With our recent cold snap in So. Cal, it's the first time I've run my '06 HCHII in below 40 degree temperatures. The car has about 14,000 miles and performs perfectly, but when I start it in these temperatures I get a slight knocking or tapping sound from the engine.

It sounds like a little piston slap or tapping lifters. It goes away once the engine is warm. I'm guessing it's perfectly normal... but just wanted to check with those of you in the cold climates! Do you all get this type of sound at warm-up? Thanks.

 

It is from the lifters in the car being cold, and the oil not completely circulating at startup. Don't worry about it, but drive gently until the car is completely warmed up.

 

Yes, it is perfectly normal. Many things are actually happening to the engine when it is cold. Everthing from changed tolerances affecting all moving parts to cold engine mounts that no longer suppress the vibrations, conspire to make the engine noisier - at least until it begins to warm up.

I suppose you have a block heater, yes? Having that on for your temps pretty much eliminates the extra noises. Too bad my temps are too low for the block heater to do anything about the noise.

Take care.

MSantos

 

In Colorado Springs, this entire week has gone by and will finish completely in the 30s or less. I've only had my HCHII going on 7 days now, but haven't had any issue with noises or rough start-ups. I'm also surprised on how often the Auto Idle Stop function works, too; figuring the cold weather would make the car work overtime in keeping itself (and me) warm, it's doing a fine job as if it were "normal" weather. Though I'm still on my first tank of gas, I seem to be keeping numbers steadily at 32mpg so far, even in the cold.

 

MyFirstHy, 32mpgs seems a few mpgs too low even in these temperatures. Check your tire pressure. It might be low due to the cold. You might want to put a few lbs in.

 

Block heaters in Southern California? Aren't they're banned here?

I suspected it was normal. Thanks for the feedback.

 

I agree with Tom concerning the tire pressures. You should be be getting higher mileages in those temps.

The noises that we're talking about about should be comparable to that of any other car under similar circumstances. However, it is more noticeable on our cars because they're pretty quiet to begin with, especially when they are warm.

Also the idle stop will continue to work until the OAT reaches a low of -12C (10F). If the temps are really cold and below that figure we can still experience the auto stops if (AND ONLY IF) we do things like covering the front grill. In doing so we can actually continue to experience the autostops at -17C (0F) but not much lower than that.


Cheers;

MSantos

 

LOL... they certainly should be !!

Cheers;

MSantos

 

Engine Block Heater, temps at 25 F all day, 137 miles driven today, 46.6 mpg at the end of the day. Not bad for 25 F temps on snow tires in hilly Western PA. The Block Heater only helped on the initial commute to the office (22 miles) as there were three other stops during the day (12 trips total) where the car only had one block of engine temp when starting the next trip. One of my lowest days sice the car was a week old (it is 23 weeks old now). Wheeeeee.

Hey MSantos - at what point do you think the Block Heather doesn't help as much ... 0 C, -10 C, -20 C, -30 C? It has been as low as -15 C here lately and I still see great FE numbers on my daily commute to the office (around 48-50 mpg on the first drive of the day) so I haven't seen any time where the Block Heater did not yield >47 mpg results. Hopefully, those Colorado and California folks will send their weather my way.

 

Ah, I've been wondering about this too!

Thinking about the big picture, how much energy does an engine block heater consume? Is it enough to offset the lower mileage you get until your engine warms up? Any solar options available?