DRR98

Just started and cant be repeated. 64k miles, no mods. Anyone else seen this. It seems like a short duration knock at near 3/4 to full throttle when cold.

Tomtwtwtw

Unfortunately not sure on that, but I'll just throw this out there - you shouldn't be doing 3/4 to full throttle on a cold engine.

DRR98

^Thanks for chiming in.

Do you own an RDX?

Ours reads warmed (7 white bars) by the time my wife (primary driver) gets on the freeway 5 mins later. So this knock never happens in a warmed up engine, in the heat of the day or the trip home. Sorry for using a confusing term. I'm not even sure its a knock.

It warms quickly due to the water jacketed exhaust manifold and water cooled turbo.

Thanks for the basic tip that most of us learned long ago. In our V8 vert I do bring it to 125 before full throttle. But I see no reason to avoid 3/4 throttle and low rpm, ever.

Anyone had my symptom in an '11 or '12?

dcmodels

Engine coolant is warn - oil is *not* warmed within 5 minutes - 15 minutes would be minimum, and 20 is more like it for heavy throttle. Not sure what you mean by *knock*. Pinging? or Pinking as the British say? heavy throttle on a cold engine (cold oil) with high turbo boost, and low octane fuel, can produce loud pinging, which you may be calling knock. The knock sensor on the engine is supposed to control/ reduce this by retarding timing, but is limited in its ability to do so.

Are you using the highest premium fuel available in your area?

More descriptive words of the noise, and specific operational conditions, might be helpful. And what is cold? ambient of zero or 100 degrees?

dcmodels

I am also completely confused by the above - it knocks in the first 5 minutes only? low speed, low gears? from a stop? accelerating onto the freeway? only at the first engine-start of the day, after sitting overnight? confused!!

Tomtwtwtw

Yes, and I haven't experienced your issue nor would I willingly try to recreate it. You got a vague answer to a vague question. But I'm sure you know there's a big difference between a big V8 which makes a e and a turbocharged 4-cyl. Like dcmodels noted, just because the coolant is warm doesn't mean the engine is warm. If you can offer up some of the details he asked for I'm sure you can get a better answer.

DRR98

Sounds like someone in Reno has some what the same problem.

Justin suggests a fuel issue and he may be on to something. Cali has different winter and summer blends.

Sounds like some folks here think its wrong to get on the freeway with a five minute warm up? Getting on the freeway at rush hour here will always require a 3/4 or better throttle position. You stop at a red light on the on ramp, then get a green and merge into traffic doing about 75 mph. Has nothing to do with my problem.

DRR98

The alum V8 has nice gauges and the 125 I was talking about is oil temp. I wish Acura would have given us real gauges! When I drive the RDX my phone or pad become the real gauges with real numbers. My wife will never do the steps to turn hers on. And even if she did she won't know what they mean in reference to proper operation.

RDX is going to the dealer Wednesday and I hope they find the cause but it will only happen when it is cold out and once the engine is heat cycled it will not repeat until the next cold morning.

Thanks for trying to be helpful though.

Tomtwtwtw

I agree on the real gauges. For what it's worth, I've read my coolant via a bluetooth adapter and android app, and that "7 bar" coolant mark encompasses a very wide temperature range. I think they have it set up to be more of a "dummy" gauge to where 7 bars includes anything in the normal range as opposed to anything remotely linear.

Although, there is a good reason...my previous car had the coolant worked into the driver's info center similar to the RDX, but displayed a temperature rather than a meter. Every other forum post was "My coolant got to 220 degrees! Is my engine going to explode???" I guess ignorance really is bliss in some instances.

DRR98

Ha yes! Bliss can be bad in the wrong hands.

I've had oil temps into the 230's in our vert in auto-x and mountain driving. The '01 and up Z model even has trans temp monitored!

dcmodels

I was aware of this - but never checked the actual range - can you say what is the range? thanks.

Tomtwtwtw

Not off the top of my head, but I'll make it a point to test out soon and report back.

DRR98

The fans come on at 185 if I remember right. Ill confirm it when I can.

DRR98

Dealer replaced left drive shaft and all is well again.

Tomtwtwtw

So finally took a drive up north through the mountains today. From what I can tell, the coolant gauge moves from 1 bar to 2 at roughly 130F, and up one additional bar roughly each 9F (5C) until 7 bars at about 175F. It took a hell of a hill with 4 passengers, 150lb of dog in the back and the A/C blowing, but at around 215F it went to 8 bars.

I saw 9 bars once (gauge exactly halfway across at that point), but didn't catch the temp. I'd guess somewhere around 220F but I didn't have the scanner running at the time and by the time it loaded I had dropped to 8 bars @ 217F.

So yeah, the "7 bars" has a range of about 40F, or basically the entire normal operating range. Even during 4 mile long engine-braked descents I never got cold enough to drop back down to 6 bars.