HT4100 4.1, 4.5, 4.9 Discussion, would an oil stabilizer help with burning in Cadillac Engine Discussion; It's been a couple of weeks since the major tune-up.
Coolant has not dropped at all and is still green ...
It's been a couple of weeks since the major tune-up.
Coolant has not dropped at all and is still green (I thought the tabs would have changed the color), and the radiator fans only try to come on when I'm at a stoplight after extended driving. So that seems good.
She's still burning varying amounts of oil. I drove it to the coast after I got it back to loosen her up and she did not lose any. Yesterday I did some out-of-town errands with about three hours of solid driving, and she is a quart low today. I'm guessing that the rings and/or valves are still my problem. Do you guys think something like Mobil 1 and some kind of stabilizer would help with any of this?
Last night while moving stuff from the Caddy to the Jeep I noticed an acrid smell from the exhaust, and there was a little bit of smoke too. The smoke is probably from burning off oil (no loss in coolant), and the smell may just be the exhaust system falling apart, or may be the oil odor (need to ask mechanic what oil they used).
She also picked up some kind of buzzing sound on the drive yesterday. No idea what it is yet. It sounds like a model airplane engine, or like a fan whacking on a power cord (it was cool yesterday and the radiator fan did not try to come on very often so that's not likely). The frequency is linked to RPM, but it's a slow change not a fast one--I'm guessing one of my auxiliary pumps is starting to fail.
The mechanic he said that he used dino stuff, and since he just replaced it and I don't want to have the potential hassle of leakage from the super-fine synthetic, I decided to drop in a quart of the Lucas stabilizer to replace what had been burned off. Kind of interesting in that I was able to tell a difference almost immediately--the engine is a lot quieter and it even seems to be a little more responsive. I won't be able to tell if it helped with burning for another week or two, but I've got another quart of the stuff ready if I lose any more. If that doesn't work then I'll switch to Mobil 1, which has a higher burning temperature.
This is all short-term solution stuff until I get around to replacing the engine of course.
The oil loss is sporadic. I've driven from Maryland to Houston and back without losing any, but I can go to the big city 40 min from here and lose a quart on the the round trip. It's almost definitely a shot ring, since one of my cylinders also has really low compression. Given the problems that the HT4100 has had I'm just going to replace it with a quality reman instead of trying to save this one. In the meantime though, I'm trying to help this one along a little.
I've driven 15-20 miles up the highway and back twice now. The pinging and ticking is gone, the thwack noise that started showing up after the mechanic used GM top-end cleaner to degunk the valves is gone, and the engine is also performing better. This shit really works.
Another data-point, my 91 Jeep Cherokee also goes through oil pretty quick, so I added a quart of Lucas to it as well. It did not seem to give me the same power boost as I got from the Cadillac, and it seems to actually make the engine have to work a little harder. We'll see how it does with the oil loss in a couple of weeks.
So far my Cadillac has not lost any more oil, so that's good.