Won't start after overheating - extremely slow cranking

[moikey]

I posted this at jeepforum.com and will try here also:

 

My son owns an 88 comanche 4.0 4x4 5-speed. He's taking it out in the mud a few times and tends to overheat quite often (I just found out he likes to get it drifting in the mud - running below redline he says). He called me a few weeks ago because it was overheated and wouldn't start. The radiator fan clutch had disingetrated (found pieces on the ground in the field he was stuck in) so I bought him a new one and he installed it but he said it wouldn't start after that. He later told me it started once but he heard a knocking so he shut it off and it wouldn't start again. When the key is turned the engine turns over extremely slowly as if it is siezed almost. I swapped batteries with my nissan truck and it did the same thing - the battery from his comanche made the Nissan starter spin quicker. I removed his starter and hooked jumper cables from the battery to the starter and shorted across the terminals and it spun quickly - didn't seem like a starter issue but I will have it checked anyway.

 

There was good spark coming out of the coil but a very weak (if any at all) spark coming out of the cap. I removed the CPS and tested the A/B ohm reading and it was about 212. I read somewhere it should be 200 _+75 when hot but I can't get it started so I can't get it hot.

 

I removed all the plugs and they were wet so it appears to be getting fuel. I had him crank the engine to make sure that all pistons/pushrods were moving and that looks good as well. I tried to get a compression test but the engine was spinning so slowly I couldn'g get a reliable test. It ranged from a high of about 165 to one cylinder that was about 80 psi.

 

So, we dropped the oil pan expecting to find pieces of metal in the pan but nothing - it was fairly clean. However, the oil was very thin and it appear that there was gas in the oil as I probably drained 7+ quarts from the jeep and the oil smelled of gas and was quite thin. I don't know if the gas was from the constant cranking without firing or cranking without the plugs.

 

I removed a rod cap and a main bearing cap and the bearings look good so I'm at a loss as to the very slow cranking and not firing. It cranks so slow that its almost like the engine is siezed but then I would expect to see something in the pan. I did take the starter in to Kragens and it passed the cranking test - they said it was in great conditon.

 

Could the overheating (apparently this is at least the 6th time he's overheated it) have caused something to warp and cause binding that I'm not seeing? I know he always refilled the radiator after the engine cooled down and it never overheated under normal driving conditions.

 

I removed the ground cable and reattached and it didn't change anything. I picked up a new ground cable at the same time as I got a new pan and valve cover gasket as some of the shielding was gone on the old one. But I haven't had time to put the new cable on yet.

 

Any advice would be appreciated as I don't want to start tearing the engine down if I don't have to right before the holidays. Thanks for your knowledge and taking the time to read this long post.

[pingpong]

WOW.... by the sounds of it he might have some ring issues by the gas in the oil. The fact that the clutch fan is toasted.. means it probrably wasnt cooling at all. Also the fact that the radiator is probrably plugged up means no t cooling very well to begin with. I suggest a cooling pressure check, and a compresion check.

[Pete M]

What condition are the battery cables in? Old cables can suck the power before it gets to the starter.

[Eagle]

Ugh.

 

Mud. Drifting. Overheated -- SIX times.

 

All you've done should have cleared it and shown any residue, but my initial reaction was "hydrolock." That might explain some of the thinning of the oil (was there any evidence of water?), and hydrolock could have cracked the top of one or two pistons, which might account for the variations in compression.

 

I just don't know. And, frankly, I don't recommend that you waste any more time trying to find out. Even ONE overheat is death to an engine. I had a heater (not radiator, just a 5/8" heater) hose burst on my hillclimb car just as I left the starting line. The moron corner workers didn't red flag me or black flag me, they let me run the whole course. So I drove something like 3 miles up a dang mountain, pretty much at redline the whole way, with no coolant.

 

Oddly and miraculously enough, once it cooled down (about a month later) the engine started and ran. It ran like crap, had uniformly low compression, and used about as much oil as gasoline ... but it ran. Clearly, the rings were toast. No point in even investigating ... I just yanked the engine and built a bigger one to replace it. I think I gave the old engine to one of the guys in my car club, and he just threw a set of rings in it and put it into a beater-mobile.

[moikey]

Battery cables appear good but I'm replacing the negative because there is some shielding missing near the block end. No water in the oil but definitely gas - probably at least a quart. It may be time to start tearing it down because at this point I'm :???:

[Eagle]

It's none of my business, but at this point I think it's time for the guy who did the damage to start doing the repairs -- and paying for them. I learned everything I know about cars, trucks and engines building and repairing (and paying for) my own rides. It taught me that there is a price to be paid if you act irresponsibly, and that breaking it really ISN'T so much fun when (a) you have to pay for fixing it, and (B) you don't have any way to get to work on Monday morning.

[moikey]

I agree. He's 17 and in high school and in football right now. The team made it to the play offs and when that's over he's getting a job. He's out there with me the whole time getting dirty and trying to get it running again. He told his mom the other night that he won't be mudding anymore because it sucks to be without his truck. There is hope.

[Eagle]

He told his mom the other night that he won't be mudding anymore because it sucks to be without his truck. There is hope.

:bowdown: :thumbsup: :clapping: