guys here can tell you at what temperature the mechanical fan clutch should engage. Then test it to verify that the clutch engages when needed.
That's just a common maintenance test to make sure all is well with your fans. They're probably fine.
Another thing a fellow can do if regularly running above 212F is use 5w40 synthetic motor oil. At 212F or less it lubricates as well as 10w30. When above 212F it will maintain your oil pressure and lubrication better than 10w30.
I would not recommend a diesel oil 5w40 because they tend to be overly thick. Before anyone argues with me, go look up the spec sheet for any 5w40 diesel oil and compare the viscosity at 40C to a 10w30 conventional oil at 40C.
However there are some excellent 5w40 designed for gas engines. Chevron Supreme 5w40 which I think they've renamed Havoline 5w40. Chevron owns Havoline. Pennzoil 5w40. Kendall 5w40. Valvoline 5w40. Lucas 5w40.
Shell Rotella 5w30 (diesel oil) has awesome specs if you can find it. It's thicker than most conventional 5w30 for gas engines. Rotella 5W30 is my current favorite oil followed by any of the 5w40 gas engine oils I recommended above. I also like Valvoline 0w40 because its viscosity specs show that it's really a 5w40 and it has a great attitude package.
If you want to stay with a conventional oil I recommend Valvoline 5W30 because it has the best viscosity at cold start and full op temp that I've seen for conventional oil. I compared the viscosity ratings in the spec sheets for many oils. The Valvoline 5w30 conventional looks the best to me of all the conventional oil choices followed by Pennzoil conventional.
Pennzoil, Valvoline, and Quaker State are all refined from East Coast USA crude oils, which is the highest quality crude oil in the world. The differences between those three brands are the refining and additives. From what I have read and researched Valvoline is the best followed closely by Pennzoil. Quaker State is not quite as good as the other two because Pennzoil does not put their best additives into Quaker State.
Valvoline and Pennzoil are still competitors with each other. Pennzoil owns Quaker State.
Different use cases I guess. Off road I'm trying to get somewhere way more often than just going for the hell of it so it's spurts of heavy activity in rough areas followed by stretches of just washed out tracks that don't really work it and let it cool down. A day of crawling is a totally different animal.
I have a brass two row core. Most will say an aluminum core is better. I don't have any direct experience. Well, I did replace the brass one with an aluminum one in my MB240D, but no clue. I do not doubt the experience of either Blue Junior or Charley. As for the fans, if your really spiking temps in traffic, I'd probably replace the clutch fan. I think the test is to get to temp, then pull over. See if the fan is hard to turn. I think the electric is also for A/C running. Lower temp thermostats will not help. For road use, 195F is the min. Especially in colder climates. Also, if your running fine, then the temp spikes, I'd look into replacing the water pump. Sometimes the impellor will come off, ie the press fit of it. Had it happen on a Dodge Neon.
If it helps make a call, my experience with my own vs others rigs, testimony and my own mat sci classes break it down like this:
Aluminum in good shape should cool a little better, all other factors held even (thermal conductivity).
Copper/brass mixes should stand up to corrosive coolant mixes better and are much more likely to be reparable after minor damage.
There's a lot of z factors including the exact materials used, the rest of the system, airflow (when talking 2 row vs 3 row) , etc.... but maybe that will help someone make a call.
Copper-brass as a material cools better than aluminum if you're just considering the materials.
However the braising material used to assemble brass-copper radiators tubes to the tanks and the little air fins to the tubes is not very heat conductive. This inhibits the ability of the heat to flow from tubes to the cooling fins. So although brass-copper are very effective materials for conducting heat, they don't make very efficient radiators designs because heat has a hard time transferring from the tubes through the braised areas to the fins because the brazing material is a poor conductor. Great materials, but poor design. Also the brazing material is not very sturdy. So copper-brass radiators are fragile and may not hold up on bumpy rides. i.e. - they're prone to leaks.
Aluminum (as a material) is less heat conductive than copper or brass. However aluminum is a reasonably conductive material that can be welded together and conducts heat well through the welds. This means that heat can efficiently pass from the tubes to the fins. So even though aluminum is a less conductive material, it allows for a more conductive design. The overall result is an aluminum radiator is slightly more heat conductive than copper-brass. There's not much difference between the two for their cooling abilities. They both get the job done fine.
The major advantage of an aluminum radiator is that it is much sturdier because it is welded together rather than braised. So the tubes are much more sturdily attached to the tanks. So an aluminum radiator can withstand much more impacts. That makes it preferable for any bumpy riding vehicle like an off-road vehicle or even a vehicle that hits potholes hard. This also means that aluminum radiators are less prone to leaks. That's a big deal to me.
