This one's got me stumped. I don't have much background with this machine. The lift pump was out when we got it. We had it (lift pump) rebuilt and it runs great now for about an hour to an hour and a half and then it blows about a gallon of oil out of the dipstick. You can let it sit and cool off and it'll run perfectly for about another hour and do it again. I checked the blowby tube and it's not stopped up. I haven't taken the breather off the valve cover to clean it yet cause something hit me as I was trying to figure it out. We have never put any oil in the engine, even though it's done this 3 different times so far. The oil on the dipstick looks brand new even though the machine has around 8200 hours. I smelled it and there's no diesel smell to it. I kinda thought maybe the lift pump was leaking into the crankcase but evidently not. Is there a way for hydraulic oil to enter the crankcase somehow? It has an Isuzu engine in it.
it'll blow oil out of the dipstick if its not clicked down properly, is it loose?
the oil cooler may have ablockage if oil very hot when blowing oil or oil filter block
I'll check to see if it's tight. The thing was overfilled with oil when we got it by over an inch on the dipstick I was told.
check the breather on the rocker cover,when was it serviced last, smell the oil you will smell if there is hyd oil mixing,but highly unlightly.
If you never had too put oil in and its done it a few times oil or diesel must be getting in somewhere, is there a auxiliary pump driving of the engine for something like hammer/magnet look there if so,fuel pump ?
Got to work on this today as we had an inch of rain over the weekend. Took the valve cover off to service the vent. It wasn't stopped up. Sprayed some brake cleaner in it and blew through it. The oil smells burnt real bad. It was 2 plus gallons low on oil when I checked it. Put it on the full mark and started it. It's knocking. Sounds like a rod bearing or a wrist pin. I don't see where there's an oil cooler on it except for hydraulic oil. It wasn't knocking Friday when we started it. It blew oil out the dipstick tube then so the operator put it on high ground knowing that it was going to rain. I don't know what else to think except that it has broken a compression ring or burned a hole in the piston to pressurize the crankcase so much that it can't vent due to oil being blown back into the oil galleries from the head?
Cut the oil filters and it has coolant in them. I couldn't see any trace when I pulled the valve cover. I guess the head is cracked or the head gasket is blown. Gotta be pressurizing the radiator. It's pushing the water out of the radiator. It overfills the crankcase and spews the oil out of the dipstick. We'll be pulling the oil pan in the next couple of days and airing up the radiator to see where it's leaking.
So if you have an EX300-1 you have a Hino with wet liners. If you have an EX300-2 or -3 you have an Isuzu 6SD1. If you have one of these, this is the only Isuzu I have encountered with an oil fed water pump for bearing lubricant.
It's a -3 with an Isuzu. Bless your heart.