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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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#27 ·
rustywrangler said:
You said you had the rad flushed but what about the block? what you just said tells me a blockage or the wrong water pump.
Yes I had the block flushed too. Sorry I did a 2 part flushing. one with rad in the heep and one where we sent the rad out.

I put a hose in the block and used the prestone flush kit.

just an off the wall thought ... what about pulling the upper and lower hoses and putting comressed air in the block? or is there to many place to block up to get a good pressure build up to blow out what ever may be blocking it?

Not sure if that would work or not.

Ya I am reaching at this point...
 
#28 ·
jeepwrnglr92 said:
Yes I had the block flushed too. Sorry I did a 2 part flushing. one with rad in the heep and one where we sent the rad out.

I put a hose in the block and used the prestone flush kit.

just an off the wall thought ... what about pulling the upper and lower hoses and putting comressed air in the block? or is there to many place to block up to get a good pressure build up to blow out what ever may be blocking it?

Not sure if that would work or not.
Ok, then its gotta be the H20 pump. Unless of course you have the tstat in backwards. I wouldn't bother with the compressed air.
 
#30 ·
jeepwrnglr92 said:
Well the part place confirmed the H2O pump was the right one so how could it still be that one?
I can get a serp. belt pump in both reverse and forward rotation. I do not know what one you need personally.
 
#31 · (Edited)
rustywrangler said:
I can get a serp. belt pump in both reverse and forward rotation. I do not know what one you need personally.
Well I called 3 stores and they only had a listing for a 92 4.0 and a serp belt pump. No reverse or fwd serp pump.

They only thing i can think of is to swap the radiator out. The one I have is "new" and past a test but who knows.
 
#33 ·
Could the Coolant Temperature Sensor have anything to do with it? Heck, I don't know. There are about 453 different sensors on these engines that tell them when to start operating and when to shut off. 453 being an exageration of course.

Oh, forgot to mention also - I had a problem like this awhile back. Problem was that the mixture of coolant to water was to high (or was it to low), it was one of the two. I had to much coolant and to little water I think it was.
 
#35 ·
OK i got the heep back home. It ran hot all the way (12 or 15 mls) never cooled down. In the past with air moving over it it would cool down. Not this time. I ran 250 and I tested it with my IR and it showed cooler on the bottom but was reading "HI" off the scale on the top.
So how can I tell if the PO put in the right rad? Would there be a part # on this thing? May be I have a 4banger rad not the 6cyl one?

I talked to the shop about the timing thing as I did think of that. and they said it was all controlled by the computer

Is there a way to see if the computer is good?
The heep seems in time.

I asked them about the distributer and if it could be off a tooth and they said even if it was it would not get that hot that fast.

I was running the heater all the way home too and that did not get the temp down. Might have saved me from over heating but did not bring it down at all.
 
#37 ·
Varnish said:
If you run it from cold with the radiator cap off, can you see any fluid movement or does it bubble up or anything unusual?
Ill have to check this Friday or over the weekend. no time to mess with it tonight.

dang getting dark early stuff stinks :thumbdown:
 
#38 ·
OK this got the better of me and i ran the jeep for a few moments. It was a little low on water/coolant but the overflow was full so I know it di dnot leak out.

I watched it with the cap off and saw some movement but nothing big. the temp gage said 210

When i shut the jeep down the fan stopped right away so that makes me believe it is a good clutch as it stopped right away and did not spin.

Im gonna get a new t stat and gasket on Friday and see what happens with that. I am going to take the one I have and drop it in a pot of water and see how long it takes to open.
 
#39 ·
I had the very same problem a few months ago, did everything you did, short of the head. Checked the timing about 5 times, everything, to no avail, got disgusted and parked it for about a month, decided to drive it to work one day, and wow, no more problem, actually runs cooler than it did originally, got me???
still going just fine. I was thinking maybe it had an air pocket or something, but really don't know, I burped it numerous times as well. Good luck
 
#40 ·
Well it is a puzzler. I just wish I could have some fun with i. But as my friend said this is par tof the fun of owning a Jeep right :confused:

I think my :cheers: :cheers2: level it to low when I work on it.
 
#42 ·
lturley said:
I had a similar problem with a Cutlass years ago. Finally fixed it by flushing the block with muratic acid, no crap. Turns out the block was so rusted it could not transfer heat efficiently. Just pour it in, let it fizz, and rinse it really good!
pour it in where the radiator ???
 
#43 ·
OK I bought a 180 and a 192 t stat today. I put them in a pan of water and made sure they open.

They do so I am trying to decide which one to put in the heep.

At least I know they work. I am going to test the one I take out also.
 
#44 ·
I just bought a new radiator for mine today. As I was talking to the guy, he was saying that Robertshaw thermostats suck big time and Stant is the brand to get. He also suggested getting the Super Stant, which, if it fails, it automatically locks in the open position, preventing major overheating. He also suggested the 180 for Florida.
Anyway, I got a heavy-duty, all-metal (no plastic tanks for me) Modine for $130 with a lifetime warranty.
 
#45 ·
hdfxrs91 said:
I just bought a new radiator for mine today. As I was talking to the guy, he was saying that Robertshaw thermostats suck big time and Stant is the brand to get. He also suggested getting the Super Stant, which, if it fails, it automatically locks in the open position, preventing major overheating. He also suggested the 180 for Florida.
Anyway, I got a heavy-duty, all-metal (no plastic tanks for me) Modine for $130 with a lifetime warranty.
Where did you get the rad?

I am not sure what t-stat is has. I bought it from Bennett
They said it was a Part master reboxed it was Stant in the box. But not super stant..

I guess I'll go with the 180 first.
 
#46 ·
jeepwrnglr92 said:
Where did you get the rad?

I am not sure what t-stat is has. I bought it from Bennett
They said it was a Part master reboxed it was Stant in the box. But not super stant..

I guess I'll go with the 180 first.
Stay at 195* Don't bother with the 180
 
#47 ·
I figured it's about time I entered this thread. I'm no cooling system expert, but I played this same "ball game" with my jeep for the last 6 or so months. Rusty up there can vouch for that.

So judging by all the posts, and all the things you have tried to do, I have what I hope is an answer to your problem. So you have an IR thermo? Perfect. Run the engine till it gets pretty warm and start diagnosing. Measure as many different spots of the block as you can and note ANY hotspots. Measure the exhaust manifold tubes for each cylinder and see if one is hotter/cooler than the other. Also, are you still going through coolant?? Have you retested the block for combustion gasses in the coolant?

If you had the head redone, and its been tested for leaks and passed, then one of the above methods should dhow something. There is probably a good chance that there is a clog in your block. There is one way to find out for sure but it really sucks. And thats to pull the motor and knock out the freeze plugs. That will allow you total access to see if there is blockage in the water jacket. My case ended up costing me a new motor. Hope this helps, Brian
 
#48 ·
Thanx for the ideas. WOW new motor. I just dumped $1200 :crying: into this heep engine. For a few more I could have had a v8 :eyebulge:

So there is no way to unplug a block?


What was wrong with yours that you needed a new engine?
 
#49 ·
jeepwrnglr92 said:
Where did you get the rad?

I am not sure what t-stat is has. I bought it from Bennett
They said it was a Part master reboxed it was Stant in the box. But not super stant..

I guess I'll go with the 180 first.
I got it from a local radiator shop that had been around for about 30 years. I like to support local businesses when I can.
And I would stick with the 195* t-stat as well.
 
#50 ·
I saw this on an XJ. We ended up swapping in a newer style coolant res. For some reason the old one would allow enough pressure to keep it cooled down.
 
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