1991Jeep_Man

So, now that the weather here in VA has been reaching the mid 90's with high humidity, my Jeep is acting up. When driving down the highway, she stays happy with a good 210*. As soon as I begin hitting town and having to stop and go, she creeps up and up. The e-fan kicks on when it should, and the temp will drop.. however, after about 30 mins of driving in these conditions, the temp hardly ever goes back down to a solid 210*. It usually tapers in between the two white lines, or sometimes even worse and sits right behind the last white line. Im at a loss, and this is my only vehicle. I am making a list for things to do, and I need some input. First off, I don't know when the last time the coolant was flushed (but bought one of those coolant testers from A/Z and only two ***** floated up.. take it that's bad when the more ***** the better). Any estimates on how much a flush might cost? Also, when I get my flush I am replacing both rad hoses, getting either a 180* or regular 195* tstat, and possibly a new temp sensor. Also, I have the dreaded cracked header.. would this in anyway cause overheating by releasing hot exhaust gas out? I'm pretty sure the crack is near the collector. And how do I clean my rad fins? I know its a stupid question, but with both the e-fan shroud and mech fan shroud in the way Im not sure how to tackle this. Finally, thinking about replacing the stock e-fan with a 97-99 XJ e-fan and wire it to cut on with not only the a/c and when the temp gets hot, but maybe even a switch so I can turn it on whenever. Thanks for all the help guys.

ken72

Wow dude you got a lot to do. First are you saying your temp runs well above 210 after a while? The fans kick on temp is about 213 or so. Does the fan kick on and keep the temp down or does it kick on and the temp keeps rising? Replacing the fans clutch could be what is wrong. You will find most places will flush the system for around $80. I have heard people suggest using a higher water to coolant mixture in the warmer season. I just used some water wetter on mine and it helped. Just as an FYI... mine moves between the 213 and under the 210 mark pretty regulary in stop and go but stays right at 210 on the highway. Also changing to a 185 t-stat is not going to help if your fan clutch or temp sensors are not working. It will only allow coolant to flow earlier than it does now, causing your jeep longer to warm up.... I would go for checking that fan first, flushing the system with a little high water to coolant mixture.... maybe 60/40 instead of 50/50 and add a bottle of water wetter.

Faol

I had the same condition going on. I had a CO2 test by a mechanic, who told me it was the head gasket. So, I replaced the gasket, and the head while I was at it (I had 188K miles). While I was at it, I replaced the temp sensor & sender. That didn't work. Then it was another thermostat, fan clutch, then water pump, etc. It turns out it was a blocked radiator. I had it tested when I removed it for the head job, by a SPECIALTY radiator shop, who gave it a green light and they were wrong. My radiator was an aluminum 3 core, 2 years old. The fluid looked great, but it still had the issue. I replaced it with a metal 2 core and the problem I was having immediately went away.

From what I have read, I would do 3 inexpensive things, which is going to do a partial 4th in the process. I would replace the coolant sensing unit (in the water outlet/t-stat housing), the t-stat itself (195*), and the fan clutch. By doing this, you are going to replace some anti-freeze anyway, so you might as well do a flush.

I am not sure about the flush, but the other 3 items are going to cost you less than $20 each for the fan clutch and coolant sensor, and the t-stat will be about $4, unless you want to get the fail-safe model, which would be about $10. You will also need some gasket sealant.

Tools: 1/2" socket & wrench for t-stat housing, and loosening power steering bolts to remove tension on serpentine belt. I believe it is a 3/4, or maybe 5/8" deep well, for the coolant temperature sensor. The fan clutch should be a 1/2" also, if I remember correctly. You are going to need to use a wrench for those 4 bolts.

I that doesn't work, I would look at the radiator next. This will be $150 or less for a dual-core all metal unit, from an online source.

My overheating problem was a $125 fix (for the radiator), after days of work, and spending $1500 for parts and tools I did not have.

96jeepxj

Seems like you are on the right track. Definitely a flush first, if you have a garden hose then go buy a cheap (3-4 bucks) prestone radiator flush kit at wal-mart, auto-zone, ect and it will have all the directions on it.

FYI when I flushed my system for the first time, the stock radiator started leaking bad (the old radiator fluid was to thick to leak). I ended up buying a more heavy duty all metal three row radiator. Not saying this is going to happen to you but don't be surprised if it does. And don't use any radiator stop leak crap because that's what caused my problems in the first place.

If you end up getting a new radiator check out radiatorbarn.com $180 shipped for the heavy duty all metal three row/ $100 shipped for a stock one row w/plastic endcaps.

All the other small mods are just a cover up if you have a bad radiator, which a radiator flush should be able to tell you whether or not it is.
just my .02

1991Jeep_Man

I noticed you both mentioned the fan clutch. I should have mentioned this, but you know when the fan clutch is fully engaged it sounds like a vacuum cleaner in the front of your Jeep? Well, even when the temp is over the 210 mark, and I drive from a stop, I dont really hear that sound all the time. Could this be an indicator of a bad fan clutch?

1991Jeep_Man

Whew, that 3-row looks like a beast.. How did you fair with it? Did it fight right in or did you have to cut anything?

96jeepxj

I think it was one of the most cost effective purchases I've made and it slides right in and hooks up no mods or problems. You lose a little space between the radiator and engine but hardly even noticeable.

96jeepxj

Also when you take off the stock radiator you realize just how dinky it is. In my opinion way too small for a 4.0 I6 engine

1991Jeep_Man

Since I don't really offroad all that much, do you think the two row radiator would do me well?

Faol

I don't do heavy off-roading myself, and my 2 row works great. I use mine to get into the backcountry to go camping, so I do forest service roads, crossing rivers & creeks, etc. It is also my daily driver, with mostly city driving with Max A/C on.

96jeepxj

I agree, if your not going to be doing very heavy off-roading a 2 row should be fine (better then stock for sure). One important thing also is whether or not it has plastic or metal end tanks. Metal being more ideal. FYI a stock radiator has plastic end tanks.

1991Jeep_Man

What about the fan clutch? If the temp gauge is reading more than 210 and I dont hear the fan making that loud sucking, is the clutch not engaging?

Faol

Yep, that is one of the things I suggested changing.

1991Jeep_Man

So if I am planning on going out and buying the 2 row rad and everything, should I consider swapping over to a dual e-fan setup or will the mech fan still have enough clearance?

fishtaconc

as long as the fan clutch is the same size as stock itll work even w/ the 3 row radiator. Also they can get kinda tight with Tcace drops. When you buy your clutch take it with you and make sure it the same