Freeze Plugs?!

[dekr]

I rolled into work this weekend amidst the tell-tale cloud of white smoke and chatter of a busted water pump. So I get a tow home, changed that out, flushed out the radiator, put in new upper and lower hoses, (thermostat was replaced 3-4 months ago btw), and did a motor flush and oil change for the hell of it.

Half an hour and ten miles down the road later, I hear this horrible whistling and gurgling sound - the sound of my engine boiling. I was nearly out of coolant and there was a steady stream coming out a really small hole on the driver's side of my engine.

So, now I've a bunch of questions. It's an 89 YJ 258i6. I've never dealt with freeze plugs before, but that looks to be my problem. What causes this? What else should I expect to fail on me as well? Having overheated a few months ago b/c of the thermostat, and these last two times, should I think about replacing the head gasket (I'm at nearly 200k if that matters)? How do I evalute the damage done due to overheating? I filled it back up to gimp home, and it didn't sound or drive much different. The temp stayed a bit high, but I think that was due to forgetting the radiator cap on the side of the road... Lastly, what's the difference between brass and steel plugs, and who can I get these from?!

Any thoughts and advice would be greatly appreciated!!

 

[jps4jeep]

from your motor possibly overheating would be my suspect. if you had too much pressure in the water jacket from the boiling water, that pressure is going to look for the easiest and quickest way out into the atmosphere, you if you had an original freeze plug that was possibly a little weak due to corrosion or age, and the fact that you have new hoses and water pump seals that probably had better integrity against the presssure than the old freeze plug. That was the easiest way out. they are easy to change, once the old is out, clean the surface real good with a scrapper and a 3M pad, get a freeze plug punch and center thefreeze plub in the boss and place the punch in it and wack it in with a dead blow hammer

 

[SteelHeadz]

You don't nescessarily have to replace the Head gasket just because the freeze plug leaked and caused the engine to overheat. If you caught the overheat condition soon enough, i wouldn't worry about it too much.. One way to evaluate the engine condition is to first replace the Freeze plug. Use a Brass plug instead of steel. The brass plug will still corrode but not as bad as a steel plug and they seal better than the steel. Napa auto parts should be able to match up the size you need. Pressure test the system after you replace the freeze plug and top off the coolant.

 

[dekr]

Thanks so much for your quick replies! How do I go about a pressure check? Also, heh, since I need a new radiator cap, what is the difference between the pressure ratings and which one is most suitable? If it makes any difference, I put in a relatively new radiator over the summer, so nearly the entire cooling system's been replaced!

I only mention the head gasket because that's what eventually happened to my last jeep. It broke several months after a bad water pump followed by bad thermostat, and I was told that the head gasket was probably weakened by age and overheating. Oh, and I've found creamy gunk on my dipstaick as of late, but several people have said that since it's not acting up in any other way, it's probably just condensation...

 

[SteelHeadz]

Thanks so much for your quick replies! How do I go about a pressure check? Also, heh, since I need a new radiator cap, what is the difference between the pressure ratings and which one is most suitable? If it makes any difference, I put in a relatively new radiator over the summer, so nearly the entire cooling system's been replaced!

I only mention the head gasket because that's what eventually happened to my last jeep. It broke several months after a bad water pump followed by bad thermostat, and I was told that the head gasket was probably weakened by age and overheating. Oh, and I've found creamy gunk on my dipstaick as of late, but several people have said that since it's not acting up in any other way, it's probably just condensation...

If you found a Creamy/ Milky substance on your dipstick that looks like a Mocha cappucino, thats a reason for concern with water mixed in with the oil. Check your engine oil. As for the radiator cap, they are usually rated 15 -18 PSI.. Napa will also have a cooling system pressure tester if you wish to test your cooling system.

 

[dekr]

The oil looked to be the normal, I'm-dirty-please-change-me color. What else ought I look for? There wasn't anything on the underside of the oil cap, and my coolant was a nice green color that didn't seem to be leaking. Both those liquids have been changed out, so if I come across any issues after it's been up and running for a while, I'll be sure to post again.

Back to freeze plugs. How many are there on a 258i6, and where are they located? Should I consider some kind of epoxy to fill the hole first or will the new plug seal it well enough if installed properly?

 

[SteelHeadz]

I dont know exactly how many there are on a 256 liter. There should be at least one on each cylinder on the driver side of the block and 1 on the rear of the block. You dont have to install any sealer on the block or the plug. Read up on Jps4jeep about 4 post ago on how to prep and install. It's what i would do if i was replacing a freeze plug.

 

[Crazy4diesels]

The "Mocha Cappuccino" (great description SteelHeadz) could be the result of a clogged PCV system. Also, when installing the welch plug ("freeze" plug) be sure to drive it in slow and steady. It should not take a lot of force to get it in - And, be careful NOT to drive it in too far (it is possible to pop them into the water jacket in some cases). An all cast iron engine can "take" overheating a lot better than one with an aluminum head so your head gasket hopefully is OK. This is one of the things that make the old 258 and 4.0 such great engines. Should be an easy fix. Best of luck - John

 

[SteelHeadz]

Yeah, I'd like 2 extra shots of espresso and a little extra chocolate please. J.K..

 

[dekr]

Mmmm... expresso. Gonna need it. I'm going to try my best today, found that there's two of em that need replacing. Thank you all so much for the advice! You've been amazingly helpful.