dave1123

What Fred has said is very true. That 0331 is like a time bomb with no warning for detonation. It is something you should consider now that you have all that time and effort invested.

Not all 0331s crack, but most do and there's no telling when or if it will happen. Because this jeep probably had multiple owners before you, It might already have a "TUPY" head on it. Take a strong flashlight and look down the oil filler cap. If you see a "TUPY" molded into the metal between the 2 valve springs you can see, you can stop worrying.

dave1123

Reading back thru your posts, and some are very long, I noticed you mentioned the cooling fans. Your 99 was the first production year for the WJ so it had 2 fans. The electric fan worked so well, they eliminated the clutch fan from the 2000 models. There's still room to mount a clutchfan, but I haven't seen the need. The only time the engine got above 220* was when the F-ing relay died! The reason it's mounted under the headlight is it runs hot and needs a heat sink. It's a pulse-modulated relay controlled by the PCM. It switches in milliseconds to control the fan speed by reducing it's "on" time. Not exactly a good design in my opinion.

lakesideguy

I actually did replace them with AutoZone (most a year ago when the codes came up) and lifetime warranty on all them. So far none of them have had any issues. So far............

I replaced, throttle position sensor, transmission speed sensor, oil pressure sensor and both the high and low AC pressure switches, thermostat and got a DayCo belt. So far so good.

With respect to the head the radiator had cracked. The engine fortunately was saved into a non-overheat situation as the car was decommissioned the minute it hit 215 degrees or about on an idle it spewed. I stopped driving it until fixed. So the engine never really got into a overheat scenario. The fluid in the radiator had the appearance of reddish brown from leaky the leaky transmission cooler. That was fixed 10k miles ago and recently I had to drain it again and it was CLEAR and CLEAN of any foreign materials so I detect nothing in the fluid for 10k miles. The oil is clean as well, no steam from exhaust and the cooling system is optimal now constantly running around 207F and NEVER moving from that. I'm feeling confidence the head is ok HOPEFULLY or I would have more than likely seen contamination by this time or noticed it I'd hope since I've drained and filled a few times since that happened. I was informed the head most likely should be fine as long as the cooling system is kept top notch and that decommisioning the car when it happened most likely saved it from overheating and cracking it.

I prefer if at all poossible not replacing a head if it's going to be ok or is ok.
I have a philiosophy being an engineer myself, do not fix something that is not broken. IT leads to trouble if you do.

lakesideguy

Yeah mine has the mechanical and electric so I don't have that issue at all.
With respect to the relay. The location of it is not a good location to put any silicon. But, if you have overheating of any relay it's normally due to excessive current draw for extended lengths of time. In this case if the car is overheating the fan is running too much. Propagation delays have more to do with heat than anything. But in this case a bad fan motor could be culprit as well. In the case of only having a single fan in the system then relocating it isn't a bad idea or throwing a heat sink on it cetainly won't hurt it at all. In my case of having two fans and this much redundancy I'm not worried about a fan relay an my electric fan constantly running.

If it's a case of they took the mechanical off later they should have relocated it or heat sinked it to begin with as they inheritently changed the design making the electric fan run more. Thus current draw is going to be more constant the relay and heat it up. In that case not a good move to change the cooling design and not take into account an electrical component that is silicon based relay that is going to heat up more due to electric fan motor having to run longer and more. So yeah I can see that. In the case of having an mechanical fan also I'd not worry with this at all. My electric fan rarely runs now (it did alot before when the radiator was a problem).

I'm not sure why anyone would locate a relay in an enclosed area like that to begin with. That's not a good move on an electronic component. Heat is the worst enemy of that. And the three things in electronics that fail and the things to check in this order are (power ,fuses relays) that is the rule of thumb before messing with anything else. And putting a relay in a tight spot where it's not well ventilated and removing a cooling system component and changing the design without considering that the relay would draw current longer due to increased use of the electric fan well was kind of stupid on Mopar's part not to have realized that when changing that. Although like I said I'm not worried mine is going to do that with the mechanical fan doing a majority of the work. Like I said the electric fan rarely works. But current draw is going to generate the heat on it and if its just electric now then well they should have looked at that scenario of that part is going to run longer and hotter. Obviously they did not! I was unaware they removed the mechanical fan that would put all the work on the electric. Saving money I guess. I read about that 331 head also, seems like they tried to save some cash by thinning the walls up eh from previous models where I suppose now if you overheat your screwed and could crack it. I just HOPE getting that cooling system in top notch and shutting it down and parking it and that I've checked on this and the fluids it's safe. Ever since this project began I've been watching for any signs of any shennanigans from the jeep. So far so god other than this exhaust issue that Dave seems to have located by listening to it.

And yes not only does it smell like rotten eggs its a profuse hideous smell of some sort of dead thing. Rotten eggs is beyond that. It's smells up the garage rather quick and sets off the gas detector. Not my carbon monoxide detector. THE GAS DETECTOR. Ive got another car in the garage that I start it and it doesn't do that. This jeep is setting off the gas alarms not the carbon monoxide alarm.

LOL

dave1123

That's fine. I just wanted to make you aware of a potential problem. Personally, I wouldn't spend any more that I had to, BUT I need it to be reliable.

My WJ has more replacement parts in it than I'm comfortable thinking about, But I can count on it and I've got no car payments!

My electric fan runs on low speed anytime the jeep is up to temperature and only runs on high above 215*F. That means the relay is cycling MOST of the time! You know, I may go find me a junkyard clutchfan. It'd good insurance.

lakesideguy

Well I appreciate it. I'm hoping there is no issue and won't be. I'm all over it watching it closely. Like I said fortunately the overheat clogged radiator scenario I think was caught in time. I didn't drive it when the radiator popped open and the idle wen tto 215 and shut it down and it stayed parked.

The past two fluid changes (oil and radiator) nothing seen in either one so far.
CLEAN.

lakesideguy

I'm not sure what my obsession was but, I was determined to fix this jeep.
And so far I'm loving the results. I cannot tell between this ride and the way it's running any my newer 2010 car. Well this one is inheritenty the better ride now. lol

But, it's almost there. If it's the exhaust that should wrap up this rotten egg.
LOL

dave1123

You're too quick! We're crossing posts! Actually I edited mine!

lakesideguy

Sorry!

LOL

I should have showed in the video where I put that check valve. It's on the small tiny vacuum line going into the firewall to the AC control unit inside the cabin. It's by the AC liquid line hose connection and the dryer (accumulator) connections to the firewall. There was a tiny black vacuum line. Once I put the check valve on it the fan vents stopped going to defrost when under hard acceleration. I found out this 99 WJ was missing the TSB issued a year or two later fixing that.

Initially this Jeep also had the Teves calipres on it and that's another story.
Now it has the Akebono's all the way around with cross drilled slotted rotorrs for heat dissipation. Brakes are all new all teh way around. And it stops quite well!

But I forgot to mention those fixes as well since the first youtube I sent last July. It's practically new. And I kid you not on that. It just about is at the moment where once I fix the exhaust and paint it it's done.

dave1123

I also made the switch to Akebono, but I made the mistake of going to ceramic pads. Wrong! They squeaked constantly when you weren't using them and caused the pistons to seize from the heat. I went back to the recommended semi-metallic and don't have problems anymore. Funny thing, the rears are still Teves units. They don't make Akebono calipers for the rear.