Hudson

Hiya,

Help, I bought a WJ Grand Cherokee 2002, 51 reg (uk) 4.0 litre with a seized engine!.
I dropped the sump pan to find number 6 piston totally smashed up into loads of pieces and just the con rod and pin up in the bore. The con rod wasnt bent).
I took the head off and also found number 6 inlet and exhaust valve bent!.
I found the bore slightly damaged with 2 small groves in it from the pin/rod.
I bought a honing tool and re honed number 6 bore which now only has a very small mark on it.
I brought and fitted a new piston (standard size,B) with rod, pin and rings and big end bearing. I fitted 2 new valve and couldnt find any cracks!
I built the engine up and started!!!
I first started the engine up only for 2 minutes without coolant and she ran fine. Then i put the coolant in and started her up to find after 1 minute, oil was getting into the sump quickly mixing with the oil. Then she started to miss fire.
I took the head back off and found oil/water (the creamy mix) only in the port hole of number 6 cylinder, only in the inlet port!!!!
Now im thinking the head is cracked and maybe whorped. So i took the head to be tested. When i showed the engineer shop, the guy said it must be cracked near the inlet seat guild. So he pressure tested it and said he was shocked to find the head passed!!!!. He said it needed skimming so he skimmed the head.
Brought new head bolts, gasket etc and this morning re fitted the head!
Guess what?? and this is why im back on your forum. The same happened, she ran fine for 2 minutes then i put the coolant in it which then after 1 minute she started to miss fire and smoke coolant again.
Now what?? what does everyone recommend??. Im thinking new head!????????????. Has there been problems with blocks?

Thanks

retreaded jeeper

if you trust the shop with the head I would suspect the block

Hudson

hi, thats the problem, i dont trust anybody. I might get it pressure tested again for another shop maybe. I think im saying this because of where the oil and water was, only in the inlet port and i hopping because heads are cheap than blocks.
Thanks

dave1123

This may sound stupid, but was the pressure test done with the head hot? There may be a small crack in the valve guide area that needs heat to leak. If the valves took a pounding, I would suggest trying another head, even a used one, which you can rebuild if it needs it. JMO

1ABrian

Most definatly when you have a major POP like that, you MUST have the head mag'ed. IMO I wouldnt trust the block either. You can get a long block used for 500-700.00 bucks. Be careful how much you pour into a head the buy another head before you pick up a used longblock.

Hommersimpson

Hate to tell you but this is why you dont rebuild motors that eat a piston and rod.... Without a machine shop to magniflux everything...Its not worth it... Our jeep... #6...same thing as you... i went to junk yard.. got a 145k motor for 149 or 180 bucks what ever it was... put in new bearings..resealed everything but headgaslet..and Timing cover... and now I have a motor that runs perfect... for about 500 bucks...you could not ask for a engine to run anybetter.....You prob have a cracked block...

1ABrian

Yupper X2.