I have 2023 Isuzu D-Max SX fitted with the 4JJ3 engine. I have discovered that it has been 'sweating oil' from the rear bottom end of the engine. The vehicle had 8800kms on it when this was discovered. The family mechanic suspects it to be the rear main seal at fault. This vehicle has had a ProVent 200 catch-can correctly installed, which includes a relief valve/spring. The filter element is changed and the hose drained every 1000km.
I took the D-Max to the local Isuzu dealer for them to assess. When I got the vehicle back, they had cleaned up the oil sweat and claimed that it's "Minor oil sweat found at rear - Not uncommon all OK". Not long after this, the oil sweat has reappeared again in the same location as it did originally.
Am I being stooged (are they trying to back out of fixing this issue)? Or is this supposed minor oil sweat normal for a modern turbo diesel engine?
Note: it has 5W30 diesel engine oil in the sump (as per Isuzu's recommendation). Would perhaps changing the oil to 10W40 eliminate or reduce this oil sweating? (10W40 diesel engine oil is also acceptable for use in this engine according to Isuzu.)
A bit of sweating around the various parts of an engine where one component joins another is definitely not uncommon and not really a problem provided it's not actually dropping oil on the ground (at which point it's a leak, not a sweat-mark). But really, an almost-new vehicle like yours shouldn't be doing this at all.
The rear-main seal on the crankshaft is a likely culprit and a common source of leaks from this area, but since it's a big job (gearbox removal) to do it, I can understand why a mechanic would declare it okay and not to worry. The problem with that is that the sweating is likely to become a leak sometime down the track, at which point you'll have to act.
The good news is that because you've flagged this problem with Isuzu while the vehicle is still under warranty, it's called a pre-existing condition and is covered by the factory warranty, even if that warranty has since expired. However, one would hope that Isuzu does the right thing in the meantime and changes the offending gasket or seal to fix the problem.
Be very wary, however, about Isuzu (or more likely the dealer) claiming the problem is being caused by the catch-can you have had fitted. A good quality catch-can, with a relief valve and correct installation should not cause a rear main seal to leak. As for changing the grade of oil you're using, I doubt that it would do much, but since the alternative is a slightly thicker oil, it might just make the difference you're chasing.
Disclaimer: You acknowledge and agree that all answers are provided as a general guide only and should
not be relied upon as bespoke advice. Carsguide is not liable for the accuracy of any information
provided in the answers.
Comments