So, I was in a hurry (first mistake, right?) and had a oil change place change my oil on my D100. They filled it up, and showed me the dipstick and it showed at full. I drove home, no issues.

Next morning I took the truck out, and it lost power and died on the highway. I restarted and it sounded like it was running rough, so I shut it off and towed it home. Checked the oil, and it was WAAY high. So I did an oil change, changed spark plugs, replaced PCV valve, and started it up. Now I have a HUGE knock on one of the cylinders. Enough to shake the truck.

I think them filling up the oil to the full mark when the engine was hot may have picked up some junk at the bottom of the oil pan and clogged a passage? Sounds like a main bearing went, or a piston is hydrolocked or something (there was oil on two of the plugs when I replaced them).

Any ideas where I can find another motor for a decent price? I've struck out on craigslist, and local u-pull it places want like $500.

Should I just try and have my motor rebuilt at a reputable shop?

My wife wants me to scrap it But I don't want to. However, if I can't fix it for under a grand, it might not be worth putting that much money into it.

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1985 D100 3.7L Slant 6, 4-speed manual.

Are you sure the noise is not from some bolt-on accessory or at the flex plate / clutch area?
If it is a bad inturnal engine knock, remove the engine, take it apart and see what it needs... then start looking for the needed replacement parts.
Some engines can be "patched" back together for the cost of a few gaskets and some good used parts. (and lots of labor time)
DD

If oil level was high, maybe fuel pump wenr bad and is dumping fuel in the case

The knock is at like a 2-3 second interval, and it is enough to shake the truck. The rest of the idle sounds fine... it is like just the compression stroke of one cylinder is messed up or something.

Oil didn't smell like fuel when I drained it.

I need to go buy a hoist and engine stand... I found a 3 ton hoist with an engine stand on craigslist for ~$230. They look good, I might pick em up and hope it is something within my capabilities of fixing.

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1985 D100 3.7L Slant 6, 4-speed manual.

Dropped a valve? I suggest you pull the valve cover, and closely watch the rocker arm and valve action while hand-turning the engine. (Pulling the spark plugs will make it easier.)
Might be that you broke a valve spring that allowed the valve into the piston travel area, and that valve is now bent over, or stuck in place, and that's what is generating the knock.

Roger

I bought my engine lift at kragen for $100 but that was almost 10years ago

I finally got some time to pull the valve cover and take a peek, here is what I found:


Just one rod had popped out of place. I'm unsure of what steps to take at this point. Do I still need to find a way to check if a bearing seized? Is there a good way to check the valve function? Should I go ahead and pull the motor and go from there?

I'm tempted to just get a few quotes from some engine shops, but I want to understand the problem before I call. Otherwise I'll be going in fairly blind as to what the cost will end up at.

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1985 D100 3.7L Slant 6, 4-speed manual.

Put a pushrod in it, fill it with oil and start it up. It may not be as bad as you think.

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Official Cookie and Mater Tormentor.

Where might I get a pushrod? I haven't seen a plethora of places to get them except in a full kit.

edit: nevermind, I found them at Napa. And should I just go ahead and replace all 6?

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1985 D100 3.7L Slant 6, 4-speed manual.

Go to Rockauto.com put your year and make and such in there. Look in Engine and pushrod. The Clevite PN 2154205 is on close out for $1.21.
At that price your in pretty good shape ordering more just in case. put discount code 2794E541593B in "Where you heard about us." That will save you some more, but your not going to see much if you only buy one. Need anything else while your there?

Check all of the pushrods on a flat surface to make sure they are true. I use the ways of my lathe to check them. Replace any part that doesn't check out perfect. If they have any bend at all, they may not rotate.

CJ

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Part of Tyrde-Browne Racing

thanks for the info. I need a new valvecover gasket and a rear main seal as well. I need to replace the clutch at some point (already have the kit, just was waiting until I got the engine sorted out first).

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1985 D100 3.7L Slant 6, 4-speed manual.

The shipping is the killer from Rockauto. Check all the pushrods first. They will ship from the same place. If you have to order another later, it'll wipe you savings out with the shipping costs.

You can also check you local parts store, or FAPS. (Favorite Auto Parts Store.) They may surprise you. More expensive, but if it's only a small amount, it's worthwhile to keep them in business.

CJ

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Part of Tyrde-Browne Racing

Heck, someone here will probably mail you one for free.

We have been known to do that here from time to time!

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

I can send you one if you need it. Can't mail it till Wednesday though. If you want it drop me a PM with your address.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I appreciate the offer! I already ordered 6 new ones though. They were cheap enough, plus I needed a new valvecover gasket and rear main seal, so the shipping wasn't bad for the lot.

I figure I won't even take the chance that any of the other ones are bent...

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1985 D100 3.7L Slant 6, 4-speed manual.