Another head gasket thread

[MindBender0001]

I'm getting another '93 4D Auto for $400 and using my current rig for parts for the new one. The one I'm getting has a leaking injector o-ring (just put 6 brand-new ones in current rig) and has been diagnosed with a bad head gasket. Guy is a mechanic (been in his shop....not a pro, but knows what he's doing). Radiator pressure test good, no coolant in oil, no oil in coolant, no bubbles in coolant, passes a leak down test. He says all the testing is showing a failure between cylinders. I can get new heads from RA for $132ea. BUT...if he truly has done these tests and they all pass, should I still replace the heads?

-Bender

 

[Anime]

The diagnosis of a 'bad head gasket' assumes the best case scenario, and is pretty general without taking into account the specifics of each vehicle.

The stock 4.0L OHV heads were pretty weak from 90-92 (known as 90TM heads), and some '93 models still came with 90TM heads until they switched to 93TM heads, which were a slight improvement, but they still aren't as strong or beefy as replacement aftermarket heads, which actually have more material and even weigh more to prove it.

Due to weakness of the heads, when a 4.0L OHV so equipped overheats, or even gets hot too many times, the heads crack, many times between the cylinders, and you get a leak that can't be fixed and so new heads are required.

That's not to say that sometimes the issue isn't just a blown head gasket - but on these vehicles, chances are good that the issues are with the head itself and not just the gasket.

When it comes to cost/benefit, generally you are better off spending the $$$ and just getting new aftermarket heads for something you are taking apart and putting new gaskets on. If you can get good quality heads for $132 a pop, I would say it's more than worth your while to get those, and not have to wonder if the stock heads are ok, or spend more money dealing with them later on, and having to waste more $$$ on gaskets and time tearing into it again and redoing everything.

If you're just building a beater and don't want to spend much, you can risk it and see what happens, but if it's a daily driver and/or your only vehicle that you depend on to get to work and everything else, the new heads seems like a smart choice to me, especially if you're also going to put on new rocker arms to fix the worn originals, which you should also consider doing at the same time.

 

[MindBender0001]

As it will be, this is my wife's rig. I agree. After pouring over thread after thread regarding heads and head gaskets, I agree. 100%. Why waste my time (gaskets and bolts are only $100) putting something back on that Murphy would totally kick me in the Jimmy 3 days down the road.

I haven't heard it run, but he says the only issues keeping it from driving are the leaking o-ring, and a slight "miss". The miss is what lead him to start checking stuff. New plugs, wires, coil pack, and it still has a miss. "I'm done f-ing with it." So, $400 for a 'running' rig that's WAY better than her current rig (tranny issues-I've got another thread going for that).

https://www.rockauto.com/catalog/moreinfo.php?pk=5540919&cc=1119620

Those are the heads I'm looking at getting. They're cheap, so makes me wonder if those are true aftermarket or just NOS...I'm gonna poke around here and see if I can find a consensus on the best budget friendly heads.

Makes me wonder if that miss is the same as our current rig. Worst case, I can't afford the heads themselves right now, and let her drive it (fixing the injectors first). Whats the worst that could happen? Get right down to it, I have another running 4.0.

 

[Anime]

Those are aftermarket. The "remanufactured" heads (which cost more, actually) are generally those few factory ones that haven't cracked yet and are sold to people who, for some reason, want OE heads on there. I suspect they are not aware of the head issues and just assume OE heads are better.

As far as I know and have heard, just about all current aftermarket heads for the 4.0L OHV are sourced from the same company in Australia (of all places). Plenty of resellers out there buy the bare heads and sell them marked up and others sell them fully assembled, often with no-name parts.

I'm not 100% sure that if you order those $135 heads you will get the Made-in-Australia ones, but it might be worth the gamble, if you can put the hardware on yourself or have a shop that can press in the guides and seats and make sure everything goes together right.

I don't recall ever hearing anyone on here had installed Enginetech brand anything, so it may also be worth the price just to add to the collective knowledge on here.

