I have a stock 1997 4.0 and I have problems with my radiator or heater core.

I cannot tell really where the leak comes from but here is what I can tell you:

It seems to spray anti-freeze from somewhere near the bottom passenger side of the radiator because I see spray pattern and droplets on my front bumper, that is coming from inside the engine compartment and out under the passenger head light.

Also when I turn the engine off, sometimes if there is fluid in the system it leaks out a puddle about the size of 1 cup or less straight down under the radiator close to the front of the vehicle near the passenger tire.

It never overheats, the only thing like that I notice is that when the overflow reservoir tank is empty, the heater seems not to heat up very well if at all.

I have to put new antifreeze and/or water in the reservoir every couple of days and it is getting to be a hassle to have to do it so often. Not to mention I also have to deal with all the helpful people who tell me I have a leak, as if I have no idea.

Anyways, thanks in advance for any help and suggestions you may have.

 

Have you checked all your hoses? Coolant can leak and run down a lot of 'stuff' ending up at odd drip points.

Follow the coolant 'system' carefully and methodically. A slit could be under a hose where you can't easily see it. Check to see if the radiator didn't spring a leak causing it to spray someplace awkward.

Also, there are dyes used with a small black light (on amazon) the are very handy for finding odd leaks. The dye shows up nicely in the black light.

Your heater core is under your dash, passenger side. You should see two hoses going into your firewall on the passenger side. Those lead to/come from your heater core. You would probably have coolant inside the cab if the heater core was leaking. The heater core is a mini-radiator, it uses the hot coolant to create heat inside the cab. If you're low on coolant, you'll have no heat.

So, if the leak is at the front, it's probably a slit/cracked hose and/or frayed at the end and needs replacing. Hoses are cheap and it's not a hard job. If they are the original hoses, they are well overdue for replacing anyway.


Bad radiator caps could cause additional pressure too. Or, the thermostat could have stuck closed and created additional pressure causing a slit/leak someplace. If that is the case, be glad the plastic radiator side(s) did blow open.

 

From your description, the two primary suspects that come to mind are the water pump or the radiator. Most likely the radiator.

You really need to isolate this ASAP, as a small coolant leak can turn into a big coolant leak in a hurry while you are driving, and that can leave you overheated, stranded or both.

Get under it with a good light and you should be able to find it. If the radiator and water pump are original equipment, I would strongly suggest you consider replacing them both. If you can do the work yourself, the parts aren't that expensive.

Nothing more important than keeping up with the cooling system.

My radiator seam on my 99 blew after about 10 years, 130k. Water pump was still working, but I replaced it at the same time as the radiator, as I had the cooling system disassembled.

 

If you still have the plastic tanked radiator they are notorious for leaking at the tank seams where they are crimped together......
You can take it to a shop and let them put a pressure tester on it (takes 5 minutes) or pull your grill and you will probably see where its leaking from.
If you get a new radiator get a all metal CSF or another brand. If you cant find them locally radiator barn and a few others online sell them.
A 3 row all metal CSF was $156 shipped to my door.

 

Ok thanks for the ideas everyone, today is the first day I have time to inspect it more and to specifically check on all the suggestions. I will let you all know what I find and if your info helps. Thanks!

 

Press check it, get the tool from the parts store, pump it up, look for leaks... easy as that.