I've noticed when cold, she really sounds like a TDI or something. It is not really valve noise. Of course it goes away when warm. So it this just part of the 2.4's design, or should I be concerned? FWIW, I am running the correct weight Mobil 1.

I get the same "dieseling" / knocking noise with my V6 on the initial start in very cold weather. But it doesn't do it continously, just for the first second of the start. I think any car would do this with cold weather starts; probably a block heater would help with this issue. :dunno: If your car's doing it continously until it warms up, I'd get it checked out, I don't think that's normal.

You sure it is not your serp. belt and or idler pulley? Mine was not making allot of noise but it was VERY noticable when I changed both out. You cannot hear the car running. Nice diff.

I've noticed when cold, she really sounds like a TDI or something. It is not really valve noise. Of course it goes away when warm. So it this just part of the 2.4's design, or should I be concerned? FWIW, I am running the correct weight Mobil 1.

You sure it is not your serp. belt and or idler pulley? Mine was not making allot of noise but it was VERY noticable when I changed both out. You cannot hear the car running. Nice diff.

The serp belt was replaced two months ago, so not sure if this is belt related.

I've noticed when cold, she really sounds like a TDI or something. It is not really valve noise. Of course it goes away when warm. So it this just part of the 2.4's design, or should I be concerned? FWIW, I am running the correct weight Mobil 1.You're 2.4 isn't the only one. The K24 in my wife's CR-V sound exactly as you described on mornings where the temp is below 20°. I run 5W20 M1. I don't worry about it, though as all of my UOA's come back clean and good...

Sounds as though you guys need a valve adjustment...lol.

Sounds as though you guys need a valve adjustment...lol.


@ 56K miles? :confused:

I don't know what my car sounds like... I know my car drives cruddy in very cold weather, but it feels real smooth when it's warm in nice weather.

my mom's crv sounded like this for about a month, until the water pump seized and the serp belt came off.
good thing she has an extended warranty.

Sounds as though you guys need a valve adjustment...lol.
:jumping::jumping::jumping::jumping::jumping:

I've noticed when cold, she really sounds like a TDI or something. It is not really valve noise. Of course it goes away when warm. So it this just part of the 2.4's design, or should I be concerned? FWIW, I am running the correct weight Mobil 1.

It's perfectly normal. I first noticed when my car was brand new. It's more noticable when it's cold out and quite, (meaning no radio). These engines have been referred to diesel sounding quite a few times in past forum conversations.

What you're describing is piston slap. All Honda 4 cylinders have it to some extent, some worse than others.
The pistons shrink when cold, and they rock slightly in the bores when first started. As they heat up they expand and the noise goes away.

There are many cars with this issue, some of the worst are Ford 5.4 V8, Chevrolet 4.8, 5.3, 6.0, and others based on the "new" small-block.
There are so many I actually can't remember them all.

It's due to the type of pistons that are used now, they all are ever so slightly oval when cold and expand to round when hot for tighter wall clearances when running to improve emissions and lower friction. They are also very "short" skirted, if they even have a skirt on them at all. The upper part (crown) of the piston is very shallow, i.e. the distance from the top of the piston to the first compression ring is very small, this reduces the amount of unburned hydrocarbons caught along the edge of the piston.

I have same sound and it does go away after it warms up

What you're describing is piston slap. All Honda 4 cylinders have it to some extent, some worse than others.
The pistons shrink when cold, and they rock slightly in the bores when first started. As they heat up they expand and the noise goes away.

There are many cars with this issue, some of the worst are Ford 5.4 V8, Chevrolet 4.8, 5.3, 6.0, and others based on the "new" small-block.
There are so many I actually can't remember them all.

It's due to the type of pistons that are used now, they all are ever so slightly oval when cold and expand to round when hot for tighter wall clearances when running to improve emissions and lower friction. They are also very "short" skirted, if they even have a skirt on them at all. The upper part (crown) of the piston is very shallow, i.e. the distance from the top of the piston to the first compression ring is very small, this reduces the amount of unburned hydrocarbons caught along the edge of the piston.


Cool. Thats very interesting to know.

My mother's 1991 Civic DX had the same issue from the day it was new. I adjusted the valves at least as often as required by the maint sched, and it never seemed to help abate the noise.

That car now has over 278,000 miles on it and it is still going strong (a friend bought it from my mother in 2004 @ 124K miles and he has an insane commute).

So if you've checked all the obvious stuff, I'd say don't worry. That's a great engine you have.

Totally normal when running 5w-20 when cold. I've noticed a lot less noise when running 5-30 or 10-30 oil, but it supposedly will reduce fuel economy.

Very interesting! I noticed that my 2.4 sounded like a diesel as well but I thought I was going crazy, as I've never been in a diesel vehicle and we know how rare they are in the US (save for semis and trucks).

Thanks for the info FredSvt!

if it's the sound that i'm thinking of, my 93 always did that in cold weather as well.... the colder it got, the worse it was...

no worries everyone....

if it's the sound that i'm thinking of, my 93 always did that in cold weather as well.... the colder it got, the worse it was...

no worries everyone....

....stiller fan is here to save the day!!! :banana::banana:

and i'll be in tokyo this wknd, living the good life.... :naughty: :salue:

I had the same issue last year my V6 sounded like Diesel too when cold, it was driving me crazy. I brought it to the dealer - they determiner exesive Pison slap - replaced the short block for free.
I had only 56000km.
Other mechanics told me it was the lifters.

What you're describing is piston slap. All Honda 4 cylinders have it to some extent, some worse than others.
The pistons shrink when cold, and they rock slightly in the bores when first started. As they heat up they expand and the noise goes away.

There are many cars with this issue, some of the worst are Ford 5.4 V8, Chevrolet 4.8, 5.3, 6.0, and others based on the "new" small-block.
There are so many I actually can't remember them all.

It's due to the type of pistons that are used now, they all are ever so slightly oval when cold and expand to round when hot for tighter wall clearances when running to improve emissions and lower friction. They are also very "short" skirted, if they even have a skirt on them at all. The upper part (crown) of the piston is very shallow, i.e. the distance from the top of the piston to the first compression ring is very small, this reduces the amount of unburned hydrocarbons caught along the edge of the piston.


The most often heard ticking and knocking when cold are the valves. A car with 10k can need an adjustment, as much as a car with 100k. Adjustment is simple on Honda's, its a threaded stud with a lock nut. Thats it.

A well adjusted valve train is very quiet and more often than not, this is the culprt.

Piston slap is thrown around the net a lot because its easy to picture and understand. But its actually pretty rare.