heating info on 4.0

[skippy62]

Thanks NIX...I went out and tightened up the serpentine belt a little. Prolly turned that little nut maybe a turn and a half.
The thermostat was new when I put in the new Rad. but I am thinking maybe something has it stuck.
There is a slight noise coming from the front and I cannot tell if it is the lifters or the water pump.I hope it is not the pump. The overflow bottle has anti freeze in it so it is not getting hot and pulling it out. I went to the store today and it ran right at the white mark after 210 and I don't know what temp. that is.... guessing 230.
the belt seemed tight enough but I did tighten it up a bit.

Thanks again

[NIX]

Was the head bled properly? Raise the rear wheels a bit and loosen the temp sensor in the head. I do it with a warm (not hot) running engine.

But I suspect the T-stat. One thing: is the rad clean? Once we had someone on the forum who had a very dirty rad...

[skippy62]

Hey NIX; Rad. is new put in about 18 months ago. This problem just started this summer.
No the head was not bled I would think if the was the case it would have happened sooner.
I am going to change the thermostat soon I have to many other project going " room addition " that is keeping me away from the xj
at any rate that is where I will start first.

Thanks...

[detectiveheiser]

Flush the hell out of your coolant system. They are prone to getting gunky. Also check your coolant to water ratio.

[NIX]

That can be wise too, but I meant the outside of the rad. Just to rule out any possibilities...

[the_fixer]

When you replaced your antifreeze, did you "burb" the air out of the system?

[skippy62]

Hey Fixer: It is a open system and no I never burped it cause I didn't think you had to. This just started a few months ago.
And like I said it has never boiled over it just looks like it is running hot by the gauge. It will run at the next white mark after the 210 mark. It will go down a little when I get on the freeway but not much. It has alwasy ran about 210 or a little under but for some reason it has started to run a little hotter by the gauge.

Thanks for you idea..

Have or did you replace your lower rad hose when you made the rad swap? If so, did the old lower have a "spring" inside? Did the new one? If the new did not, did you reuse the spring from the old hose?
Given your symptoms, I would check the electric fan to see if it is working. It should start whenever the A/C is turned on. If it doesn't you have a problem there, either with the relay, the override or the fan itself. Next you need to verify that the mechanical fan clutch is operating properly. Forget about the Haynes and Chiltons manual test. If, you don't hear that mechanical fan ROAR when you rev the engine, you need a new clutch. I would rec you avoid the cheap aftermarket units sold by most of the chains as they are horribly inefficient, power sucking cheap crap. They will cool alright but they will KILL your gas mileage.

[krabysniper]

A. An open system would tend to run a tad hotter as you don't have the pressure on the system that you have with a closed system (only takes a couple pounds difrence).

B. Never trust dashes gauges to read acurately, they are merely guides for the general ignorant masses, if you want to know true engine temp, pop the hood and shoot it with a thermal gun, that will give you a much more acurate idea of whats going on.

C. Temp sending unit is on left rear of head, and it is normal for analog gauges to do that.

Sounds to me like it's running just fine, don't over analyze [img]/ubbthreads/images/graemlins/wink.gif[/img]

[JohnXJ]

Try using Redline water wetter or a similar product. I had good luck with it.