They do have a website and contact info, so you could always give them a call or shoot them an email and inquire about where those particular heads are manufactured. If they are made in Australia, go for it.

http://enginetech.com/cylinder-heads.php


If you do go with RockAuto for the heads, be sure to use their 5% off discount code. It's not much, but it does take a little off to defray the shipping:

http://www.explorerforum.com/forums/showthread.php?t=350140

 

[MindBender0001]

Oh crap. I assumed those heads had the guides in them, just no valetrain. That in itself deseves an email to them!!! If there's no bubbles, and no coolant/oil mixing, I may just fix the injectors and let her drive it. Get a head each payday or something. I already know there is no oil/coolant issue as I checked the oil when I first looked at the rig. It's used oil. Not old, but not new, and not milkshake.

 

[MindBender0001]

I just checked their website and the same heads are $178. Comparing the valve guide ID they state to the intake valve shaft OD on RA, the guides are already in. I've replaced valve guide seals with heads on and off the engine, so swapping the valvetrain from one set to another isn't that much work in the scheme.

 

[Anime]

When I read "bare head", I usually take that to mean the head only has the plugs in it, with no guides or anything else. Even if it has guides in it, you will still need to have the correct valve seats pressed in, and the proper way of assembling a head is also to make sure the valve seals completely all the way around. Just pounding valve seals in and sticking valves on is a good way to have valves that don't seal, leading to a host of other problems, including valve, seal, and head damage that can result.

That's part of the reason fully assembled heads are big sellers - all the valve assembly work has been done for you. It's either that or having a shop that knows what they're doing when it comes to cylinder heads assemble it for you. You can of course do it yourself with the right equipment, but most people don't have the right equipment and so its easier/cheaper to just have a shop do it the few times you need it done, or get already assembled heads.

Even if you go with the heads that are on there, it's still worth knowing the options and planning ahead of time if they do wind up needing to be replaced.

 

[MindBender0001]

Hmmmm....awsome advice on the valve seating. In my limited expierience with R&Ring heads, I've never actually swapped the valve over. I have seen, but never used the tools my step-dad used for lapping the valves and seats by hand. As of right now, I'm gonna start gathering parts for an eventual head job. I'm gonna take your advice and go for a set of assembled heads. Might be more money now, but less messing around. Escpecially since I'm about 100 miles from the nearest city with and automotive machine shop.

 

[MindBender0001]

Alrighty. Got new x home. It's actually a '92. Couldn't start it where it sat because of the fuel leak. The 'small fuel leak' ended up being a HUGE fuel leak, but once I had it apart, it was obvious. The upper o-rings on all six injectors were shredded. Fixed that. The 'slight miss' i never got to hear, but before buttoning everything up, I double checked the plug wires. I swapped two wires on driver's side on the '93 and that made it run pretty rough. Yup. This one was the same. Corrected the wires. Fired right up and purred like a kitten. Even shifts REAL nice (THAT'S the whole reason I wanted this rig). ANYWAYS. Back to original question.

The ONLY evidence I have of anything wrong with heads/gaskets is a tiny bit of oil in the radiator. I have NO coolant in oil pan. I have NO bubbles in radiator. I took it for two 15 minute drives, and I wasn't babying her either. Nothing left radiator, nothing more in oil, no smoke, no drips. Radiator still just where it was before second drive. I had her running for about 30 minutes in driveway before second drive with radiator cap off letting her puke out a bit of water (and oil), adding back as needed. I only lost MAYBE 1/4 cup each time it flowed over. Temp gauge hasn't gone past the spot between N and O on the gauge.

So if I've got oil in radiator and bad heads/gaskets, shouldn't I also have oil in crankcase? The oiling system of the engine runs at what, 30PSI and the cooling system is at 13PSI. While engine is running, I can see oil getting pumped into the cooiling system, but not from heads/gaskets (crack in block?). Flip side of that, when engine is off, the 13PSI in cooling system is still there. Wherever the oil is getting in the cooling system while running, the coolant SHOULD then be able to make it's way into the oiling system after engine is off. After two decent test drives (90 degrees outside, both got up to 60MPH, one uphill, one downhill), I would think there should be a pretty good milkshake in one or both??? I've had two vehicles give me the milkshake, so I know what to look for and I don't have any evidence of it other than oil in radiator. Even then, its just droplets...barely covers the surface. I'm thinking of taking it to work in the morning which is a 30 minute drive at 70MPH, two decent hills between.

