YJ running hot.... stumped

[bails85]

92 4.0 ax15....... i just replaced waterpump, tstat and housing, heatercore, all hoses, and put in a hayden fanclutch. jeep is bouncing around from 190 to 235. and thats being nice to it not driving it hard or uphill. it hasnt popped the cap yet but it does run too warm for my liking especially since most claim theirs run at 195 and never go over 210. the only thing i didnt change was the radiator but it still looked good and looked new..ish. i flushed the hell out of it and put everything back together and added a flush kit in the heater line to be able to get all the air out. i have got it up to temp and checked it a few times and have not had to add any water. any ideas what to try? my wife will be driving this and i want to make sure its ready. thanks

[Jeeperator]

My tj always ran on the high side ~225 ish especially when under a load like on the freeway or going up a long grade. I had a new 3 row brass radiator also. I decided to try a 2 row all aluminum one off eBay and it rarely sees 200 degrees now. Thinking the 3 row brass is not as efficient or airflow wasn't as good because of the 3 rows. You wouldn't think that was the case but old blue runs a lot cooler now.

[USMC 0369]

[COLOR="#800000"]I am seriously NOT trying to insult your intelligence....do you have a fan shroud? I don't and my '90 runs hot sometimes when the weather heats up. I'm looking for one.[/COLOR]

[bails85]

yes i have a fan shroud. i cant for the life of me figure out why its running so warm. and that was later in the afternoon when it wasnt as hot outside. would dropping the temp on the t stat to 180 from 195 help at all? the engine sounds good and feels plenty strong. i just cleaned the intake and all the sensors out when i welded up the header. what is the best radiator to get? i might just get a new one and see if it makes a difference. there might be something on the inside that im not seeing.

[6spdYJ]

If you have the stock radiator, it's probably clogged pretty good by now. I might get poo-poo'ed for it but I replaced mine with a brass 2-row. My reasoning was that I can solder any cracks that may develop. The reason I replaced my stocker was that the aluminum eroded around one of the tanks. The aluminum is way more efficient to transfer heat, but I have no overheating problems - and I can fix it if I have to. I used 1800radiator and it was delivered to my driveway.

[bails85]

when i flushed it water was flowing freely out of the petcock and upper hose lower hose and cap holes. not sure if thats a good way to tell or not but i didnt see much junk coming out. ive always heard to go with 3 row over 2 row but then there are those that say 2 is the way to go. on my xj i put a 3 row in it fixed the problem. im just getting annoyed with the 1 step forward 5 steps back. anyone ever used csf for a radiator? they seem to be pretty popular amongst the xj crowd. im thinking of using a csf 3 row. the pass and the 138 are pretty tough on cars so over cooling wont be an issue for me. thoughts?

[daniel_buck]

is it possibly the gauge?

[hes4all]

Yes check the gauge.

I have gone with aluminum radiators and electric fans on my Jeeps now. They work great with the slow speed that crawlers do a lot!

3 core radiator don't have as much air flow and sometimes a stuck open thermostat can lead to over heating because the water moves to fast through the radiator and doesn't get cooled. I found this out when I took at a thermostat many moons ago.

[bails85]

whats the right way to test the guage? i assumed it was working properly because its constantly changing temps. the jeep will get to the line after 210 then bounce back down when i let off the pedal going down hill. it stay at 210 for a minute then climbs up again. everything is new except the radiator. when i had everything apart i took the rad out and soaked it with clr and filled it up with clr for a few days while it was out of the jeep. i sprayed it out with the hose really well before i put it back in the jeep. whats a good radiator to get i have about 2bills to spend. the fan clutch seems to be pulling air like crazy so i dont think it is the problem. i bought the hayden one because it was recomended by the guys on naxja and xjs constanly overheat.

[6spdYJ]

Your feet are going to hate me for this... Go to the most reliable stretch of road where you can repeatably get the same movement on the gauge. Go ahead and heat it up the normal way and cool it down the same. Make sure you see exactly the same readings and responses. Then turn the heater on full blast and do it again. You will be effectively adding 20% more radiator to the equation. If the readings change, you likely have some clogged tubes. Even though the CLR is good to clear scale, if it can't flow through the tube due to blockage it likely will never break through a clog. It will however get your clear tubes to flow like new.
If they stay the same, you probably have a gauge or sensor wiring issue. Mine will show warmer and then suddenly lower after accelerating if my fluid is low.

[bails85]

good idea ill give it a try this weekend.

[Lumpy Grits]

If this is the OEM radiator and you used 'tap' water mixed with a'freeze.
It's clogged with hard deposits. Our desert water is very rich in calcium.
If this a is brass radiator you can have it 'rodded-out' or recored.
X2 on a shroud.
Use only distilled water with anti-freeze--
LG

[mrchips]

use a mechanical gauge to get an accurate reading

[bails85]

is the stock rad brass or aluminum? how many rows? i found an all aluminum 2 or 3 row for under 200. they claim the 3 row works better than the 2 even in a jeep application and its yj specific.

[6spdYJ]

Stock is 2 row aluminum with plastic tanks and a steel clamping ring for the caps. Galvanic corrosion tends to erode the aluminum lip that seals the tank.