More Coolant Leak Problems

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CJ_TJ

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So I changed out most of the coolant system: new radiator, hoses, thermostat, water pump, etc. Has been running fine for several months now, but recently got a CEL code P0128 for a low engine temp. To preface this, my heater core is going out because there is coolant pooling under the car on the passenger side (mainly from the A/C drain). That's for another day...

The main leak that I can actually see looks like its coming from the water pump. When I get under the car I can see a stream of coolant on the lower radiator hose, and after some time some droplets on the ground from right about where the water pump is. Looking into the engine there is what can only be called "coolant crust" (the best way to describe it) coming from the thermostat, too. So I am hesitant to assume that this is all from the heater core. Maybe the gauges from the thermo/water pump are bad already?? I figured if there was a problem with replacement that I would have seen a problem much earlier...like a couple weeks after I did them?

I can post some pics so its easier to visualize. I'm also going to replace the radiator cap, which I have yet to do. So with that, any ideas as to what this could be?

Also, in the next week or so I'm going to do a heater core bypass and get that new radiator cap, and then I'll post an update.

Thanks!
 
What kind of hose clamps are you using?

When the weather starts getting cooler here in South Carolina I start getting leaks from the ends of the hoses. I have the worm screw clamps on right now, but plan to go back to the factory constant tension hose clamps soon when I redo my cooling system. If you have worm screw hoses, snug them up a little bit and see if the leak stops.

The leaks your describing have nothing to do with the heater core (except the one you said from the A/C drain). Water pumps have weep holes in them that leak when it goes bad. When it leaks from that hole, it can follow many different path making it look like it's leaking from something else on the ground. Same for the T-stat housing and hoses. Sometimes a small inspection mirror helps when looking for a leak. Try washing any leaked coolant off the engine, hoses, etc with a water hose and try to get it dried up. Take the jeep for a short drive, then come home and pop the hood and look for the leak.

You could always do a pressure test too.

Pictures would be helpful too.
 
MountaineerTom said:
What kind of hose clamps are you using?

When the weather starts getting cooler here in South Carolina I start getting leaks from the ends of the hoses. I have the worm screw clamps on right now, but plan to go back to the factory constant tension hose clamps soon when I redo my cooling system. If you have worm screw hoses, snug them up a little bit and see if the leak stops.

The leaks your describing have nothing to do with the heater core (except the one you said from the A/C drain). Water pumps have weep holes in them that leak when it goes bad. When it leaks from that hole, it can follow many different path making it look like it's leaking from something else on the ground. Same for the T-stat housing and hoses. Sometimes a small inspection mirror helps when looking for a leak. Try washing any leaked coolant off the engine, hoses, etc with a water hose and try to get it dried up. Take the jeep for a short drive, then come home and pop the hood and look for the leak.

You could always do a pressure test too.

Pictures would be helpful too.
Click to expand...
I still got the factory clamps on both the upper and lower radiator hoses, they seem to be holding fine. But I like the idea of washing it down and going for a drive to get a better look at it. I'll check it out.
Could a leak from either the water pump or thermostat cause a low engine temp though?
 
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Oh, I forgot about that one. Your thermostat could be stuck open, not letting the engine warm up enough in the time required before setting a code. Or your sensor went out.

Do you know if the thermostat you used was a fail safe type? They designed to stick in the open position in the event of a overheated condition, but are known to stick open when not overheated.

Do you know if you’ve over heated lately.

If you know it was a fail safe style t-stat and you haven’t overheated, I’d change the thermostat to a not failsafe. A Stant SuperStat or a MOPAR thermostat will work great.
 
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If you have already done it, make sure your fluid level is where it should be too.
 
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There is no need for guess work when it comes to coolant leaks. Cooling systems have not changed that much since the model T. Pressure test your system and repair the leaks. They will jump out at you. If it is running too cold, that is your T-stat. Replace it with a quality 195°. Stant would be my first choice. If coolant is coming out of the AC drain pipe, the heater core is likely bad, replace it. If you have AC, replace the evaporator at the same time and save yourself a return journey at a later date. All of these parts are consumable items.
 
Is it possible you are holding too much pressure in the system? Radiator caps can (rarely) set up causing HI pressure in the system. This could explain why you have coolant at so many places at once on a mostly rebuild system. Or the fluid is the wrong mix letting it start to steam from lack of glycol in the mix. Not common, but I've seen it (once).
 
Goatman said:
Is it possible you are holding too much pressure in the system? Radiator caps can (rarely) set up causing HI pressure in the system. This could explain why you have coolant at so many places at once on a mostly rebuild system. Or the fluid is the wrong mix letting it start to steam from lack of glycol in the mix. Not common, but I've seen it (once).
Click to expand...
Could be the rad cap. Im using 50/50 mix from Autozone (which I know is not recommended) since Jeeps should use MOPAR. The t-stat is 195 non-fail safe STANT. I highly doubt its the t-stat since I just changed it a few months ago and haven't seen any problems until now. It would make sense that if the system was building too much pressure fluid would likely leak out from several places. This weekend I'm going to pressure test to make sure that it can still hold and go from there.
 
MountaineerTom said:
Oh, I forgot about that one. Your thermostat could be stuck open, not letting the engine warm up enough in the time required before setting a code. Or your sensor went out.

Do you know if the thermostat you used was a fail safe type? They designed to stick in the open position in the event of a overheated condition, but are known to stick open when not overheated.

Do you know if you’ve over heated lately.

If you know it was a fail safe style t-stat and you haven’t overheated, I’d change the thermostat to a not failsafe. A Stant SuperStat or a MOPAR thermostat will work great.
Click to expand...
No overheating at all. Stays somewhere between 195-210F. The only thing that I notice is the coolant reservoir gets low every so often so I just top it off and good to go.
 
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