Catastrophic engine failure - share your stories

Joined
May 11, 2022
Messages
28
This is a V8 diesel generator engine I’ve been looking at for work. Engine failure during 100% load test. Number 7 piston got slightly warm.
Liner cracked which allowed oil pan to fill with coolant.

View attachment 112098 View attachment 112099 View attachment 112100

Finally got back to this one today. Tried to beat the piston/rod out from the bottom with marginal success—access was difficult.

Having nothing to lose by further damaging the piston, I drilled and tapped the piston crown and pulled it out with a slide hammer.

The cause of failure was immediately apparent—piston cooling jet plugged solid with silicone. I noticed that someone had, at some point in the past, assembled the oil cooler/filter base assembly using silicone as a gasket. Guys, this is why we must be careful about using silicone in an engine. I pretty much never use the stuff for this reason, and also bc I prefer anaerobic sealants.

We do annual 100% load testing on many generators, and this engine failed during one such test.

524BB763-BEE2-4B23-8553-035359264DAD.jpeg
72DC4D67-42C0-442D-A8B1-091CF26847EA.jpeg
16F8543D-D785-46BC-9B08-21D1D1A41787.jpeg
 
Last edited:

wwillson

Staff member
Joined
Aug 20, 2003
Messages
5,202
Location
Naperville, IL
The cause of failure was immediately apparent—piston cooling jet plugged solid with silicone.
So if we ever wonder just how much heat the cooling jet removes from the piston, this is an outstanding real-world example. How long did the engine run after the silicone was added? This is an epic piston failure, I'm wondering how much time at full load does it take to melt a piston without the cooling jet?
 
Joined
May 11, 2022
Messages
28
So if we ever wonder just how much heat the cooling jet removes from the piston, this is an outstanding real-world example. How long did the engine run after the silicone was added? This is an epic piston failure, I'm wondering how much time at full load does it take to melt a piston without the cooling jet?

Not sure how long. We believe the oil cooler/filter base was done before my company took over maintenance of the unit maybe 5 yrs ago. Being a stand-by, it only has about 300 hours on it. Only runs at 100% load for 2 hours every year, for testing.
 

wwillson

Staff member
Joined
Aug 20, 2003
Messages
5,202
Location
Naperville, IL
Not sure how long. We believe the oil cooler/filter base was done before my company took over maintenance of the unit maybe 5 yrs ago. Being a stand-by, it only has about 300 hours on it. Only runs at 100% load for 2 hours every year, for testing.
So 10 hours of run time is the minimum time the engine has run in the past five years?
 
Joined
Jun 19, 2017
Messages
1,267
Location
New Hampshire USA
The 77 in my sig lost the cam recently. Will be installing an LS with 6 speed soon, will be done in a shop as a bad back won`t allow bending.
An update, the cam was a Crane Commander installed 20 years ago and at some point an oil not suited for flat tappet cams was used. The last OC was with Castrol Muscle Car oil which did not cause the problem as the performance was slipping before. Less than 1000 miles per year was driven on this original owner stepside, looking back I should have installed a roller cam.
 
Joined
Aug 4, 2003
Messages
2,601
Location
NJ
Never blew an engine but blew a turbo with only 20k on it in my Forester XT.

Factory turbo was replaced under warranty at around 60k miles due to oil getting past the seals. I started pushing my intervals with the new turbo, despite Subaru of America cutting back on the original 7,500 mile OCI (normal service) and mandating all turbos to fall under the 3,750 mile severe service OCI due to AVCS and turbo banjo bolt filters getting clogged.

After I loaded up the car for a trip from NJ to SC at around 80k on the car, I noticed a ticking sound from the engine. I thought it might be from using a different oil filter, and didn't realize it was actually the sound of a clogged banjo bolt filter. I decided to take a chance and make the drive and somewhere around DE/MD, my check engine light came on and I read the code with my code reader. It was a P011 and P021 which basically confirmed a clogged banjo bolt filter.

Called my dealer and spoke to my tech (the only one that worked on my FXT) and he said it's likely turbo failure and that I would probably be fine continuing the trip. Of course, it started burning oil badly and smoking up the interstate and I bought whatever xW-40 oil that I found along I95. On the way back the oil burning increased as well as the smoke. At a rest area, a guy asked if that was my car smoking on I95 and he said it smelled like gunpowder. :ROFLMAO: My apologies to the environment. I did make it back home though.

I put over another 100k on that turbo despite still running all banjo bolt screens on the new turbo. It was a popular mod at the time to remove them. The dealer tech convinced me to leave them in because he felt the benefits (keeping debris out of the turbo) outweighed the risks of another failure. Cutting my OCI to 5k running mainly Euro oils probably helped as well. Sold the car with over 190k on it after I got rear-ended and the car was totaled.
 
Joined
Aug 25, 2022
Messages
90
Location
West Central Indiana
Several years ago, I bought a 1990 Chevy Beretta 3.1L V-6 from a little old lady but which sat at the edge of a field. My intent was to allow my soon-to-be 16 y/o son to demolition derby the car. After some early preparation, the oil light came on. Knowing it was full of oil, I ignored it and soon the lifters began to peck and I decided that the light was legit. I thought that at this point it would be a good learning opportunity for my son and decided to show him what a blown engine experience was like. We parked the car was parked in a convenient place and I drained all the oil at this point. I instructed my son to start the engine and matt the throttle. To our surprise it took about a minute of the rev limiter's control and the engine suddenly locked up and a single rod cap jettisoned through the oil pan. I did an autopsy on the engine and found a mouse nest under the intake manifold the was restricting the oil flow back to the pan.
My son was impressed....
 
Top