Running warm and warmer.....what would you do next?

'96 XJ...3 year old Flow Kooler water pump..flushed the block REALLY well when I installed the pump...... nice clean coolant that has 2 years left on 5 year lifespan.

Always had great running temp around 205.... then it started creeping up.....
Started running warm .....220-225 at idle.....215 at speed....temp comes down to around 210 when heater is turned on

Had a leaky heater valve so I replaced that....replaced the thermostat next. I think the one I replaced was partially closed because the heat was minimal.And tightened up the serpentine belt.

Had the engine scanned and there are no codes.

I'm thinking the guage has gone bad because if the engine temp really is at 220-225 and there are no PCM codes then the auxillary fan should be kicking on and it doesn't.

My reasoning is that there are PCM codes that appear when the sensor is bad and when the fan relay has gone bad....sooooo maybe it is simply the guage, which I don't believe has a PCM code.

What would you do next?

Change the coolant again. Five-year lifespan isn't realistic it seems. Make sure it's 50/50, and what temp is your thermostat? SHould be a 195* and hopefully has the bleed hole at 12 o'clock.

Thanks for the reply.

Thermostat I installed didn't have a bleed hole. The one I took out also didn't have one and that one ran just fine for 3 years.

The bleed hole is a convenient way to help prevent air bubbles from getting trapped. Check out http://www.yuccaman.com/jeep/cooling.html for some other ideas.

And don't use the pink stuff, it's crap.

Thanks again Yucca-Man.

Read your essay. Yes I'm using a 195 degree thermostat and only distilled water over the last few years and flushes.

Oh yeah the silicon clutch fan is only about three years old.

I do have a tranny cooler. Last time I checked the tranny coolant level after running on the highway for about an hour, the dipstick was barely warm to the touch.

Flush and fill, water wetter, get the aux fan running.

There is a "new" t stat out....Called failsafe....if it fails,it stays in the open position....It works,had very little heat in mine last week...pulled the t stat Sunday....stuck open....Put in another gots lotsa heat...
@$10.95 local Autozone...

I had some guy come into my store and tell me that he thinks the failsafe idea is stupid. He said he would reather have the t-stat fail in the closed position. I tryed telling him that a permanently closed t-stat is going to cause overheating and the moron told me I didn't know what i was talking about.

Failsafe t-stats have been around for a few years and they work great. The few people that actually realize it's worth the exrta investment love them.

Is the radiator stock? I would try flushing/replacing that if it doesn't cool down. My Jeep had a problem of overheating, did the same things you did, new t-stat and heater valve, new hoses and water pump. That brought it down some but it still would overheat under highway speeds or hot days, changed the radiator, barely even touches 215. The old one had about 4-5 vains clogged up.