Mechanic says the radiator is fine, but...

dreynolds_500 · 03-12-2008, 06:09 PM

So, I've got an 02 with 70K miles on it that has a thirst for antifreeze. Based on the research I was able to do on the forum, I narrowed it down to either a radiator leak or an engine block leak (bad head gasket). Armed with this knowledge, I took it to my mechanic for a pressure check to determine if it was a simple rad replacement or something much more expensive. After testing it for several hours, he came back and said the rad is holding pressure and the engine block passed its test too (carbon, no coolant in the oil, no smoke from the tailpipe, no coolant in the tranny).

I'm filling up my reservoir every 2 or 3 days ( it's my DD and I drive ~50 miles a day on backroads). If I run on the interstate, I'm refilling after about 2-3 hours of driving. When parked, there are no visible leaks under the Jeep, but you can smell coolant when driving (stopped at a light, etc.).

Does anyone have any ideas? I don't want to replace the rad just for the sake of replacing it, but I will if I have to. Thanks in advance for your help!

**Jerry Bransford** · 03-12-2008, 06:16 PM

Did he use a "sniffer" to look for the presence of combustion or exhaust related gasses in the coolant? A test strip can do the same thing, they test the coolant via the radiator cap's opening.

HipCheck_1 · 03-12-2008, 06:26 PM

Sounds like a possible leak in the heater core.

dreynolds_500 · 03-12-2008, 06:29 PM

He did do the sniffer test (according to him). How do I check to see if there is a leak in the heater core?

HipCheck_1 · 03-12-2008, 06:32 PM

I am not sure how to check it on the Jeep but I had a '97 eclipse with a bad heater core.

The windshield would fog up all the time, could smell the coolant, and started seeing coagulated coolant on the carpet in the passenger side by the firewall.

**tjthorson** · 03-12-2008, 06:58 PM

It may hold pressure when cool. Under heat and pressure, you may have a leak.

Check for antifreeze crust under the waterpump. There is a weep hole that will start to leak when the seal is wearing out.

Also look for crusties around the tank clamps, hoses, etc.

mcg311TJ · 03-12-2008, 07:04 PM

I'm guessing it's a stock rad?

dreynolds_500 · 03-12-2008, 07:32 PM

Yup, it's a stock rad - I know they're prone to fail right around now. As far as crustys, I'm not seeing any. I know he tested my rad when it was hot b/c the car was hot when I picked it up and watched them pull it out of the bay.

Please keep asking questions and throwing out ideas - I just want this fixed before summer (traffic + heat+ bad rad = towtruck).

1BadJeepX06 · 03-12-2008, 07:35 PM

Had a chevy with the same problem... Heater core fixed the problem... :my2c

DH

dreynolds_500 · 03-12-2008, 07:40 PM

If the heater core were bad, would I still have hot air coming out? The heater works like a champ - gets nice and toasty in there!

cj847 · 03-12-2008, 08:12 PM

If the heater core is leaking you should get some dampness in the passenger foot area (damp carpet, etc).

Based on the age/mileage I would be saving up for replacement parts even if they are good right now.

Has the jeep ever actually overheated? You mentioned a thirst for antifreeze - if you overfill it, it will push that antifreeze out when hot (ie it you continually refill your overflow bottle, it will continually go down to a certain level). I would suggest keeping a gallon of 50/50 in your jeep and drive it until it actually starts to heat beyond normal before adding more antifreeze.

dreynolds_500 · 03-12-2008, 08:25 PM

I've never run it until it overheated. However, when I fill the overflow bottle to the 'Full' line, I've let it run until it's completely bone dry in there - about 3.5 days. At that time, I fill it back up b/c I don't want to be "that guy" on the road blocking traffic because my rad overheated.

I'll check for dampness on the pass. side and see if there is any.

**tjthorson** · 03-12-2008, 08:33 PM

Quote:

Originally Posted by dreynolds_500

If the heater core were bad, would I still have hot air coming out? The heater works like a champ - gets nice and toasty in there!

It would still work - but to be leaking as much as you say - it would be getting oily residue on the window, smelling real strong, and fogging the windows constantly as it atomized the antifreeze.

I would add a UV dye to the overflow and radiator and get one of those UV penlights. You will find it.

If you absolutely dont - its burning it somewhere then internally and its time to pull the head.

Its not doing it because it doesnt like you.

The antifreeze is going somewhere....

dreynolds_500 · 03-12-2008, 08:40 PM

OK - 1) Where do I get a UV dye? 2) Where do I add the dye (overflow or rad)? 3) I assume that means running it in the dark? What's a safe way to close a garage and vent out the fumes? 4) Are you positive it doesn't mean it just doesn't like me?

JFM626 · 03-12-2008, 08:49 PM

You can eliminate the heater core if you don't mind being a little cool for a couple of days. Remove the heater hoses where they go into the heater at the firewall, and join them together. This will put the heater core out of the equation. If you now continue to lose coolant, well it won't be the heater core will it. If you don't lose any more coolant, best to put a weekend aside to change out that heater core. Without going outside to look, I seem to remember that the heater hoses are different sizes 5/8 and 3/4???