4.7L HO Grand Cherokee with combustion leak - what to do?

theksmith

Explorer
130K miles on it, combustion leak, and i want to keep the jeep for a long time... what should i do (heads only, new engine, etc)?

looks like HO head kit is gonna be over a grand, a fully reman'd longblock is $4,500, or a used engine with 90k on it is $2,500-ish

background - overheated a while back due to lost radiator drain plug, was worried, but everything seemed ok for past few months, then cooling system has been wonky lately...

after checking and changing a few things, finally noticed repeatable results of coolant being puked after reaching operating temperature, and never coming back into the system from the overflow jug. then noticed that everytime i removed the radiator cap after it cooled down, there was a rush of air... thought at first it was a vacuum as it should be sucking IN after having puked, so replaced the cap...


new cap didn't help, and then finally realized it was air pushing out everytime i opened it - so the system is holding pressure, but where's this air coming from? well, turns out not air, but combustion leak:

P1120340.JPG



i'm guessing i'll just do heads as i don't really have $4,500 for a new engine, and a used engine at 100k on it just seems like why bother?

anyone have experience with specific head reman places? any writeups for swapping them?
 

theksmith

Explorer
You should be able to find an engine for much cheaper than $3k, called your local salvage yards?

yes, used are $2k-$2,500 - but most have nearly 100k on them, so i was looking at rebuilt

monday i'm going to get someone with electronic sniffer to double verify my results and then call some places about heads and/or engines
 

BlaZeJeep

New member
yes, used are $2k-$2,500 - but most have nearly 100k on them, so i was looking at rebuilt

monday i'm going to get someone with electronic sniffer to double verify my results and then call some places about heads and/or engines

Have enjoyed reading your build on your WJ. If it were me the last the thing I would do is a JY engine. If you were not having problems with oil comsumption or oil pressure (sign of bad bearings) prior to your overheating issue, I would rebuild the heads or buy replacements before JY or a new "rebuilt" (Jasper rebuilt) engine. Reason is you know what you have, how it was treated, how it was maintained etc. If it overheated the head gasket is probably your issue, possibly the head is warped. If so the head gasket set alone is only a hundred $$, and good machine shop can tell you if the head is warped or cracked. If the head is warped, a few minutes on a surfacing machine will true it up, replace the valve seals, do a valve job if needed and you are good for another 100,000. If they find a crack, a JY set of heads, or a replacement set from Mopar, or aftermarket might be the answer.

I'm sure there are many reputable shops around the Phoenix area that would be able to do the job. If you can pull the heads your self, you could save big$$. Not that big a job if you take your time and follow the torque specs etc. I did my first one when I was 17 or 18 on my 1974 Dodge Charger, boy those were the days. In some ways it is easier today with all the plug and play connectors and fuel injection, just less space to do it in...Good luck
 

shortbus4x4

Expedition Leader
Have enjoyed reading your build on your WJ. If it were me the last the thing I would do is a JY engine. If you were not having problems with oil comsumption or oil pressure (sign of bad bearings) prior to your overheating issue, I would rebuild the heads or buy replacements before JY or a new "rebuilt" (Jasper rebuilt) engine. Reason is you know what you have, how it was treated, how it was maintained etc. If it overheated the head gasket is probably your issue, possibly the head is warped. If so the head gasket set alone is only a hundred $$, and good machine shop can tell you if the head is warped or cracked. If the head is warped, a few minutes on a surfacing machine will true it up, replace the valve seals, do a valve job if needed and you are good for another 100,000. If they find a crack, a JY set of heads, or a replacement set from Mopar, or aftermarket might be the answer.

