Hi Guys,

I have a problem with my 1995 Jeep Cherokee XJ has a 4.0 engine and an automatic transmission.

The problem arises when accelerating, the temperature begins to increase, ie, when I'm driving on the freeway and accelerated steadily to reach speeds between 60-85 MPH, the needle on the temperature starts to rise from normal (the line before 210 degrees, up to the line that follows the 210). This seems very strange since earlier when driving on the highway the temperature tended to decrease. Two days ago I had to make a trip of about 200 miles and it was a nightmare, I could not pass 60MPH because the temperature began to rise.

Both fans (Electrical and Mechanical) work well, the temperature sensor is relatively new (4 months). 5 months ago I would service the radiator and water pump change in February this year.

I would appreciate any help you can give me about it.

Thanks in advance.

 

"Would service the radiator": as in "were planning to" or " have done" ?
Assuming your WP is working: how old is your thermostat?

I'd look at radiator (also cleaned outside from bugs etc, after summer?), thermostat, radiator cap next.

 

Thanks for responding, sorry for my English, I meant that the service had already done the radiator. I changed the thermostat too along with the water pump. The radiator cap is the original 16psi should change it?

The radiator seems to be clean, but tomorrow I will clean it and at first glance does not seem to insects or other dirty, but it's always good to make sure.

 

All cooling system parts play together in keeping your engine at operating temp under different circumstances. So, every sub-par item will add to the end result. The radiator cap is actually a maintenance item, and if its the original, is might by now have well lost it's full 'sealing' capacity. Loosing pressure = decreasing boiling point > running warmer under normal circumstances. It's a cheap item, replace it.

Your thermostat: you replaced it with a 195 F stat? Tested it before putting it in? I found my Gates thermostat didnt even open half as much as the OEM one I eventually got from the dealer (the one with the little hole in it). Temp has been very stable since I put the OEM stat in.

 

Thanks again, I will replace the radiator cap. As for the thermostat, I placed a Stant 45359 195 degrees. It has worked fine since I made ​​the change, but will replace it.

 

How do you know ? You didnt mention when this all started, but yes, it could be working fine. Or just fine enough, untill now. Not saying it is the cause, but in my case the difference was striking.
All bits could add up... see how you go.

 

There's only one way to positively clean the rad internally. The tanks must be separated from the core and each tube in the core is "rodded" out. Is that what was done? If not, then u don't know the internal condition of the rad. A rad that's half plugged internally will still flow water....but only remove 1/2 the heat necessary. Highway speeds require a 100% efficient rad and fast coolant flow thru ALL of the tubes.

The t-stat is the only cooling system component that can easily be tested (no special tools). Got a stove, a small pot u can fill with water and place the stat in and a cooking thermometer? Don't toss the stat into boiling water. Put both stats in the pot of water and compare them to each other. They should just barely begin to open at their temp rating, continue to open slowly/smoothly and wide open should be about 1/4".

 

OK, seeing it from that point of view, it makes sense that both recommend me, today I'm going to do things as follows:

I'll go to a garage that specializes in radiators and I will make sure to do the internal radiator flush as recommended djb383. Once this is done, I will proceed to do a test on the highway, if the temperature continues to rise, then I'll buy a radiator cap and new thermostat.

I know it would be easier to start with replacing the two pieces, but I have a sneaking suspicion that the radiator flush that did not follow the procedure previously described by djb383, so I decided to start with this alternative.

Thanks again for your help and I will be leaving you my feedback once I've done the tests at the end of the day.

 

Will keep an eye out.

 

A radiator "flush" is virtually worthless and I doubt u'll find a reputable rad shop that says they can "flush" a radiator out and guarantee all of the tubes r 100% unplugged. A reputable rad shop will disassemble the rad (separate the tanks from the core) and insert a rod into each tube, thus clearing/knocking out any scale/solid obstruction that's inside each tube. It's called "rodding out" the rad, not flushing the rad. +/-$110 buys a new rad so get an estimate on how much to "rod out" a rad 1st.

 

Water pump. How long has it been on there.

 

I'd be willing to bet if the radiator is fairly old The process would bust those **** plastic tanks and he'd need a new one anyway.

 

Can radiators with plastic tanks be rodded out?

If it's it's possible, I would think it would cost more than a new radiator.

 

Mine does the same thing . '98 XJ , 40,000 miles , new 3 core radiator , high flow water pump , high flow thermostat & housing , triple threat fans ( 3 electric fans with shrouds ) 2/3 distilled water & 1/3 antifreeze with Red Line Water Wetter added . No head gasket problems & uses no oil - WTF ???

 

And new radiator cap !