TwistedWrench

^^^ This.

94XJAZ

Just in case you were curious, after driving my XJ for 12 days after I replaced the broken T-stat,,, No temp issues at all and it has been plenty hot around here.

HappyTrails

I did the complete cooling service earlier this year. Very happy with the results.
Hesco High Flow Pump
Hesco High Flow T Stat housing
2 row all brass/copper CSF radiator
New hoses
Complete Flush
New Fan Clutch
New Mr Gasket t-stat

In fact, it is running so cool in hot weather that when I took out the aux fan to tighten the steering box, I never put it back in just to see if it made a difference. Nope. Not even on 100F days going up steep extended hills.

What I suspect some people are encountering when doing this project is installing a t-stat that does not accommodate the high flow of the Hesco pump and t-stat housing.

Just some thoughts from the field. It might be worth running w/out the t-stat for a bit to see if you are stilling having high temp issues. (Remember that without the t-stat you might have low temp issues).

vank

Thanks for the reply. I am running a high flow t-stat in complement to my hesco pump and housing. I also tried running without a t-stat and was still seeing temps in excess of 210.

vank

Update time.

So against some other members' better judgement. I installed a used head last night. I purchased the head from FN Jeep in Colorado Springs for $50 + tax. Really a great deal versus the $600 for a new head. They had somewhere around 15 useable heads so I was able to examine them all and pick the best. Many were still built up and even had spark plugs installed. Unfortunately they don't keep a very good record of what they came out of but looking at carbon build up and plugs I was able to put together what I thought was a good story. The head I picked had nice carbon throughout telling me it wasn't being washed with coolant, and the plugs looked to be in the nominal range based on the chart provided in an earlier post, so I figured it wasn't running hot.

I took it home checked for flatness and pulled all the valves. The valves and seats looked nearly new with very minimal pitting and the head was flat with no measurable warpage.. I decided to grind all the seats and valves anyway just for good measure. I decided to forgo bringing it to have it magnafluxed since it's not 100% accurate and I could always go back to FN and swap to another head if I was still having issues.

I then tore apart my jeep and pulled the old head. Because the old head had less than a 1000 miles on it I used the valve seals from it... Got it all put back together around 0200 this morning, caught a few Zs and drove it 30 miles to work. I'm now no longer overheating! I am however burning oil like crazy. Those valve seals I thought I'd save $30 on by reusing must not be sealing properly and now I've got to tear into the engine again. Either that or my fresh valve job destroyed my piston rings (too much compression on used rings). I know what I'm doing tonight.

TL;DR I put a different head on and am not overheating, however I was dumb and re-used old valve seals and am now burning oil.

Firestorm500

As I said earlier, it was the head.

I'll bet you're getting real good at pulling and putting by now.

Glad to know no overheating at this point, though.

Turbo X_J

I used the least expensive replacement parts from advance auto at easily 1/3 the cost of all this bling. In the end, exact same results and yes I'm a cheap bastard.

"when I took out the aux fan to tighten the steering box,"
^
The steering box can't be "tightened" btw.

HappyTrails

^
The steering box can't be "tightened" btw.[/QUOTE]

Uh, but I did. And it did. About 1/4 turn is all it took. Major improvement.

Turbo X_J

^
Correct spec for bearing preload is between 4 - 10 inch pounds, no spec exists for used/worn out parts.

Firestorm500

Uh, but I did. And it did. About 1/4 turn is all it took. Major improvement.[/QUOTE]

I just feels like an improvement. For now. When you tighten down on the preload, all it really does is wear out the bearings even quicker.

HappyTrails

I just feels like an improvement. For now. When you tighten down on the preload, all it really does is wear out the bearings even quicker.[/QUOTE]

Yes it is wearing out. It is 20 years old. I adjusted it to correct performance. Why drive with slop? Done this on lots of old cars. Wearing out quicker? Another 20 years maybe. Maybe lots sooner if I did a lot of strenuous wheeling. But it works lots better and that's the easy way for right now.