Ralph77

Thinking he grabbed you the ZJ fan clutch. I have read about lots of guys doing this. When I replaced mine I asked my boss, I work at a Napa, if I should go with one of those instead. He asked me if I was having any cooling problems in my '00. I said no. He said unless you are having problems or tow probably should not. Said it would be noisy and MPG would most likely tank. From what you posted seems he might have been right.

mannydantyla

Went on a test drive on the interstate for about 25 minutes yesterday and it didn't run hot! It wasn't a long enough test drive by far, but last summer thats all it took for the temp to start creeping up in temperatures like this (100+ F). Will go on a longer test today

I looked up the part number at it says that it's for a 4-cyl XJ. Maybe it's the HD clutch for those engines...?

I hate to see the MPG go down but I'm trying anything and everything. But right now I'm failing to see how a stiffer fan clutch will help when I'm going over 70 miles per hour. I think any speed above 40 mph you don't need cooling fans because the air is passing through the radiator fast enough on its own, and at high enough speeds they say that the wind is actually pushing the fans faster than they would normally spin! http://www.onallcylinders.com/2016/0...to-avoid-them/

But then I've read several accounts of folks who had similar problems as mine and they said upgrading to the bigger clutch fixed all their problems. Only thing I can think of as to how that would help on the highway is that the stiffer fan clutch is actually slowing down the flow in the radiator somehow and that solves a physics phenomenon where the air is going too fast through the radiator - something to do with laminar flow and boundary layers. Makes me wonder... I have the air dam, hood vents, no ac condenser. The air should be really flying through that radiator when going 75+. I mean, how else can you explain that it runs hot at 75 mph but not 60 mph?

Maybe I should put the normal clutch back on and see how it fairs with the other upgrades. Should have only changed one thing at a time, now I don't know what fixed my problem or if the new fan clutch is helping or hurting.

I actually have three 10" electric cooling fans and a fan shroud for them (from Dirtbound Offroad) sitting in my garage. Maybe I'll throw those on. I bought them a few months ago but decided not to put them on when I read that the mechanical clutch fan is more powerful then the electric fans will ever be. The actual outer diameter of the fans are 11" and don't totally fit the shroud - that was another deciding factor. I haven't returned them yet though so maybe it's worth trying and seeing what happens. If its true that the wind speed at 70+ mph is pushing the fans faster than they would normally be spinning, then they could actually be acting as tiny generates and adding amps to me system!

Ralph77

Now that you mention it maybe we list a HD version for an XJ and that is what I asked about.

mannydantyla

Wondering if the catalytic converter is partially clogged or something

That would explain why the intake manifold pressure is reading a little low and of course why it's struggling on the highway

I will say that it doesn't feel very fast on the highway. I can keep it at 75 mph but it takes a long while to get up to that speed

mannydantyla

Things I'm going to check to see if it's running lean or otherwise having issues:

• the temperature of the header tubes while at 2.5k rpm. This is my favorite way to see if the cylinders are running lean/hot. Back before I had an IR temp gun, I would just put some spit on my finger and quickly touch the header tubes and listen to them sizzle!
• the catalytic converter. Supposedly the best/easiest/fastest way to test it is to point the IR temp gun at the input and output ports of the cat. The output port should be much hotter than the input
• Fuel pressure
• ignition timing
• intake/vacuum leak. I already tested this with a can of starter fluid but the can ran out real quick and it wasn't very thorough. It would have to be a small leak though as idle RPMs are not high
• exhaust leak, especially at the flange donut blowing hot air onto the block
• o2 sensor
• TPS
• MAP sensor

Spark plugs look a little on the white side but not crazy white.

It doesn't sputter, it doesn't hesitate, it idles fine, it accelerates fine I think. Good MPG. But it runs too hot. And everyone always talks about how these motors really scream but that is not how I would characterize my engine. I'm always the slow poke in traffic. Maybe it's low on HP?

jordan96xj

If your transmission is running hot, it can affect the coolant temperature (they share the radiator). Does it only ever heat up like this when it is moving? Or will it get hotter while idling as well?

If you see this temperature increase at higher speeds out on the open road, you may want to test that your torque convertor is locking up properly. With a tachometer you can observe the lock up behavior by:

1. Go 55-60 mph straight and level.
2. Note your tachometer reading
3. While maintaining gas pedal position, tap the brake slightly just once (just enough to activate the brake switch/lights)
4. Engine RPM should jump/increase almost instantly about 300-400 rpm
5. After just a few seconds, the RPM should drop quickly back to the originally observed value.

You can also take your IR temp gun with you and when things get hot, jump out and shoot a few measurements underneath of the transmission and pan.

mannydantyla

I'll check those things too!

I have an auxillary trans oil cooler sitting in front of the radiator. I could try moving it to another position...