Don't know if it matters, but he also replaced the water pump, fan clutch, thermostat, and radiator. All that SCREAMS it had overheating issues, but as of yet, nada. Could some oil be getting into cooling system at the water pump/timing cover (looks like the timing cover has been off as well)? Possibly residual from some previous failure? Am I missing something? I don't got a problem doing a head job, but if I don't HAVE to right now......

 

[jd4242]

You dont ALWAYS get water in the oil or oil in the water or even water out the exhaust. .it just depends where the crack is and typically its only seen when magnaflux and under pressure. ..I would replace them and be done with it..dont forget new bolts and I always suggest the SD super duty felpro head gaskets, last I check its the same price..

These are the heads I use, they are nice
http://www.ebay.com/itm/170434742301?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[MindBender0001]

With those heads, did you use your old valves/springs/etc or did you get all new hardware?

 

[jd4242]

With those heads, did you use your old valves/springs/etc or did you get all new hardware?

Ive used those heads many times..but yes I and others have used them with all stock parts.just swap valves, springs, retainers and locks..they flow better and are aftermarket. .only time I suggest new springs if doing a cam or HIGH mileage.

Those heads are whats on my forged supercharged motor and ported to crazy levels, they are a good thick cast also the 95tm were on my old supercharged motor which I blew the gaskets off and drove/ overheated for a LONG LONG distance and didnt damage them

 

[MindBender0001]

Since I already run super in all my rigs anyways, should I just go with the 95TM's? I can get them for the same price from RA...

 

[jd4242]

Since I already run super in all my rigs anyways, should I just go with the 95TM's?

Unfortunately they dont make them anymore and NOONE else makes true 95tm..you can run 98tm but has smaller exhaust ports.not much of a difference on a stock vehicle but then again whats really the point of running higher compression on a stock vehicle? ? That higher compression usually is ran with a cam or other mods to really take advantage of it.

 

[jd4242]

Those on RA are not true 95tm..they are 98tm/95tm which are just 98tms..honestly they shouldn't list them like that as putting 95tm on a 98tm motor is not recommended. .the 98tm are fast burn and use different cats..

 

[MindBender0001]

It's guys like you that I love (and hate) listening to. We talked about it for a bit and figured $300 aint really that much in the grand scheme. I bought the rig knowing it probably had head gasket issues, just so happens new heads go along with that. Comparing how the '93 runs and drives, this '92 already would run circles around it. She's worth another $300. Thanks for all the advice.

For the record, she wants THOSE heads.

 

[jd4242]

 

[MindBender0001]

I read your 'oil in radiator' thread....sounds just like mine. Curious, have you had any more problems with the heads/company? Seemed like you had two bad heads before you got one good one...Found another place on 'Bay that has a pair, assembled, for $410 to my door...cost wise (for new components), it's a wash. Just trying to be objective here. My wife's NOT gonna be ok if I have to do this again even IF it's the company's fault.

 

[jd4242]

I read your 'oil in radiator' thread....sounds just like mine. Curious, have you had any more problems with the heads/company? Seemed like you had two bad heads before you got one good one...Found another place on 'Bay that has a pair, assembled, for $410 to my door...cost wise (for new components), it's a wash. Just trying to be objective here. My wife's NOT gonna be ok if I have to do this again even IF it's the company's fault.

Im pretty sure that that was results of a bad lower intake. I also had a thread with a bad oe head..hell I went through ALOT for awile there

I have had a bad head from them but dont think it was ever installed.it was the middle rocker pad was drilled and tapped to deep.it came through into the intake port.I noticed that before tho.but their customer service was excellent and sent me one right out.ive used 4-6 of their heads sense then

 

[MindBender0001]

Jd......
Question is, since I have a bit of oil in radiator, do I need to do anything special before draining radiator? Its got a new radiator in this rig and I really don't want to mess it up in this process. Also, I tried looking for the step-by-step head thread on the forums, but I couldn't find it. I'm gonna start the tear down today, but I'll hold off on cracking into the cooling system in any way till I hear from ya.