If it is coming from the reservoir, then it is either leaking at the tube or the plastic is cracked. Replace the reservoir and ensure the tube is a good mate. You can cut the end of the tube, too.

 

The ends of the radiator are plastic. They are known to develop hairline cracks. It will weep fluid when hot. You can smell it but not see it. Eventually the crack will grow to the point your get a big steamy leak. usually on the battery side.

 

So replaced the cap and the reservoir. I was thinking everything was solved but come to my truck after work and my whole right side windshield is fogged with some weird fluid. My friend said same thing happenes to his jeep and it was a heater core issue.

So...is this heater core? Whats thr problem and how easy is this to fix?

1996 xj is case it wasnt stated.

 

That would leak inside of the vehicle. Is the carpet wet? Is the matting under the carpet wet?
If the heater core is leaking, then it needs to be replaced. It is a big job because you have to remove the dash completely. It is fairly easily and cheaply bypassed which is why older cars sometimes don't have heat.

 

Fogging as described is a classic symptom of a leaky heater core.

Like gat mentioned - check the passenger side floor for coolant leaking. If it is - then as mentioned. A simple and quick bypass will be sufficient - but you'll lose cabin heat. A replacement core is technically easy, but a ton of work.

 

How much work are we talking? A mechnic is quoting for 800 no way im paying that.

Could i fix it in a day?

 

If a mechanic is saying $800, they believe it will take them about 7 hours to complete (possibly they realistically believe it will take 4-5) -- assuming the going rate for labor where you live is roughly $100/hour.

I would give myself at least 2-3 full days, but if you are extremely proficient with assembly and disassembly and everything goes well, it's certainly -possible- to do it yourself in a day.

 

Watch a video of it on YouTube. Watch several and decide. Bypass for now. You can drive it no problems when bypassed. Either pay or fix once you feel comfortable with your decision.

 

Let’s slow down a bit, review the symptoms and what we know and give us more facts. A new, second leak seems unlikely. The parts are trying to tell you a story but you have to listen to them. Follow a consistent process of plan/do/check. Something like this helps: 1) gather data and facts. What do you know for certain? For what you don’t know try to get more details. Understand the system you are addressing; 2) review data and plan a corrective action; 3) implement; 4) verify; 5) with what you have learned revise and improve corrective action as needed. Just replacing parts without having a good reason to do so is not the best approach regarding time or cost. For us to effectively help a detailed report back on what you see and what you have done/not done helps a lot.

* Was the windshield fogged on the inside or outside?

* Did you confirm a leak/damage/crack at the overflow tank or hose from the radiator? We understand that you replaced the tank. Anything else?

* After replacing the tank did you see signs of a leak in that area as reported before?

* After replacing the tank did you see a significant change in the level of coolant in the tank? Need to add a lot? How much?

* At this point we are not sure you initially had a cooling system leak. You had coolant escaping but was it a leak or from the overflow, from a leak somewhere else? What did you smell? (hot antifreeze has a characteristic odor) Did you perform a pressure test? Did you rule out the potential of combustion gas entering the cooling system (combustion leak tester)? If you have a significant path from a combustion chamber(s) to the cooling system the resulting gas and higher pressure in the cooling system could cause apparent boil over or releasing of gas/coolant through the coolant reservoir.

* Any signs of coolant following one of the heater or air conditioner tubes (or around fan motor) from the engine compartment into the HVAC ducts on the interior. What do you see? Put clean paper, plastic or cardboard under the vehicle and look for evidence. Wrap a paper towel around fittings. Observe location of any leaks. Note that there is a drain intended for AC condensate from the ductwork to the exterior in the general area of the passenger side lower firewall. Find that and see if coolant is coming out of it.

 

So today I noticed a bunch of fluid around the t stat and the main front inside around the belt. It was spalshing up on the inside of the hood as well as spilling out thr bottom. I noticed some fluid on the lower left of the radiator as well.

It only fogged once amd it was the inside and no wet mat.

Edit:
I got a pressure tester today, I noticed the lower rad hose was loose and was leaking, so I tighten that, but noticed leaking pretty bad from the main radiator. I am not sure if I over-pressurized the system (only went to 15lb) but I noticed both the side and bottom of the radiator were leaking pretty bad (which matches up with the leaks this morning) so I bought a new one I will slap in this weekend.

So that will be that...except for the random single fogging and fluid loss once.

 

The pressure is the only way to test once you've used it.

 

If unable to find a coolant leak, you need a cooling system pressure tester, basically a hand pump with gauge that pressurizes the cooling system from the radiator fill.

Leaks, spills on the ground may only occur when high pressure (sometimes in different areas) of a cooling system occur.

My temperature gauge started to act strange sometimes normal other times fluctuating between ~200 and ~220 deg F, occasionally would creep up beyond 220 and then go back down to around 200.

If your temperature gauge is fluctuating is a sign you have a leak somewhere.

I also was low on coolant so filled the radiator and recovery using distilled water.

Eventually after a while of temperature fluctuation I went to the local grocery store and on the way out notice green antifreeze on the ground underneath my ZJ (4.0L).

So I removed the radiator and found one side of the radiator where the core connects to a plastic side tank was greenish in color. Apparently the seam after years developed a leak in the OEM Mopar plastic radiator with two row alum. core.

I probably should have put a cooling system pressure tester on the cooling system to make certain, prior to pulling the radiator, but I was fairly certain the leaking problem was with the radiator as all the hoses checked out ok with no signs of leaking.

Anyway if having problems locating a leak I think you can buy or rent a cooling system pressure tester. Or find one on eBay.

When you pressurize a cooling system there should be no pressure drop. If a leak the pressure gauge will drop over time and most likely there were be signs of leaking coolant somewhere that indicates the location of a leak(s).