For those with an automatic transmission, adding a transmission cooler helps keep the engine cool by removing some of the heat load from the main radiator, and it also helps cool the transmission.
'I also like Valvoline 0w40 because its viscosity specs show that it's really a 5w40 and it has a great attitude package.'
Some will tell you, I have enough attitude already. I am running Rotella 5W-40 presently. I think synthetics if not only reduce temps by a little, help protect engines that run at a higher temp. Still, modern conventional oil, is a quantum leap from even 10 years ago.
What Blue Junior wrote is about what I understand as for cooling vs longevity. If aluminum radiator, then I'd use Zerex ZO-5 coolant. You can mix different dilutions, for higher temps. Use distilled water. Also, there is a 'high performance' radiator that uses single row. They are wider and airfoil shaped. A bit pricey though.
I know there are some high-performing 1 row radiators for TJs. Do they also exist for XJs? For XJ the traditional performance radiator has 2 rows and those are all that I'm aware of for XJ.
I used to have a Dodge ex police car with a 4 rows radiator.
I remember a thread that had listed a 1-row HD radiator, that I thought was for the XJ. I remember it being $500. Also, I think the shift from brass to aluminum is cost.
I do have a '75 Bricklin. 3-row from factory. One of the repair shops or after market supplies a 4-row. Suppose to work well. I did try the Evans coolant. Not sure on results. Also, airflow through the radiator can vary car to car. The vendor does make an improved chin scoop. The Brick's temps make a XJ seem cool.
I run a 3 row and a 195 degree t-stat. My t-state housing is leaking but I don't touch 200 degrees unless I'm in low range and crawling in 85+ degrees. During the winter it's around 170ish? Still closed cooling, 50/50 premix, mobil 1 10w30 high mileage (i usually run the 10-40 but they were out)
I've put 3 new t-stats in it (this last one just started leaking every so slightly) and it never made a difference. The radiator seems to work too well for the closed cooled XJ
Where did you get the 3 row radiator? I guess my Jeep is okay now but certainly wouldn't mind having the peace of mind with the 3 row and keeping temps below 200.
CSF is the most popular brand, available through amazon and several other vendors. I'll let him fill in the specific P/N though, just though you might want to read up.
My new one is a champion 2-core all aluminum (mimics the factory towing rad except it has welded on aluminum side tanks instead of pressed in plastic), which works MUCH better than the factory unit already but I haven't been able to fully test it. Factory unit worked right up until it started leaking, but it spent a lot more time with the e-fan on. This one sits stead at 210 when the old one would creep and then come back down with the e-fan. I broke a tab off the damned fan shroud during the install and now the fan gets into the shroud if i get on the gas hard so we'll see about the full towing/wheeling test when I replace it.
You really do wanna stay 205-215, though. That's where the 4.0 likes to be, even if it seems hot compared to most engines. If I couldn't get mine over 200 I'd put in a 205* thermostat instead of the factory 195*
You really do wanna stay 205-215, though. That's where the 4.0 likes to be, even if it seems hot compared to most engines. If I couldn't get mine over 200 I'd put in a 205* thermostat instead of the factory 195*
Less than 230 to prevent engine damage. Ideally 220 or less. 220 gives ample safety margin.
205 to 212F for maximum efficiency. It's hot enough to burn fuel efficiently; and cool enough that efan is off, and mechanical fan clutch is disengaged (minimal drag on engine).
My stock efan kicks on at 215F, which increases alternator drag on motor and reduces gas mileage. I'm not sure what temp mechanical fan clutch engages, but when it does it causes additional drag and reduces gas mileage. That's why I like to stay below 215F (if possible) for efficiency reasons, but that's not always possible.
Plan A is 205 to 212F for maximum efficiency (when possible).
Plan B is 220F or less for engine protection.
Plan C (last resort) is less than 230F for engine protection. That should be possible in all circumstances.
A little update. July 4 I ran up and over Monitor Pass, about 5000 feet to 9500 feet. Pretty steady climb up the mountain. Mid to upper 90's air temperature. Running with a/c on engine temp stayed at 220. Then suddenly spiked to 250 and "check gauges" warning light came on.
I immediately pulled over and shut off the a/c. Letting it idle and less than 30 seconds was back at 220. Ran rest of the way up the mountain with a/c turned off and it stayed at 220. Once at the top it went back to 210 and stayed there.
Keeping temp below 200 degrees is too cold for efficiency, and it doesn't protect the engine either. You just get a really dirty engine.
It's much better to run at 205 to 212F.
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