Outer Limits 4x4 Board

I recently overhauled my 12HT engine and I think there is excessive noise . Whenever I am on high RPM on low gear I felt something is hitting inside the engine somewhat fast like ‘tak-tak-tak’ and then at the same time there is the normal sound of the diesel engine humming . My mechanic is a petrol engine expert and he and is pretty sure he has overhauled it correctly.

I wanted to know is there any way to determine through engine sound on the engine condition? Or is there any testing checklist to make sure on engine condition.

I recently went on long trip but had to return back as I noticed the engine oil was leaking through the filter and was worried incase if there was exceesive pressure built up? My mechanic is somewhat confused as new problems seemes to surface up and I thought I can provide him a checklist to make sure he verifies it and get potential issues sorted out incase if he has inadvertently goofed up.

Without being able to actually hear it....first guess would be a rocker not adjusted correctly - i.e. valve clearances not set, although this is usually evident across the rev range.

Second, based on oil in the filter, it could be that he has screwed up and broken some rings when installing and this is pressurising the sump.

As far as being a 'petrol' mechanic, the basic principles of re-building the engine are no different, it's only the fuel system that's different, and on a 12HT it's not that complex. You shouldn't have to be telling the mechanic what to look for - that's their job!

Did you replace the injectors at the same time? Overhaul the pump? Replace/overhaul other ancillaries, power steering pump, aircon, alternator? The noise could be from a range of sources.

Were all the clearances checked? Could be a piston tapping the head like in a 1HDT when the big ends start to go.

It sounds more like a bottom end knock .... with oil leaking from the oil filter

Roktruk wrote:Without being able to actually hear it....first guess would be a rocker not adjusted correctly - i.e. valve clearances not set, although this is usually evident across the rev range.

Second, based on oil in the filter, it could be that he has screwed up and broken some rings when installing and this is pressurising the sump.

As far as being a 'petrol' mechanic, the basic principles of re-building the engine are no different, it's only the fuel system that's different, and on a 12HT it's not that complex. You shouldn't have to be telling the mechanic what to look for - that's their job!

Did you replace the injectors at the same time? Overhaul the pump? Replace/overhaul other ancillaries, power steering pump, aircon, alternator? The noise could be from a range of sources.

I have made recording of the engine sound as per below link from mobile handset by placing it on the upper floor of car interior near the manual gear in between the 2 front seats and this sound becomes more clear once engine reaches say around 2000 RPM and more on any gear mainly on 1st and 2nd gear and even on idle . The somewhat bottom "tap-tap" sound can be heard more prominently after 40 seconds on https://soundcloud.com/naveed-ahmed-25/ ... gine-sound" onclick="window.open(this.href);return false;

Thanks for all the feedback... I will go through all the suggested checklist with mechanic today ... hopefully i will be able to resolve this

Yup, that's a bad noise. Does sound like a bottom end knock.

I thought you were getting oil into the air filter, not that the oil filter was leaking. It's probably just loose.