I'm sure there are many reputable shops around the Phoenix area that would be able to do the job. If you can pull the heads your self, you could save big$$. Not that big a job if you take your time and follow the torque specs etc. I did my first one when I was 17 or 18 on my 1974 Dodge Charger, boy those were the days. In some ways it is easier today with all the plug and play connectors and fuel injection, just less space to do it in...Good luck

Exactly. Your heads are probably fine, nothing a headgasket set can't fix. With the heads off have them checked for leaks and resurfaced by a machine shop.
 

theksmith

Explorer
here's what i've decided to do and how i arrived at that conclusion (i offer this long winded post for any that might face a similar predicament):

first of all, keep in mind i originally cooked this engine to the point that it temporarily seized and wouldn't turn over at all and had smoke coming out both sides. and also i don't have another vehicle besides the GF's (and she needs it for work everday), so my goals are to just get this back on the road in a reliable fashion as soon as possible.


option 1. just fix whatever the problem is:

could be just a head gasket, could be warped heads, could be cracked heads. also should check compression and leak down on the "good" cylinders to see if rings going bad. everyone's guess that i talked too is 50/50 whether is warped or just head gasket.

even if just head gasket, i would probably get new heads because after talking to some shops and reading up on my engine - these bad boys have pressed in valve seats that can drop, especially after they've been overheated (because the sintered metal seats expand/contract differently at those temps than the surrounding aluminum heads). also i don't want to mess around with taking it all apart, then taking to machine shop, hoping everything within tolerances that is fixable, etc. add to that that i don't know squat about valve-train, so if i attempted this "just fix the problem" option, i would really most likely buy assembled heads and swap them in.

then it's arguable whether it's doable in the vehicle or easier to just take out the engine. also everyone i talked with said to do timing chains, tensioners, guides and oil pump while doing this. now that's half-way to a rebuilt engine except i'm keeping my bearings, rings, mains seals and such that could still go bad.

with assembled HO heads being $1k+, and me having 130k on a toasted engine - it would be alot of money to dump into something that could still have more problems soon. oh and no-one i could find had HO heads assembled, i'd have to send them my core, but only of course if they were usable cores.


option 2. salvage engine:

ok, with leaning towards wanting to replace everything to give myself peace of mind on reliability, next i considered junk yard engines. about $2,500 but all i could find had 80k to 100k+ miles on them. again, for that much time and effort and money, i could be just swapping in another problem.


option 3. new (used) jeep:

i could get a new-to-me used Grand Cherokee with no body damage ;) then swap all my junk to it... i'd have to buy the lift and have it installed first because that was all weld on and all the OEM suspension is cut off... that's $3,500 plus the cost of the jeep, plus all my time to move everything to the new one.

quick look says that in the current crazy used market, another 02-04 limited or overland 4x4 v8 would be $8k to $11k... and they all have 80K to 100k+ miles on them for that price!

so this seems like costly and time-sucking project that gets me nothing more reliable really, just maybe a different color and prettier body.


option 4. rebuilt engine:

first check on ebay says my 4.7 HO costs $4,500 for a fully re-manufactured long block! so originally this option was out - back to option #1!

then i call around some places and found better prices - Promar wanted $3,300, Jasper wanted $3,800 - they both had the parts ready to build one or had one ready and i could send my core after i got the new one, and those prices include shipping both ways. i also talked to rebuiltcrateengines.com in texas, they didn't have one, but would rebuild mine for $2,800, plus $500 shipping total both ways, would take 2 weeks (assuming my core is usable). i called some others found on the net including gearheadengines.com, but no-one had HO parts and so could only rebuild mine and had longer turn-arounds.

so for the $3,300 i was strongly considering a whole reman engine, feel like this would be good peace of mind for another 100k+ miles...

i called local places including phoenixengine.com and enginehouse.com (bad reviews from some people on engine house) - they wanted weeks to do the engine, and needed a good core.

i called Greenway Auto Repair here in North Phoenix as they are an authorized Jasper dealer, they wanted $6700 for parts and labor to do a full reman swap. that was including the $3,800 Jasper engine with extended warranty for $170 and they were figuring $270 of misc parts, the rest was labor.

i called discountenginesaz.com in mesa and they didn't have a set rebuild price, wanted to take it apart and then quote me.

i called Hopper's in tempe and they were nice, but didn't call back yet.