I remember checking it with my IR gun after a 30 minutes highway drive yesterday and the trans oil cooler didn't seem really hot (the IR guns have a problem with shiny surfaces so it may have been inaccurate). Next time I'll point it at the transmission itself, why didn't I think of that!

Sloerolla

[QUOTE=mannydantyla;3499761]

TimV

Kudos on a job well done! I mean both the elbow grease and this thread. Sure appreciate yer taking the time to share.


And so, one little idea to share: my wife's XJ was getting overly warm on slightly longish drives. Did this for a few years, I didn't sweat it. (get it? her jeep, I didn't sweat....)



Anyway, twas at the rad cap. Note at the rad cap, not the rad cap. The plastic threading for the cap was not holding the rad cap securely. As the cooling system built heated up and built pressure, coolant was very slowly pushed out to the overflow bottle and system pressure decreased. This took about an hour.



Pressure is needed. Without pressure, steam cavities will form in the head. Steam does not cool an engine.


I bent the little ears of the rad cap to make it seat more securely. End of problem.


Here's to hoping your issue may be resolved so easily.



Tim

97XJ Journey

Looks like the only differences in our XJ's is color and mine is 2wd.

Went to the parts store to get the reman head that I ordered last week,,,It was the wrong casting number! The casting number was 170505, mine is 0630. Probably no difference in the castings but since I know so little about the Jeep parts I was not taking the chance. Ordered a reman head from a different store, should be here next Wednesday.

I plan to replace my lifters, I have never heard about all this fuss when replacing lifters,,,Is it a Jeep thing??? Going to soak them in oil and pump them up, then put some motor honey on them and the other parts when it gets assembled. Will be changing the oil (Rotella T4) and filter,,,what Wix filter did you use???

mannydantyla

i got lucky and didn’t have any problem with the new lifters and the old cam playing nicely together, but from everything that I read it can be a roll of the dice. And the truth is my new lifters aren’t any quieter than the old ones! If you want new lifters, I would definitely put a LOT of assebly lube on the bottoms, the grey kind that has molly and graphite in it. I think Rotella T4 is a fine oil to use when breaking them in, but some say there’s too many detergents in it but we’re not dealing with aggressive cams and performance springs so who knows...

——————

i’m trying to decide if my catalytic converter is bad and causing back pressure. Looking at the downstream o2 sensor values, they’re supposed to stay around 0.8v and that’s mostly what the value is but they waiver a bit too much maybe. Maybe the cat is not in perfect shape but it’s still working and not clogged I think



i also measured its temperature and the exit pipe was about 50 degrees F hotter than the inlet pipe. It should be 30 to 100 degrees hotter so I guess that checks out alright.

finally I hooked up the vacuum gauge to the intake manifold with engine fully warmed up. At idle it was reading 16 or 17 inches of mercury steady, a little higher than before. I hit the throttle and it quickly dipped down and then jumped up quickly to 20 inches and held it while I held the throttle. From what I read, that is the normal operation and if there was back pressure there would be much less vacuum

mannydantyla

[accidental double post]

mannydantyla

I’ll just get right to it: I went on a long (1 hour) test drive and temp never creeped past 205*F. It wasn’t as hot today at 87 F, but I can’t control that (I wish)

i spent much of the day checking all the things on my list.

- I checked the cat converter and o2 sensors, they look good.
- I checked for vacuum leaks, this time with a propane torch, could not fine one. If I put it in the air intake, the RPMS dropped fast and almost stalled the engine...? That at least tells me that its not running/idling lean
- i looked at the ignition timing with a timing light. I couldn’t actually see the timing light shine in the timing marks, but I was just looking to see if it was jumping around a lot (sign of a bad timing chain) but it looked good I think. It was a little jumpy at idle, maybe that's normal idk, and it steadied and smoothed out when giving it throttle.
- I topped off the radiator and overflow bottles, both were low. Air escaping the cooling system? First time I have seen that, but I put a bleed hole in the thermostat just now so ??
- I cleaned the nss sensor. Didn't fix my reverse light problem though
- I adjusted the exhaust so it wouldn’t bang against my homemade skid plate

Bugout4x4

Since it's running too cold now I think you are good man.

mannydantyla

Yup! I think so too


In fact, I think it was fixed all along once the new head gasket was in place. Only reason it ran a little hot on that first test drive was because of a few small problems that added up: (1) I didn't properly bleed the air out of the cooling system, (2) I was using too much antifreeze and not enough water by mistake, and (3) it was really really hot that day! And it the temp wasn't creeping up, it just rose a little and then stopped at about 220.

But it just occurred to me that the engine used to make a "gurgling" noise when going really hard/fast up a hill. Now, I don't hear that! At all! I thought it was intake noise but maybe it was exhaust air rushing into the cooling system..?!

DONE

FIXED

MOVING ON