70hemicuda

Well, I overheated the jeep today. Was coming home from a trip and it blew the top heater hose. Got pretty warm on the highway, like 220ish then as I was pulling off it shot to 260 for like 30 seconds before I could get to a place to stop. Funny thing is I had the damn hose in my trunk so I got it back together, got coolant in and started it up. All seemed fine and it ran great, so I drove it home 3 hours with not an issue. Checked when I got home and no white smoke in tail pipe and oil did not have any mix. Well, I have the 0331 head and so far it seems I may have gotten super lucky and no damage was done. My question is did I get super lucky? Or am I just driving a ticking time bomb now. I am going to get a new head but it's still the dead of winter so if I could get it till spring that would be great. What do you guys think?

cruiser54

Only time will tell.

Keep an eye on the coolant level and oil condition.

CoffeeCommando

It's ticking faster. Change the filter and oil, and ensure if you use store-bought oil from the parts store you add a 16oz bottle of TB Zinc Plus. You should be doing that every oil change, and I personally recommend you don't use synthetic oils as they compete for space with ZDDP. ZDDP protects your cam and lifters, and if anything dies on your jeep it's going to be those two items.

I overheated while it was snowing out in south carolina on a long trip. I had to get a radiator replaced there locally. By the time I got to north carolina the following week the cam wiped out a lobe and the engine wouldn't speed up past 3000 RPM's.

There may not be any scientific testing behind it, but it might be a good idea to go ahead and order up some real break in oil AND add in the Zinc additive on top of it, and re-do that process. I'm sure peeps will naysay, but I bet you have new wear on one or two of the cam lobes where the zinc-phosphate acrylic layer that keeps it protected has done worn down and you potentially have metal rubbing on metal. IF that's the case, and you're not going to know unless you pull it apart, it ain't long for this world. I wouldn't drive it at all until you do that process.

I recommend either Brad Penn or Joe Gibbs Driven. You specifically want oil that says "Break In". Not just any higher zinc oil. Those types of oil have less detergents in them so the ZDDP can do it's gap-filling job on the cam lobes and lifters.

Having all the trouble I've had and seeing increasing amounts of 4.0's pop up on YouTube with lifter noises, I recommend you proceed to use 10W-30 2000ppm ZDDP oil, or you can get away with using a store oil and just adding the Lucas 16oz TB Zinc Plus treatment. It's 31,000 ppm so it levels out to above 5,000 according to the math, but their data sheet says it's less than that. I don't know what that's about, but it's more than enough for a 6 quart standard oil. The engineering design of a cam-in-block setup with pushrods is less forgiving than an overhead cam design, so zinc is more imporant. Unfortunately the EPA has cut the numbers by 33% in the past 15 years, but at one point it used to be over 2000ppm. That would be back when the 4.2 was prominent.

I also recommend you start putting magnets on the filter to catch all metal particles. I read a hot rod article that said 70% of all engine wear comes from microns 15 and smaller. Oil filters only catch 25 and larger, and not 100% of it. Magnets will solve that issue, and I am certain you have metal circulating in your oil now. Before you do the cam break-in, or even if you don't decide to do it, get some motorflush and a new oil filter and do that for 10~ minutes or as the bottle says. Then put your new oil in.

Oil filter recommendation: Wix XP, AMSoil, or Royal Purple.

Experience: 4 wiped cam lobes. If

P.S. If you ever get a new cam, research it break in procedures. You should be using break in oil for the first 500 miles, then using race oil (and I still recommend you add in the zinc additive to be safe) for the first 10k miles. The factories used tons of zinc during break in process. I read somewhere in the past that there are two types of zinc, and the break in style wears down into the coating faster. I haven't been able to find any information on that recently. So don't think you can just use break-in oil solely. Only use it for the break in period.

Tbone289

I would also have an analysis done on the oil that's in there to check potassium and sodium levels.

CoffeeCommando

You do need to find out why the top heater hose blew off. If I had to speculate I would venture it's plugged. I can't fathom any other reason it would blow off. That would cause heat and pressure backed up to the thermostat housing to inflate the temp sensor reading. Has anyone ever used a radiator stop leak in it before? Plugged heater cores down the road I've read can be found in the wake of using those products. Make sure you burp all the air in the system properly. Make sure the overflow is filled up too because the cooling system cools down and contracts sucking any fluid in the container back into it. The hose attachment actually runs down to the bottom of the container. If there's air in there, there's going to be air in your cooling system.

It wouldn't be a bad idea to verify your radiator cap is working at 16 PSI and your thermostat is opening correctly. You can get a tester for the cap and a thermometer with some boiling water while watching it is all you do for the thermostat.

Remove the hoses and blow some compressed air through the top or bottom inlets of the core. If it's blocked it needs bypassed until you can pull it. It's a weekend job and not a fun task. You will have to disconnect the AC evaporator at the firewall so you'll want to get your AC properly evacuated and capped off. It only takes a drop of moisture to ruin that system.

70hemicuda

Well, the reason the hose blew was because it had that plastic tee in there hose for flushing the radiator. It cracked right at that spot. So 100% my fault, I was gonna change it out in the spring after flushing the coolant as it was due from last time I did it. Just really sucks it happened

cruiser54

Gotcha. Keep an eye on it.

70hemicuda

Just ordered a test kit from Blackstone labs so we shall see what the test says. Been driving it since it happened and checking the oil after every trip. So far it looks clean. Had that stupid tee on there 5 years and just forgot about it.

CoffeeCommando

If it's a white vacuum T, how did you seal it off? 200 degrees under 15 PSI should have blown any non-silicone vacuum cap apart. Only those black Eldon James connections are rated at 275. I'm not sure what the stuff at the store is but I'm sure it's not good for over 175. I think Nylon is good for that temp. Auto parts T's might be around 140 or 150.

Tbone289

I had one of those Prestone tees in mine for a couple years as well. Never again. Luckily, mine fell apart in my hands one day while I was changing the valve cover gasket, rather than while I was driving it.

Bugout4x4

And if they get low it's going to need an IV...

Lol... Did you catch that awhile back when Clown made this same crack? I LMAO but in that particular thread I had nowhere to go further with it.

Tbone289

I missed that one! LOL! I suppose if you want to bring the levels up at home, feed it a salty banana?

Bugout4x4

Or Gatoraid! lol Yeah, he made a comment about XJ's needing electrolytes. lol

70hemicuda

Well I changed the oil today. No sign of coolant and oil was clean of sparkly metal bits. Used rotella t6 and also a bottle of shell zddp for extra precaution. I'll keep checking it every time I drive until I can get a new head.

Martlor13

you should have saved some to send to Blackstone for analysis. With today's oils, it's pretty hard to see antifreeze in the oil unless it's an excessive amount.