I have a 2.5L turbocharged diesel Toyota engine with 187,000 kilometers. 2012 model year SUV. Bought it at 150k
I used to get around 14-16km/L on my 400km journeys a year ago. Now it's dropped to about 10-12km/L. I check everytime I full my tank.
Looked at everything that could affect mileage except the engine. Everything looks good.
While idling, I opened the oil filler cap and saw oil and air blowing out. A little white smoke too but only after removing the cap.
Had the oil changed and bought a new engine air filter thinking it might be the problem since the old filter came with the car is dirty.
The new filter looks identical to the old one but somehow it's tighter in the filter box and harder to lock in place.
Now, checking filler cap, there is more white smoke coming out and constantly too. White smoke is coming out the dipstick tube now too. Engine seems to be louder and shaking more when idling compared to the dirty filter. It's more responsive now though. Also got 10km/L in my last tank.
I tried idling without the engine air filter and white smoke still comes out both holes. Tried covering the air intake with my hand and the smoke stops similar to the dirty filter. No noticeable oil and coolant consumption.
Mechanic said it could be piston ring and blowby. Is he correct? Should I be worried?
Things done to the engine:
-EGR cleaning (previous owner)
-Changed oil brand from Mobil to Goodyear same 15w-40
- replaced top cover gasket (previous owner) 140k KM
- replaced leaky top cover gasket (me) 160k KM
-replaced leaky top cover gasket again along with bolts 185k km
-EGR cleaning 185k km
-timing belt, tensioner and leaking oil gasket 185k
-changed leaky oil cap 185k km
-changed engine air filter 185k km
PS, it looks like top cover is starting to leak at some points
Thank you for your time and great work!
Welcome new member. I wish I had better news, but you likely do have a serious problem. I agree with @scottykilmer that the engine is likely to need a rebuild.
I would get a second opinion from another diesel mechanic. If he confirms that your engine is near end of life, I would look into installing a low-mile JDM engine (if that is allowed where you live). Would probably be cheaper than rebuild.
Well I would assume your mechanic is correct. As the engine wears inside, you get more blow by. It's just how diesels are. Just keep adding oil when it loses it and watch your coolant and pray the engine lasts a while because rebuilding a Toyota diesel engine cost a fortune and hardly anybody will touch them
Would it be better to use the new engine air filter or the dirty one? Should I go back to the Mobil motor oil, maybe it could help? Somehow its more expensive for the same rating compared to other brands.
Would it be better to use the new engine air filter or the dirty one?
Assuming it fits well enough and it doesn't leak a clean filter is better than a dirty filter.
Should I go back to the Mobil motor oil, maybe it could help?
The brand name isn't important. Just make sure your oil meets the API specifications set forth in the owners manual. https://www.api.org/products-and-services/engine-oil/eolcs-categories-and-classifications/oil-categories#tab-diesel-c-categories
What could have happened for this problem to occur? I changed oil every 5k kilometers except that one time it took 6k before the change.
Improper maintenance by the previous owner.
But the engine was ok when I bought it. I got better mileage then.
Diesel blow-by has a lot of causes: worn piston rings, cylinder damage, cracked pistons, cracked block. Inadequate maintenance can certainly contribute, but so can overheating, bad fuel, and just normal wear and tear. The only way to get a confirmed diagnosis is to take it apart and see. (In a gas engine, sometimes looking through the spark plug hole with a bore scope can give you clues, but diesel obviously doesn't have spark plug holes and getting visualization often requires disassembly.
I'm curious about the bad fuel you mentioned. Previous owner used the cheapest diesel he could find. I changed to a reputable brand. Could build up from cheap diesel mask the effects of blow-by which then got cleaned by better fuel with additives?
Why would using a dirty filter stop the white smoke from appearing?