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Jeep still over heating even after head job

28K views 202 replies 51 participants last post by  rm56 
#1 · (Edited)
OK this is getting old really quick

I changed the water pump, tstat fan belts, had the head done and the radiator flushed and tested.

What else could it be. THe stupid thing is still over heating.

New shroud and new fan/clutch Sorry left that out
EDITED TO INCLUDE MORE INFO:

Hi All,

I decided to clean this post up and be a little clearer on what has been done to the heap to this point.

Truck seemed to be running fin when I first bought it. But it was cooler in Jan.

I did the basics:
Plugs
Wirers
Oil/filter
Air filter
{Shock,Brakes,Tirers/rims} Yes no affect on cooling I know, just part of the list
Flushed the coolant (block and radiator ) with Prestone kit.
Hoses checked ok
Changed out tstat
Clutch fan
Flushed and pressure tested radiator
No coolant in oil
New water pump
Another new tstat
New belt
Pulled the fuel tank and replace bad hose to fuel pump
New radiator cap (x2)
Pulled head and had it rebuild and resurfaced Put in new seals, gaskets etc.
new fan shroud
Some of this I did some the mechanic did so I am going to check his work when it gets home.
 
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#177 ·
Well the junk yard just called and they have a 5 blade in GA they are going to ship me, should be here by Friday so hopefuly that will resolve things.

Ill post an update when I get teh new one. They were really nice about it too. No charge for the mistake and they do not want the 7 blade back. ill just hold on to it incase someone needs one later on.
 
#178 ·
jeepwrnglr92 said:
Yes I am. Please explain why? I had both types on it and neither one made a diffrence.
Todays radiator caps on closed cooling systems, allow bidirectional flow. When the coolant expands, there is a diaphragm that opens, and allows the coolant to "over flow" into the over flow bottle. When the coolant cools, it creates a partial vacuum in the radiator, and the cap will "open" to draw coolant back from the bottle.

This type of system assures a full cooling system at all times. If your cap does not allow coolant to be drawn back in, then you would be operating with an air (vacuum) pocket until everything heats back up.

Worse, if could collectively over time continue to pass small amounts out, but never letting any back in...compounding the problem over time.

Most manual pressure relief caps do not allow automatic flow out of the radiator...yours may, but all the ones Ive dealt with did not...getting a stock (factory) cap is the best bet.
 
#180 ·
Well I got the new fan on today. But I have to wait to road test it. I notice my battery try was rusty so I pull it to paint it. Ya I should have waited and road tested first.

oh ya I put on a new rad cap too
 
#181 · (Edited)
Well here is the latest. New fan is on. See how nice it looks.


Still have not drive the Jeep yet. When i was bolting on the bumper I notice some wettness on the rear wheel.. Well my left rear wheel cyliner let go on me. arg... :brickwall :brickwall

So off to the parts store. May be tomorrow or next weeked to replace them.

But I am learning a lot from this forum and from my Jeep. Just glad I like working on cars. I could never afford to pay someone to have all this fun :drool:

Oh ya i stuck a piece of paper on the front of the rad and i had to shut the Jeep off to get i off. man that thing pulls good air now.
 
#182 ·
Get an aftermarket Temp Guage with the heavy mechanical lead to the sending unit. Pull the upper hose off one end and insert the pickup for the guage so that you can force the hose back onto the water outlet. If you need to pack a little something around the tube to stop it form leaking, just don't bend/break the water oulet. Fire it up and compare this gauge to the one you have been watching. Then you will know for SURE that you have a problem with the engine, not the sending unit.
 
#184 ·
HighCountry said:
Wow! I failed to notice that this was already an encyclopedia before I posted that... Oops!
Ya its been an ordeal to say the least. I tried the after mkt guage and it read the same as the stock one. I have a good feeling about the new fan But thanx. :tea:
 
#185 ·
Just a little hint... having been in and out of the parts business for 25 years! With a Jeep, do NOT use the YJ,XJ,ZJ designation with an aftermarket parts person. They have no clue. You have no IDEA how many times I have had to 'correct' someone that called a GRAND Cherokee a Cherokee and the other way around. There was even a CJ way back that had decals on the hood that said Cherokee... When you are buying parts, if they don't 'look' right they probably are NOT right!

