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Overheating uphill only

CherokeeManatee

NAXJA Forum User
Location
Camarillo, CA
I've searched and trouble shot my problem and it has improved but I want my rig 100% before I go out again. I'll start with the history:
1993 manual 180xxx decent maintenance from what it sounds like.

Bought it a year ago and it had no issues with cooling. Did a flush to replace brown liquid and it ran about 10* cooler than it did before (was at 210 normal before). Lifted, regeared, 33"s and still no cooling issues even on the trail.

Around the same time I go through a deep mud pit 3-4 months ago (desert mud that cakes on) I start overheating on the freeway and trail. Not around town.

I cleaned out most of the mud by now around the engine and radiator fins. Performed a flush and cleaning (only the 30 minute kind), replaced all radiator hoses, and a new radiator cap and thermostat (I have to drill the 1/8 hole in the thermostat).

Recently I ran a trail and was overheating. Ended up blowing my upper radiator hose which prompted me to replace them all. Engine temp spiked past red on this occasion but after refilling the radiator and connecting my other fan (I stupidly forgot to reconnect it the day prior) I was able to drive home.

I had driven above normal temp to the red zone prior to spiking and blowing the hose.

So today after all my replacements I run under 210 around town and on the freeway. I overheat when going uphill at 50+ mph and have not tested it on the trail at low speeds. I can be going flat on the freeway but as soon as the road goes a decent climb my temps will climb. I don't know if they will go very high as I stopped climbing when they reach 230ish.

Do you guys think fixing my thermostat bleed hole will solve this problem? Did I wreck my engine from running hot? What about a new water pump since my belt slowly has been loosening - I've already tightened it once in the past 6 months.
 
If you have (had) a fail-safe t-stat, it overheats once and then is open forever. It also sounds like even though you cleaned out "most" of the mud, did you get between your rad and condenser (assuming you have A/C)?

That's all I got!!
 
Pull the radiator and really clean it out, do the best you can with the condenser.
 
Also, change your radiator cap. They should be changed about every 2 years. Make sure it is a 16# cap.
 
If you can do the labor, I'd replace BOTH the radiator and the water pump. The parts themselves are not that expensive and then (along with your new hoses, cap, stat) you would ensure that your cooling system is up to the job.......

When I have the radiator out, I generally replace the pump (unless it is newer) as it is right there.......
 
you could have overheated the trans fluid (assuming automatic) and the resulting loss of hydraulic pressure in the transmission may be showing itself when the trans. is under load (pulling a hill)
 
A couple of things:

OP states overheating climbing hills AND on the trail. A weak/failing fan clutch would be more of an impact on the trail.

I would get a good radiator cleaner, the kind you put in and drive for 3-6 hours--can be over multiple days--that will really clean the system out.

DEFINITELY listen to the others and make sure the radiator/condenser fins are clear.

Once you overheated your thermostat is probably locked open and needs to be changed. I recommend the Stant SuperStat Premium.

The life expectancy of a water pump is about 4 years. If you replace it buy NEW, not reman.

One often overlooked item with highway overheating is a worn timing chain.

Change your coolant mix to 30/70. 30 ethylene glycol and 70 distilled water. Ethylene glycol is a good antifreeze, but a lousy cooling agent. Run 30/70 late Spring-early Fall, then switch to 50/50 for the rest of the time.
 
Wow! Lots of responses.

Yes the Tstat was stuck open - replaced that

Why do I not need the bleed hole?

Did 2 flushes within the year and my fluid is pretty clean. Friend also keeps saying use the 500 mile cleaner.

I tried different mixes of fluid with no noticeable difference.

I have a 13lb cap because the napa guy didn't believe me that I needed a 16lb. He's right on everything else he's told me so I went with it. I'll get the 16lb.

Radiator and condenser fins are decent. Mostly bugs and Rocks that won't come out and not so much mud.

Since my belt is sloooooooowly loosening could that be due to a bad waterpump? I have no clue when it was last replaced. What are symptoms of it going bad?

I can do the labor myself so the plan of attack is to get the 16lb cap and 500 mile cleaner and see what happens.

I'm willing to bit the bullet n replace the radiator n waterpump though.

Thanks for the help!
 
Thanks for the link Al Bundy.

I've been thinking about it and I'm sure the radiator and water pump are nearing the end of their life (17 years for the radiator probably).

I'm debating whether to drop $200 to get a nice 3 core from dpgoffroad or just a stock one for cheaper. I have friends on both sides of the fence.
 
It won't hurt to put a hole but you just don't need it. I have a '93 and I know that it fills and self bleeds with the Stant Superstat (or whatever) as is. It may make it a bit easier to fill but I wouldn't take an installed one out of the housing just to drill the hole. Just my thought.
 
I would do a Cylinder Leak Down test before replacing anything. I replaced the entire cooling system and it would only overheat when going uphill (or making horsepower) otherwise it would run cool. Turn out I had a cracked block.
 
I remembered now why I didn't get the 500mile flush stuff...no autoshop in town has it...

Called a local shop and they said it sounds like a bad water pump not circulating or possibly a cracked cylinder head - I was considering that but wanted to see what naxja said about it before I did anything more.

I'm going to have them test it tomorrow and see what they say. I will probably end up replacing the radiator and pump anyways seeing as they are both old.

Will report back with results.
 
No one carriers Prestone or Zerex radiator cleaner? Surprised, I am. Its actually 3-6 hour flush, and can be over a number of days.

Good luck.
 
Got the jeep back today - shop found a crack in the passenger-side tank. I only ever found a puddle underneath the jeep once since I've had this problem and that's because the petcock unscrewed itself slightly. The crack is rather small so I can see how I missed it...they pressure tested it. Also explains why my overflow keeps emptying...which I forgot until now.

They confirmed there was no engine damage :yelclap:and no PPM's present from the hydro-carbon test (what does this mean?). There is also a list of stuff they said I need to fix haha.

I'm going to order a new radiator from dpg offroad and pick up a new water pump from napa. Might as well do my belt while I'm at it

Since I already replaced my tstat and it hasn't gotten near the red on the gauge do I still need to replace it again? I'm pretty sure it isn't stuck open.

Thanks for the help and suggestions. I'm glad this turned out well (with luck, an end to 4 months of troubleshooting).
 
You replaced the hoses? I thought I read that in there somewhere.

Don't let the parts guy tell you that your lower radiator hose doesn't need a spring on the inside.

You'll suck the hose shut at higher rpms. You usually don't notice it until the tranny kicks down to do things like passing or going up a hill.

I fought that for 6 months until someone told me the "springless" hoses don't work. I actually spent less money at Napa for the cheap one with the spring than I would have on the fancy one without a spring.
 
I was overheating before I replaced the hoses..I did have a spring in the lower hose.

I salvaged the old spring and will put it in the new hose when I do my radiator. Thanks for the reminder.
 
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