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Yep I have searched, 89 XJ stock motor, lifted and such. Radiator 2 years old, heater core 18 months old, OEM thermostat, coolant levels all okay, heat not real good. watching the temp gauge will go up to 210, thermostat opens and drops down to 160, then back up. will not stay warm, thinking another thermostat, but will this not just do the same???
One thing I didn't see listed in the stuff you've already run through: the fan clutch. If it's dead and has reverted to the locked position, in the weather we're having right now it's going to be hard for the XJ to maintain temperature since it's going to be sucking the maximum amount of cold air over the radiator all the time.
Just mentioning this because I did the ZJ über-fan-clutch upgrade over the summer, and I noticed that the Jeep now runs progressively slightly cooler than the thermostat rating the further down from freezing it gets. Should probably make a grille cover to combat that...
I had the same issue. Xj would warm up , thermo opens and drops engine temp to 160*, then took another ten minutes to warm back up to operating temp. I was using an OEM t-stat and switched to the Stant unit for the bypass hole. Now once the engine warms up it stays warmed up. HTH
I was kinda leaning towards the thermostat but was hoping that there might be something else. not sure what. I may have used the Stant, but thought it was the OEM one, Thanks I'll let you know
bdahlg, it will fluctuate a bit but not nearly as bad before the Stant thermo. Before it would hit 195*, thermo would open letting the ice cold coolant from the rad enter the block and then the temp would drop to 160* before the thermo would shut again. It would repeat untill all the coolant was around 195*. Took about 20 to 30 mins of drivng to be fully warmed up. Now she is warm in about 15 mins of driving. I do, however, let her warm up a bit before I start driving (remote start for the win).
Yep, that's what mine has always done; operating temp - drop to like 160, operating temp - to to lilke 170 and so on, until fully warmed up, which can take anywhere from 15 - 25 mins. With the heat on it will take much longer. it doesnt really ever stay around where its supposed to, always swinging no matter how long I drive.
Seems to stay pretty constant at idle and highway driving, then say if I drive away from a stop light, the temp would drop a little.
I don't get it at all. Was definitely much worse before I put the Stant in, but it definitely still not as constant as I would like it to be. It should rise to 195, thermo should open, then circulation should begin and a constant reading of 205-210 should evail.
I've never seen this in my Jeep and have replaced everything but the hoses and waterpump.
wait you have a 1989 cherokee with the stock T stat? Its something I replace right when I buy a vehicle, and probable as often as I change my trans filter.
A rad cap is an often overlooked item. The spring and rubber gasket can wear out, then your rad cant hold pressure. I like the stant one with the Red plastic lever on top. I feel like it gets a better seal.
Stant cap and Stant Superstat are like 8 bucks total at RockAuto.
A rad cap is an often overlooked item. The spring and rubber gasket can wear out, then your rad cant hold pressure. I like the stant one with the Red plastic lever on top. I feel like it gets a better seal...
Yea, I replaced both the rad cap and tstat w/Stant. I also like the cap with the red lever.
Still having the same problem however...
I'm pretty sure the OP also replaced the thermo at one point, but he's not sure if it was OEM or Stant. This is the only instance on the internet where I have found someone that is having the same problem, and I have been looking for a VERY long time, so I am interested in what people have to say about it.
Your fan clutch could be hanging up engaged causing too much cooling, or if so equipped the aux fan could be sticking on, again causing too much cooling to drop you from one end to the other extreme.
Your fan clutch could be hanging up engaged causing too much cooling, or if so equipped the aux fan could be sticking on, again causing too much cooling to drop you from one end to the other extreme.
Yes, I have thought of this numerous times. I installed the new fan clutch about a year ago. Since I've had it, I've always thought of it as being defective. When the engine is stone cold, the clutch is generally easy to spin. When its hot, its still the same stiffness.
I thought the idea of the clutch was to vary the air flow to compensate for the heat, but mine does not do this. Could this still be a reason or is my clutch operating as its supposed to?
Do not mean to hijack at all, it's just I've been wanting to tackle this for a long time.
Yeah, the fan clutch when stone cold should be stiffer because the silicone fluid seeps out of the reservoir overnight. Essentially, when you start the engine in the morning a properly functioning fan clutch will be engaged for a short time until all of the silicone fluid gets spun back into the reservoir.
Now, when the fan clutch isn't engaged the fan should rotate at 30 percent of shaft speed.
When the temperature of the air passing through the radiator and hitting the bi-metal spring on the front of the fan clutch hits 170 degrees, then the bi-metal spring starts to open the valve and the silicone fluid starts coming out and the fan clutch eventually fully engages. At this point a standard fan clutch will be turning at 60-70 percent of shaft speed.
So, when cold in the morning before starting the fan clutch should feel stiff. After about 5 minutes of engine operation if you shut it off and spin the fan clutch it should move easier than when stone cold. Then, once the engine has reached full operating temperature, say about 20 minutes of driving, pull over let the engine idle a few minutes (if coming off the highway), then shut it down and spin it--it should be equal in stiffness to how it was in the stone cold morning or possibly stiffer to turn.
There is an FSM procedure to test the fan clutch, if you need it I will search for it and post it again or a link to it.
The FSM one is with the blanket and timing light, correct? I have that saved somewhere in my favorites I believe.
If at stone cold, the fan clutch should make a "roar" on initial start-up if it's suppose to be stiff. Mine is not stiff at all prior to start-up and does not roar at all; nor is it stiff when I have checked it under multiple driving conditions. basically is the same stiffness everytime I have checked it.
I just find it hard to believe that a new fan clutch is defective, but I did read that the parts monkeys sometimes stock them in the wrong position, thus rendering the "new" clutch useless due to the silicone or something along those lines.
Is there any truth in this?
This might be kind of 'ghetto' but what about running a piece of card board in front of the rad/mech fan? That would limit the amount of air it pulls through the rad. Only down fall I can see is it turning to a wet sloppy mess.