I would be willing to say that your problem is now fixed, and it was all caused by someone elses "I kin fix thut!" knowledge...
 
#187 ·
NJeepyj91 said:
Update? We done here?
Well I have to fix the rear brakes before I test drive it. I was hoping to do that this weekend. Just before I took it out I noticed a leaky left wheel cylinder. :(

It has been cold for SFL so I'll wait until it warms up (by the weekend back in the 70s now in the 30s here this is nuts)
 
#188 ·
I think this is finally a closed issue. I took the Jeep out today for a drive and it stayed just above 210. So I give the gauge a few deg for being off etc.

Thanx to all those that offered help. And I hope others learned something from this too.:cheers2: :2thumbsup:
 
#189 ·
question for you... did your mech change to a different temp t-stat? if you go to a cooler one it could overheat. if you dont let the water in the radiator stay long enough to cool down it does no good. if the water is cycled too fast it will over heat because the water isnt given enough time to cool down. stock t-stat is best which is a 185. hi flow pumps you dont need, stock works just fine.
 
#190 ·
Well I hate to report this back but it drove fine all day then when I let it idle in the drive for a good while it did go back up to 240. I am going to try adding an addation electric fan to see if that helps at idle. :brickwall :brickwall
 
#192 ·
Its back

OK so it still over heats a bit at idle after a while. :brickwall :brickwall
I put a small electric fan on it this weekend and will see if that halps. If it does then Ill either look for the Ford tauras fan or swapp the clutch out on the stock fan.

here we go again.
 
#193 ·
Couple of guys suggested it, but can not tell if you did it. Isolate the heater
core, and flush the block........hard. Put the nasty caustic stuff in, run it, and
flush the crap out of it again. Repeat a couple of times. You got sludge moving around. The key was how the heater core went "luke warm" when you
changed from straight water to mix. No more parts just acid and flush. Good Luck!
 
#194 ·
Pauliewog said:
Couple of guys suggested it, but can not tell if you did it. Isolate the heater
core, and flush the block........hard. Put the nasty caustic stuff in, run it, and
flush the crap out of it again. Repeat a couple of times. You got sludge moving around. The key was how the heater core went "luke warm" when you
changed from straight water to mix. No more parts just acid and flush. Good Luck!
Yes I did that several times and even bypassed the heater core. Core is now HOT as ever.

Thanx for the input.
 
#195 ·
Took the heep out today and went offroading. She did not have any issues with over heatin . I am so happy afoter a year of this stuff. I finally got it out on the trials.

Thanx to all for the advice.

CJ
 
#197 ·
Yes... Summary: I had a bad mechanic and did a lot of un needed work. I found out I had a wrong facing fan blade. I got a fan blade off the internet for about $48 shipped to me and viola no more issues... TO DATE. now that I woke up Murphy..

I took it out off roading with the local Jeep club and she ran 210 all day. I still have an extra electric pusher fan on the rad just in case. I will swap over to the tauris fan when I can find one.
 
#198 ·
WOW! Congrats on finally figuring it out. Thanks for posting all of your tribulations Hopefully if anyone else runs into a similar problem they can use this as a guide.

I almost feel like I should send you flowers or something for enduring such great pain and finally conquering the beast... will you settle for this:
 
#201 ·
Wow ! I just spent the last 2 hours reading through this entire post and about half way through it I thought..........

"Hmmmm......wunder if his fan blade is on backwards so it is pushing air into the rad instead of pulling air through it" ? That would explain why it would really over heat quick on the road because you've then got wind in opposing directions, canceling each other out.

Very interesting. Way to stick with it, I think I would have wound up rocking in my chair in the corner after all that !

JJF
 
#202 ·
talk about back from the dead
 
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