Coopduc

A couple of months ago I bought a '99 roller, engine has a bad knock like a bad rod bearing or something similar. Also shows milkshake in the coolant, but nothing in the engine oil. PO told me the car had a bad head gasket and was replaced and ran fine for a while after that until the knock started. Not sure I believe that. Possibly the coolant wasn't cleaned thoroughly after the repair.
Engine will run, but I never start it so I don't damage it any further. I thought before I decide on a course of action, I'd get a Durametric and see if I can gain any intelligence on what may be going on inside. So I hooked it up and see a cyl 1 misfire, no other codes, no range 2 ignitions, and only 792 range 1 ignitions. This tells me the car has led an easy life, but what concerns me is that the last range 1 was only about 1 hour ago. I'm trying to put together a story that makes sense and things to check before pulling the engine.

5CHN3LL

My last range-1 ignition was probably about 5 operating minutes ago - but my car visits redline frequently. I'm betting the car hasn't been driven much or at all since the initial misdiagnosis of a blown head gasket.

The combination of "blown head gasket" and recent range 1 ignitions suggest that somebody was beating on the car, it overheated, the "head gasket blew."

I'm guessing the knock "started" as soon as the engine was cobbled back together well enough to start after the overheating-related failure.

Mike Murphy

Coopduc

5chn3ll - your theory makes sense. I'm wondering if the root cause was a water pump failure.
Murph- it's a bit of a story, but I promised my wife I wouldn't touch the car until Feb 3., but the first thing I plan to do is check the oil and filter. I don't think durametric can give me any temperature history.

cds72911

The durametric is cool, but I'd also be inclined to do a physical inspection of the engine to see if you can get any other clues. Drain the oil, drop the oil pan, inspect for foreign materials in the sump. Get a borescope (they're dirt cheap now), pull the plugs and do a visual inspection of the cylinders. Drain and flush the cooling system - see if you get any interesting clues in what drains out: bits of water pump, etc. I suspect there are other reasons you'd have oil in the coolant - maybe the oil cooler on top of the engine failed... Would a vacuum or pressure test of the cooling system give you any clues? You could keep gong depending upon what you found - pull the valve covers, etc. The more you inspect, the more you are likely to learn.

My '00 had an engine that didn't run, and had indications of intermix. Taking the sump off told me a whole lot about why - big D shaped chunk of aluminum, sludgy glitter all over the sump plate, etc.

Don't forget to budget for all new hoses (there are a ton of them). They oil in the intemix breaks them down, and with all the sitting your's is doing, odds are you will end up needing to replace a lot (all) of them.