wanting to get this thing back on the road, it was down to Jasper or Promar - i couldn't see any benefit to Jasper except that they offered a much better "premium" warranty, but that put the price up to almost $4k. Promar came out to $3,450 due to $75 each way surcharge to have a truck with liftgate come (since i don't have a forklift or loading dock). Jasper wanted $1080 core charge up front, refundable upon receipt of a good core. i'm not sure my heads will qualify, i know my block is good though. Promar doesn't charge an up-front core charge, but bills you $500 if you don't return a core within 30 days. They also accept any condition core, they'll just use whatever they can off it.


the conclusion:

with these last facts, i decided to just order the Promar. They should have it built in 3 to 4 days, and delivered to my driveway in another 4 business days. So i'm out $3,450 but should have a whole reman'd engine middle of next week. it really boiled down to not wanting to do a bunch of work to 1/2 the engine after toasting the thing and having 130k on it just hope the other 1/2 stays reliable. if it wasn't my only vehicle and the vehicle that takes me hundreds of miles into nowhere often, i would be much more willing to take time to find and fix just exactly whatever the current issue was.

other than standard rebuilding stuff like timing and oil pump and such, i did verify that they press in new valve guides on the heads for this engine too.

now i need to figure out exactly which gaskets i need (timing, intake manifold?, exhaust header, ?). i already have new plugs, 02 sensors, water pump, thermostat, knock sensors, PS pump, coolant, PS fluid, and heater hoses all sitting here - and the radiator and main hoses were replaced just a few months ago (i was planning to do a "longevity tuneup" and address a couple DTC codes already, hence the pile-o-parts).

i'm going to also put in new y-pipe to get new mini-cats. originally i was going to go with the Mopar mandrel bent pipe for about $900, but with needing to now spend all this other money, i'm going to just go with the Walker aftermarket y-pipe for more like $350.

tonight i'll start pulling stuff out of the engine bay! my goal is to have it ready to put in the new engine when it gets here next week, and then have the new one in within a few days after that - so i could be back and running in 2 weeks and only have to leave the house for some gaskets, bolts and to borrow a cherry picker, and *should* have a reliable Jeep again that i'm not afraid to expedition with


cr4.7.jpg


i'm looking at the whole thing as a chance to invest in the longevity of my jeep... yeah, that's what i'll keep saying to myself ;)
 
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shortbus4x4

Expedition Leader
If you cooked it to the point where it wouldn't turn over til it cooled off then don't bother with the heads, do the whole engine.
 

fasteddy47

Adventurer
Just looked on E Bay at the ProMars..... Looks like a decent rebuild. I can get you a Brand new Chrysler not a reman drop shipped to you in Pheonix for $6800.....:Wow1:

I would do the Promar...if they follow all the rebuilding procedures they say they do...It should be a good engine. Remember to prime it before firing it.

I rebuilt my 4.7 about 6 months ago. Even with my price on parts....with all the machine work and BS..... It still cost me $2800. And I paid the Tech who helped me $500.....

ProMar uses New Head Bolts and New Main Bearing bolts.... That speaks loads about the quality. If you can get ARP rod bolts put in.....for the extra $50 it would be worth it.
Remember to go down to the local Dodge store and buy the factory Black filter.... The original one that came when it was new. They cost about $2 more than the mopar ones but weigh twice as much...they have a .0002 Micron rating.

If the Dodge Partsmen doesnt know the number PM me and I will call work and find out for you. I am on holidays this week.

PS if you need any schematics or paperwork...let me know and I can go online to Chrysler and download it for you!!
Cheers
Eddy
 

theksmith

Explorer
Just looked on E Bay at the ProMars..... Looks like a decent rebuild. I can get you a Brand new Chrysler not a reman drop shipped to you in Pheonix for $6800.....:Wow1:

I would do the Promar...if they follow all the rebuilding procedures they say they do...It should be a good engine. Remember to prime it before firing it.

I rebuilt my 4.7 about 6 months ago. Even with my price on parts....with all the machine work and BS..... It still cost me $2800. And I paid the Tech who helped me $500.....

