thumping noise from engine

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Dec 8, 2007
I've had a long standing problem with my PZJ70 which has stumped the best workshops and garages, including the Toyota dealership, in my city.

The problem is a thumping noise noise that emanates from the engine. Everybody thought that it was a case of leaking valve(s). So the head and the valves were lapped and everything reassembled but to no avail. The thumping noise persisted.

We also tried another trick to confirm if the valves were still leaking. This was done as follows: A rear wheel was jacked up; that real wheel was turned so that both the intake as well as exhaust valve in a particular cylinder was closed, this was confirmed by removing the head cover; and air was forced in through the glow plug hole by using an air tight adapter; no sound was heard either on the head or the exhaust confirming no leakage; this process was repeated for all cylinders with no leakage.

All other things seem in place. However, there is a plastic socket and plug right above the air filter cleaner box, this device i'm told is an 02 sensor. Since I've run out of all options, could this faulty sensor or problems with the electric system or fuel pump be responsible for the THUMPING noise?

These engines make noise - sounds lame but true - as they get older new sounds start - and for the most part they bug the s*** out of us but they are not problematic. You can keep spending money trying to track something down that you might never find - or something that will never cause you a problem - it is up to you.

Most common noises that you will never really find or fix, fuel pump, wrist pins, and my truck has what I think is a power steering pump noise, a/c pump noice, etc etc. The 1HZ's high milers have start to sound like a north american diesel after abnout 250-300K kms on them - try tracking that noise down without rebuilding the whole engine:)

Good luck with it - but I suggest just driving it unless you are finding metal shavings or burning oil etc etc.


I'm planning an engine swap with either the 1HZ or 1HD-T soon. So I'm not really obsessed the noise.

What has begun to worry me about the swap is the transmission issues I may have. I have a 4 speed R141f and I dont' know if it'll be compatible with the 1hz or 1hd-t.

Thanks- Ishobie!
You'll have to change the input shaft and the bellhousing. I have a bellhousing and a new shaft - but the housing might be spoken for.

Use the toyota EPC - chach and see that the part numbers are different.
Thanks, Ishobie!

I'm in Kathmandu, Nepal! So, buying stuff off of you might be a bit difficult. LOL

However, would you have any idea if I'll have to make any modifications to the cross member or body if I'm able to procure the 1HZ/1HD-T engine with a gearbox?

Thanks a bunch.

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