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Engine clacking when engine was cold - Something to be worried?

Hey. I have an 06 Hyundai Tucson that was given to me and this night when I went out the engine was clacking I believe when cold. If I rev it up a bit to like 2k~3k the clacking was faster. When the engine eventually warmed up I couldn’t hear it anymore at a stop light.

Now I just want to make sure what’s up. The engine isn’t that old 220K KM (137K Miles).

I read it might be piston slam which is no cause to worry and shouldn’t damage anything?

They made a diesel CRDI version in 2006.This could be normal if yours is a diesel.

Your mom gave it to you
Are you 18 and live at home and possibly have driven it before?
Or are you 30 and have your own place and have never driven it?
Asking about history.
What did it sound like 1 month ago.

Did you check the oil level, and correct it if necessary?
Is the oil that is currently in the crankcase the correct viscosity?
Has the oil been consistently changed in accordance with the mfr’s maintenance schedule in terms of both odometer mileage and elapsed time? (Hint: If this vehicle was frequently used for short-trip local driving, the elapsed time factor is much more relevant than the odometer mileage factor.)

If the answer to all of the above questions is “yes”, then you might want to consider adding a can of Seafoam to the oil, and then change the oil a few hours later.

I may be missing something as usual. The OP has a thread wanting to extend oil changes on this vehicle ( did they not buy a bunch of tools and an expensive work bench ) and now the thing has a clatter so maybe synthetic oil might not be a good choice. What happened to the BMW from previous threads.

It’s not a diesel.

Yes I’ve driven it before but not a whole lot. Didn’t seem like it did the noise before since my mom was surprised when I asked her.

Yes that’s me. I had an accident with the 330ci and it got totalled. The M3 I still wasn’t ready to purchase. I haven’t done an oil change on the Tucson yet. It’s mostly had full synthetic.

Sounds like valve train clatter

Add some marvel mystery oil, when you perform that oil change you were mentioning

It can’t hurt, and it might actually help the situation, but I wouldn’t expect miracles

Like I said a former co-worker just had his Hyundai engine replaced at 90K. I don’t know what the problem was but it just quit, period and they replaced it under warranty. A mechanic listening to it should be able to determine if its piston slap or valve clatter though so might be worth the trip to figure out the prognosis.

That would be piston slap. You can tell it is this if it gets much louder while accelerating the engine…like when revving in PARK or driving away from a stop. I would let the engine warm up a few minutes at idle to minimize it.

Yes sorry, slap.

Yep, it was doing louder/quicker when I was revving it up a bit. Took the car out 30 mins ago and it wasn’t doing it, since I suppose it wasn’t that cold. Hmm

You might want to try a genuine Hyundai oil filter on it. My son has a 2014 Sonata bought new and the first time he put an aftermarket oil filter on it. it sounded terrible clattering like mad. When he put the factory filter on it , it sounded fine. I can’t explain it but he told me he found a TSB in it.


There are Hyundai and Kia TSBs. The problem is lack of or inadequate anti- drain back valves in some aftermarket oil filters. Here is a link to the
TSB 12-EM-006.

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Was it intermittent or at all start ups? It’s been 3 days now that have been as cold as the day I heard the knock/slam and have not heard it again.

But yeah my mom probably doesn’t have an OEM filter on now since she did her oil changes at Midas.

Sounds like you got your answer. Do a proper oil change with OEM parts.

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Use a short length of discarded garden hose as a stethoscope, see if you can narrow down which part of the engine it is coming from. I had a chattering noise on my truck one time that I thought was lifter noise but the garden hose stethoscope indicated the sound was coming from the water pump area. Replacing the water pump fixed the problem.

Yeah thanks for the idea. Next time it does it I will definitely get out and open the hood and hear around.