Oil and Coolant Loss at the track

[swooper]

[quote=“swooper” post=66096]Ok. I just did a dry compression test and the all cylinders were very low 70-100 PSI. I did a wet compression on cylinders 1-3 and the results were about the same as the dry compression. I also did a leak down on cylinder three and could hear air coming out of the tail pipe, cylinders 2 and 4 and I think near the air intake. I looked again and the oil leak does seem to be coming from near the oil filter. So, what do you all think? Should I pull the head and check the block?

Why didn’t you do all six cylinders?

What leak down numbers did you see? I’m going to guess that it was way over 15%, in which case the head needs to be rebuild since you could hear air leaking past the valves.[/quote]

Jim,

I’m taking an automotive class and we did the diagnosis there. We only did wet compression on three of the cylinders because the instructor said that we might try something else with the other three, but we didn’t end up doing that. Regarding leak down, we started running out of time in class, so we just put cylinder 3 on TDC and checked for for air leakage, which we heard/felt out of the tail pipe, the adjacent cylinders, and the intake. We also removed the valve cover and confirmed that the cam is not holding the valves open.

What do you recommend doing next? I’m guessing the head will need to be rebuild, not sure about the bottom end.

[jlevie]

With known leakage past the valves and the probability of an overheat you have two economical choices. You can replace the engine or rebuild the head and then check leak down to find out if the rings and bores are worn. I favor the latter because even if the bottom is bad you still have a good head.

Well I guess there is a third choice and that would be a full rebuild. But that is pricey. Pistons alone are than the cost of a good used engine.

[swooper]

[quote=“jlevie” post=66128]With known leakage past the valves and the probability of an overheat you have two economical choices. You can replace the engine or rebuild the head and then check leak down to find out if the rings and bores are worn. I favor the latter because even if the bottom is bad you still have a good head.

Well I guess there is a third choice and that would be a full rebuild. But that is pricey. Pistons alone are than the cost of a good used engine.[/quote]

Thanks Jim. I guess what I’ll do is take the head off and inspect for any visible damage to the bottom end. If the cylinders are scored, then I guess its time to buy a new engine. If the bottom end looks ok, I’ll need to decide if I want to buy a new engine or rebuild the head and go from there.

BTW, here are my original compression numbers.

Cyl Dry Wet
1 68 72
2 81 77
3 85 80
4 97 x
5 77 x
6 99 x