ProMar uses New Head Bolts and New Main Bearing bolts.... That speaks loads about the quality. If you can get ARP rod bolts put in.....for the extra $50 it would be worth it.
Remember to go down to the local Dodge store and buy the factory Black filter.... The original one that came when it was new. They cost about $2 more than the mopar ones but weigh twice as much...they have a .0002 Micron rating.

If the Dodge Partsmen doesnt know the number PM me and I will call work and find out for you. I am on holidays this week.

PS if you need any schematics or paperwork...let me know and I can go online to Chrysler and download it for you!!
Cheers
Eddy


interested in part number for that special filter, the only one i have is 5281090... and the local parts counter guy would look for a piston return spring in the computer for an hour if i let him, so he's no help.
 

theksmith

Explorer
is that installed? I bought a reman'd 4.0 long block a few years ago for $1100. $4500 seem pretty high

ha, i wish - 4.0's are a dime a dozen compared to V8's, and the darn HO is apparently made of platinum as it's another grand nearly compared to the regular 4.7. a few years ago i had a brand new factory fresh 4.0 sitting in my garage that i think i paid like $1,800 for (including all covers, gaskets and such, better than a rebuilt).

the $4,500 was high, i eventually ended up finding ones for $3300 and $3800 - but still :(
 

BlaZeJeep

New member
With the additional information on your engine problem, I would probably do what you are doing. When the engine seized to the point of not turning over it is time to look for a new long block if possible. If it was 5.2 I would be less concerned about the lower end(they are nearly indestructable), but I wouldn't chance the 4.7 with the overhead cams and chains, tensioners etc.



As far as filters go I like the Purolator Pure One with the textured grip. It does a nice job of filtering (20 micron) and is rated at 99.9% efficient (whatever that means??) according to their website. I use them in all 4 of my vehicles and one in my ATV. Not sure of the .00002 micron rating on the Mopar filter, everything I read was 20-30 micron. Particles in smoke are about 1 micron ( like carbon) for comparison so .00002 would let nothing pass through, including the oil. Mopar are made by Champion Labs in West Salem, Illinois. They also make filters for STP, K&N, Mobile, TRD, Mopar, Royal Purple, etc. according to their website. They make a couple of different qualities of filter, like STP low quality (cheap -$5) with cardboard filter material. Also a more expensive one with much better oil resistant material with better filtering quality and thicker canister material (K&N performance -$20).
 
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theksmith

Explorer
With the additional information on your engine problem, I would probably do what you are doing. When the engine seized to the point of not turning over it is time to look for a new long block if possible. If it was 5.2 I would be less concerned about the lower end(they are nearly indestructable), but I wouldn't chance the 4.7 with the overhead cams and chains, tensioners etc.



As far as filters go I like the Purolator Pure One with the textured grip. It does a nice job of filtering (20 micron) and is rated at 99.9% efficient (whatever that means??) according to their website. I use them in all 4 of my vehicles and one in my ATV. Not sure of the .00002 micron rating on the Mopar filter, everything I read was 20-30 micron. Particles in smoke are about 1 micron ( like carbon) for comparison so .00002 would let nothing pass through, including the oil. Mopar are made by Champion Labs in West Salem, Illinois. They also make filters for STP, K&N, Mobile, TRD, Mopar, Royal Purple, etc. according to their website. They make a couple of different qualities of filter, like STP low quality (cheap -$5) with cardboard filter material. Also a more expensive one with much better oil resistant material with better filtering quality and thicker canister material (K&N performance -$20).

a micron is 0.00003937 inches, so i believe fasteddy meant 0.00002 inches or under a micron, which would still be way crazy if other filters are at the ~20 micron level.

anyway, good reading on oil filters here: http://www.carjunky.com/news/motor_oil/mom7.shtml

i find it interesting that most oil filter manufactures only list relative terms like "30% more filtering than conventional paper filters". blah blah blah. i see at least amsoil give you some hard numbers based on a standardized test: http://www.amsoil.com/storefront/eao.aspx purolator does give results from the same test but at a different micron level, so it still hard to compare apples to apples.

what do you guys think of the filters with "anti-drain back valves"? marketing hype, or useful technology?
 
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